Acari Control

1. Acari Control 1

2. Monitoring of pests and naturalenemies Chemical control– aa.ii. lesstoxic to naturalenemies Regulatory control – quarantines, pestexclusion, and regulations Cultural control – sanitation, pruning, rotations, fertilization, dust management, and irrigation Integrated Mite Management Host-plantresistance and host-planttolerance Biological control – classicalbiological control; naturalenemiesconservation; augmentation

3. BIOLOGICAL CONTROL • Classical: • Release of naturalenemies in an environmentwheretheir native populationisnotpresent (importation and release from the area of origin of a foreignpest); long periodeffects, no experiences in the control of phytophagousmites. • Efficient applications of classical biological control of weeds by means of mites (Texas and Australia), of springtails by means of predatory mites (Bleddose lapidaria and Neomolgus capillatus) (Australia and South Africa).

4. BIOLOGICAL CONTROL AUGMENTATIVE strategydistincts in: • Inoculative: • Release of naturalenemies in an environmentwhere the native populationisstronglyreduced or absent; short and medium periodeffects; requires IMM application. • Inundative: • Release of naturalenemies in a “isle”; short termeffects.

5. BIOLOGICAL CONTROL Predators (mites or insects) can be «released» in protected environments (inundative method) or fixing a new ecological balance (inoculative method) in fields or greenhouses. More commonly, Phytoseiulus persimilis is released in protected environments against the two-spotted spider mite. The application of «biological» pesticides (fungi, microrganisms, biocides produced by microrganisms) is still limited to a very few cases of at an experimental step. • Natural enemies and their applications • Predators +++ phytoseiids, cheyletids • Parassitoids - - - insect control • Parassites and pathogens + fungi

6. MITES AS PREDATORS • phytoseiidsreared, wide bio-ethologicalknowledge, applied • cheyletids some applications in storedenvironments • laelapidspromising candidate for the control of Rhizoglyphusrobini, applied Othertaxaactive in the natural control • ascids, trombidids, tydeids, tarsonemids macrochelids bdellid stigmeids anystid cunaxid piemotids

7. INSECTS AS PREDATORS Mainlyoligophagous with high preyconsumption and high fertility. Theybecomeinterestingwhenphytophagousmitesreach high density. • lady beetlesStethoruspunctillum • lacewings1reared in bio-firm, some applications are known in semi-protectedenvironments (e.g. strawberry under tunnel againsttwo-spotted spider mites) • antochorids2promisingcandidates Othertaxaactive in the natural control • thrips3, mirids, coniopterigids, staphylinids4, cecidomiids, syrphids (from Hoy, 2011) 2 1 4 3

8. PREDATORS Predatory impact • Stethorus punctillum • Scolothrips sexmaculatus • larvae of Chrysopa spp. • juveniles of Orius spp. • Phytoseiulus persimilis an ovigerous female can feed on 50-100 spider mites per day. an ovigerous female can feed on till 85 eggs or not movable instars of spider mites per day at 35°C 30-50 mites per day 30-40 eggs of spider mites per day ~ 18 eggs of two spotted spider mite per day

9. Stethoruspunctillum Adult black, 1-1.5 mm long, covered by a thin hairy. Groups of 4-10 individuals overwinter under bark crevices and other sheltered sites. 3 generations/year. Eggs laid singly or in small groups on the underside of the leaf. Larva feeds on till 40 mites/day; ovigerous female feeds on 50-100 mites/day. Larvae and adults are sensitive to the insecticides on the contrary of pupae and eggs.

10. Stethoruspunctillum Specialized predator of mites. It goes away in case the prey is absent. It requires a high prey density to be efficient: density threshold is 70-80 mites per 100 leaves.

11. FUNGI Infection by specialised spores which attach to the integument, germinate and passes through the mite cuticle by developed hyphae. They require high humidity of the environment and their action is affected by fungicides.

12. FUNGI Neozygetesfloridana: Appliedagainsttwo-spotted spider mite in the USA. Hirsutellathompsonii: Mycar (Abbott, USA – 1975-1985) againstPhyllocoptrutaoleivora; in Brasil and Argentina. Strains under investigations. Metarhiziumanisopliae: Appliedagainstticks. Beauveriabassiana: Promising and available on the market.

13. Tetranychusurticae Phytoseiuluspersimilis 15°C 6.7 5.3 6.6 18.6 20°C 2.8 2.3 3.1 8.2 25°C 1.3 1.2 1.4 3.9 15°C 3.0 3.9 4.1 11.0 20°C 1.1 1.4 1.6 4.1 25°C 0.6 0.8 0.8 2.2 BIOLOGICAL CONTROL: predator requirements • Comparison on the speed growth between predator/prey:predator cycle length ≤ prey cycle length; phytoseiids have cycle shorter than spider mites; insects have life cycle largely longer than that of mites as preys; predator prey (means in days) instair L Pn Dn total

14. BIOLOGICAL CONTROL: predator requirements • prey density: ability of predators to remain into the sites also with low prey density. Stethorus requires high prey density; some phytoseiid species are efficient also with low prey density; • alternative preys and food Ecological classes in phytoseiids • obligatory predators Phytoseiulus persimilis, Metaseiulus occidentalis • generalist predators Typhlodromus pyri • generalist and facultative predators • - oligophagous • - polyphagous Typhlodromus exhilaratus

15. BIOLOGICAL CONTROL: predator requirements • reproductive fitness:scarce meaning in a short term control. The phytoseiids have a low mean fertility and a long egg-laying period; • amount of prey: Stethorus punctillum is very voraceous; specific predators feed on a large amount of mites; • micro-habitat:similar to those of the prey; • chemical messengers perception • good ability in prey searchingalso at a low prey density. Phytoseiids are characterized by a notably mobility but they inspect a small surface; Stethorus and lacewings can inspect a larger surface; • ability of adaptation at the environment (tolerance to the adverse environmental conditions: climate and pesticides).

16. BIOLOGICAL CONTROL: weakpoints • Release rates (depending on plant feeders density, host plant, and environment); • Timing of release; • Multiple release; • Expensive; • Shipping; • Handling at release; • Pesticide resistance; • Agricultural production practices; • Pesticide applications; • Nectar and pollen sources; • Overwintering sites.

17. CULTURAL CONTROL • Dust management: dust on foliage makes it easier for spider mites to become serious pests; • Water management: water stressed plants allow spider mite populations to increase more rapidly. • Polycropping; • Crop rotation: • Fertilizing management. (from Hoy, 2011)

18. CHEMICAL CONTROL Kind of application depends on: crop • annuals, non horticultural crops unusual applications • annuals, horticultural crops, ornamentals frequent applications, mainly on protected ones • orchards possible applications • populations • Presence/absence of natural enemies • density and thresholds of the phytophagous species

19. (at 20 Oct 2011) Revokedavailable up to 31 Dec 2011)

20. CHEMICAL CONTROL Kind of application depends on: • Timing of application • winter (related to the overwintering populations) • late winter • spring and summer

21. CHEMICAL CONTROL Acaricides Insecticides with acaricides effects

22. CHEMICAL CONTROL Acaricides

23. CHEMICAL CONTROL

24. CHEMICAL CONTROL http://www.irac-online.org/ resistance phenomenon Pay attention to:

25. CHEMICAL CONTROL: IRAC recommendations a - do not apply more than one a.i. of the same class on the same crop and in the same season; where more than one pest should be controlled, do not apply aa.ii. belonging to the same class. b - each a.i. must be applied only once per season and per crop. c - mixture of aa.ii. of the same class is strongly not recommended. d - the aa.ii. must be applied according to strategies which can reduce the side effects on beneficial insects and mites. e - the aa.ii. must be used at the recommended doses and timing. f - monitoring for the assessement of the resistance must be carried out.

26. SULFUR (inorganic compound) • efficient against powdery mildew • produces toxic (H2S) gases for sublimation; these gases have a good diffusion; the sulfur substitutes oxygen allowing the production of H2S instead of H2O • dust in different commercial products • not toxic for human; can be sprayed just before the harvesting • phytotoxic at high temperature (>40°C)

27. efficient against eriophyoids, tenuipalpids, some tetranychids (Oligonychus, Eotetranychus, Tetranychus) • doubtful influence on predators and parassites Micronizedas WP (Thiovit) diferent doses diferent doses

28. Micronizedas WP (Thiovit) diferent doses

29. MITE GROWTH REGULATORS (MGRs) • Some of theseaa.ii. are veryspecificagainst spider mites and notdangerous for the naturalenemies (selectivity). • The most of theseaa.ii. are able to get the best results on low or moderately dense populations. • Goodpersistence. • Clofentezine, Etoxazole, Hexythiazox

30. MITE GROWTH REGULATORS (MGRs) • Clofentezine • Appliedmainlyagainstoverwinteringeggsaround 15-20 daysbeforetheirhatching (pome or stonefruittrees: pre-flowering treatment). • Itinhibits the synthesis of chitin. • Ithas a slow actionat the beginning, with the first deathafter 48 hours since the spray, and reaches the maximum activityafter 4-5 dayssince the spray. • Long persistance (2-3 monthsatleast) whichallowsreducing the number of sprays. • Very high selectivitytoward the beneficial fauna. • Knowncases of resistance in spider mites.

31. MITE GROWTH REGULATORS (MGRs) • Etoxazole • long persistance and large selectivity; • inhibits the respiratoryprocesses in the eggs; • inhibits the moulting.

32. MITE GROWTH REGULATORS (MGRs) Hexythiazox • It can influence the respiratoryprocesses in eggs just laid; it can influencenegatively the synthesis of chitin in eggslaid time ago, suchas on larvae and nymphs. • Ithasalsosterilizingeffects on ovigerousfemaleswhich can layeggsunable to hatch. • Knowncases of resistance. • Knownitsselectivitytowardphytoseiids. • Periodbetween treatment and harvesting: 7-14 days.

33. ORGANOTINS • They are consideredunable to developresistance. • Selective • Persistent • (usageauthorized up to 31.xii.2011) Fenbutatinoxide

34. METI = Mitochondrial electron transportinhibitors • They can cause a suddenmortality of the target. • Risk of cross resistance. • Selectivityisnotalwaysrelevant. • Some are phytotoxic for some hostplants. • Some have long persistance (tebufenpyrad) • Efficacyisinfluenced by the temperature (fenazaquin – 10-30°C) • Fenazaquin (Magister), Fenpyroximate (Miro), Pyridaben • Tebufenpyrad (Oscar)

35. Inhibitors of the oxydativephosphorilation • Propargite • Long persistance. • Killing effectsvisibleafter 24 hours after the spray, with a peakat 5 dayssince the treatment. • Some problems with resistance, phytotoxicity and mixtureincompatibility. • Inhibitors of the lipidsynthesis • Spirodiclofen • Resistanceapparentlyscarcelyprobable. • Efficientagainstall the developmentalinstars of tetranychids and eriophyoids: • causes a reduction on the hatching rate of eggs; • inhibits the moulting in juveniles; • interferes with the eggdevelopment and laying.

36. Neurotoxic • Bifenazate • Itinhibits the passage of stimulus from the nervoussystem to the muscolarsystem; itinhibits the ATP synthesisat the level of mythocondria. • The treatedmites are hyperactivewithin 3 hours and the mortalityoccurswithin 3-4 days. • Contact and ingestingpesticide.

37. Abamectin • Acaricide, nematocide and insecticideisolated from a toxinproduced by Streptomycesavermitilis. • Avermectin B1a (80%) and avermectin B1b (20%) Avermectin B1a Avermectin B1b

38. VERTIMEC binds to GABA & Glutamate-H receptor sites - - GABA receptor (chloride channel) VERTIMEC - - - - - - - - - - - - - - - muscle - - - - - - - -ve - - GABA release - - - - - - - - - - Irreversible flow of - chloride ions into muscle PERMANENT RELAXATION - - Glutamate H-receptor (chloride channel) - Abamectin It inhibits the transmission of neuromuscular signals (it blocks the gamma-aminobutyric acid) and provokes the individual paralysis. • Traslaminarproperty, able to penetrate rapidlyinto the plantcellswhere can persist for a long time (28 days). • The residues on the vegetalsurfaceisrapidlydeterioratedensuring a goodselectivitytoward the beneficial fauna.

39. CHEMICAL CONTROL • Abamectin • Larvicide (mortality) - adulticide (effect on the fertility). VERTIMECprotects plants from feeding damage within few hours of application FEW HOURS

40. CHEMICAL CONTROL: weakpoints • Harmfulness to natural enemies (selectivity), soil, water supply, agricultural workers; • Risk of residues on foods • Timing of application; • Multiple applications; • Expensive; • Development of resistance; • Few new products; • High costs to develop and register new products; • Long time to develop and register new products.