Natural Enemies of Corn Pests

8/13/2019 Natural Enemies of Corn Pests

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Photo by Jewel Kinilitan-Bissdorf

Corn

Scientific name: Zea maysFamily: Poaceae

Growth stages Pests

For weedsand diseasesplease see further down on this page. For rodents,snailsand slugsplease clickhere

Seed

Sown seeds AntsSeedcorn maggotWhite grubWireworm

Seedling Stage

Roots Root knot nematodeSeedcorn maggotWhite grubWireworm

Stem Cutworm

Leaves Corn flea beetleCorn leafhopperCorn stalk borerCutwormRice/Corn seedling maggot
http://www.oisat.org/pestsmap.htmhttp://www.oisat.org/pests/insect_pests/termites_ants/ants.htmlhttp://www.oisat.org/pests/pests__insect_mite/flies/seedcorn_maggot.htmlhttp://www.oisat.org/pests/pests__insect_mite/caterpillars_grubs/white_grub.htmlhttp://www.oisat.org/pests/pests__insect_mite/caterpillars_grubs/wireworm.htmlhttp://www.oisat.org/pests/nematodes/root_knot_nematode.htmlhttp://www.oisat.org/pests/pests__insect_mite/flies/seedcorn_maggot.htmlhttp://www.oisat.org/pests/pests__insect_mite/caterpillars_grubs/white_grub.htmlhttp://www.oisat.org/pests/pests__insect_mite/caterpillars_grubs/wireworm.htmlhttp://www.oisat.org/pests/insect_pests/caterpillars_grubs/cutworm.htmlhttp://www.oisat.org/pests/insect_pests/caterpillars_grubs/cutworm.htmlhttp://www.oisat.org/pests/insect_pests/beetles/flea_beetles/general__information.htmlhttp://www.oisat.org/pests/insect_pests/hoppers/leafhoppers/general_information.htmlhttp://www.oisat.org/pests/pests__insect_mite/caterpillars_grubs/corn_stalk_borer.htmlhttp://www.oisat.org/pests/insect_pests/caterpillars_grubs/cutworm.htmlhttp://www.oisat.org/pests/pests__insect_mite/flies/rice_seedling_maggot.htmlhttp://www.oisat.org/pests/pests__insect_mite/flies/rice_seedling_maggot.htmlhttp://www.oisat.org/pests/insect_pests/caterpillars_grubs/cutworm.htmlhttp://www.oisat.org/pests/pests__insect_mite/caterpillars_grubs/corn_stalk_borer.htmlhttp://www.oisat.org/pests/insect_pests/hoppers/leafhoppers/general_information.htmlhttp://www.oisat.org/pests/insect_pests/beetles/flea_beetles/general__information.htmlhttp://www.oisat.org/pests/insect_pests/caterpillars_grubs/cutworm.htmlhttp://www.oisat.org/pests/pests__insect_mite/caterpillars_grubs/wireworm.htmlhttp://www.oisat.org/pests/pests__insect_mite/caterpillars_grubs/white_grub.htmlhttp://www.oisat.org/pests/pests__insect_mite/flies/seedcorn_maggot.htmlhttp://www.oisat.org/pests/nematodes/root_knot_nematode.htmlhttp://www.oisat.org/pests/pests__insect_mite/caterpillars_grubs/wireworm.htmlhttp://www.oisat.org/pests/pests__insect_mite/caterpillars_grubs/white_grub.htmlhttp://www.oisat.org/pests/pests__insect_mite/flies/seedcorn_maggot.htmlhttp://www.oisat.org/pests/insect_pests/termites_ants/ants.htmlhttp://www.oisat.org/pestsmap.htm


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Vegetative Stage

Stems Corn borerCorn stalk borer

Leaves AphidsArmywormCorn borerCorn stalk borerLocusts

Reproductive Stage

Silk Corn borerCorn earwormJapanese beetle

Spider mitesTassel Corn borer

Corn earwormSpider mites

Corn ear Corn borerCorn earwormCorn stalk borer

Grain Corn borerCorn earwormCorn stalk borerSmut

Maturation stage

Corn ear Corn borerCorn earworm

Grain Corn borerCorn earworm
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Rice/Corn seedling maggot

Photo courtesy of IRRI & University of Queensland

Natural enemies

Parasitoids

1. Trichogramma

Predators

1. Ground beetle2. Spider

Management and cultural practices

1. Plant at the beginning of the rainy season to avoid seedling flies during seedling emergence.This is applicable to areas where there are 2 distinct seasons: wet and dry.

2. Avoid planting during the peak of seedling maggot population. Inspect the neighboring fieldsplanted 1 week ahead of manifestation of damaged leaves and deadheart.

3. Inspect seedlings thoroughly after emergence. Damage begins during crop emergence.During heavy infestation replanting the area is deemed necessary.
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Photo courtesy of Sylvie Chenus,

Cornell University

Trichogramma

Common Name: Trichogramma, Tricon

Scientific name: Trichogramma spp.

Hymenoptera:Trichogrammatidae

Type

Egg parasites

Hosts

Trichogramma species parasitize eggs of over 200 species of moth and caterpillars. Among these are;

the rice and corn stem borer, cabbageworm, tomato hornworm, Heliotisand Helicoverpa species,

codling moth, cutworm, armyworm, webworm, cabbage looper, fruit worms, and sugarcane borer.

Description

Trichogramma adults are extremely small. The female adult lays her eggs on other moths' eggs. First,

she examines the eggs by antennal drumming, then drills into the eggs with her ovipositor, and lays oneor more eggs inside the moth's eggs. She usually stays on or near the host eggs until all or most of them

are parasitized. When the parasitized moth's eggs turn black, the larvae parasites develop within the

host eggs. The larva eats the contents of the moth's eggs. Adults emerge about 5-10 days later

depending on the temperature. Adults can live up to 14 days after emergence. Female adults can lay up

to 300 eggs.

Conservation and management


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Trichogramma species differ in their searching behavior, host preferences, response to environmental

conditions, and suitability in biological control uses. The timing of Trichogramma releases in the field is

important. Non-parasitism could be due to the use of less suitable Trichogramma strains to the host

pests, environmental conditions, and untimely release of parasitoids. It is best to release of parasitoids

at the beginning of a pest infestation (when moths are first seen in the field), followed by regular

releases until a natural breeding population of Trichogramma is established.

An example of this approach is the corn borer control. The first release should be during the first

appearance of moths and corn borers' eggs in the cornfields. Weekly releases thereafter are to ensure

the Trichogramma population build-up and parasitism occurrence. The build-up of the parasitoids

depends on the presence of the pest or alternative hosts and food for adults. It is important to regulary

monitor pest population, egg parasitism (parasitized eggs are black in color), and the larval infestation.

Trichogramma are released as pupae in parasitized host eggs. The pupae can be pasted on cards or put

in various containers. To be successful in the field, food, host eggs and shelter must be available.

Modify cropping practices by practicing crop rotation and by planting cultivars which are favorable to

Trichogramma population build-up such as wild carrots, dill, golden rod, leguminous plants, and

flowering vegetables. Adults feed only on nectar, pollen, and honeydew. Many of these species are

found naturally occurring in agricultural and garden habitats. Many adult parasitoids and predators

benefit from sources of nectar and the protection provided by refuges such as hedgerows, cover crops,

and weedy borders. Avoid indiscriminate use of hazardous pesticides to ensure their presence in

agricultural fields.


Ground beetle


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Common name: Carabid

Scientific name: Calosoma spp., Cicindela spp., Megacephala spp., Ophionea nigrofasciata, Pterostichus

spp.

Coleoptera:Carabidae

Type

Generalist predator

Hosts

Cabbage root maggots, cutworms, snails, slugs, (Ellis; Bradley, 1996: pp. 294-295), leaffolder and

planthoppers larvae (Rice IPM, 2001).

Description

Eggs are normally laid singly in the soil.

Larva is elongated and tapered toward the end, worm-like in appearance and have a large head directed

forward.

Pupa is brownish black, small and found in the soil.

Adult ground beetles or Carabids are about 2-6cm long, dark shiny brown to metallic black, blue, green,

purple, or multi-colored. They vary in shapes,- from elongated to heavy-bodied, - tapered head end with

threadlike antennae, and have a ringed wing cover. Some species do not use their wings however, like

many other insects they are also attracted to light. They use their wings to fly at night to be near to the

source of light. Their heads are usually smaller than their thorax. Both adults and larvae have strong

pincher-like mandibles. They have prominent long legs, which make them fast moving insects. Most

species are nocturnal and they hide during the day in soil crevices, under rocks and stones, decaying

logs, leaf litter, or composting materials. When disturbed or when other vertebrates prey upon them,

they emit an odor or gas, as a type of defense mechanism, preventing them from being eaten by other

predators. Ground beetles live on or below the ground, hence the name. Development from the egg to

the adult stage takes about a year, although adults may live 2 to 3 years or longer.

Conservation

1. Practice mulching in some sections of your field to provide a habitat for the ground beetles.

2. Provide permanent beds and perennial plantings to protect population.

3. Plant white clover and/or amaranth as ground covers (Ellis; Bradley, 1996: p. 295).


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Spider

Arachnida:Araneae

TypeGeneralist predator

Hosts

Brown planthoppers, stem borers, leafhoppers, moths, flies, and other agricultural pests they cancatch.

Description

1. Crab Spiders (Thomisidae) are colorful crab-like spiders generally found on the blossoms of

plants. They have the tendency to camouflage in their habitat so as to catch prey, unawareas they pass by. They are called crab spiders because their first four legs are larger thantheir hind legs and because of their capability to walk forward, backward, or sideways like acrab (CABI, 2000).

2. Dwarf spiders (Atypena formosana) are very small and are always mistaken for spiderlings(newly hatched spiders) of other spider species. They measure about 1 to 5 mm in length.

Adults have three pairs of spots or gray markings on the dorsal part of their sphericalabdomen. They are normally found in groups at the base of a plant. They build webs andcatch their prey by trapping them in their webs. However, they can hunt directly and feed on4-5 leafhopper/planthopper nymphs a day, and also other small insects (IRRI, 2001).

3. Grass spiders are moderately sized, brownish-gray weavers of funnel-shaped webs. Theirwebs are not sticky and can often be found on low-growing shrubs (CABI, 2000).

4. Jumping spiders (Phidippus sp. ) are brown jumping spiders with brown hairs covering their

body. They have two bulging eyes and these are arranged in three distinct rows. They havebroadly or partly ovoid abdomens with light transverse basal bands. They feed onleafhoppers and other small insects (IRRI, 2001).

5. Long-jawed spiders (Tetragnatha maxillosa) have long legs and bodies, measuring 6 to 10mm in length. Their eyes are arranged in two distinct rows. Their abdomens are brownish-yellow, with or without markings and are usually four or more times longer than their width.They prey on moths and flies and can consume 2 to 3 preys a day. Once their prey arecaught, these are wrapped with silk in their webs (IRRI, 2001).


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6. Orb weavers, Argiope spiders (Aranaeus spp.) are large yellow-black garden spiders whichproduce zigzag stitches in the bottom center of large webs hanging between stems of plants.They have poor vision and can locate their preys by the vibrations and tension on their webthreads (IRRI, 2001).

7. Wolf spiders (Lycosa pseudoannulata) have forked or Y-shaped median light bands on theirouter coverings. Wolf spiders prey on moths and butterflies. They feed on 5 to 15 preys daily

and they eat each other when their population is high (IRRI, 2001).

Some spiders' eggs are laid in a cluster in silken sacs, while some species lay their egg massescovered with silks within folded leaves. Some of these sacs are attached to the mother spiders ormothers stay nearby to guard their egg sacs. Eggs usually hatch into spiderlings within three weeks.The spiderlings may remain attached to the mother for several days on some species, but for somespecies they are left on their own.

Spiders are not insects. They have 8 legs while insects have 6. They do not have wings whereasinsects do. They have two body sections; a united head and thorax and abdomen, while insectshave three; head, thorax, and abdomen.

A female can produce 200-400 eggs but only 60-80 spiderlings can hatch from these. Females cansurvive 2-3 months. In some species, females die after laying eggs.

All spiders are poisonous to insects but only a few species are poisonous to humans, the Blackwidow and the Brown recluse (CABI, 2000; IRRI, 2001).

Conservation

Mulching along some sections in dikes of rice paddies, in field corners, or a portion of the fields canincrease the number of spiders. They can hide in the layer of mulch that serves as their alternatehabitat. They can also prey on other small insects inside the mulch.

Remember, that the more food the spiders can eat, the faster their population build-up will become.Cover crops are also important to provide over-wintering sites of spiders sacs.

A spider population depends on the availability of food, the habitat, and the environmentalconditions. Avoid use of pesticides as much as possible, for broad-spectrum insecticides can easilykill them (Reissig; et al., 1986: pp. 119-127).


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White grubs

Photo courtesy of Texas A&M UniversityDepartment of Entomology

General Information

Common name: White grubScientific name: Holotrichia spp., Leucopholis irrorataColeoptera:ScarabaeidaeHost plants

White grubs feed on the roots of corn, sorghum, sugarcane, cotton, soybean, strawberry, potato,rice, bean, and other cultivated crops.Distribution

India, Indonesia, Madagascar, Malaysia, Philippines, Canada, USADamage

White grubs feed on the main roots of the plants. They cut the main stems and roots of plants belowthe surface of the soil. They tunnel into tubers of root vegetables and root crops. These feedinghabits affect the underground portion of the stems and roots causing the plant to wilt and eventuallydie (Hammond, 1944).Description

The white grubs are the larvae of Japanese and May/June beetles. They are white or yellowish in

color, with tan or brown heads, and with 6 spiny legs. They have fleshy, wrinkled C-shaped bodies.

Upon hatching they are quite small but can measure up to 2-4 cm when they mature (Chamberlin;Callenbach, 1943).

Natural enemies

Parasitoids


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1. Tiphia wasp

Predators

1. Ants2. Birds3. Chicken

Bacteria

Bacillus popilliaeand B. lentimorbusare microbial insecticide products that kill grubs and adultJapanese beetles. Infected grubs are filled with a milky white liquid full of bacterial spores. Theyinoculate the soil as they move (Ellis; Bradley, 1996: pp. 460-461). The advantages of usingcommercial preparations of B. popilliaeare; they are host specific meaning, only effective againstJapanese beetles and their persistence is longer lasting (Cornell University, 2003).Monitoring

Monitor white grub population prior to planting. To sample, in 50 x 50 cm soil area, dig soil about 15cm deep using shovel or hole-digger. Sieve the soil. Repeat this method randomly at least 10times.Economic threshold levels are: 1 white grub found in sandy soil and an average of 2 whitegrubs in silty-loam soil (University of Illinois Extension, 1999).Management and cultural practices

1. Remove old plants and weeds. Plow and harrow the field twice during sunny days to exposegrubs to predators and weather. Hot sunny days destroy many of the exposed eggs and killnewly hatched grubs.

2. Grow healthy plants by planting good seeds, providing enough water and fertilizer. Healthyplants can tolerate grub feeding without serious damage. Other healthy ones compensate

for damage to one root.3. Ensure proper drainage. Grubs love moist soil, especially with decaying organic matter.

Female beetles prefer to lay eggs on moist-decaying organic matter.4. If heavy infestation occurs, avoid planting the same crops the whole year. Practice crop

rotation always. Soybean is found to be resistant to white grubs.5. Goodtrap crops are African marigold, sunflower, mirabilis, and castor. Repellents plants are

chives, garlic, tansy, and catnip. The crops trap and repel adult beetles from attacking themain crop grown (Golden Harvest Organics, 2003).
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Photo courtesy of The Ohio State University

Tiphia wasp

Scientific name: Tiphia vernalis, T. koreana, T. popilliavora, T. pygidialisHymenoptera:Tiphiidae

Type

Grub parasite

Hosts

Larvae of Japanese beetles and scarab beetles (IRRI, 2001)

Description

The female wasp burrows into the ground in search of a grub. She lays her eggs on a white grub.She stings the grub to temporarily paralyze it and lays a single egg on a specific location (depending

on her species). The paralyzed grub recovers from the sting to be the source of food when the egghatches. The tiny wasp's larva starts to feed by biting the grub's skin. It feeds slowly on the bodyfluids of the grub.The larva molts 5 times taking about 2-3 weeks to complete. Before pupating, the larva eats theremainder of its host and then spins a small, fuzzy, brown ovate-shaped cocoon.

Adult Tiphia wasps are shiny dark-colored and about 1cm-2cm long wasps. They are similar towinged black ants. The female wasps' bodies are heavily set built for digging soil in search of beetlegrubs. The male wasps are slender and smaller, have tiny hooks at the end of their abdomens whichare used for mating. Tiphia wasps feed primarily on the honeydew emitted by aphids, scale insects,and leafhoppers but they also feed on the nectar of blossoms.Tiphia wasps are native to Japan, Korea, and North China. They are now found in cooler climateswhere they have been introduced to control Japanese beetles and other scarab beetles (CABI,

2000).

Conservation

Tiphia wasps' presence is greatly influenced by the availability of adult food sources. The femaleadults feed in the morning in vegetations for food, such as nectar or honeydews (emitted by aphidsor whiteflies), before looking for grubs to deposit their eggs. Under favorable conditions they canparasitize up to 60% of beetle larvae in a given area. Like other insects, they are killed by pesticide,so it is not advised to use pesticides indiscriminately (Ohio State University, 2003).


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Cutworm

Photo courtesy of Clemson University-Department of Entomology

General Information

Common name: CutwormScientific name: Spodoptera litura, S. littoralis, S. frugiperda, S. eridaniaLepidoptera:Noctuidae

Synonyms: Cotton leaf armyworm, Climbing worm, Common cutworm, Tobacco caterpillarHost plants

Cotton, crucifers, cucurbits, solanaceous, groundnut, maize, sweet potatoes, rice, wheat, legumes,onionsDistribution

Africa, Australia, Pacific Islands, southern Europe, AsiaDamage

Seedlings are often cut off at ground level. Cutworm larvae can be found in the soil (up to a depth ofabout 5 cm) near the plant host. They always curl-up when disturbed. Cutworms feed only at night.Generally, they are not found on plants or on the soil surface during the day. n

Young caterpillars eat the soft leaves of the plant. The full grown caterpillars are capable of eatingthe entire plant. The newly hatched larvae feed from the base towards the tip of the leaf. At thisstage, they first feed on the epidermis and may discolor the entire leaf surface.

The yellowing of the leaves is a typical symptom of Spodoptera when they cause damage to thick-leaf plants such as castor. But the larvae can devour the entire leaves of rice and other cereals(Mochida, 1973: pp. 16-24). In beans, larvae will feed on leaves, buds, flowers, and pods. Largerlarvae will tunnel into and destroy the bean pod and seeds. In corn, larvae will feed on leaves, silk,and ears.Description


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Eggs are tiny pearl white, round, and have a ridged surface.

The newly hatched Spodoptera larvae are greenish and about 1 mm long. The full-grown larva has acylindrical body, brown or brownish-black with a tinge of orange. Thethoracic segments have one totwo dark spots near the base of the legs. The abdominal segments generally have two light brownishlateral lines on each side, one above and one below thespiracles.Above the top lines are broken

lines composed of velvet semi-crescent patches that vary in color among cutworms.

The pupa is black or brown in color and measures about 22.5 mm long and 9.2 mm wide.

The adult has dark brown forewings with distinctive black spots and white and yellow wavy stripes.The hind wings are whitish with grayish margins. The total developmental period from egg to adult isabout 35-40 days.Other cutworm species

Black cutworm(Agrotis ipsilon)

Eggs are white, ball-shaped, and sculptured with numerous vertical ridges. They are laid in groups of

10-20 eggs. Newly hatched larvae are about 5 mm and nearly 5 cm long when fully grown. Theircolor ranges from gray to nearly black. The center along the back has a pale rather indistinct narrowstripe. The skin texture distinguishes them from other cutworms. It consists of convex, rounded,coarse granules with smaller granules interspaced in between. The moths are brownish in color withblack slashes near the outer edges of the front wings. Adults are similar in size and shape with othercutworm species. There is no distinguishing characteristic to differentiate them from othercutworms.

Photo courtesy of University of Nebraska

Variegated cutworm(Peridroma saucia)

Variegated cutworms are dull-colored ranging from 1.5-5 cm in length. Mature larvae are 3.8-5 cm

long with a smooth skin. Body color varies from pale gray to dark mottled-brown intermixed with red

and yellow dots. There is usually a narrow orange-brown stripe on the sides. This climbing cutworm

usually feeds on buds and leaves of plants.

Granulate cutworm(Feltia subterranean)
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Granulate cutworm larva is gray to reddish-brown with dull yellowish sub-dorsal markings on the

abdominal segments. The head is yellowish to brownish. The under-surface of the body is flecked

with white. It causes its most serious damage by cutting-off small plants near the ground. If the plant

is too large to be severed at ground level, the larva climbs the plant and feeds on the foliage.

Natural enemies

Parasitoids

1. BraconidSnellenius manilaeis a small Braconid wasp species. It looks like Cotesia except that it hasa triangular closed cell on its front wing and has hairy eyes. This parasitoid wasp is hostspecific. It only parasitizes cutworm larvae. A female wasp lays 3-5 eggs in a cutworm larva.The parasite eats the body fluids and the larva for its development. Cocoons are formednext to the host's body. Lifecycle takes about 4-8 days. A wasp lives for about 1 week

(Reissig; et. al., 1986: pp. 99-109; IRRI, 2001).2. Cotesia3. Tachinid fly

Predators

1. Ground beetle2. Lacewing3. Praying mantis4. Weaver ant

Monitoring

Tomonitor for cutworm, count damage and freshly cut leaves, freshly cut young plants, and holes inleaves and in stems.Economic threshold level is 2-4% plants cut below the ground or 6-8% plantscut above the soil surface (University of Nebraska, 2001). Widely accepted threshold are 2, 3, 5, and7 cut plants per 100 plants during seedling stage (Tooker, 2009)Management and cultural practices

1. Removal of weeds in and around fields will reduce egg-laying sites and will help in theprevention of cutworm infestation. Do this at least 2-3 weeks before planting to reduce theincidence of cutworm larvae transferring to newly planted crops.

2. Plow andharrow fields properly before planting. This will destroy eggs and expose larvae to

chicken, ants, birds, and other predators.3. In rice fields, keep area flooded. This will prevent cutworm population.4. Plant corn, alfalfa, or beans after rice. This will provide rich fauna forbeneficial

insect species which will control cutworm build-up.5. Interplant main crops with onion, garlic, peppermint, coriander, or garlic every 10-20 rows to

repel cutworms. Sunflowers and cosmos can also be planted as a trap crop in or aroundfields (Garden Guides, 2001).
http://www.oisat.org/control_methods/natural_enemies/parasitoids/cotesia.htmlhttp://www.oisat.org/control_methods/natural_enemies/parasitoids/tachinid_fly.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/ground_beetle.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/lacewing.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/praying_mantis.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/weaver_ant.htmlhttp://www.oisat.org/display_popups/31.htmlhttp://www.oisat.org/display_popups/33.htmlhttp://www.oisat.org/display_popups/90.htmlhttp://www.oisat.org/display_popups/84.htmlhttp://www.oisat.org/display_popups/84.htmlhttp://www.oisat.org/display_popups/84.htmlhttp://www.oisat.org/display_popups/84.htmlhttp://www.oisat.org/display_popups/90.htmlhttp://www.oisat.org/display_popups/33.htmlhttp://www.oisat.org/display_popups/31.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/weaver_ant.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/praying_mantis.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/lacewing.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/ground_beetle.htmlhttp://www.oisat.org/control_methods/natural_enemies/parasitoids/tachinid_fly.htmlhttp://www.oisat.org/control_methods/natural_enemies/parasitoids/cotesia.html


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Photo courtesy of Cornell University

Cotesia

Common name: Cotesia wasp, CotesiaScientific name: Cotesia spp.

Hymenoptera:Braconidae

Type

Larva parasitiods

Hosts

Armyworm, bollworm, cabbage looper, cabbageworm, celery looper, corn earworm, cutworm,diamondback moth, gypsy moth, hornworm, stem borer, tobacco budworm, webworm

Description

Eggs are ovate, clear, and shiny and increase in size after they are laid. They hatch 2 days later.

The first instar parasitoid larvae begin feeding internally after 3-4 days. The immature parasitoidsdevelop through three larval instars in the host body, and then emerge from the host by chewingthrough the skin. After emergence from the host, the last instar larvae immediately spin cocoons andpupate.

Pupae vary according to species; some are either in an irregular mass of yellow silken cocoonsattached to the host larva or to plant leaves, and some in white cocoon, about a size of rice grain.The cocoons are usually found inside host feeding tunnels in leguminous plants. Pupation takes 4-6days after which adults emerge.

Adults are small wasps, about 3-7mm in length. They are dark-colored and look like flying ants ortiny flies. They have two pairs of wings and chewing-lapping mouthparts. They have curvedantennae, the males having much shorter antennae than the females. A female abdomen has adownward curve extension, called the ovipositor- with which she lays her eggs. The adult femalelooks for hosts in leaves and in tunnels of crops. Some species lay about 15-65 eggs in the bodycavity of the host while some lay a single egg. A single wasp can parasitize 200-300 host caterpillarsduring its 10 to 14-day life. The life cycle, from egg to adult, is approximately 15-30 days, dependingon the species and the temperature.


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Conservation

Cotesia wasps can be conserved by planting flowering herbs as a source of food for the adults suchas; wild carrot, wild mustard, and sweet alyssum.


Tachinid fly

Common Name: DipteraScientific name:Bombyliopsis abrupta, Lixophaga sp.Diptera:Tachinidae

Type

Larvae and adult parasitoid

Hosts

Aphids, armyworm, beetles, bollworm, bugs, cabbage looper, cotton stainer, cutworm,grasshoppers, hornworm, leafhoppers, mole crickets, moths, sawflies, scale insects, stem borers,stick insects (CABI, 2000).

Description

Eggs are ovate-shaped and white in color. They are found in the skin of the host insect or in leavesnear the host and are hatched when the host ingests them.The larvae or maggots are worm-like and lack appendages like all other fly larvae. They aregreenish-white in color. They have three larval instars and then leave the hosts to pupate in the soil.Before pupation, some mature maggots produce hard cocoons. The larval stage takes about 4 daysto 2 weeks depending on the climatic conditions. The newly hatched larvae enter into its host andfeed on the content before pupating into the soil. Some tachinid species are hosts' specific, forexample for a certain species; it is parasitic only on leaf rolling caterpillars, or only on sugarcanestem borer.Pupae are oblong, yellowish and turn dark-reddish as they mature.

Adults measure between 3 and 10 mm and have very stout bristles at the tips of their abdomens.They look very similar to the common housefly but are larger with stocky and soft bodies. They varyin appearance from gray black to brightly colored, or sometimes looking like bees. Adult Tachinidflies have only 1 pair of wings. They feed on honeydews and flower pollen. Different species havevaried modified sucking type mouthparts: the cutting sponging, the piercing-sucking, and lapping-


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Eggs are found on slender stalks or on the underside of leaves. Each egg is attached to the top of ahair-like filament. Eggs are pale green in color.

Larvae are known as aphid lions. Newly hatched, they are grayish-brown in color. Upon emerging,larvae immediately look for food. They grow to about 1 cm in length. They attack their prey by takingthem with their large sucking jaws and injecting paralyzing poison, and then sucking out the body

fluids of the pest. A larva can eat 200 or more pests or pest eggs a week. An older larva canconsume 30-50 aphids per day. It can consume more than 400 aphids during its development. Thelarvae resemble alligators with pincers like jaw. However, they become cannibalistic if no other preyis available. They feed for 3 to 4 weeks and molt three times before pupation. They cover theirbodies with prey debris.

Pupae are cocoons with silken threads. These are found in cracks and crevices. The pupal stagelasts for approximately 5 days.

Adults are green to yellowish-green with four, delicate transparent wings that have many veins andcross veins. Adults are about 18 mm long, with long hair-like antennae and red-gold eyes. Eachadult female may deposit more than 100 eggs. Many species of adult lacewings do not prey onpests. They feed on nectar, pollen, and honeydew. An adult will live for about four to six weeks

depending on the climatic conditions.

Conservation

Flowering plants such as dill, cosmos, sunflower, carrots, dandelions are good source of pollen andnectar for adults. Provide source of water during dry season.

Photo courtesy of R. Bessin,University of Kentucky

Praying mantis

Common name: Praying mantids (plural)Mantodea:Mantidae

Some important mantids species

1. African mantis (Sphodromantis spp.) found in Africa2. Chinese mantis (Tenodera aridifolia sinensis) found in China3. Devils flower mantis (Blepharoppsis mendica) found in Asia4. Giant Malaysian shield mantis (Rhombodera basalis) found in Malaysia


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5. Giant mantis (Hierodula spp.) found in Asia6. Ghost mantis ( Phyllocrania Paradoxa) found in Africa and Madagascar7. Indian flower mantis (Creoboter meleagris) found in India8. Leaf mantis (Deroplatys spp.) found in Asia9. Madagascan marbled mantis (Polyspillota aeruginosa) found in West Africa and

Madagascar, Nigeria and Kenya

10. Malaysian orchid mantis (Hymenopus coronatus) found in Indonesia, Malaysia, and Sumatra11. Spiny flower mantis (Pseudocreobotra spp.) found in Africa12. Twig mantis (Popa spurce) found in Africa13. Wondering violin mantis (Gongylus gongylodes) found in India and Sri Lanka

Type

Predator

Hosts

Aphids, fruit flies, grasshoppers, caterpillars, and they eat each other when no food is available.

Description

The eggs are laid in groups. Each group of eggs is encased in a foamy substance that hardens intoa tough protective casing called ootheca. Eggs hatch after 3 - 8 weeks, although not all eggs willhatch as young mantids.

The young mantids are hatched as pro-nymphs. They are surrounded by a protective membraneand move like grubs to the surface of the ootheca. In some species, there is a single exit hole at thebottom of the ootheca, where the young emerge individually. In others, the young emerge throughthe oothecal wall nearest the egg cell and will hang on silken cord from the ootheca until the skinhardens.

The adult praying mantis varies in color depending on the habitat it is living in. It camouflages theleaves, flowers, twigs, barks, trees where it is found. Its size varies depending on the species, fromabout 3 cm-18cm. It has strong spine-forelegs and usually sits and waits motionless amongvegetation for prey, with its forelegs held together in a prayerful manner, hence the name 'Prayingmantis'. It has strong mouthparts for chewing, large eyes, well-set on its mobile triangular head, withantennae that are slender and segmented. It has a neck that can rotate its head while waiting forprey.

Some species have powerful forewings for protection and flying. While flying, it can be mistaken asfor a small bird. Other species are wingless, odd-looking, flower/leaf-shaped, and others are so thinto be recognizedthat they are hardly recognizable. They will rise up in a threatening manners readyto attack, when disturbed.

A female adult should be well fed prior to mating or else she will kill the male once she is hungryafter mating. A female mantis lays up to a few hundred frothy liquid eggs in habitats where mantidslive.

Conservation

Avoid indiscriminate use of pesticides, for pesticides kill and reduce the numbers of praying mantidsand other beneficial insects. Maintain vegetation to provide natural habitats for the mantids.


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Photo courtesy of Takumasa Kondo

Weaver ant

Scientific name: Oecophylla smaragdinaHymenoptera:FormicidaeOther name: Green tree ant

Type

Generalist predator

Hosts

Citrus stinkbug, leaf-feeding caterpillars, aphids, citrus leafminer, leafhoppers, plant hoppers, bugs,moths, adult black bugs, and small animals.

DescriptionThe life cycle of the ant has four stages: egg, larva, pupa, and adult.

The queen ant starts the ants' nests/colonies. She flies and searches for mate/s. She can mate withone or a few males ( one at a time) in the air, or on low vegetation, or on the ground. Once mated,she looks for a nest site, either on trees or open fields. Once situated, she gets rid of her wings,seals herself into a small chamber and lays a small batch of eggs. The eggs then hatch into larvae.The queen is located in one nest and her eggs are distributed to all the other nests where workersand soldier ants are found. She spends her life laying eggs. The workers are females and do thework in the nest. The larger ones are the soldiers who defend their colony.

Fertilized eggs develop into females (workers and the queen) and unfertilized eggs into males.Female ants have 2 copies of each chromosome while males have one.

The larvae feed on the unfertilized eggs as food which the queen lays especially for them. The firstbrood of workers are normally smaller since she can only provide a limited amount of food. Once theants mature, they leave the nest and begin to look for preys. They bring food to the queen and theirsiblings so that later offspring are bigger. As the colony reaches maturity, it begins to produce thequeens and males for the next generation. Males can remain in the nests for some months and mostof them will die within a few days after leaving their nests.The larvae have special glands to produce lots of strong silks (adults do not produce silk). Onecolony is found over several nests that may be placed in various locations in a tree, or several trees,


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or in fields.

The worker ants form a chain along the edge of the leaf and pull the edges together by shorteningthe chain by one ant at a time. Once the leaf edges are in place, each ant holds one larva in itsmandibles and gently squeezes the larva to produce silk. The silk is used to glue the leaf edgestogether.

Adult weaver ants are reddish to brown in color and have 10-segmented antennae with 2-segmentedclubs. Their eyes are relatively larger than those of other species of ants. They do not have stingers,but can give painful bites caused by the chemicals secreted from their abdomen. They make nests intrees or on leaves of legumes, or in bunds or levees of the fields. They have the most complex nestsamong ants' nests. They use fresh leaves to build nests .

Weaver ants get their name from their habit of binding fresh leaves with silk to form their nests. Theirlifecycle spans a period of 8 to 10 weeks.

Conservation and management

Weaver ants thrive well in undisturbed places and plenty of green leaves. Plant fruit trees or shrubs

in or around your new citrus orchard however, banana, sapodilla, and papaya are less suitable.

Introduce only native weaver ants to the orchard when no black ants' species are present to ensurethe establishment of a weaver ant colony.

Provide them with food during the dry season such as dried fish and shrimp, cut into pieces that aresmall enough for the individual ant to carry.

Put bamboo or wooden strips between trees to guide the ants to transfer from one tree to another forthem to build new colonies in other trees.

To expand weaver ants' colonies to other field crops, tie a rope to a tree where they live, to guide

them to the areas you want them to colonize. Monitor regularly the ant colonies. Like other insects,ants are easily being killed by pesticide.

Ask for assistance from your local agriculturist office.

Armyworm

Photo courtesy of University of Arkansas


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General Information

Common name: ArmywormLepidoptera:NoctuidaeHost plants

Armyworm larva feeds on almost all agricultural crops.Distribution

India, Asia, Australia, New Zealand, Canada, and USADamage

The larvae can eat the entire leaves of field crops and grasses. When feeding, they chew from theleaf edges until only the midrib is left. They feed on various crops and grasses during their migration,and often bare crops of tender leaves after passing through. They travel from field to field in greatnumbers, hence the name "armyworm".Description

Source: University of Nebraska-Lincolnr

The larvae are described to differentiate the several armyworm species from each other.

1. American or Southern armyworm, Fall armyworm, Grass worm, Overflow worm (Spodopterafrugiperda)Mature larvae measure 3.6-4 cm long. They are gray to black in color with alternately brightand pale yellow stripes running longitudinally along their bodies. Black crescent spots arefound next to the stripes (IRRI, 2001).

2. African armyworm, Black armyworm (S. exempta)Mature larvae measure up to 4 cm long and are generally black, heads faintly mottled with


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dark brown spots, and with light yellow stripes at their backs. They are characterized by thepresence of C-shaped dark spots along their backs (IRRI, 2001).

3. Grass armyworm, Rice swarming caterpillar (S. mauritia)Mature larvae are 3.8-4 cm long and have shades of green, gray, or brown with dark dulldorsal and subdorsal longitudinal stripes. Two rows of C-shaped black spots are distinctalong the backs (Reissig; et. al., 1986: pp. 99-109).

4. Paddy armyworm, Rice armyworm, True armyworm, Rice ear-cutting caterpillar (Mythimnaseparata)Mature larvae are 3-4 cm long and are green to pink in color, with longitudinal light grey toblack stripes running along the entire length of their bodies. They have brown to orangeheads with an A-marking (Reissig; et. al., 1986: p. 102).

5. Yellow striped armyworm (Spodoptera praefica)Mature larvae are about 4 cm long and black in color with yellow or orange stripes alongtheir sides. These are bordered below by a white-stripe on each side. They have aninverted-white-Y on the front of the heads (IRRI, 2001).

6. Armyworm (Pseudaletia unipuncta)The full grown larva is 3-4 cm long with two orange stripes on each side. Above and belowthe spiracles, there is a pale- orange and white-bordered stripe. Less distinctive brownstripes are found on the body (CABI, 2000).

7. Beet army worm (S. exigua). The larvae are 3-4 cm long, green in color with many lightstripes along the backs and a broader stripe down the sides. The undersides are usuallyyellow color (Ellis; Bradley, 1996: pp. 270-271.10).

Morphology

Eggs of armyworms are white and are found in clusters. One egg mass contains 200-300 eggs.

These turn yellowish when mature. Hatching occurs in about 2-5 days.

The larva varies its colors according to the species. Sizes vary from 2-4.5 cm long. The larva has 6

small legs just behind the head and 10 fleshy legs at the rear. The larva eats voraciously as it grows.

It digs 3-6 cm below the soil surface to pupate.

The pupa is brownish red in color and about 2-3 cm long. Pupation takes about 7-16 days depending

on the climatic conditions.

The moth has 3- 4 cm wingspan and 1.5 cm long. Colors vary from light green, light pink, tan, to dark

brown in color. The tiny white dot in the center of each forewing is an important feature to identify the

armyworm moth. The moth is seldom seen because it is active only at night time, either mating or

searching for suitable egg-laying sites. The female moths lay eggs on the lower leaves of growing

grasses or small grains.

Natural enemies

Parasitoids

1. Braconid
http://www.oisat.org/control_methods/natural_enemies/parasitoids/braconid.htmlhttp://www.oisat.org/control_methods/natural_enemies/parasitoids/braconid.html


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2. Cotesia3. Tachinid fly

Predators

1. Damsel bug2. Ground beetle3. Lacewing4. Praying mantis5. Weaver ant

Monitoring

Tomonitor the presence of armyworm, conduct visual inspection by going around the field. Look infield margins, low areas where plants have lodged, beneath plant debris around the base of plants,and underneath the plant leaves. Examine 100 plants at random by examining 20 plants from 5locations. The general recommendation of theeconomic threshold level on grain crops is 60 larvaeper linear meter (Scott, 2003).Management and cultural practices

1. Practice proper field sanitation. Cut weeds from bordering fields. Remove weeds regularly toreduce breeding sites and shelter for armyworm. Remove all plant debris after harvesting.

2. Employ proper seed selection when seeds for sowing are taken from the previous harvest.Adults might have laid eggs on the seeds during armyworm infestation.

3. Plow andharrow field thoroughly. Sometimes, the small grains or grasses are plowed-underafter the eggs are laid on them. As the field is planted and the plants begin to grow, thelarvae will continue to develop and will start attacking the plants.


Braconid
http://www.oisat.org/control_methods/natural_enemies/parasitoids/cotesia.htmlhttp://www.oisat.org/control_methods/natural_enemies/parasitoids/tachinid_fly.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/damsel__bug.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/ground_beetle.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/lacewing.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/praying_mantis.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/weaver_ant.htmlhttp://www.oisat.org/display_popups/31.htmlhttp://www.oisat.org/display_popups/33.htmlhttp://www.oisat.org/display_popups/42.htmlhttp://www.oisat.org/display_popups/42.htmlhttp://www.oisat.org/display_popups/33.htmlhttp://www.oisat.org/display_popups/31.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/weaver_ant.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/praying_mantis.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/lacewing.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/ground_beetle.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/damsel__bug.htmlhttp://www.oisat.org/control_methods/natural_enemies/parasitoids/tachinid_fly.htmlhttp://www.oisat.org/control_methods/natural_enemies/parasitoids/cotesia.html


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Common Name: BraconScientific name: Bracon spp.Hymenoptera:Braconidae

Type

Eggs, larvae, pupae, and adult parasitoid

Hosts

Ants, aphids, armyworms, beetle's larvae, bollworms, cabbageworms, caterpillars, codling moths,corn borers, cutworms, imported tent caterpillars, leafhoppers, leafminers, maggots, midges, plantbugs, scales, tomato hornworms, weevils

Description

Eggs and larvae of Bracons are found inside the hosts' bodies.

The larvae are tiny, cream-colored grubs that feed in or on other insects. Larvae molt five times andundergo 5instars.

Pupae of somespecies live and pupate within the host until they mature; others pupate insilkencocoons on the outside of the body of the host, while others spin silken cocoons away fromthe host.

Adult wasps are tiny, about 2.5 mm in size, slender black or brown with threadlike waists. Femalewasps lay eggs into the eggs of hosts' pests but prefer caterpillars' bodies.

In cases where aphids are the host pests, aphids are not killed instantly. Aphids continue to feed onplants tissues until the Braconid larvae inside their bodies completely consume them. The fully-

grown Braconid larvae cement the dead aphids to the leaf surface making aphids' shells black andmummified. About a week later, the adult Bracon wasps cut round holes in the mummiesandemerge. The empty mummies remain on the leaf. The presence of mummies in a colony of aphids isa sign that Bracons are present.

Conservation

Adult Bracons feed on nectar,honeydew,or pollen before laying eggs. Dill, parsley, yarrow, zinnia,clover, alfalfa, parsley, cosmos, sunflower, and marigold are flowering crops that attract the nativebraconid populations and provide good habitats for them.
http://www.oisat.org/display_popups/95.htmlhttp://www.oisat.org/display_popups/149.htmlhttp://www.oisat.org/display_popups/94.htmlhttp://www.oisat.org/display_popups/148.htmlhttp://www.oisat.org/display_popups/36.htmlhttp://www.oisat.org/display_popups/36.htmlhttp://www.oisat.org/display_popups/148.htmlhttp://www.oisat.org/display_popups/94.htmlhttp://www.oisat.org/display_popups/149.htmlhttp://www.oisat.org/display_popups/95.html


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Source: University of Georgia

Damsel bug

Common name: NabidsScientific name: Nabis ferus, N. aternatus, N. capsiformis

Hemiptera:Nabidae

Type

Generalist predator

Hosts

Aphids, armyworms, asparagus beetle, Colorado potato beetle eggs and nymphs, corn earworm,corn borer, imported cabbageworm, leafhoppers, mites, moth eggs, sawfly larvae, and tarnishedplant bug nymphs. Although they can survive for about two weeks without food, they will eat eachother if no other prey is available.

Description

Eggs are deposited in soft plant tissues where they are so difficult to find.

Nymphs resemble adults and develop through 5 nymphal stages in about 50 days.

Adults are tiny, about 2-4 mm long, with slender bodies and are yellowish or gray or reddish-brownin color. They have piercing-sucking mouthparts, a 4-segmented beak, elongated heads, and 4 longsegmented antennae. They are fast runners with long slender back legs and enlarged forelegs forgrasping prey. They are commonly found in most agricultural crops, especially legumes, throughoutthe year. Adults begin laying eggs soon after emergence.

ConservationThey prefer to live in soybeans, grassy fields, and alfalfa. You can collect damsel bugs in alfalfafields and release them around your garden.


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Corn borer

Photo courtesy of Kansas State UniversityDepartment of Entomology

General Information

Common name: Corn borerScientific names: Ostrinia furnicalis, O. nubilalisLepidoptera: Crambidae

Synonyms: Asian corn borer, Oriental corn borer, European corn borerHost plants

Corn is the preferred crop but it will infest other plants, including bean, cotton, tobacco, beet, celery,potato, pepper, tomato, soybean, sorghum, and weeds.Distribution

Asia and in all areas where corn is grownDamage

Corn borer larvae begin feeding on leaf surface or in the whorl. There are pinholes on leaves at thewhorl stage. As the plant grows, they bore holes into leaf midribs down into the stalks. Excreta orfrass are found near entrance holes. Tassels are clumped where they later feed. Stalks and tasselsare broken. They feed last on corncob and cause ear to drop, in severe cases (PCARRD, 1981). Description

The egg is white and laid in masses like fish scales. An egg mass has 5-50 eggs. The egg mass or2-3 more can be found on the plant leaf. Eggs become cream-colored and dull as they mature.

Before hatching, the black heads of the larvae can be seen through the transparent egg membrane.

Eggs hatch 4-9 days later.

The larva is flesh colored, ranging from light gray to light pink with small round dark brown spots on

each segment. The larva has a brown head and indistinct reddish stripes running the length of its

body. A mature larva is about 2-3 cm in size. The reddish brown pupa is found inside the larval


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home (inside the stems or ear where it has been feeding).

The pupa is reddish-brown and approximately 2-2.5 cm long with segments evident on half of the

body. The pupal stage lasts about 2 weeks.

The adult female is a creamy, brownish yellow moth, and about 3 cm long. The forewings of thefemale are usually lighter in color than that of the male. The hind wings of both males and females

have light markings. The reddish-brown male has a long slender body and is smaller than the female

(Bureau of Plant Industry, 1987: pp. 13-14).

Natural enemies

Parasitoids

1. Braconid2. Tachinid fly3. Trichogramma

Predators

1. Hoverfly2. Lacewing3. Ladybird beetle4. Minute pirate bug5. Praying mantis6. Spider7. Weaver ant

Monitoring

Monitor plant growth throughout the growing season to observe crop conditions and to recognize thepotential corn borer attack. To monitor, start looking for corn borer egg masses when the plant is amonth old. The egg masses are found on the surface and underneath the leaves near the midrib.Randomly select 50 plants and count the total number of egg masses and multiply by 2 to obtain thenumber per 100 plants. The critical levels of corn borer are: 40% of plants are infested during whorlstage; 3-4 egg masses/100 plants are found; and 40% of the remaining tassels are infested afterdetasseling (Bureau of Plant Industry, 1987: pp. 10-17).Management and cultural practices

1. Practice proper plant spacing within the rows. Sow 1-2 seeds per hill. Crowded plants aredifficult to weed, to fertilize, and to monitor crop condition.

2. Practice crop rotation. Grow leguminous crops as rotation crops. This will improve the soilstructure; destroy the weeds and corn borer lifecycle.

3. Plant together with other farmers. Late or early planting will provide stem borer anenvironment for their continuous breeding activities.
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4. Practice proper field sanitation. Corn borer laid their eggs on grasses and weeds surroundingyour field. Ideally, all crop residues should be cut for animal feeds immediately after harvest.The remaining stubbles should be burned and be plowed under.

Hoverfly

Common name: Flower fly, Syrphid fly, SyrphidaeScientific name: Eristalis spp., Volucella spp.Diptera:Syrphidae

Type

Generalist predator

Hosts

Aphids, thrips, psyllids, scale insects, small caterpillars, and larvae of Heliotes

Description

Eggs are tiny, about 1mm in size, ovate-shaped, and glistening-white. These are found laid singlyand close to the developing aphid colony in the leaves, shoots, or stems of the plants. They hatchwithin 2-3 days.

The larvae, known as Syrphids, are legless slug like maggots, about 1-13 mm in length dependingon their larval stages. They usually have a mottled-gray, beige, or light-green color. They lift theirpointed heads to look for preys. Once preys are located, their mouthparts suck out the contents ofthe preys. Larvae are frequently found feeding on aphids in the sheltered and curled portion ofleaves. They blend well with their habitat and therefore they must be looked for closely to locatethem.

Pupae are teardrops shaped and are found in the soil surface or in the plant's foliage.Adult hoverflies are true flies with only two wings instead of four which most insects have. Adults arelarge and beautiful insects about 13 mm long. They have a dark head, a dark thorax, and a bandedyellow and black abdomen. They closely resemble bees or wasps rather than flies. Their habit ofhovering like humming birds gave them the names hoverflies or flower flies. They are experthoverers, able to remain absolutely stationary in midair. In some species, males will hover in certainspots to attract the attention of females while other species patrol a wider area of up to 100 yards tofeed and mate. They dart from flower to flower making them easy to distinguish from the bees andwasps. They feed on pollen, nectar, and honeydew. They are good pollinators.

Conservation

Hoverflies are attracted to all flowering plants but even more so to small-flowered herbs like wildmustard, coriander, dill, lupins, sunflower, and fennel. It is advisable to have multiple crops as adultsbasically feed on pollen and nectar and it is advisable to allow flowering weeds such as wild carrotand yarrow to grow between crop plants.

Hoverflies' larvae are most noticeable in the latter half of the growing season when aphids areestablished.


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Photo courtesy of L. T. Kok

Ladybird beetles

Common names: Ladybird beetles, Ladybugs, Lady beetles, Coccinellid, Coccinellid beetlesScientific names: Harmonia conformis, H. axyridis, Hippodamia convegensColeoptera:Coccinellidae

Type

Generalist predators

Hosts

Aphids, leaffolders, leafhoppers, mealybugs, planthoppers, scales, spider mites, whiteflies, and otherleaf feeding insects.

DescriptionEggs are yellow to orange in color, football-shaped, and are laid in circular clusters of 10 -50 eggson the underside of leaves or near the aphid colony.

Newly hatched larvae are gray or black and less than 4 mm long. They emerge as dark alligator-likeflightless creatures with orange spots. Adult larvae can be gray, black, or blue with bright yellow ororange markings on the body. They are usually patterned with colors similar to their parents, andmany are adorned with spines. They have long sharp mandibles and feed on small insects like theiradults. The larvae are elongate and slightly oblong in shape. They undergo four instars beforepupating.

The pupae are usually brightly patterned and can be found attached to the leaves and stems ofplants where larvae have fed and developed.

Adults are oval to hemispherical and strongly convex with short legs and antennae. Most species arebrightly colored. Body length ranges from 0.8-16 mm. Their colors tell other predators that they aretasteless and toxic. When disturbed, some of them emit a strong smelling yellow liquid as aprotection against other predators. Their colors vary from red, orange, steel blue, yellow brown, oryellowelytra,frequently spotted or striped with black. They feed on pollen, nectar, water, andhoneydew but aphids or other prey are necessary for egg production. They are the best-knownpredators of aphids and are capable of eating up to 50-60 per day and about 5000 aphids in theirlifetime.
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Many species are well-known for their use in biological control, and have been distributed to variousparts of the world to combat insect pests of agricultural crops. However, members of the subfamilyEpilachninae are foliage feeders and are sometimes pests of several crops.

Conservation

Lady bird beetles are found in most agricultural and garden habitats. Their presence indicates thatnatural biological control is occurring. It is important to maintain habitats planted with severalflowering crops. These give the ladybird beetles varied food sources. When food is not available,they tend to eat each other. Their beneficial predatory behavior and activities are continuous whenthere is no indiscriminate use of synthetic pesticides.

Photo courtesy of Department of Entomology,Texas A&M University.

Minute pirate bug

Common Name: Minute pirate bugs, Insidious flower bugsScientific name: Orius tristicolor, O. insidiosusHemiptera:Anthocoridae

Type

Generalist predator

Hosts

Aphids, bollworm, potato leafhopper nymphs, spider mites, scale insects, insect eggs, small cornborers' larvae, thrips, other small caterpillars, whiteflies

Description


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Eggs are elongated, very small, about 0.25 mm, and are clear or milky white in color. The red eyesof the embryo are seen through the shell before hatching. Eggs are laid inside the plant tissues.Incubation takes about 4-7 days.

Nymphs are small, wingless, teardrop-shaped and yellow-orange to brown in color. Nymphs passthrough five instars before becoming adult. With each molt, the young closely resemble the adults

they will eventually become. The nymphal stage takes about 2 weeks.

Adults are also very tiny, about 2 mm long, ovate, and black with white wing patches. Their head andthorax are shiny and black, and their beak extends to between the bases of the first pair of legs.They have flattened bodies that are colored black or brown with lighter markings like pirate flags,hence the name. They possess efficient searching behavior and are voracious general feeders.They are able to aggregate in areas of high prey density and increase their numbers rapidly wherefood is abundant. They can consume 30 or more spider mites per day. Both nymphs and adults feedon a variety of pests as their primary source of food. Their lifecycle takes about 20 days underoptimum conditions to complete. Adults live for about 3 - 4 weeks.

Conservation

Minute pirate bugs are commonly found where there are flowering shrubs and weeds. These insectsare also found in corn, peanut, peas, cotton, soybeans, alfalfa, strawberries, and grapes. When theyare in corn silks, they eat the corn earworm eggs and other small insects found on the silks.Insecticide applications to crops can greatly reduce their numbers.

Corn earworm


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Photo source: Minnesota Vegetable IPM NewsletterUniversity of Minnesota

General Information

Common name: Corn earwormScientific names: Helicoverpa/Heliothis zea, H. armigeraLepidoptera:Noctuidae

Synonyms: Tomato fruitworm, Sorghum headworm, Cotton bollwormHost plants

Corn, sorghum, soybean, peanut, tobacco, cotton, cowpea, tomato, okra, pechay, radish, lettuce,and beansDistribution

Helicoverpa/Heliothis zeais found in Canada, South America, and USA while H. armigera is found inAsiaDamage

Larvae feed on leaves, tassels, whorl, silks, and within ears. When larvae feed on corn silks, theyclipped these off prior to feeding on the corn ears. The ears are the preferred sites for corn earwormattack. Ear damage is characterized by extensive excrement at the ear tip. They remain feeding inthe tip areas until they leave to pupate in the soil.Description

Eggs are pinhead-sized and yellow-green in color. These are found singly laid on the silk and

occasionally on the husks of the corn ear. Hatching occurs within about 2-5 days.


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Larvae vary in color from bright green, pink, brown, to black, with lighter undersides. Alternating light

and dark bands run lengthwise along their bodies, the heads are yellow and the legs are almost

black. Mature larvae vary in length about 3-5 cm. They drop to the ground to burrow into the soil to

pupate. The larval stage lasts from 12-24 days.

Pupae are yellowish green and turn brown as they mature. Pupation takes place under the soil.

Pupal period is 12-24 days.

An adult male is yellow-brown while a female is orange-brown in color. It has a wingspread size of

about 3.8cm. Each female may deposit 200-2,000 eggs in her entire lifetime. Total development

period from egg to adult is 34-45 days.

Natural enemies

Parasitoids

1. Braconid2. Tachinid fly3. Trichogramma

Predators

1. Damselfly2. Hoverfly3. Lacewing

4. Ladybird beetle5. Minute pirate bug6. Praying mantis7. Spider

Monitoring

Start corn earworm monitoring 1-2 weeks prior to the silking stage. To monitor, look for eggs andsmall larvae in the silk and husk. Moth population can be monitored with light traps and pheromonetraps. Generally, the presence of 5-10 moths caught every night by light traps in the field is sufficientto stimulate pest control practices (Hoffman; Wilson; Zalom, 1991).Management and cultural practices

1. Practicecrop rotation.Avoid planting crops successively that are hosts to corn earworm likecorn, cotton, sorghum, tobacco, soybean, and tomato.

2. Choose corn varieties with tight husks to prevent larva from entering. These varieties showsome characteristics and tolerance to the feeding habits of the corn earworm. Askassistance from the local agriculturist office for these varieties are available in the markets.

3. Two weeks before planting, remove weeds and grasses to destroy earworm larvae andadults harboring in those weeds and grasses.
http://www.oisat.org/control_methods/natural_enemies/parasitoids/braconid.htmlhttp://www.oisat.org/control_methods/natural_enemies/parasitoids/tachinid_fly.htmlhttp://www.oisat.org/control_methods/natural_enemies/parasitoids/trichogramma.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/damselfly.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/hoverfly.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/lacewing.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/ladybird_beetles.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/minute_pirate_bug.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/praying_mantis.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/spider.htmlhttp://www.oisat.org/display_popups/50.htmlhttp://www.oisat.org/display_popups/50.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/spider.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/praying_mantis.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/minute_pirate_bug.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/ladybird_beetles.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/lacewing.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/hoverfly.htmlhttp://www.oisat.org/control_methods/natural_enemies/predators/damselfly.htmlhttp://www.oisat.org/control_methods/natural_enemies/parasitoids/trichogramma.htmlhttp://www.oisat.org/control_methods/natural_enemies/parasitoids/tachinid_fly.htmlhttp://www.oisat.org/control_methods/natural_enemies/parasitoids/braconid.html


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4. Plow andharrow fields at least 2 times beforesowing seeds. This will expose pupae of cornearworm to chicken, birds, ants and otherpredators.Corn earworm pupates in the soil. Afterharvest, remove cornstubbles by feeding to carabaos and cows.


Damselfly

Common Names: Bog dancer, Damselfly, Damsel, Narrow wingScientific name:Agriocnemis femina femina, A. pygmaeaOdonata:Calyopterygidae

Type

Generalist predators

Hosts

Leafhoppers, moths and butterflies, plant hoppers (Shepard; Barrion; Litsinger, 1987: p. 127)

Description

Eggs are laid in emerging plants, in floating vegetation, or directly in the water. The hatched eggs donot go through the larval and pupal stages.

A naiad (nymph of damselfly) lives in water, has an elongated body, long legs, and three leaf-like

appendages or gills on its tail. These appendages are used for oxygen transport. A naiad moltsseveral times before emerging. At this stage, naiads are very good predators. They prey aquaticinsects and other arthropods within their reach. They grab their prey with their modified lower jaw. Atthe last stage, a naiad swims out of the water and clings to a plant to dry its skin. After a few minutesof drying in the sun, its outer skin splits open at the head and the adult damselfly strains to pull itselfout of its old skin. The new legs harden to hold onto the plant. Its wings slowly expand and arepumped open by fluid from its abdomen.

An adult damselfly has a long thin body which is green, blue, red, yellow, black, or brown and is
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often brightly colored. It has an oblong head with bulging eyes and very short antennae. Whenresting, it holds its four large membranous wings of nearly equal size vertically rather thanhorizontally. It is a delicate and weak-flying insect. Its wings are usually clear except for a spot at theend of the wing called a stigma. The male sex organ is located at the front part of the abdomen.Damselflies commonly fly in pairs during mating. Damselfly adults use their hind legs, which arecovered with hairs to capture prey as they fly. They hold the prey in their legs and devour it by

chewing. Adults are usually found flying near plants, usually in irrigated rice fields during the daytimethroughout the year. The damselfly's mating pattern is unusual. The male deposits sperm by bendingthe abdomen forward and then clasping the female behind the head with its claspers on the tip of hisabdomen. The female then loops her abdomen forward and picks up the sperm from the male. Themating pairs are seen flying and clinging in tandem. Most species have one generation per yeardepending on the species, although they complete their life cycle from 1-2 years.

Conservation

Damselflies live in rice paddies, streams, and ponds with good water quality at low and middleelevations. They are often used as an indicator of whether the water is clean or not (IRRI, 2001). Toconserve them, avoid using indiscriminate use of pesticides.

Aphids

Photo courtesy of INRA Versailles

General Information

Common name: AphidsHemiptera:Aphididae

Synonym: Blackflies, Greenbugs, Greenflies, Plant lice

Important aphid species

Black bean aphid (Aphis fabae)Corn leaf aphid (Rhopalosiphum maidis)


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Cotton aphid (Aphis gossypii)Cowpea aphid (A. craccivora )Greenbug (Schizaphis graminumGroundnut aphid (Aphis craccivora)Soybean aphid (A. glycines)Cabbage aphid (Brevicoryne brassicae)

Host plants

Aphids are pests of vegetables, legumes, plantation crops, shrubs, flowers, fruit trees, andornamental plants.Distribution

WorldwideDamage

The mouths of the aphids are like tiny straws. The aphids, both thenymphs and the adults, piercethe plant tissues to feed on plant sap. The leaf becomes severely distorted when the saliva of aphidsare injected into it. The heavily infested leaves can turn yellow and will eventually wilt because ofexcessive sap removal. Aphids feeding on flower buds and fruits cause malformed flowers andfruits.

Aphids produce large amounts of a sugary liquid waste calledhoneydew.A fungus, calledsootymold,grows on honeydew deposits that accumulate on leaves and branches, turning leaves andbranches black. The appearance of a sooty mold on plants is an indication of an aphid infestation.

In cotton, heavy infestation causes crinkling and cupping of leaves, defoliation, square and bollshedding, staining of the lints, and stunted growth.

In beans, the growing points are withered, brown, or dead. The leaves are crinkled and mottled.They become sticky because of black sooty mold growing on them. The plants are stunted anddeformed.

In crucifers, the infested seedlings are distorted and stunted. Their continued feeding on matureplants causes wilting, yellowing and a general stunting of the plants.

In corn, the leaves will wilt, curl, and have yellow patches. The tassels and silks are covered withhoneydew. Damage, during the late-whorl and pollination stages, causes shortening of the inter-nodes, shriveled and shrunken ears, and empty cobs.DescriptionEggs are very tiny, shiny-black, and are found in thecrevices of bud, stems, and barks of the plant.

Nymphs look like the young adults, they mature within 7-10 days, and are then ready to reproduce.

Adults are small, 3-4 mm long, soft-bodied insects with two projections on the rear end and two long

antennae. Their body color varies from yellow, green, brown, to purple. Females can give birth to live

nymphs as well as can lay eggs. However, the primary means of reproduction for most aphid
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species isasexual,with eggs hatching inside their bodies, and then giving birth to living young.

Winged adults, black in color, are produced only when it is necessary for the colony to migrate, or

there is either overcrowding in colonies, or unfavorable climatic conditions.

Natural enemies

Parasitoids

1. Braconid

Predators

1. Aphid midge2. Damsel bug3. Ground beetle

4. Hoverfly5. Lacewing6. Ladybird beetle7. Rove beetle8. Spider

Monitoring

Tomonitor aphid populations, examine the undersides of the leaves and the bud areas forgroups or colonies of aphids. Prompt control is necessary as aphids can multiply rapidly.

Management and cultural practices

1. Grow different crops or grow crops in rotation every cropping season. This practice providesfood, shelter, and it increases the number ofnatural enemies that prey on aphids. At thesame time, it disrupts the aphids' lifecycle and maintains its population below the economicthreshold level

2. When transplanting, use aphid-free seedlings only, because often they are the source ofinfestation. Typically aphid populations introduced through transplanting are not evenlydistributed in the field but rather form clusters of infestation.

3. Plant trap crops such as lupine, dill, nasturtiums, and timothy grass near the crop to beprotected (The Bug Lady, 2004). Anise, chives, garlic, onions, and radish are also goodcompanion crops (Ghorganics, 2004).

4. Control and kill ants. Plow and flood the field. This will destroy ant colonies and expose eggs

and larvae topredators and sunlight. Ants use the aphids to gain access to nutrients fromthe plants.5. Avoid using heavy doses of highly soluble nitrogen fertilizers. Aphids love tender, juicy

leaves. Instead apply fertilizer into 3 phases: during seeding, vegetative, and reproductivestages of plant growth.
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Photo courtesy of Jim Kalisch & Barry Pawson,UNL Entomology.

Rove beetles

Common Name: StaphylinidScientific name:Aleochara bilineataColeoptera:Staphylinidae

Type

Rove beetle larvae are maggots and pupae parasites when they are about to pupate, but both adultand larva are generalist predators

Hosts

Both adults and larvae are predators of root maggots' eggs and larvae, mites, worms, nematodes,and other small insects. Adults tend to be cannibalistic, eating their own eggs and attacking otheradults when food supply is low.

Description

Eggs are tiny, about 0.5 mm long and 0.4 mm wide, pear-shaped, pale green in color, and arecovered with a gelatin-like material. These are laid by female adults in the soil among the roots ofthe root-maggot infested plants. The eggs hatch 5-10 days later.

The first instar larvae are pale brown, about 1.5 mm long, slender, segmented, and tapered towardthe anterior. They have large heads. The parasitic second and third instar larvae are white, haverudimentary legs, and are found within the host puparium.

Before pupating, a larva will actively search for a host (pupa of maggot) in the surrounding soil. It willpupate in the pupa of the maggot by entering into its cocoon and feeding its contents, and thenpupate itself inside for about 3-4 weeks before emerging as an adult. It is possible that two or morelarvae enter into one maggot pupa but only one will survive and mature.

Adult rove beetles are brown, reddish-brown, or black or have gray markings on the wings andabdomen, with slender elongate bodies. Their wing covers are shorter than the abdomen wheremost part of the abdomen is exposed. Both adults and larvae have well-developed 'jaws' cross infront of the head. They live mostly in decaying organic matter but are also found in moist agriculturalsoils or in habitats where large numbers of fly larvae live. When disturbed, they run very fast, withtheir abdomen lifted upward, like that of scorpions. Adults are good fliers as well.


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Conservation

Provide ground covers or mulches within and around fields for rove beetles love to stay in moistdecaying organic matter; provide hiding sites and alternative habitats and plant flowering borders,hedges, and other perennial habitats as a source of food and shelter; and provide protection by notspraying broad spectrum pesticides.

http://www.oisat.org/crops/staple_food/corn.html

Aph idoletes aphidimyza

(Diptera: Cecidomyiidae)

The aphid midge,Aphidoletes aphidimyza, is a cecidomyiid fly whose larvae are effective predators of aphids. Initiallya new species was described for every different prey attacked, and at least 24 previously described species have

been determined to beA. aphidimyza. This midge is an important component of biological control programs for

greenhouse crops and is widely sold in the U.S.

Appearance

Adult aphid midges are small (2-3 mm), delicate, mosquito-like flies with long, dangling legs and long antennae. Eggs

are oval, minute (about 0.1 mm by 0.3 mm), and orange. The larvae, which look like orange maggots, are tiny,

growing through three instars from minute to 2-3 mm. Depending on their food source, they are bright orange to red,

and their bodies narrow toward the head. The larvae have strong "jaws" with which they grasp their prey.

Habitat (Crops)

Cole crops, potatoes, greenhouses, backyard gardens, ornamentals, orchards, berries. In the greenhouseA.

aphidimyzahas become very important for aphid control on long term vegetable crops. Although very few field

introductions have been reported, studies indicate there is the potential for aphid control in many outdoor crops. A.

aphidimyzahas been found on cabbage, apples, blueberries, and ornamental bushes, and is recognized as being an

important naturally occurring control agent of aphids on Russian and Egyptian cotton.

Pests Attacked

A. aphidimyzaattacks over 60 species of aphids.
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The onset of shorter daylength toward the end of summer can induce diapause. This can be averted in the

greenhouse by nocturnal use of 100 W incandescent light bulbs spaced 22 m apart when the canopy is open, with

closer spacing when the canopy is dense.

Pesticide Susceptibility

Most sprays are toxic to midges. Adults may be more susceptible than larvae.

Conservation

Aphid midges are native to much of North America and will overwinter, although winter mortality may be high. High

humidity and shelter from high temperatures and strong winds will encourage midge activity. In greenhouse

environments, adult midges are most effective at 20-26 degrees C with high humidity. Adults also need a source of

honeydew for feeding and to improve egg laying. Larvae need slightly moist soil for successful pupation.

For general information about conservation of natural enemies, seeConservationin the Tutorial section on this

site,Feature Articleon conservation in Volume II, No. 1 ofMidwest Biological Control News.

http://www.biocontrol.entomology.cornell.edu/predators/Aphidoletes.html

http://www.biocontrol.entomology.cornell.edu/predatorsTOC.html
http://www.nysaes.cornell.edu/ent/biocontrol/what.html#conservhttp://www.nysaes

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Natural Enemies of Corn Pests

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