• 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