Dr. Oscar E. Liburd Professor of Fruit & Vegetable Entomology http://entnemdept.ufl.edu/liburd/fruitnvegipm/teaching.htm
Lecture 2: Biological Control 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
History of Biological Control in the US Introduced into southern California between 1873-1876 Threated the citrus industry by 1885 C.V. Riley (Chief entomologist for US) arrange a trip to Austrailia Albert Koebele subsequently traveled to Australia DPI
History of Biological Control in the US Rodolia cardinalis Coccinellidae DPI http://tolweb.org/cryptochetidae/10588 Cryptochetum iceryae Cryptochetidae
Success and Failures in Biological control Programs fs.usda.gov. A.Brousseau Klamath weed (St. John s wort) Chrysolina spp. adult Chrysomelidae
Success and Failures in Biological control Programs Success Prickly pear cactus (Genus Opuntia ) in Australia in the 1920s. The cactus moth, Cactoblastis cactorum native to South America was introduced into Australia in 1925 and eradicated prickly pear cacti in a few years Failures: Introduced into Nevis in 1950 was found in Florida in 1989 threatening the survival of native species of cacti and Mexico Cactoblastis cactorum Wordpress.com
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
Strategies for Biological control 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 Augmentative releases 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
Strategies for Biological control Conservation and Enhancement of Natural Enemies The use of selective insecticides to avoid natural enemy mortality Increasing plant diversity Providing resources including food, overwintering sites water Strip harvesting
Factors influencing the type of releases Cost of releasing the organism Type of pest and duration of pest in the field Whether the pest is native or invasive Abiotic factors temperature, humidity etc.
Agents of Biological Control As a group natural enemies may function as I. Parasites II. Parasitoids III. Predators IV. Pathogen Non-arthropod Predators Birds, amphibians (toads, frogs) Reptiles (lizards, snakes, turtles) Mammals (bats, rodents)
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 generally have a narrow host range Only one host is required to complete development 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.
Common Parasitoids used in Fruit & Vegetable IPM Aphelinidae Encarsia formosa Aphelinidae Lysiphlebus testaceipes Braconidae Cotesia plutella Trichogrammatidae Trichogramma spp. Braconidae Diachasma alloeum Univ. of Ca
Predators Predator - any organism that attack and feed on other animals (prey) and consumes more than one animal during its lifetime They are generally two feeding types: - Specialist Generalist Predatory Mites Pytoseiulus persimilis Neoseiulus californicus
Insect Orders with Predatory Significance Coleoptera - Coccinellidae; ladybird beetles aphids scale insects spider mites - Carabidae; ground beetles Cabbage maggot Weed seeds Lepidoptera eggs
Diptera Insect Orders with Predatory Significance Syrphidae; Hover or Flower flies Neuroptera: Chrysopidae Green lacewings Larvae feed on aphids scale insects Larvae feed on aphids scale insects thrips
Insect Orders with Predatory Significance Hemiptera Lygaeidae Anthocoridae Bigeyed bug, Geocoris spp. Minute pirate bug, Orius spp. Coccinellidae Lady beetle Delphastus pusillus
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