Acari Control 1 Monitoring of pests and natural enemies Chemical control – aa.ii. less toxic to natural enemies Regulatory control Cultural control – sanitation, pruning, rotations, fertilization, dust management, and irrigation Integrated Mite Management Host-plant resistance and host-plant tolerance – quarantines, pest exclusion, and regulations Biological control – classical biological control; natural enemies conservation; augmentation 2 BIOLOGICAL CONTROL CLASSICAL: • Release of natural enemies in an environment where their native population is not present (importation and release from the area of origin of a foreign pest); long period effects, no experiences in the control of phytophagous mites. • 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). 3 BIOLOGICAL CONTROL AUGMENTATIVE strategy distincts in: INOCULATIVE: • Release of natural enemies in an environment where the native population is strongly reduced or absent; short and medium period effects; requires IMM application. INUNDATIVE: • Release of natural enemies in a “isle”; short term effects. 4 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 +++ • Parassitoids --• Parassites and pathogens + phytoseiids, cheyletids insect control fungi 5 MITES AS PREDATORS • phytoseiids • cheyletids • laelapids bdellid reared, wide bio-ethological knowledge, applied some applications in stored environments promising candidate for the control of Rhizoglyphus robini, applied stigmeids anystid Other taxa active in the natural control • ascids, trombidids, tydeids, tarsonemids macrochelids cunaxid piemotids 6 INSECTS AS PREDATORS Mainly oligophagous with high prey consumption and high fertility. They become interesting when phytophagous mites reach high density. • lady beetles Stethorus punctillum • lacewings1 reared in bio-firm, some applications are known in semi-protected environments (e.g. strawberry under tunnel against two-spotted spider mites) • antochorids2 promising candidates Other taxa active in the natural control • thrips3, mirids, coniopterigids, staphylinids4, cecidomiids, syrphids 1 2 3 4 (from 7 Hoy, 2011) PREDATORS Predatory impact • Stethorus punctillum an ovigerous female can feed on 50100 spider mites per day. • Scolothrips sexmaculatus an ovigerous female can feed on till 85 eggs or not movable instars of spider mites per day at 35°C • larvae of Chrysopa spp. • juveniles of Orius spp. 30-50 mites per day 30-40 eggs of spider mites per day • Phytoseiulus persimilis ~ 18 eggs of two spotted spider mite per day 8 Stethorus punctillum 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. 9 Stethorus punctillum 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. 10 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. 11 FUNGI Neozygetes floridana: Applied against two-spotted spider mite in the USA. Hirsutella thompsonii: Mycar (Abbott, USA – 1975-1985) against Phyllocoptruta oleivora; in Brasil and Argentina. Strains under investigations. Metarhizium anisopliae: Applied against ticks. Beauveria bassiana: Promising and available on the market. 12 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) Tetranychus urticae Phytoseiulus persimilis 15°C 20°C 25°C 3.0 1.1 0.6 3.9 1.4 0.8 4.1 1.6 0.8 11.0 4.1 2.2 instair L Pn Dn total 15°C 20°C 25°C 6.7 2.8 1.3 5.3 2.3 1.2 6.6 3.1 1.4 18.6 8.2 3.9 13 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 14 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 searching also 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). 15 BIOLOGICAL CONTROL: weak points • 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. 16 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,172011) 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 18 Active ingredients In Europa ABAMECTIN Authorized ACRINATHRIN Revoked BEAUVERIA BASSIANA ATCC 74040 Authorized BIFENAZATE Authorized CLOFENTEZINE Authorized CYPERMETHRIN Authorized DELTAMETHRIN Authorized DIFLUBENZURON Authorized DIMETHOATHE Authorized ETOXAZOLE Authorized FENAZAQUIN Revoked FENBUTATIN OXIDE Revoked FENPYROXIMATE Authorized FLUFENOXURON Revoked HEXYTHIAZOX Revoked IMIDACLOPRID Authorized METHIOCARB Authorized MILBEMECTIN Authorized PIRETHRIN Authorized PIRIMPHOS METHYL Authorized PROPARGITE Revoked PYRIDABEN Revoked SPIRODICLOFEN Authorized TAU-FLUVALINATE Authorized TEBUFENPYRAD Authorized SULFUR Authorized (at 20 Oct 2011) Revoked available up to 31 Dec 2011) 19 CHEMICAL CONTROL Kind of application depends on: Target instar/s Active ingredient/s eggs clofentezine, spirodiclofen, (spiromesifen) eggs and mobile instars etoxazole, hexythiazox mobile instars others Timing of application • winter (related to the overwintering populations) • late winter • spring and summer 20 CHEMICAL CONTROL Acaricides Chemical classification Active ingredient/s Inorganic compounds sulfur Organic containing nitrogen clofentezine, etoxazole, fenazaquin (R), fenpyroximate, pyridaben (R), tebufenpyrad, bifenazate Organic containing nitrogen and hexythiazox (R) sulphur Organotin fenbutatin oxide (R) Tetronic acids spirodiclofen, (spiromesifen) Antibiotics abamectin, milbemectin Sulfur-organic propargite (R) Insecticides with acaricides effects Chemical classification Active ingredient/s Pyrethroids acrinathrin (R), cypermethrin, deltamethrin, tau-fluvalinate Organic containing nitrogen diflubenzuron 21 CHEMICAL CONTROL Acaricides Mode of action Active ingredient/s sulfur Mite Growth Regulators clofentezine, etoxazole, hexythiazox (R) Inhibitors of mitochondrial ATP synthase fenbutatin oxide (R), propargite (R) Mitochondrial complex I Electron Transport Inhibitors (METI) fenazaquin (R), fenpyroximate, pyridaben (R), tebufenpyrad unknown or uncertain bifenazate Inhibitors of acetyl CoA carboxylase spirodiclofen, (spiromesifen) Chloride channel activator abamectin, milbemectin 22 CHEMICAL CONTROL Mode of acquiring Active ingredient/s contact clofentezine, pyridaben, propargite, fenbutatin oxide contact-ingestion abamectin, milbemectin, bifenazate, fenazaquin, fenpyroximate, tebufenpyrad, etoxazole, hexythiazox, spirodiclofen gas Sulfur – in closed environments (rarely relevant in mites) Translaminar property abamectin, milbemectin, tebufenpyrad, clofentezine, etoxazole, hexythiazox, spiromesifen 23 CHEMICAL CONTROL Pay attention to: http://www.irac-online.org/ resistance phenomenon 24 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. 25 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) 26 • efficient against eriophyoids, tenuipalpids, some tetranychids (Oligonychus, Eotetranychus, Tetranychus) • doubtful influence on predators and parassites Micronized as WP (Thiovit) 27 Micronized as WP (Thiovit) 28 MITE GROWTH REGULATORS (MGRs) • Some of these aa.ii. are very specific against spider mites and not dangerous for the natural enemies (selectivity). • The most of these aa.ii. are able to get the best results on low or moderately dense populations. • Good persistence. Clofentezine, Etoxazole, Hexythiazox Mode of acquiring Active ingredient/s contact clofentezine, pyridaben, propargite, fenbutatin oxide contact-ingestion abamectin, milbemectin, bifenazate, fenazaquin, fenpyroximate, tebufenpyrad, etoxazole, hexythiazox, spirodiclofen gas Sulfur – in closed environments (rarely relevant in mites) Translaminar property abamectin, milbemectin, tebufenpyrad, clofentezine, etoxazole, 29 hexythiazox, spiromesifen MITE GROWTH REGULATORS (MGRs) Clofentezine • Applied mainly against overwintering eggs around 15-20 days before their hatching (pome or stone fruit trees: pre-flowering treatment). • It inhibits the synthesis of chitin. • It has a slow action at the beginning, with the first death after 48 hours since the spray, and reaches the maximum activity after 4-5 days since the spray. • Long persistance (2-3 months at least) which allows reducing the number of sprays. • Very high selectivity toward the beneficial fauna. • Known cases of resistance in spider mites. 30 MITE GROWTH REGULATORS (MGRs) Etoxazole • long persistance and large selectivity; • inhibits the respiratory processes in the eggs; • inhibits the moulting. 31 MITE GROWTH REGULATORS (MGRs) Hexythiazox • It can influence the respiratory processes in eggs just laid; it can influence negatively the synthesis of chitin in eggs laid time ago, such as on larvae and nymphs. • It has also sterilizing effects on ovigerous females which can lay eggs unable to hatch. • Known cases of resistance. • Known its selectivity toward phytoseiids. • Period between treatment and harvesting: 7-14 days. 32 ORGANOTINS • They are considered unable to develop resistance. • Selective • Persistent (usage authorized up to 31.xii.2011) Fenbutatin oxide Mode of acquiring Active ingredient/s contact clofentezine, pyridaben, propargite, fenbutatin oxide contact-ingestion abamectin, milbemectin, bifenazate, fenazaquin, fenpyroximate, tebufenpyrad, etoxazole, hexythiazox, spirodiclofen gas Sulfur – in closed environments (rarely relevant in mites) Translaminar property abamectin, milbemectin, tebufenpyrad, clofentezine, etoxazole, 33 hexythiazox, spiromesifen METI = Mitochondrial electron transport inhibitors • • • • • • They can cause a sudden mortality of the target. Risk of cross resistance. Selectivity is not always relevant. Some are phytotoxic for some host plants. Some have long persistance (tebufenpyrad) Efficacy is influenced by the temperature (fenazaquin – 10-30°C) Fenazaquin (Magister), Fenpyroximate (Miro), Pyridaben Tebufenpyrad (Oscar) Mode of acquiring Active ingredient/s contact clofentezine, pyridaben, propargite, fenbutatin oxide contact-ingestion abamectin, milbemectin, bifenazate, fenazaquin, fenpyroximate, tebufenpyrad, etoxazole, hexythiazox, spirodiclofen gas Sulfur – in closed environments (rarely relevant in mites) Translaminar property abamectin, milbemectin, tebufenpyrad, clofentezine, etoxazole, 34 hexythiazox, spiromesifen Inhibitors of the oxydative phosphorilation Propargite • Long persistance. • Killing effects visible after 24 hours after the spray, with a peak at 5 days since the treatment. • Some problems with resistance, phytotoxicity and mixture incompatibility. Inhibitors of the lipid synthesis Spirodiclofen • Resistance apparently scarcely probable. • Efficient against all the developmental instars of tetranychids and eriophyoids: - causes a reduction on the hatching rate of eggs; - inhibits the moulting in juveniles; - interferes with the egg development and laying. 35 Neurotoxic Bifenazate • It inhibits the passage of stimulus from the nervous system to the muscolar system; it inhibits the ATP synthesis at the level of mythocondria. • The treated mites are hyperactive within 3 hours and the mortality occurs within 3-4 days. • Contact and ingesting pesticide. 36 Abamectin • Acaricide, nematocide and insecticide isolated from a toxin produced by Streptomyces avermitilis. • Avermectin B1a (80%) and avermectin B1b (20%) O O HO HO O O O O O O H O O 25 O O H O O O O O O OH O 25 O O OH O H OH Avermectin B1a H OH Avermectin B1b 37 Abamectin It inhibits the transmission of neuromuscular signals (it blocks the gamma-aminobutyric acid) and provokes the individual paralysis. VERTIMEC binds to GABA & Glutamate-H receptor sites -GABA - receptor VERTIMEC (chloride channel) - -- - ---- - - muscle -- - --ve - - GABA release -- Glutamate H-receptor (chloride channel) - - Irreversible flow of - chloride ions into muscle PERMANENT RELAXATION • Traslaminar property, able to penetrate rapidly into the plant cells where can persist for a long time (28 days). • The residues on the vegetal surface is rapidly deteriorated ensuring a good selectivity toward the beneficial fauna. 38 CHEMICAL CONTROL Abamectin • Larvicide (mortality) - adulticide (effect on the fertility). VERTIMEC protects plants from feeding damage within few hours of application INGESTION CHLORIDE FLOW MUSCLE PARALYSIS FEEDING STOPS DEATH 39 CHEMICAL CONTROL: weak points • 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. 40