Biological Control of Insect Pests Prepared by: Hamid El Bilali and Vito Simeone

1. CIHEAM- Mediterranean Agronomic Institute of Bari Biological Control of Insect Pests Prepared by: Hamid El Bilali and Vito Simeone

2. Contents • Main non-pesticides control tools: micro-organisms, macro-organisms, natural products and semiochemicals; • Definition of biological control; • Biocontrol history; • Basic biological control theories; • Biological control objectives; • Biocontrol approaches; • Biological control agents: parasitoids, predators and pathogens.

3. Pests control in organic agriculture In organic agriculture, crops protection is based first of all on a good deal of knowledge on agroecosystem (biocenocis and biotope) and information about the target pest, prevention, interactions plant- environment-pest and finally on the use of the allowed pesticides (Annex II-B of the E.C.R. N° 2092/91).

4. Pests management • Knowledge of the pest: key pest, identification, bio-ethology and techniques of monitoring and sampling. • Monitoring: Pheromone/chromotropic traps, sticky barriers… • Prevention techniques. • Biological control. • Cultural management: • Appropriate species and varieties: tolerant or resistant cultivars; • Appropriate rotation programmes; • Longer fallow period and more frequent grass rotation. • Irrigation and fertilisation; • Pruning, leaves removal… • Mechanical practices: Use of mechanical barriers- insect-proof net; floating row covers; plastic tunnels, reflective mulches (aphids)… • Use of authorised bio-pesticides. • Mechanical barrier against Otiorrhynchus cribricollis

5. Prevention techniques • Site selection (climate and soil): Effective for nematodes and soilborne pathogens ( Armillaria, Fusarium, Plasmodiophora, Sclerotium, Verticillium, Phytophtora, Pythium and Rhizoctonia). • Use of healthy material: Certified seeds (pathogen-free seeds) and propagation material (transplants). • Use of forecasting model can help in the management of some diseases like fungal ones. • Inoculum reduction: • Crop rotations; • Soil solarisation; • Preventing the introduction of the inoculum by exclusion practices; • Use clean pots, trays and potting mix; • Inoculum eradication; • Soil tillage….

6. Prevention techniques • Use of resistant varieties and root-stocks; • Shifting the cropping period: Coordinate planting and harvesting dates to avoid pests. • Field sanitation (roguing): Removal and destruction of diseased, dying and dead plants; • Promoting crops aeration by canopy management practices: Effective against fungal diseases. • Rational fertilisation (balanced in nitrogen) and irrigation (clean water at proper amount); • Promoting beneficial insects. • Use of indicator plants: Rose for grapevine powdery mildew.

7. Pests biological control • Release of reared beneficial predator and parasitoid arthropod, insects and mites, (inoculative, augmentative or inundative releases): Psyttalia (Opius) concolor against olive fruit fly, Bactrocera oleae. • Mating disruption. • Use of antagonist micro-organisms: bacteria, Bacillus thuringiensis against Lepidoptera, fungi Ampelomyces quisqualis against powdery mildew; Protozoa; nematodes; baculovirus and granulosis virus. • Biological control of powdery mildew with: Orthotydeus lambi (Tydeidae mite), Bacillus (subtilis) sp., Trichoderma harzianum , Verticillium lecanii, Tilletiopsis sp. …

8. Pests biological control • Trap plants: Phacelia tanacetifolia againt Frankliniella occidentalis, Tagetes sp. against nematodes (Meloidogyne spp.). Oilseed radish could be a potential trap crop for cyst nematode ( Heterodera spp.). Phacelia tanacetifolia

9. Bio-pesticides • Advantages: • Low mammalian toxicity; • Minimal effect on beneficial insects; • Fast action and breakdown so low environmental impact; • High selectivity; • Short pre-harvest interval; • Low phytotoxicity. • Limit: Contact products so adequate coverage is essential to have a good efficacy. • Types: • Naturally occurring substances; • Substances of plant origin (botanicals); • Substances of animal origin; • Microorganisms-based bio-pesticides.

10. Types of bio-pesticides • Naturally occurring substances: Sulphur and lime sulphur (calcium polysulphide), copper (up to 6kg/ha/year); quartz sand.. • Botanicals(plant origin): Azadirachtin (Azadirachta indica), rotenone (Derris spp., Tephrosia spp. and Lonchocarpus spp. ), pyrethrins (Chrysanthemum/ Tanacetum spp), Quassia amara extract, Nicotiana tabacum extract, Sabadilla (Schoenocaulon spp.), Hellebore (Veratum album), croton (Croton tiglium), Yam bean (Pachyrhizus erosus ), Ryania (Ryania speciosa), thunder god vine (Tripterygium wilfordii), Amur corktree (Phellodendron amurense), Heliopsis longipes..

11. Types of bio-pesticides • Plants oils: Mint, pine and caraway (Carum carvi ) linseed, hempseed, cottonseed, rapeseed (colza), castor bean (Ricinus communis), coconut, soybean, palm, corn... • Substances of animal origin: beeswax, gelatine, hyrolysed proteins… • Animal fats: Whale, fish (cod, herring, menhaden, sardine), degras (wool grease), lard, neatsfoot… • Substances used in traps and/or dispensers: Diammonium phosphate, metaldehyde, pheromones, pyrethroids (Deltamethrin and Lambda-Cyhalothrin) • Others: Paraffin and mineral oils, K-permanganate...

12. Pests biological control • Use plant suppressive effects on diseases: Broccoli on Verticillium dahliae microsclerotia, cover crops like mustards and sudangrass on soilborne pathogens. • Bio-fumigation: Use of compost and organic amendments (castor, neem and argan cakes) supressive properties due to their content in allelopathic substances to kill soil pathogens (nematodes and soil-borne pathogens).

13. Non-pesticides control In “The Manual of Biocontrol Agents” (Copping, 2004) there are 373 entries of which: • Micro-organisms: 112 entries (species/ isolates/ formulations). • Macro-organisms: 126 entries (insects and mites, arthropods); • Natural products: 57 entries (microorganism- and plant-derived products). • Semiochemicals: 55 entries (sex, aggregation, and alarm pheromones); • Genes: 19 entries (resistance to hrerbicides, insects, and viruses inducers).

14. Non-pesticides control (Copping, 2004)

15. Natural products especially plant- and microorganisms- derived ones

16. Natural products use in biocontrol (Copping, 2004)

17. Natural products use in biocontrol (Copping, 2004)

18. Azadirachtin • Source: Neem tree, Azadirachta indica ; • Family: Meliacae; • Natural Habitat : South Asia, in particular India ; • Extracted from seeds (Kernels);

19. Azadirachtin: active ingredients • Principal active ingredients: Azadirachtin A (AZA) (C35H44O16) with its 7 isomers and Azadirachtin B ; • Mechanism of action: repellent, growth regulator, anti-oviposition, reduces adults fecundity and eggs vitality. • Mode of action: Contact, ingestion with a systemicactivity; • Activity spectrum: Effective against at lesat 200 insect species, nematicide, acaricide with a certain fungicidal activity. • Pre-harvest interval: 3 days;

20. Rotenone • Plants : Derris elliptica , mistica and malaccensis; • Lonchocarpusutilis, urucu, nicou and chrysophyllus; • Tephrosiamacropoda, toxicaria, vogelii and virginiana; • Family: Leguminosae; • Extracted from roots; Derris elliptica Lonchocarpus sp.

21. Rotenone • Principal active ingredients: Rotenone or Nicouline (Isoflavonoid, Alkaloid) ; • Mechanism of action: Interference with respiration and with perpherical nervous system; • Mode of action: Mainly by contact and sometimes via ingestion; • Activity spectrum: Non-systemic selective insecticide (Diptera, Coleoptera, Lepidoptera, Hemiptera, Thysanoptera, Hymenoptera) with a secondary acaricidal activity. • Pre-harvest interval: 10 days;

22. Pyrethrins • Plant: Tanacetum (Chrysanthemum) cinerariaefolium and T. cineum. • Family: Compositae; • Natural habitat: China, east of Africa and Japan; • Extracted from flowers; • Main active ingredient: Pyrethrin I; • Mode of action: Contact and ingestion; • Mechanism of action: Acts on peripherical and central nervous system causing an immediate insects paralysis; • Activity spectrum: mainly an insecticide with a certain acaricidal activity; • Pre-harvest interval: 2 days;

23. Pyrethrins: Active ingredients There are six different active ingredients (pyrethrins) resulting from the combination of two acids and 3 alcohols

24. Semiochemicals: Reppelents, attractants and sex, alarm, and aggregation pheromones.

25. Semiochemicals use in biocontrol (Copping, 2004)

26. Sex pheromone: • Males locate and subsequently mate with females by following the trail or pheromone emitted by virgin females. • The indiscriminate application of high levels of sex pheromone in traps and dispensers interferes with this natural process since a constant exposure to high levels of pheromone makes trail following impossible (habituation/adaptation phenomenon). • The use of discrete source of sex pheromone released over time presents the male a false trail to follow (sexual confusion/ mating disruption). • Control is subsequently achieved through the prevention of mating and consequently the laying of fertile eggs. • Sex pheromone are species-specific. Semiochemicals

27. Semiochemicals • Aggregation pheromones: • Males and females locate host trees by following a plume of air enriched with a mixture of the odour of the host tree and the aggregation pheromone. • Evaporation of pheromone vapours from dispensers attached to host trees attract both males and females of the insect pest to the baited trees and establiches conditions for mass attack of baited trees by the insect pests. • The baiting of selected areas and trees reduces the number of attacks in the main orchard or forest areas. • The baited trees and those trees closed to them should be felled before the progeny emerges from the infested trees. • Aggregation pheromone can be also used in monitoring. • They are effective in the case of beetles (Coleoptera). • Attractants are used in traps for monitoring and time management decisions of pesticides applications.

28. Semiochemicals • Alarm pheromones: • Alarm pheromones are released under natural conditions when the population in threatened or being attacked by a predator. • The result of this release in an increase in the activity of phytophagous insects with the subsequent higher exposure to a co-applied pesticide. • Alarm pheromones are often mixed with conventional pesticides (especially acaricide) and show an increase in the mortality of pests (mites). • The alarmed pests (e.g. spider mites) feed less than undisturbed ones.

29. Semiochemicals • Reppelent pheromones: • Reppelent pheromones are emitted naturally by some insect pests (e.g. beetles) when they reach a critical density in order to repel additional insects and, thereby to protect the food supply needed by these insects and their offspring. • A slight chemical alteration can change an attractant to a reppelent (e.g., Seudenol which is an attractant of douglas fir and spruce beetles was transformed into 3-methyl-cyclohex-2-en-1-one which is a reppelent of the same species). • The use of reppelent pheromone on healthy trees can be combined with the use of aggregation pheromone on dead or dying trees.

30. Mass trapping: Attract&Kill method • Attractant: Ammonium bicarbonate; • Pheromone: Virgin female sex pheromone; • Insecticide: Pyrethroids (Deltamethrin in Eco-trap or Lambda-Cyhalothrinin Agrisense). Agrisense Eco-trap 30

31. Definition of biological control

32. 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 continued reliance on pesticides.

33. Biological control definition • One definition of biological control that is easy to use and to remember is that biological control is "three sets of three". The sets of three represent: • 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.

34. Biocontrol history

35. Biocontrol history • Predation, parasitism and insect pathology have different histories; • Predation has been more easily observed and recorded than parasitism and disease because of larger size of insect predators with respect to pathogens and parasitoids. • Records from southern China indicate that weaver ant, Oecophylla smaragdina, nests have been gathered, sold, and placed in citrus orchards for approximately 2000 years. • Date growers in Yemen placed colonies of predatory ants in date palms for insect control. • The beneficial aspects of coccinellid predation has been recognized in Europe since the 13th century.

36. Biocontrol history • Interpretation of insect parasitism and the development of insect pathology were dependent upon the invention of microscopy. • The earliest recorded observations in western Europe of insect parasitism occurred during the 1600s. • In 1602 Aldrovandi recorded observations of parasitic larvae of Apanteles (Cotesia) glomeratus exiting from cabbage butterfly (Pieris rapae) and spinning external cocoons. • In 1670 Martin Lister correctly interpreted insect parasitism in a letter published in the Philosophical Transactions of the Royal Society of London.

37. Biocontrol history • The importation of the vedalia ladybird beetle to California citrus orchardsbeetle to reduce the population level of cottony cushion scale can be considered as the beginning of the modern era of biological control. • This importation project saved the developing citrus industry in California in the late 1800s and provided the impetus for biological control efforts within California. • This spectacular biological control success in California was repeated in several other countries. • Nowadays, many biological control agents are used with success for the containment of many pests in almost all the countries.

38. Basic biological control theories: populations dynamics, density-dependance and alternative theories.

39. Basic biological control theories • There is a high diversity and complexity of theories and models in biological control that try to understand the biology of natural enemies and their impact on host (prey) population dynamics. • The process by which densities of populations are maintained in nature is referred to as "natural control". • Natural controlserves as the basis for biological control and other pest control tactics. • 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. • Biological control has contributed significantly to the theoretical understanding of natural control..

40. Basic biological control theories: population dynamics • A population is a group of interbreeding individuals of the same species located in a defined area. • Early history of the field of ecology reflected the interest of ecologists in determining a theoretical structure to explain the observed patterns of population dynamics in order to identify the relative role of factors responsible for causing population change. • Understanding of natural control to which the majority of biological control specialists subscribe is that populations exists at a characteristic abundance, which is defined as the long-term expected numbers of individuals in a population.

41. Basic biological control theories: population dynamics • Presence of a characteristic abundance suggested that populations were being maintained around a given level (density) through the actions of factors found in the local environment. • Reduction and maintenance of introduced pest populations following introduction of "exotic" natural enemies was seen as confirming both the existence of a characteristic abundance and the role natural enemies play in maintaining insect population densities.

42. Basic biological control theories: Density-dependance • Maintaining population density around a characteristic abundance required the action of factors that behaved in a density dependent fashion. • The tendency for population to be maintained around a characteristic abundance via action of density dependent factor(s) is referred to as population regulation. • A factor that acts in a density-dependent fashion increases its impact on the affected population as the density of the population increases. • Thus, natural enemies whose percentages attack rate increases in response to host (prey) density increases are said to be acting in a density-dependent fashion.

43. Basic biological control theories: Density-dependance • The need to have density-dependent factor(s) regulating populations around a characteristic abundance was seen as necessary to counter the potential exponential growth rate that all populations possess. • Without a factor(s) that acted in a density-dependent fashion, populations would eventually grow to the point where they consume their resource base and crash towards local extinction. • The persistence of populations, and the relative lack of data for local extinctions, was seen as confirming evidence for the existence of density-dependence factors and the regulation of populations in nature. • Other than natural enemies, factors that act in a density-dependent fashion are intra-and inter-specific competition and territoriality.

44. Basic biological control theories Illustration of natural control: the population number is fluctuating over time it is bounded within a range. The population's "characteristic abundanc“, the long term expected number of individuals in the population, is represented by the yellow. Example of a factor that acts in a density-dependent fashion (http://www.inhs.uiuc.edu/cee/biocontrol/theoriesmodels/natcontrol.html)

45. Basic biological control theories: Alternative theories • Historically, the major challenge to the "density-dependent school" came from those who felt that the evidence for population stability in nature was not proved, and that the numbers of individuals in a population was largely determined by the time available for population growth. • Population control can be accounted for via vagaries in environmental limits that are not related to density per se. • Whereas followers of the density-dependent school saw populations existing in a characteristic abundance, those of the density-independent school saw populations in flux, with extinctions common and the long-term expected number of a population only a statistical, not biological, reality. • The abundance and distribution of populations reflected adaptation to local conditions that are limited as to the nature, magnitude and direction of change.

46. Basic biological control theories: Alternative theories • Populations track environmental change, expanding in favourable times and contracting during unfavourable periods. • Population control was seen to have elements of maintenance within boundaries ("control") and return to equilibrium ("regulation"). • Extinction of populations happens and the imposition of density- dependence occurs for only relatively short time periods. • For the most part, it is a combination of so-called "imperfect density-dependent" factors (including natural enemies) and density-independent factors (primarily weather) that influence population dynamics.

47. Basic biological control theories: Alternative theories • "Conditioning factors" uninfluenced by density, will control or set the framework of environment upon which density dependent factors act. • At lower densities, either density-independent factors "relax" or the population goes extinct. At higher densities, the only "perfect" density-dependent factor, intra-specific competition prevents continued population growth and causes the population to decline to lower levels. • Uunderstanding of the role of natural enemies in the natural control of insect populations has evolved over time: Originally seen as acting as so-called "perfect" density-dependent agents regulating populations, more synthetic theories place the impact of natural enemies within a context of overall environmental impact on population dynamics.

48. Biological control objectives: reduction, prevention or delay of infestation

49. Infestation reduction • Reduction of a pest population after it occurs at a damaging level • It approximates the use of pesticides. • A biological control agent is used after the pest population has exceeded the economic threshold, with a goal of sufficiently reducing pest density and maintaining a lower density over a long period of time. • The pest is not eradicated but simply reduced to non-pest status. • This has been the historical approach for importing natural enemies against exotic pests: Vedalia ladybird beetle against cottony cushion scale.

50. Infestation prevention • The objective is to keep the population of a potential pest from reaching a high, or economic, level. • Prevention requires early intervention, before a pest build-up occurs. • The action of a natural enemy early in the life cycle of the potential pest can keep the population from reaching pest status. Infestation delay This objective is similar to prevention, in that both require early intervention, before a population exceeds a threshold. However, delay means that the population will eventually build up to a high level, but it does so at a time when the species is no longer considered a pest.