Biological Control of Insect Pests

1. Biological Control of Insect Pests

2. Bio-pesticides Advantages: • Low mammalian toxicity; • Minimal effect on beneficial insects; • Fast action and breakdown • High selectivity • Low phytotoxicity. Types: • Substances of plant origin (botanicals). • Substances of animal origin. • Microorganisms-based bio-pesticides.

3. Definition of biological control

4. Biological control definition Biological control can be defined as the use of natural enemies to reduce the damage caused by a pest population. Biological control is an approach that fits into an overall pest management program, and represents an alternative to pesticides.

5. Biological control definition • The "who": The natural enemies themselves that is to say predators, parasitoids and pathogens. • The "what": The objective to achieve which can be prevention, reduction or delay of infestation. • The "how": The approach that is taken with the natural enemy to achieve the objective which can be conservation, augmentation or importation.

6. Basic biological control theory Understanding the major concepts of natural control is key to understanding how natural enemies control pests and how they can be used in biological control programmes.

7. Biological control agents: parasitoids, predators and pathogens.

8. Macro-organisms use in biocontrol (Copping, 2004)

9. Phytophagous biocontrol agents (Copping, 2004)

10. Parasitoids

11. Parasitoids • Parasitic insects (also known as parasites and parasitoids) are insects whose immature stages (larvae) develop by feeding on or in the bodies of their host arthropods, which are usually other insects. • Host: The organism attacked and used as a food source by the parasite. • Parasites: are organisms that live in or on , and at the expense of other organisms (host). The parasite provides no benefit to the host, which is weakened or damaged, and eventually destroyed or unable to reproduce. Parasitic insects are unique, because it is the immature stages that kill the host.

12. Parasitoids • Nearly all parasite immatures develop on or in a single host. • Parasites are holometabolous, having complete development (egg, larval, pupal and adult stages). • Adult parasites are free living; some species will feed on hosts (predators), in addition to ovipositing in or on the hosts. • In the world of parasites, only females are significant players, as they are the ones that find and attack hosts. For some species, males are not known to exist.

13. Parasitoids types • Where the egg is laid • (inside the host = endoparasite • outside the host = ectoparasite).

14. Parasitoids types • The feeding habit of the immature stage: • Egg parasite: Parasite adult attacks the host egg, and the parasite progeny emerge from the egg. • Egg-larval parasite: Parasite adult attacks the host egg, but the parasite progeny emerge from the larva. • Larval parasite: Parasite adult attacks the host larva, and the parasite progeny emerge from the larva. • Larval-pupal parasite: Parasite adult attacks the host larva, but the parasite progeny emerge from the pupa. • Pupalparasite: Parasite adult attacks the host pupa, and the parasite progeny emerge from the pupa.

15. Parasitoids types Number of parasites’ progenies : • Multiparasitism: A single host is attacked by more than one species of parasites.( when females of more than one species oviposit in individual host) • Superparasitism: Several females of one species of parasite attack the same host, female oviposits more than one egg to a host than can successfully develop to maturity.

16. Parasitoids types • Hyperparasitism Hyperparasitism is a multilevel trophic system in which one species develops as a parasitoid of another parasitoid. The species attacking the free living organisms (herbivore) is called a primary parasitoid, the primary parasitoid is attacked by a secondary parasitoid.

17. Parasitoids taxonomy • Although parasitism is found in several insects orders, primary orders of parasites are Hymenoptera and Diptera. • The greatest diversity of parasites is found in Hymenoptera. • The most important parasitic families within Hymenoptera e.g wasps. • Several Diptera families have members that are parasitic:

18. At least 65000 species of Hymenoptera are parasitoids, but only 765 species have been used in biological control programs worldwide.

19. A tiny wasp injects eggs into a plant bug nymph

20. Wasp larvae coming out of a caterpillar

21. Predators

22. Predators • Predation can be defined as a trophic level interaction in which one species derives energy from the consumption of individuals of another species. • A predator is considered an entomophagous species that generally consumes more than one prey individual to complete its development. • Over 16 orders of insects contain predaceous members, in approximately 200 families. Including spiders and mites, there are probably in excess of 200,000 species of arthropod predators.

23. Predators • Among the non-insect arthropods, spiders (Araneae) . Spiders have been little utilized in biological control. • Mites (Acari) have a number of predaceous members. Mites have been used in a number of biological control projects. • Monophagy: The predator may feed on one or a very limited number of species within the same genera. • Oligophagy: Predators feed primarily on aphids preys, or on whiteflies or scales. • Polyphagy: A broad prey range, may include plant materials (fluids, nectars, pollen), insects and fungi.

24. Predators’ characteristics • kill and consume more than one prey organism to reach maturity. • Relatively large size compared to prey. • Predaceous as both larvae and adults. Diet may be influenced by: • Prey environment. • Competition with other predators. • Suitability of prey.

25. Preys location and capture Strategies used by predators to locate and capture preys include the following: • Directed searching: Movement may be guided by features of the environment that increase chances for encountering prey. • Active searching: Use of visual to orient to prey at a distance. • Ambushing: Waiting for prey , e.g. raptorial legs (praying mantids) they clasp their preys. • Trapping: Neuropterans prepare conical pits in loose sand, larvae wait at the bottom with large sickle shaped jaws. • Attracting: Lightning bugs, flashing of one species to attract males of another. Females then consume males.

26. Predators groups (Copping, 2004)

27. Predatory insect groups The major groups of predaceous insects belong to the following orders: Coleoptera, Dermaptera, Diptera, Hemiptera, Hymenoptera, Mantodea, Neuroptera, Orthoptera and Thysanoptera. • Coleoptera: • Coleoptera (beetles and weevils) is the largest order in the class Insecta. • Many Coleoptera species are herbivores, others live on fungi but many beetles are predators. There are even few parasitic beetles. • The most important Coleoptera predaceous families are the following: (ground beetles); (tiger beetles), (soldier beetles) and (ladybird beetles).

28. Predatory insect groups • Dermaptera: • Members of the order Dermaptera are recognized by pincers at the tip of the abdomen. These structures are used to hold prey while it is being consumed. • The predaceous species feed on soft bodied insects (e.g. aphids, leaf hoppers, larvae of Coleoptera and Lepidoptera). • The most important Dermaptera predatory are: (spine tailed earwigs)

29. Predatory insect groups • Diptera: • Some flies are predators of other arthropods (e.g., robber flies), but most of them are external parasites (e.g., mosquitoes and deer flies). • Hemiptera: • The most Hemiptera predatory are: assassin bugs, stink bugs.

30. Predatory insect groups • Hymenoptera • Hymenoptera is one of the larger orders of insects, includes sawflies, wasps, bees, and ants. • Females of Hymenoptera typically have a special ovipositor for inserting eggs into hosts or otherwise places, often modified into a stinger. • The most important Hymenoptera predaceous groups are: wasps and ants.

31. Predatory insect groups • Neuroptera: • The insect order Neuroptera includes the antlions. • The adults of this order possess chewing mouthparts, and most are predatory. • Orthoptera: • The Orthoptera order includes the grasshoppers, crickets and locusts. • The most important Orthoptera predaceous species are included Omnivorous on soft bodied insects, aphids and scales.

32. Predatory insect groups • Thysanoptera: • Most species of Thrips feed on plant tissues . • The most important Thysanoptera predatory is Banded thrips. • Mantodea: • Mantids have elongate bodies that are specialized for a predatory lifestyle: long front legs with spines for catching and holding prey, a head that can turn from side to side. • The most important predaceous is praying mantid.

33. Predator-prey interactions Prey habitat location: • Olfactory and visualare likely used by adult predators to locate suitable habitats. • Volatile are known to be used as attractants by selected insect predators. • For some predatory species, a blend of compounds, including volatiles from the plants in the habitat as well as prey volatiles, are involved. This blend is called synergistic mixture of plant and prey derived.

34. Predator-prey interactions • Prey location: • Physical and chemical are used by many predatory species to locate prey. Vision may be important for ambush type predators or other predators of slow-moving prey.

35. Predator-prey interactions • Prey acceptance: • The following may influence prey acceptance: size of prey and composition of cuticle. • Morphological and physiological factors can influence prey acceptance. • Size, shape, movement, and external and internal chemical of prey are factors that can be used as stimuli to induce prey acceptance.

36. Predator-prey interactions • Prey acceptance: • Physical factor that influences prey acceptance is the size of prey relative to the predator. • Prey integumentary chemicals (e.g., waxes) may serve as phagostimulants for some predatory species. • Some prey (e.g. aphids) kick, run, drop, or fly away, or noxious chemicals.

37. Rove beetles eating a maggot

38. Sub phyllum chelicera • Composed of three classes of over 63000 species. • The most important class with regarded to applied biological control is the Arachnida, divided into 13 orders, we will consider only the two most important, the Araneae (spider) and Acariformes (mites)

39. Spider • Carnivore • Have long life cycle • Do not have distinct performance for a given prey species. • Increase in attacks occurs in response to increasing prey density.

40. A scorpion eating a cricket

41. A spider eating an insect.

42. A lacewing larva eating an aphid Howard Russel, Michigan State University

43. A spider eating a moth

44. A big-eyed bug glues a whitefly to a leaf and eats it.

45. Pathogens

46. Pathogens • Associations between Microorganisms and insects range from mutualistic associations to those where the microorganism causes fatal disease in the insect host. • Infectious insect diseases, usually causing effects in the host, occur frequently in insects and often act as important natural control agents. • Insect pathogens are most often viewed as microbial insecticides.

47. Pathogens • Entomogenous: Organisms growing in or on the bodies of insects; usually a parasitic or other intimate symbiotic relationship. • Entomophagous: Insectivorous; the consumption of insects and their parts. • Entomophilic: Associations between insects and other organisms, e.g. plant, microorganisms, Protozoa, and nematodes. • Horizontal transmission: Transmission of a pathogen from infected individuals to another • Vertical transmission: Transmission of a pathogen from one generation of host to the next.

48. Pathogens • Invasion/Infection: Invasion is the entry of a microorganism into the host body. Primary invasiveness is a property of pathogenic microorganisms. • Latent infection: Unapparent infection; the pathogen is in a non-reproductive phase and a pathogen-host equilibrium is established. • Pathogenicity : Pathogenicity is the ability of an organism to invade the host and cause disease.

49. Beaveria bassiana Fungal insecticides Grows naturally in soils Acts as a parasites on various insect species causing white muscardine disease Belong to entomopathogenic fungi