Post on 12-Aug-2020
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• Biological control is defined as any activity of one species that reduces the adverse effect of another • Biological control is one of the oldest methods of insect control
• Earliest record dates back to 300 BC where the Chinese use ants to control citrus pests including caterpillars and beetles.
• It became established in the US in 1888
- introduction of vedalia beetle, Rodolia cardinalis for
control of the cottony cushion scale, Icerya purchasi
Lecture 2:
Biological Control
• Cottony cushion scale (CCS), an invasive species was
introduced into southern California between 1873-1876
• By 1885, CCS was threatening the citrus industry in
southern California.
• C.V. Riley (Chief entomologist for US) examined specimens and
determined that the pest had been introduced from Australia.
• C.V. Riley arranged a trip to Australia to collect natural enemies of
CCS for introduction into southern California.
• Albert Koebele subsequently traveled to Australia and shipped a
parasitic fly, Cryptochaetum iceryae, and the vedalia beetle to San
Franciso, where they were reared and sent to Los Angels.
History of Biological Control in the US
Success: • Klamath weed (St. John’s wort) in the western US in the (1940s)
introduction of Chrysolina quadrigemina (Chrysomelidae) to control
this weed in the Western US
• Prickly pear cactus in Australia in the 1920s (the cactus moth
Cactoblastis cactorum is native to South America)
Failures: • Introduced into the Caribbean in the 1950 and was found
in Florida in 1989, threatening the survival of native species
of cacti in the US and Mexico
Success and Failures in Biological control Programs
Agents of Biological Control
• Vertebrates
• Microorganisms
• Nematodes
• Invertebrates (other Insects)
As a group, natural enemies may function as
I. Parasites and Parasitoids
II. Predators
III. Pathogen
Parasite
Parasite – is an animal that lives on or within a larger animal
(host) - Requires one or a few host in its lifetime
- A parasite rarely kills its host, it can weaken the host that can
eventually die
- Nematodes are good examples of insect parasites that can suppress
populations
Steinernema carpocapsae
Parasitoid
Parasitoid- an insect usually a wasp that develops within
the body of another insect
• They are parasitic in their immature stages and free-living as adults
• They generally have a narrow host range
• Only one host is required to complete development
• Populations can be sustained at low host levels
• Host can live for a long time
• They always kill their host
Hyperparasite (secondary parasitoid) - a parasite that feeds on
another parasitoid. Encarsia pergandiella and E. tricolor are
hyperparasites of E. formosa.
Encarsia formosa Cotesia plutella
Braconidae
Hymenoptera
Aphelinidae
Common Parasitoids used in Fruit & Vegetable IPM
Braconidae
Diachasma alloeum
• Predator - any organism that attack and feed on other animals
(prey) and consumes more than one animal during its lifetime
Predators
They are generally two feeding types: - Specialist Generalist
Pytoseiulus persimilis Neoseiulus californicus
Predatory Mites
Insect Orders with Predatory Significance
Coleoptera
- Coccinellidae; lady beetles
- Carabidae; ground beetles
aphids
scale insects
spider mites
Cabbage maggot
Weed seeds
Lepidoptera eggs
Insect Orders with Predatory Significance
Neuroptera: Chrysopidae
Green lacewings
Diptera Syrphidae; Hover or Flower flies
Larvae feed on aphids
scale insects
Larvae feed on
aphids
scale insects
thrips
Bigeyed bug, Geocoris spp. Minute pirate bug, Orius spp.
Insect Orders with Predatory Significance
Hemiptera Anthocoridae Lygaeidae
Damsel bug, Nabis
aphids
caterpillars
Nabidae
Insect parasitic nematodes
Nematodes are thin, un-segmented round-worms, which
are parasitic on plants and other animals, or are free-living
in soil or living water
Important families in the class Nematoda
• Steinernematidae - Steinernema carpocapsae - beetle grubs
• Heterorhabditidae - Heterorhabditis bacteriophora - maggots
• They are used mostly as a bio-pesticides in high and medium value
crops including cole crops, berry crops and turfgrass for control of
borers, root maggots and cutworms
Strategies for Biological Control
• Introduction - referred to as ‘classical biological control’. Involves
the deliberate introduction and establishment of natural enemies into
areas where they did not previously exist
• Conservation and Enhancement - Activities designed to improve
survival, dispersal and reproduction of native natural enemies
• Augmentation - Any biological control activity designed to increase
the population of natural enemies
Introduction - Classical Biological Control
- Identification of the pest and its native area - Conduct surveys for natural enemies of the pest in its native area - Shipment of species to a quarantine facility in the area where natural enemies will be released - Host evaluation studies in quarantine facility - Special permit for releasing in specific areas for further evaluation - If successful, final release
Strategies for Biological control
The use of selective insecticides to avoid natural enemy mortality Increasing plant diversity Providing resources including food, overwintering sites water Strip harvesting
Conservation and Enhancement of Natural Enemies
Strategies for Biological control
• Inundative releases - The release of large quantities of natural
enemies with little or no impact expected from their progeny
(several applications)
Green lacewings; Chrysoperla carnea
Ladybird beetles, Hippodamia convergens
• Inoculative releases - The release of natural enemies with the
expectation that they will reproduce and spread throughout the area.
Neoseiulus californicus
Augmentative releases
Strategies for Biological control
Birds, amphibians (toads, frogs)
Reptiles (lizards, snakes, turtles)
Mammals (bats, rodents)
Non-arthropod Predators