Naled

Abstract: During 1962–63 cane-fiber squares saturated with a solution of methyl eugenol-3% naled (by volume) and dropped from the air or suspended from trees eradicated a heavy infestation of oriental fruit flies, Dacus dorsalis Hendel, from the semi-isolated 33-square-mile Island of Rota, Mariana Islands. Most of the squares were dropped at 2-week intervals from an airplane flying over lines 1/5 mile apart. In inhabited areas permanent bait stations, re-treated monthly, were suspended from trees in lieu of aerial drops. Only 3.4 g of toxicant/acre were required for the entire operation. Male fly populations declined 99.6% within 1 generation. Virgin, sexually mature females were attracted and killed by the lure, but only after the male population was depressed 99%. Virgin females constituted 93% of flies caught in the 4th month; this response may have increased the efficiency of the method. Fly catches and fruit infestations ceased during the 6th month. The island has been free of oriental fruit flies for more than 24 months.

Abstract: Oriental fruit flies, Bactrocera dorsalis (Hendel), were treated with 10 insecticides, including six organophosphates (naled, trichlorfon, fenitrothion, fenthion, formothion, and malathion), one carbamate (methomyl), and three pyrethroids (cyfluthrin, cypermethrin, and fenvalerate), by a topical application assay under laboratory conditions. Subparental lines of each generation treated with the same insecticide were selected for 30 generations and were designated as x-r lines (x, insecticide; r, resistant). The parent colony was maintained as the susceptible colony. The line treated with naled exhibited the lowest increase in resistance (4.7-fold), whereas the line treated with formothion exhibited the highest increase in resistance (up to 594-fold) compared with the susceptible colony. Synergism bioassays also were carried out. Based on this, S,S,S-tributyl phosphorotrithioate displayed a synergistic effect for naled, trichlorfon, and malathion resistance, whereas piperonyl butoxide displayed a synergistic effect for pyrethroid resistance. All 10 resistant lines also exhibited some cross-resistance to other insecticides, not only to the same chemical class of insecticides but also to other classes. However, none of the organophosphate-resistant or the methomyl-resistant lines exhibited cross-resistance to two of the pyrethroids (cypermethrin and fenvalerate). Overall, the laboratory resistance and cross-resistance data developed here should provide useful tools and information for designing an insecticide management strategy for controlling this fruit fly in the field.

Abstract: The development of permethrin resistance and its effect on existing resistance toward DDT, methomyl, and three organophosphates were examined in a strain of the house fly, Musca domestica L. (Diptera: Muscidae). This strain was collected from a dairy near Horseheads, N.Y., after 4 years of localized permethrin spraying during which time no increase in permethrin resistance (from the basal level of 1.8-fold) was detected. Under laboratory selection, resistance to permethrin developed rapidly, attaining a 5,945-fold level by generation F22. Additionally, resistance to naled, methomyl, DDT, and dichlorvos significantly increased ( P ≤ 0.05) following permethrin selection, indicating that pressure by this insecticide can enhance further the existing cross- and multiple-resistance in the strain.

Abstract: Trace residues of organophosphorus (OP) pesticides are associated with fruits and vegetables that have been sprayed with those OP pesticides to guard against insect pests. Human dietary exposure to these OP pesticides is commonly estimated by measuring the amount of OP metabolites in urine, assuming a stoichiometric relationship between a metabolite and its parent insecticide. Dialkylphosphates (DAPs) are the OP metabolites that are most often used as markers in such biomonitoring studies. However, abiotic hydrolysis, photolysis, and plant metabolism can convert OP chemicals (OP residues) to DAP residues on or in the fruits and vegetables. To evaluate the extent of these conversions, OPs and DAPs were measured in 153 produce samples. These samples from 2 lots were known to contain OP insecticide residues based on routine monitoring by California producers and shippers. A total of 12 OPs were quantified, including mevinphos, naled, acephate, methamidophos, oxidemeton-methyl, azinphos-methyl, dimethoate, malathion, methidathion, phosmet, chlorpyrifos, and diazinon. All OP insecticide residues were below their respective residue tolerances in 2002-2004. A total of 91 of 153 samples (60%) contained more DAP residues than parent OPs. The mean mole fractions [DAPs/(DAPs + OPs)] for the first and second lots of produce were 0.62 and 0.50, respectively, and the corresponding geometric means were 0.55 and 0.34. The corresponding mean mole ratios (DAPs/OP) were 7.1 and 3.4, with geometric means of 2.1 and 0.9. Any preformed DAPs ingested in the diet that are excreted in urine may inflate the estimated absorbed OP insecticide doses in occupational and environmental studies. In subsequent prospective studies, time-dependent production of dimethylphosphate (DMP) and dimethylthiophosphate (DMTP) in strawberries and leaves following malathion sprays occurred concomitant with the disappearance of the parent insecticide and its oxon. DAPs are more persistent in plants and produce at routinely measured levels than their parent OP insecticides.