Sequential testing scheme for the assessment of the side-effects of plant protection products on the predatory bug Orius laevigatus

This paper describes a number of test methods, to beused in a sequential scheme, for testing the side-effects ofplant protection products on anthocorid bugs. Orius laevigatuswas used as test species. A `worst case' laboratory method wasdeveloped for evaluating the effect on mortality of the nymphsand the reproduction of the adults. An extended laboratory methodgives information on the effect of pesticides on adults undermore natural conditions. A semi-field test is executed in smallplots under field (glasshouse) conditions. Finally a field testsimulates the conditions in a commercial crop. For harmfulchemicals, both a laboratory and a semi-field persistence testwas developed to determine the safety period after which thepredatory bugs can be re-introduced in the greenhouse withoutbeing adversely affected. The total result of this sequentialscheme should indicate whether, and with what restrictions, aparticular pesticide can be implemented in IPM programs in whichO. laevigatus is used for control of western flower thrips(Frankliniella occidentalis). Twenty-two pesticides were testedincluding five fungicides, twelve insecticides and fiveacaricides. The fungicides captan, carbendazim, sulphur, thiram,tolylfluanid and the insecticides or acaricides pymetrozine,pyriproxyfen, tebufenozide and hexythiazox were harmless in the`worst case' laboratory test and thus did not need furthertesting. Imidacloprid, diafenthiuron, lufenuron, tebufenpyrad,abamectin, pyridaben and bifenthrin were harmful in thesemi-field test and should, in the tested concentrations, betternot be used simultaneously with the predatory bug. Theinsecticide dichlorvos was found harmful but short-lived in thepersistence test; it should be used before the introduction ofthe predatory bug O. laevigatus only when a safety period of 7days is respected. Pirimicarb was slightly toxic in thesemi-field test but short-lived. In IPM programs this aphicideshould be used at a low application frequency.     

Toxicities of 26 pesticides against 10 biological control species

To determine selective effectiveness for specific pesticides on biological control species we evaluated the contact toxicity of 16 insecticides, 2 acaricides, 3 fungicides, and 5 biopesticides. Targeted species included 3 predatory mites (Phytoseiulus persimilis Athias-Henriot, Amblyseius swirskii Athias-Henriot, and Neoseiulus californicus McGregor), 5 hymenopteran parasitoids (Diglyphus isaea Walker, Aphidius colemani Viereck, Encarsia formosa Gahan, Eretmocerus eremicus Rose and Zolnerowich and E. mundus Mercet), and 2 hemipteran predators (Orius laevigatus Fieber and Nesidiocoris tenuis Reuter) in laboratory condition. In addition, residual toxicity was evaluated on P. persimilis, E. formosa, and O. laevigatus. For contact toxicity, five insecticides (spinetoram, spinosad, lepimectin, chlorfenapyr, and dinotefuran + spinetoram) showed high toxicity to predatory mites. Most pesticides tested were highly toxic to all hymenopteran species except for D. isaea which showed low susceptibility to 11 pesticides. Bistrifluron + flubendiamide and B. valismortis were less toxic to A. colemani, and only B. valismortis was safe to both E. mundus and E. eremicus. Insect growth regulators (methoxyfenozide and bistrifluron), chlorantraniliprole, and bistrifuron + flubendiamide were not toxic to hemipteran predators. Fungicides and biopesticides were safe to hemipteran predators except for two biopesticides (B. subtilis and P. fluorescens). Most pesticides had low residual toxicity to P. persimilis, with the exception of chlorfenapyr whose toxicity persisted over 7 days. One insecticide (cyantraniliprole), 2 acaricides (spiromesifen and fenpyroximate), 1 fungicide (metrafenone), and 4 biopesticides (B. subtilis, P. polymyxa, P. fluorescens, and B. valismortis) showed a much lower residual toxicity to E. formosa. Eight insecticides, 2 acaricides, 3 fungicides, and 5 biopesticides showed low residual toxicity to O. laevigatus.     

Further non-target effects of citrus pesticides on Euseius addoensis and Euseius citri (Acari: Phytoseiidae)

A series of leaf-disc bioassays were conducted to determine the detrimental effect of field-weathered residues of various pesticides used on citrus in southern Africa on the adult females of two species of Eusei us (Wainstein). Acaricides, insecticides and stem- or soil-applied systemics were tested against E. addoensis (van der Merwe and Ryke). Fungicides were tested against E. citri (van der Merwe and Ryke) because it is the dominant predatory mite on citrus in the regions where most fungicides are used. The residual toxicity and persistence of most acaricides and fungicides were relatively low. Aldicarb was the only systemic product to cause more than 5% mortality. The most detrimental insecticides tested were cypermethrin, formetanate, fluvalinate, omethoate plus mineral oil and fipronil. Of the insect growth regulators tested, diofenolan was the most detrimental. All the fungicides suppressed fecundity whereas most of the systemic products stimulated fecundity. The other compounds had variable effects on fecundity.     

Reducing the impact of pesticides on biological control in Australian vineyards: pesticide mortality and fecundity effects on an indicator species, the predatory mite Euseius victoriensis (Acari: Phytoseiidae)

Laboratory bioassays on detached soybean, Glycine max (L.) Merr., leaves were used to test 23 fungicides, five insecticides, two acaricides, one herbicide, and two adjuvants on a key Australian predatory mite species Euseius victoriensis (Womersley) in "worst-case scenario" direct overspray assays. Zero- to 48-h-old juveniles, their initial food, and water supply were sprayed to runoff with a Potter tower; spinosad and wettable sulfur residues also were tested. Tests were standardized to deliver a pesticide dose comparable with commercial application of highest label rates at 1,000 liter/ha. Cumulative mortality was assessed 48 h, 4 d, and 7 d after spraying. Fecundity was assessed for 7 d from start of oviposition. No significant mortality or fecundity effects were detected for the following compounds at single-use application at 1,000 liter/ha: azoxystrobin, Bacillus thuringiensis (Bt) subsp. kurstaki, captan, chlorothalonil, copper hydroxide, fenarimol, glyphosate, hexaconazole, indoxacarb, metalaxyl/copper hydroxide, myclobutanil, nonyl phenol ethylene oxide, phosphorous acid, potassium bicarbonate, pyraclostrobin, quinoxyfen, spiroxamine, synthetic latex, tebufenozide, triadimenol, and trifloxystrobin. Iprodione and penconazole had some detrimental effect on fecundity. Canola oil as acaricide (2 liter/100 liter) and wettable sulfur (200 g/100 liter) had some detrimental effect on survival and fecundity and cyprodinil/fludioxonil on survivor. The following compounds were highly toxic (high 48-h mortality): benomyl, carbendazim, emamectin benzoate, mancozeb, spinosad (direct overspray and residue), wettable sulfur (> or = 400 g/100 liter), and pyrimethanil; pyrimethanil had no significant effect on fecundity of surviving females. Indoxacarb safety to E. victoriensis contrasts with its toxicity to key parasitoids and chrysopid predators. Potential impact of findings is discussed.     

Acaricide,Fungicide and Drug Interactions in Honey Bees (Apis mellifera)

Background

Chemical analysis shows that honey bees (Apis mellifera) and hive products contain many pesticides derived from various sources. The most abundant pesticides are acaricides applied by beekeepers to control Varroa destructor. Beekeepers also apply antimicrobial drugs to control bacterial and microsporidial diseases. Fungicides may enter the hive when applied to nearby flowering crops. Acaricides, antimicrobial drugs and fungicides are not highly toxic to bees alone, but in combination there is potential for heightened toxicity due to interactive effects.

Methodology/Principal Findings

Laboratory bioassays based on mortality rates in adult worker bees demonstrated interactive effects among acaricides, as well as between acaricides and antimicrobial drugs and between acaricides and fungicides. Toxicity of the acaricide tau-fluvalinate increased in combination with other acaricides and most other compounds tested (15 of 17) while amitraz toxicity was mostly unchanged (1 of 15). The sterol biosynthesis inhibiting (SBI) fungicide prochloraz elevated the toxicity of the acaricides tau-fluvalinate, coumaphos and fenpyroximate, likely through inhibition of detoxicative cytochrome P450 monooxygenase activity. Four other SBI fungicides increased the toxicity of tau-fluvalinate in a dose-dependent manner, although possible evidence of P450 induction was observed at the lowest fungicide doses. Non-transitive interactions between some acaricides were observed. Sublethal amitraz pre-treatment increased the toxicity of the three P450-detoxified acaricides, but amitraz toxicity was not changed by sublethal treatment with the same three acaricides. A two-fold change in the toxicity of tau-fluvalinate was observed between years, suggesting a possible change in the genetic composition of the bees tested.

Conclusions/Significance

Interactions with acaricides in honey bees are similar to drug interactions in other animals in that P450-mediated detoxication appears to play an important role. Evidence of non-transivity, year-to-year variation and induction of detoxication enzymes indicates that pesticide interactions in bees may be as complex as drug interactions in mammals.     

Use of pesticides for mass production of vesicular-arbuscular mycorrhizal inoculum

Nine fungicides, 3 nematicides and 5 insecticides/acaricides were incorporated into the pot cultures of the VAM fungusGlomus fasciculatum in order to study their effect on the mycorrhizal association and the contaminant organisms. All the pesticides were found to be deleterious to VAM at the recommended level. Captan and carbofuran, at half the recommended level (125 mg and 144.5 mg respectively/2.5 litre of the substrate mix), increased significantly the percentage root colonization, extra-matrical chlamydospore number and inoculum potential. Captan and carbofuran at this level also significantly suppressed the contaminant fungi and nematodes in the pot cultures ofG. fasciculatum. The insecticides/acaricides formothion and malathion at half the recommended level, had no deleterious effect onG. fasciculatum but suppressed mites and collumbola in pot cultures.     

Laboratory pesticide screening method for the aphid predatory midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae)

A laboratory pesticide screening method is described for the aphid predatory midge Aphidoletes aphidimyza. Four acaricides, 10 fungicides, 11 insecticides and one herbicide, all of which are in common usage, were evaluated against both the adult and larval stages of the predator. The acaricide dienochlor, the fungicides benomyl, bupirimate, chlorothalonil, iprodione and hexaconazole, the herbicide tralkoxydim and the insecticides Bacillus thuringiensis and diflubenzuron were all safe to both adult and larval A. aphidimyza. Adults were more susceptible to the pesticides than larvae. Pesticide was exposed to adults as a residue on glass plates and to larvae on a leaf section mounted on agar. The leaf material remained healthy and supported host aphids for several days without deteriorating. The method and apparatus have potential for use with many other pests and beneficial organisms required to be caged for several days on detached leaf material.     

Historical tests of the toxicity of pesticides to Typhlodromus pyri (Acari: Phytoseiidae) and their relevance to current pest management in New Zealand apple orchards 2. Short-term field tests

A two-part review is presented relating historical tests of the toxicity of pesticides to Typhlodromus pyri and their relevance to modern pest management in New Zealand pome-fruit orchards. Over the past 30 years, the initial need for T. pyri to be resistant to broad-spectrum pesticides has substantially declined as a growing array of new selective chemicals have come into use. In Part 2, a short-term field test is described for determining the toxicity of single applications of pesticides at recommended rates to European red mite (ERM), Panonychus ulmi, and its predator, an organophosphate (OP)-resistant strain of T. pyri on apples in New Zealand. For each pesticide, changes in mite density were measured from pre-treatment to 2, 7 and up to 25 days post-treatment compared with a water-sprayed control. Density was recorded and analysed for live adult and immature ERM, and live and dead eggs, larvae, nymphs and adults of T. pyri. Fifteen acaricides, 17 fungicides and 17 insecticides were evaluated. Chemicals more toxic to T. pyri than ERM were aminocarb, amitraz, binapacryl, chlordimeform, etrimphos, fenvalerate + azinphos-methyl, mancozeb + dinocap, methidathion, methiocarb, omethoate, oxamyl, pirimiphos-methyl and pyrazophos. Chemicals equally or less toxic to T. pyri than to ERM were acequinocyl, azocyclotin, benzoximate, bromopropylate, chlorpyrifos, clofentezine, cycloprate, cyhexatin, dinocap, mineral oil, propargite, triazophos and vamidothion. The remaining 23 chemicals (primarily fungicides and OP insecticides) had slight or no toxicity to ERM and T.pyri. The short-term field tests provided a useful guide to the long-term effects on ERM and T. pyri populations of almost all the pesticides. However, the potential disruptive effect of pyrazophos was not found in long-term field trials, and conversely, the apparently harmless dithiocarbamate fungicides were later shown to be highly disruptive when repeatedly sprayed, as in commercial practice. Most of the chemicals tested are no longer used in commercial pome-fruit orchards in New Zealand, all of which now practise integrated fruit production or organic fruit production based on selective pest management methods. The tested pesticides of continuing importance are identified and discussed with special emphasis on the current need to retest for dithiocarbamate resistance in T. pyri, some populations of which have been exposed to these compounds for up to 40 years. This and the changes in pesticide use in New Zealand are paralleled by similar developments in most pome-fruit growing areas of the world.     

Effects of greenhouse pesticides on the soil-dwelling predatory mite Stratiolaelaps scimitus (Acari: Mesostigmata: Laelapidae) under laboratory conditions

Knowledge of the effects of pesticides on biological control agents is required for the successful implementation of integrated pest management (IPM) programs in greenhouse production systems. Laboratory assays were conducted to assess the effects of an acaricide (dicofol), two insecticides (chlorpyrifos and pyriproxyfen), and two fungicides (fosetyl-Al and mefenoxam) on Stratiolaelaps scimitus (Womersley), a soil-dwelling predatory mite widely marketed in North America under the name Hypoaspis miles (Berlese) as a biological control agent of dark-winged fungus gnats (Bradysia spp.). Eggs, larvae, protonymphs, deutonymphs, and adult male and female mites were first assayed using dicofol, an acaricide used in the experiments as a positive control, applied to filter paper in an enclosed arena. Protonymphs were assayed for lethal and sublethal effects against the remaining pesticides at maximum label-recommended rates applied to filter paper, by using dicofol as a positive control and water as a negative control. The larva and protonymph were the life stages most susceptible to dicofol, with estimated 24-h LC50 values of 9 and 26 mg m(-2), respectively. Chlorpyrifos was highly toxic to the protonymphs of S. scimitus, causing >95% mortality after 24-h exposure and 100% mortality after 48 h. In contrast, the insect growth regulator (IGR) pyriproxyfen was much less toxic to protonymphs of S. scimitus; pyriproxyfen caused no significant mortality, compared with <5% mortality in the water control. Mortality caused by the fungicides was also relatively low; 72-h exposure to fosetyl-Al and mefenoxam resulted in 17.4 and 27.5% mortality, respectively. The IGR and fungicides increased the duration of the protonymphal stage by 1.2-1.8-fold, but they had no effect on the duration of subsequent life stages, nor on the duration of preoviposition, oviposition, and postoviposition periods of adult females. Total numbers and viability of eggs laid by mites exposed to the IGR and fungicides did not differ from the negative control, although the average rate of egg production during the oviposition of mites exposed to fosetyl-Al was increased. Pyriproxyfen, fosetyl-Al, and mefenoxam are likely to be compatible with S. scimitus under field conditions, because these pesticides caused little mortality of protonymphs, and they did not negatively affect the development and reproduction of S. scimitus under extreme laboratory conditions. In contrast, the use of chlorpyrifos in conjunction with S. scimitus is not recommended unless more comprehensive testing under semifield or field conditions demonstrates compatibility.     

Effects of 45 insecticides,acaricides and molluscicides on the rove beetleAleochara bilineata (Col.: Staphylinidae) in the laboratory

Effects of 45 insecticides, acaricides and molluscicides on adult females of the rove beetleAleochara bilineata were investigated in the laboratory. The pesticides were tested in concentrations equivalent to the highest recommended dosages for practical use. Mortality, egg production and hatch of the eggs were measured. The reproducibility of the test and the suitability of the strain ofA. bilineata used are discussed. The toxicity of the cholinesterase inhibitors tested was varying, but in general high. Only pirimicarb and acephate showed low toxicity. The pyrethroids tested were highly toxic, even though fluvalinate allowed a few eggs to be laid. The test did not give conclusive results for insect growth regulators. The ecological relevance of laboratory results is discussed, and it is concluded that only for pesticides with no or low toxicity can the results be used for prediction of effects in the field.     

11种常用农药对地熊蜂工蜂的毒性和风险评估

【目的】评估常用农药对地熊蜂Bombus terrestris的生态风险,为设施大棚合理施用农药提供科学依据。【方法】分别采用饲喂法和接触法测定了6种杀虫剂(虫螨腈、高效氯氟氰菊酯、氟吡呋喃酮、螺虫乙酯、异丙威和除虫脲)、3种杀螨剂(丁氟螨酯、唑螨酯和联苯肼酯)及2种杀菌剂(春雷霉素和啶酰菌胺)共11种常用农药对地熊蜂成年工蜂的急性经口和急性接触毒性,并评估其生态风险性。【结果】11种农药经饲喂法测定,对地熊蜂工蜂的急性经口毒性除高效氯氟氰菊酯、异丙威和虫螨腈为高毒,氟吡呋喃酮和唑螨酯为中毒外,其余药物均为低毒。经接触法测定,对地熊工蜂的急性接触毒性除高效氯氟氰菊酯和异丙威为高毒,虫螨腈为中毒外,其余药物均为低毒。生态风险评估表明,对地熊蜂工蜂而言,异丙威和高效氯氟氰菊酯的经口与接触毒性为中风险,氟吡呋喃酮、啶酰菌胺、除虫脲、唑螨酯、联苯肼酯、螺虫乙酯、春雷霉素、丁氟螨酯的经口与接触毒性为低风险;虫螨腈的经口毒性为中风险,接触毒性为低风险。【结论】在设施作物花期使用地熊蜂授粉时,建议禁用异丙威、高效氯氟氰菊酯和虫螨腈这3种存在中风险的农药,慎重使用氟吡呋喃酮和唑螨酯这2种农药,以避免对地熊蜂造成危害,而另外6种低毒农药可根据田间情况合理施用,并可采取通风晾晒、设置间隔期等方式降低农药对地熊蜂的生态风险。     

The susceptibility and resistance of fry and fingerlings of Oreochromis mossambicus Peters to some pesticides commonly used in Sri Lanka

The acute toxicity (48 hr LC₅₀) of seven herbicides, three acaricides and eight insecticides used in the Control of agricultural pests in Sri Lanka to the fry and fingerlings of Oreochromis mossambicus Peters were investigated in freshwater at 28–29°C under static laboratory conditions. The fry were more susceptible to the pesticides tested than were the fingerlings. Most of the pesticides tested induced severe behavioural changes in the exposed fish. Exposure to some herbicides and insecticides resulted in lateral and upward bending of the body, while higher concentrations of some pesticides caused excessive mucous secretions, rupturing of eyes and production of haemmorrhagic patches. Of the pesticides tested on fry and fingerlings, Ronstrar, Elsan and Endosulfan are the most toxic herbicide, acaricide and insecticide, respectively, while Basfapon, Rogor and Azodrin 60 are, respectively, the least toxic herbicide, acaricide and insecticide.     

Pesticide Susceptibility of Two Coccinellids (Stethorus punctum picipes and Harmonia axyridis) Important in Biological Control of Mites and Aphids in Washington Hops

The susceptibility of Stethorus punctum picipes (Casey) and Harmonia axyridis Pallas larvae to pesticides used or with potential for use in Washington hops, was examined in laboratory bioassays. All pesticides tested except the miticide, hexythiazox, the insecticides, chlorpyrifos and pirimicarb, and the fungicide, mycobutanil, produced 100% mortality in S. punctum picipes at concentrations equivalent to field rates. The insecticides, pirimicarb, endosulfan, and thiamethoxam were least toxic to H. axyridis. Bifenthrin, diazinon, dimethoate, methomyl, carbaryl, malathion, phosmet, imidacloprid, and chlorpyrifos were highly toxic. The miticides, abamectin and fenpyroximate were highly toxic, milbemectin was moderately toxic but all other miticides tested were non-toxic. All fungicides had low toxicity. Selection and use of pesticides compatible with natural enemies and conservation biological control in Washington hop production is discussed.     

Effect of Fungicides and Insecticides on Growth and Enzyme Activity of Four Cyanobacteria

Cyanobacterial populations introduced into crop fields as biofertilizer become non-target organisms for the pesticides and fungicides applied in the field. Effect of four commonly used pesticides viz. Bagalol, Mancozeb (fungicides), Thiodan and Phorate (insecticides) was studied on growth and different enzymes of four cyanobacterial species viz. Nostoc ellipsosporum, Scytonema simplex, Tolypothrix tenuis, and Westiellopsis prolifica. EC 50 concentration of each pesticide was determined for all cyanobacteria. Bagalol and Thiodan were found to be the most toxic. Both the fungicides and insecticides inhibited the activity of nitrogenase and glutamine synthetase (GS) at EC 50 concentration in all the four species studied. Bagalol incurred maximum inhibition of nitrogenase and GS activity on N. ellipsosporum and S. simplex while Thiodan and Phorate had maximum effect on T. tenuis, and W. prolifica. Mancozeb had lesser effect on all the above enzymes. One catabolic enzyme of carbohydrate metabolism, isocitrate dehydrogenase (ICDH) and one anabolic enzyme isocitrate lyase (ICL), which is related to glyoxylate pathway as well as gluconeogenesis, were also assayed. Cell free extracts of cyanobacteria treated with pesticides for 7 days show a drastic reduction of ICDH activity. ICL activity was induced in the organisms when treated with pesticides.     

Laboratory method for testing side-effects of pesticides on the rove beetleAleochara bilineata — Adults

Tests were conducted in glass cells containing moistened sand sprayed with the concentration recommended for the pesticide or with demineralised water (controls). Adult females (1–2 weeks old) ofA. bilineata were placed on the fresh residue in the cells and provided daily with fresh fly eggs as food. The duration of the test was 5 days, mortality being recorded every day. The side effects of the pesticide were expressed as reduction in egg production ofA. bilineata during the whole test period. Results permitted classification of the pesticides according to the 4 categories of harmfulness used by the IOBC working group. 23 pesticides were tested, and the reproducibility of the test appeared to be satisfactory. Generally, insecticides/acaricides had a pronounced effect on the beetles whereas fungicides and herbicides were less detrimental. Exceptions were the insecticides Tedion V 18 and Kilval, classified as harmless, and the fungicides Morestan, Pomarsol forte and Afugan rated as moderately harmful. Among growth regulators Prosevor 85 was highly detrimental while Cycocel Extra and Rhodofix had no effects. Excepting Morestan, Pomarsol forte and Ustinex PA the pesticides did not affect the hatching of eggs. The work was financed by the Danish Environmental Protection Agency.     

Does pollen availability mitigate the impact of pesticides on generalist predatory mites?

The effect of the provision of pollen on the impact of pesticides on the predatory mite Kampimodromus aberrans was assessed at individual and population levels. In the laboratory we evaluated the influence of pollen amount and pollen application frequency on lethal and sub-lethal effects of chlorpyrifos and spinosad. In a potted plant experiment, the effects of pesticides and pollen were assessed on predatory mite population abundance. In the laboratory, survival and fecundity of predatory mites were reduced by insecticides, and spinosad was more toxic than chlorpyrifos. In the same experiment, high pollen application frequency alleviated the sub-lethal effect induced by chlorpyrifos. On potted plants, pollen applications reduced the impact of chlorpyrifos on K. aberrans, whereas without pollen applications the impact of spinosad and chlorpyrifos on the predatory mite population was similar. Results obtained here highlight that the provision of fresh pollen is of particular importance for predatory mites when pesticides are applied.     

Side-effects of pesticides on the predatory bug Orius laevigatus (Heteroptera: Anthocoridae) in the laboratory

Laboratory trials were carried out in order to test the effects of 29 pesticides on the predatory bug, Orius laevigatus. To evaluate residual contact activity, newly moulted fourth instar nymphs of O. laevigatus were placed on treated Petri dishes and their mortality was checked after 7 days. The fecundity of surviving females was tested for 14 days. Young O. laevigatus adults were fed with eggs of Ephestia kuehniella, treated with the (above-mentioned) pesticides, to assess the effect of pesticides by ingestion. Adult mortality, female fecundity and egg hatching were recorded. Azadirachtin, granulosis virus products, mineral oil, pirimicarb, tebufenozide, clofentezine, hexythiazox and copper oxychloride had no significant effect on the survival and fecundity of O. laevigatus when predators were exposed to pesticide residues by contact or by ingestion. Triflumuron and diflubenzuron appeared to be harmless by contact, but diflubenzuron was slightly toxic when ingested. Buprofezin and teflubenzuron were slightly to moderately toxic, while hexaflumuron, flufenoxuron, and lufenuron showed a marked toxicity by contact as well as by ingestion. A number of organophosphates, endosulfan and deltamethrin were detrimental especially by contact. Imidacloprid was very toxic by contact but only slightly toxic when ingested. Indoxacarb and methoxyfenozide were less toxic than imidacloprid. These findings should be considered when releases of O. laevigatus are used in greenhouses or on outdoor crops.     

Toxicity of Pesticide Tank Mixtures from Rice Crops Against <Emphasis Type="Italic">Telenomus podisi</Emphasis> Ashmead (Hymenoptera: Platygastridae)

The use of insecticides, herbicides, and fungicides commonly occurs in mixtures in tanks in order to control phytosanitary problems in crops. However, there is no information regarding the effects of these mixtures on non-target organisms associated to the rice agroecosystem. The aim of this study was to know the toxicity of pesticide tank mixtures from rice crops against Telenomus podisi Ashmead (Hymenoptera: Platygastridae). Based on the methods adapted from the International Organisation for Biological and Integrated Control of Noxious Animals and Plants (IOBC), adults of T. podisi were exposed to residues of insecticides, herbicides, and fungicides, individually or in mixture commonly used by growers, in laboratory and on rice plants in a greenhouse. The mixture between fungicides tebuconazole, triclyclazole, and azoxystrobin and the mixture between herbicides cyhalofop-butyl, imazethapyr, imazapyr/imazapic, and penoxsulam are harmless to T. podisi and can be used in irrigated rice crops without harming the natural biological control. The insecticides cypermethin, thiamethoxam, and bifenthrin/carbosulfan increase the toxicity of the mixtures in tank with herbicides and fungicides, being more toxic to T. podisi and less preferred for use in phytosanitary treatments in the rice crop protection.     

Results of a joint pesticide test programme by the Working Group: Pesticides and Beneficial Arthropods

The side effect of 20 commercial pesticides (10 insecticides/acaricides, 6 fungicides, 4 herbicides) on 6 different beneficial arthropods was tested by members of the IOBC/WPRS Working Group “Pesticides and Beneficial Arthropods” in 3 countries. The tests were done according to standardized methods based on common rules, which, among others, emphasize the reduction of the beneficial capacity as the relevant parameter for evaluation. The beneficials tested were:Trichogramma cacoeciae Marchal,Pales pavida Meig.,Phygadeuon trichops Thomson,Leptomastix dactylopii (How.),Coccygomimus turionellae (L.) andChrysopa carnea Steph. The insecticidal biopreparation Dipel, the acaricide Torque, the fungicides Nimrod, Cercobin-M, Ortho Difolatan, the herbicides Betanal and Illoxan were harmless to slightly harmful to all the natural enemies tested. These chemicals should be examined further for their possible recommendation for integrated control. Other pesticides gave less favourable results. It is hoped that the results would help other WPRS Working Groups and plant protection advisers in the development of rational control programmes.     

Susceptibility of Various Stages of Trichogrammatoidea armigera Nagaraja to Some Pesticides and Effect of Residues on Survival and Parasitizing Ability

The toxicity, persistence and effect on parasitism of 10 insecticides, eight fungicides and one acaricide on Trichogrammatoidea armigera Nagaraja, an egg parasitoid of a Helicoverpa armigera (Hb), were investigated in the laboratory and under field conditions. At field recommended dosages, the fungicides oxycarboxin, copperoxychloride, streptomycin sulphate + tetracycline hydrochloride and 2‐bromo‐2‐nitropropane‐1,3‐diol and the acaricide dicofol were safe, while the insecticide phosalone and fungicide tridemorph were moderately toxic to adults. All other insecticides tested, namely dimethoate, fenitrothion, monocrotophos, phosphamidon, endosulfan, cypermethrin, decamethrin, fenvalerate and fluvalinate, and the fungicides carbendazim, methyl thiophenate and carboxin were toxic to adults. A high level of parasitism was recorded for all fungicide treatments and for dicofol and fluvalinate. The larval stage of the parasitoid was more tolerant than other stages. The residual toxicity of all fungicides, and dicofol, did not affect the ability of the parasitoid to parasitize its host, while the insecticides phosalone and fluvalinate were slightly persistent, favouring 44.7% and 49.3% parasitism after 15 days. Residues of dimethoate, decamethrin, cypermethrin, fenvalerate, monocrotophos and phosphanidon were moderately persistent, while fenitrothion and endosulfan were persistent.