The sequencing of several nematode and insect genomes has accelerated our understanding of the molecular and functional diversity of gene family members and their functional roles. The nicotinic acetylcholine receptor (nAChR) gene families, members of which mediate fast synaptic transmission and serve as targets for human and anthelmintic drugs as well as insecticides, are of considerable interest. Genomes of the free—living nematode and genetic model organism, Caenorhabditis elegans as well as the parasitic nematode Brugia malayii have been sequenced. Following the sequencing of the genome of the fruitfly Drosophila melanogaster, genomes are now available for the malarial vector Anopheles gambiae, the stored agricultural products pest Tribolium castaneum, a species of considerable agricultural benefit, the honeybee Apis mellifera, and other insects. Some nematode nAChR families are among the largest nAChR families known with many subunit isoforms, whereas insect nAChR families are often more compact. However, alternative splicing and RNA editing can ensure an equally rich molecular diversity of insect nAChRs. Subunits making up the L-type nematode levamisole-sensitive nAChR and the N-type nicotine-sensitive nAChR have now been identified and functionally expressed. Imidacloprid-sensitive nAChRs have also been expressed using hybrid receptors containing insect α subunits. Such studies are enhancing the prospects of receptor target-based screening for new animal health drugs and agricultural products.

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Biomimetic oxidation of a trans isomer of permethrin, fenvalerate, together with the corresponding chrysanthemic acid and alcohol moieties was conducted using catalytic amounts of six iron-porphyrins having different substituents, not only at β- and meso-positions but also the axial ligand of iron in the presence of hydrogen peroxide or meta-chloroperbenzoic acid as an oxidant. The several degradation products via cleavage of ester and ether linkages and hydroxylation were identified and some were found to be in vivo metabolites previously reported in plants, animal and insects. The introduction of electron-withdrawing substituents at β- and meso-positions of a porphyrin ring resulted in higher conversion and the weak electron donor as the axial ligand of iron was found to increase the oxidative reactivity of porphyrin.

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Ninety formulations of neem oil (Azadirachta indica), N1; nicotinic acid, N2; and Ferula asafoetida, N3 at different concentrations with α, β-unsaturated carbonyl compounds (1a–1i), were screened in vitro against Sclerotium rolfsii ITCC 5226 and Macrophomina phaseolina ITCC 0482 following the Food Poisoning Method. Formulation 3 : 1,1a-N2(−) was found to be the most effective against S. rolfsii, enhancing the activity of 1a 2.7 times at 66 ppm, whereas 3 : 1,1f-N3 was found to be 5 times more active against M. phaseolina than 1f alone. A number of other formulations also showed significant synergistic effect in increasing fungicidal activity. The current study showed that the combination of synthetic and natural products may be an effective novel alternate approach to control pathogenic fungi.

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Insecticides are the primary means of controlling mosquitoes in Turkey, especially Culex pipiens and Anopheles maculipennis complex species. To better understand how the resistance status affects the success of vector control programs, we investigated the level of resistance of strains collected from seven localities to 4 larvicides (temephos, fenthion, Bacillus thuringiensis israilensis (Bti), and Bacillus sphaericus (Bs)) and 4 adulticides (DDT, malathion, deltamethrin, and permethrin) that are registered (except DDT) and are used heavily in mosquito control programs in Turkey. High levels of resistance were found to temephos in the Birecik, Viransehir, Mersin, Ankara, and Antalya strains, and we found resistance to fenthion in the Birecik, Mersin, Cankiri, and Antalya strains. Resistance levels to other larvicides (Bti and Bs) and strains (to temephos and fenthion) were less than 10-fold. We determined low mortality rates with the diagnostic dosage of DDT in all strains. Birecik and Viransehir mortality rates were lower than 30%. The diagnostic dosage mortality rates of the other adulticides varied widely (65.8% malathion Antalya, and 97.5% malathion Birecik, and deltamethrin Hatay) but Ankara and Antalya strains appeared to be resistant to all adulticides tested. The other strains were placed in the surveillance category according to the WHO categorization. Diagnostic dosage experiment results revealed that DDT resistance exists in all populations, although this insecticide has not been used for 30 years in Turkey. Our results indicated that Bti and Bs are very effective control agents for larval control while permethrin and deltamethrin are effective for adult control.

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A simple and rapid screening method of 95 acidic pesticides in agricultural products was developed. As acidic pesticides adsorb on the primary secondary amine mini-column with fatty acids which become interfering peaks during GC/MS analysis, they were not included in multi-residue analysis entailing PSA clean-up. In this study, the intermediate extracted solutions before PSA clean-up were analyzed by LC/TOF-MS. Accurate mass measurement of TOF-MS enabled the detection of molecular ions and fragment ions with high selectivity. Mean recoveries of 95 pesticides added to 6 agricultural products at 0.1 μg/g were 49–127% with RSD <20%. Limits of quantitation were 0.01–0.02 μg/g for 95 pesticides. The method was applied to 140 samples, and 2,4-D from lemon and orange, fluazifop from baby kidney bean, dichlorprop from apple were detected, respectively, at 0.02–0.03 μg/g below MRLs. The proposed method showed good sensitivity for 95 acidic pesticides and enabled rapid screening in combination with our multi-residue method targeted to 520 pesticides.

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An improved simulation model for predicting pesticide behavior in paddy fields based on PADDY was developed to include photoisomerization and metabolic pathways and applied to the herbicide pyriminobac-methyl. Isomerization of pyriminobac-methyl in paddy water by sunlight was modeled as a reversible first-order reaction between the (E)- and (Z)-isomers in response to UV-B irradiation. The formation and degradation of its main metabolites in flooded soil were expressed as consecutive first-order reactions. The model was validated by comparing calculated values with measured values from paddy lysimeter and field experiments. The improved PADDY model successfully simulated changes in the concentrations of pyriminobac-methyl and its metabolites over time under paddy conditions.

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Insecticide toxicity is commonly evaluated for disease vectors by either the WHO test or Bottle assay. More recently, a high-throughput screening (HTS) system was developed for testing insecticide effects on mosquito behavior and mortality. We compared HTS with the Bottle assay to evaluate the toxicity of insecticides in a population of Aedes aegypti from Thailand. Both the HTS and Bottle assay system were determined to be equivalent. The two systems mainly differed (1) in reaction time, with mosquitoes reacting faster in the Bottle assay than HTS, (2) in knock-down and mortality at low doses. This information will guide the testing protocol for evaluating chemical effects on behavioral responses in various vector populations.

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