Azinphos-methyl Residues Research Articles

PESTICIDE RESIDUES ON FRESH AND PROCESSED VEGETABLES

A research project was undertaken in 1990 with the objective of improving both quality and productivity of peas, beans and sweet corn grown and processed in Quebec (Canada). It was conducted with the technical and financial help of five proccessing companies. Cultivar trials were undertaken as part of this project together with an evaluation of commercial practices in the areas of pest control, fertilization and crop management. Samples of fresh and processed products were analysed for nutritional quality and pesticide residues. During this presentation we will show preliminary results of the pesticide residue analyses and will compare fresh and processed products. So far, determination of dimethoate, trifluralin and bentazone (peas), azinphosmethyl and permetrin (beans) and cypermetrin (sweet corn) showed no concentration exceeding the Canadian norm (<0, 1mg/kg), with the exception of a bean field with azinphosmethyl residues. Canning and freezing operations greatly reduced pesticide residues so that all processed samples tested below detectable levels.

Toxicity of Pesticides Used on Walnuts to a Wild and Azinphosmethyl-Resistant Strain of Trioxys pallidus (Hymenoptera: Aphidiidae)

Effects of azinphosmethyl, chlorpyrifos, endosulfan, methidathion, or phosalone on a wild and a laboratory-selected strain of Trioxys pal/idus Haliday were tested. A clip cage was used to confine insects on walnut foliage treated in the field. Mortality of adults was assessed after 4, 8, 18, 24, 48, and 72 h at 27 ± 1.5°C. Residues ranged from 1 to 35-d-old. One-day-old residues of chlorpyrifos were the most toxic to the wild colony; 1-d-old residues of azinphosmethyl, methidathion, phosalone, and endosulfan were progressively less toxic. Azinphosmethyl residues remained more toxic to both colonies for the longest time of any of the pesticides tested. Methidathion residues were toxic to the wild colony after 28 d (survival at 72 h, 56%), but survival of the Selected strain on 14-d-old residues was 94% even after 72 h of exposure. Residues of phosalone and endosulfan exhibited low toxicity (survival >86%) to both strains after 14 d. The azinphosmethyl-selected strain of T. pallidus survived all pesticide residues significantly better than the wild strain (except the 14-d-old endosulfan residues, on which both survived equally well), indicating that cross-resistances developed through artificial selection with azinphosmethyl. Implications of the new azinphosmethyl-resistant strain of T. pallidus for walnut pest management and orchard management are discussed.

Effects of Surface Residues of Azinphosmethyl on Apple Maggot Behavior, Oviposition, and Mortality1

Two types of laboratory bioassays were conducted to determine the quantitative effects of surface residues of azinphosmethyl on the behavior, oviposition, and mortality of the apple maggot (AM), Rhagoletis pomonella (Walsh). In one bioassay, groups of AM females were continuously exposed to uniform residues for various time periods by confining them in a glass sphere coated with azinphosmethyl. At the recommended rate (313 ppm AI), 39% of the flies died after only 5 min of exposure, and 92% mortality occurred after 20 min. The results of this test were fit to a dynamic model of insecticide effectiveness. In a second bioassay, single females were caged for 48 h on apples coated with the insecticide. The insects were observed less frequently on fruit with increasing residues, and oviposition was reduced even on apples with sublethal levels of insecticide. Equations were developed from these two studies to predict AM mortality and oviposition inhibition resulting from different residues of azinphosmethyl on apples.

A NEW APPROACH TO SAN JOSE SCALE CONTROL (HEMIPTERA: DIASPIDIDAE)

AbstractA laboratory experiment demonstrated that in San Jose scale, Quadraspidiotus perniciosus (Comstock), the male is susceptible to a number of insecticides. Diazinon was the most effective as it killed the males before they emerged from their shells. Males emerged and survived for a short time before being killed by residues of azinphosmethyl and endosulfan. In an orchard, a petal fall spray of diazinon or Penncap E applied when male scales started to emerge gave good control of San Jose scale and was as effective as three summer sprays of diazinon timed to emergence of crawlers. Penncap E was ineffective against the crawlers. Post-bloom sprays are necessary to control infestations of incrusted scale because a pre-bloom oil application usually fails to contact live scale that may be underneath one or more layers of old dead scale.

Pesticide residues and greedy scale control on kiwifruit

Abstract Experimental sprayings of kiwifruit vines with azinphos-methyl, diazinon, and omethoate were carried out in 1973 and with azinphos-methyl in 1974. Repeated azinphos-methyl applications gave virtually scale-free leaves and fruit at harvest. Residues of azinphos-methyl and omethoate were unusually high immediately after spraying (up to 18 mg/kg and 11 mg/kg respectively) and residues from some treatments remained above the relevant New Zealand maximum residue limits (MRL) (2 and 0.5 mg/kg) for in excess of 5 weeks. Diazinon residues were lower and decayed to below the New Zealand MRL within 10 days. The surface hair on the fruit contributed significantly to the high azinphos-methyl residues.

Persistence of Foliar Residues of Dimethoate and Azinphosmethyl and Their Toxicity to the Apple Maggot12

Field tests indicated that dimethoate was more toxic than azinphosmethyl to adults of Rhagoletis pomonella (Walsh) caged on sprayed foliage. Based on probit analysis using foliar residues, the LC50 for dimethoate was 2–10 times less than that for azinphosmethyl. Time till 50% kill (ET50) was 5–10 days longer for dimethoate than for azinphosmethyl. EC formulations were not effective longer than wp formulations. Initial deposits of azinphosmethyl on foliage were higher than those of dimethoate regardless of formulation used. Highest initial deposits occurred when the EC formulation of azinphosmethyl was applied. Loss of residues from foliage closely fitted a 3 parameter asymptotic regression curve with the equation Y = A + BRx, where Y is the amount of residue remaining at time X, A is the asymptote of Y, B is the scaling constant, and R is the rate of degradation. Although azinphosmethyl residues persisted at higher levels than dimethoate throughout, the rate of loss was similar for each compound, regardless of formulation used.

Dislodgeable azinphosmethyl residues from air blast spraying of apple foliage in Ohio.

The distribution and decay rates of dislodgeable residues of azinphosmethyl applied by two types of air blast sprayers on apple foliage in Ohio were investigated. Leaf discs were taken from nine sites located on the periphery of Cortland apple trees at five dates after spraying. The sprayer delivering the higher airflow rate, but lower velocity, deposited the pesticide much more uniformly over the trees and applied more in the top of the tree. The other sprayer deposited the greatest proportion of pesticide on the site nearest the sprayer. The residue decreased at all sites and ranged from 42 to near 100% decrease at 14 days after spraying.

Susceptibility of Chrysopa rufilabris1 to Selected Insecticides and Miticides2

Two days after moulting to the 3rd instar, larvae of Chrysopa rufilabris Burmeister were exposed to technical and commercial formulations of 5 pesticides. Technical pesticides in decreasing order of toxicity to C. rufilabris larvae were: azinphosmethyl, carbaryl, ethion, carbophenothion, and chlorobenzilate. Residues of commercial azinphosmethyl 2 EC and carbaryl 50% WP had high and medium toxicity, respectively. Ethion + oil, carbophenothion 2 EC, and ethion 4 EC had low toxicity, while chlorobenzilate 25% EC had 0 toxicity. Azinphosmethyl and carbaryl residues were toxic up to 22 days postapplication. Ethion + oil, carbophenothion, and ethion showed 0 toxicity after 6 days.

Chrysopa rufilabris: Effect of Selected Pesticides on Duration of Third Larval Stadium, Pupal Stage, and Adult Survival

Technical and commercial preparations of chlorobenzilate, azinphosmethyl, carbophenothion, ethion, and carbaryl were tested against larvae of Chrysopa rufilabris Burmeister two days after they molted to the third instar. The third larval stadium was significantly lengthened in individuals which survived topical treatment with azinphosmethyl, ethion, carbophenothion, and carbaryl, whereas chlorobenzilate and one-day-old residues of all commercial pesticides had little prolonging effect. The pupal stage was significantly prolonged by commercial ethion and ethion + oil as well as by topical applications of all technical pesticides except chlorobenzilate. Emergence was lowest among individuals topically treated with azinphosmethyl and carbaryl and highest with chlorobenzilate. In decreasing order, residues of commercial azinphosmethyl, carbaryl, ethion + oil, ethion, carbophenothion, and chlorobenzilate reduced the numbers of individuals surviving to adulthood.

Toxicity of Several Commonly Used Orchard Pesticides to Adult Hippodamia convergens1 , 2 , 3

The toxicity of ½ and full recommended orchard dosages of 8 pesticides to Hippodamia convergens Guérin-Méneville was assessed in the laboratory and the field. Endosulfan and binapacryl and the low dosage of oxythioquinox allowed 50% or greater survival of nondiapausing adults when sprayed directly upon the beetles in the laboratory. The higher dosage of oxythioquinox and both dosages of DDT allowed only 21–29% survival at 72 hours. Diazinon, carbaryl, parathion, and azinphosmethyl were highly toxic, allowing no survival after 6 hr. Essentially 100% mortality of nondiapausing adults resulted after 48-hr exposure in the laboratory to the residues of all 8 pesticides. In orchard tests, the low dosages of endosulfan, binapacryl, oxythioquinox, and DDT allowed 64% or greater survival of adults after 7 days' exposure to residues on peach foliage. Both the high and low dosages of diazinon and carbaryl were highly toxic through 7 days'. exposure but some beetles survived after exposure to 8- to 14-day-old residues. Residues of azinphosmethyl and parathion were highly toxic with no adults surviving after 7 or 14 days. Log dosage-probit curves for topical application of these pesticides with diapausing adults show a wide range of response, With LD 50 values from 0.005μg per beetle With azinphosmethyl to 5.5μg per beetle with binapacryl. The order of toxicity was azinphosmethyl>parathion>carbaryl>diazinon>DDT>endosulfan>binapacryl.

Extraction Efficiency Study—Examination of Three Procedures for Extracting 14C-Labeled and Unlabeled Residues of Organophosphorus Pesticides and Carbaryl from Bean Leaves and Kale

Abstract Two rapid extraction procedures which consist of sample blending with ethyl acetate or acetonitrile and an exhaustive Soxhlet extraction procedure using 10% methanol in chloroform were tested for efficiency of extraction of 14C-labeled residues of carbaryl, malathion, and phosphamidon on laboratory-grown and treated bean plants. The extraction procedures were also tested on field-treated kale containing 7–11 day old residues of azinphosmethyl, parathion, and malathion. The extraction efficiencies of the 3 procedures were in very close agreement for all residues in both studies. More than 90% of the 14C-containing residues were extracted from treated bean leaves. The extraction efficiencies for field-weathered residues on kale were judged to be essentially 100%, since several hours of additional Soxhlet extraction did not remove any more residue.

A modification of Miles' method for determining azinphos-methyl residues in crops.

Meagher's, Bluman's and Miles' methods for determining azinphosmethyl residues were assessed on a range of crops. Some shortcomings were encountered with the three methods and, to overcome them, a modification of Miles' method, involving the use of acetone extraction, is proposed and evaluated. The cleaned-up extract can also be used in an established chromatographic identification procedure.

Polarographic determination of azinphos-methyl residues in certain crops

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