thiophanate and cyhalothrin

Although reptiles are non-target organisms of pesticide applications, their ecological niche and trophic role suggest that the use of these compounds in agriculture can have toxicological effects on them. Our recent field study on Italian wall lizard Podarcis siculus in hazelnut orchards evidenced that the use of pesticides-mixtures, consisting of thiophanate-methyl (TM), tebuconazole (TEB), deltamethrin (DM), lambda-cyhalothrin (LCT), besides copper sulphate, induced an increase of the total antioxidant capacity toward hydroxyl radicals and caused DNA damage; however, it did not cause neurotoxicity, and did not induce the glutathione-S-transferases' activities. These results raised some questions which were answered in this study by carrying out analyses on 4 biomarkers and 5 chemical substances in the tissues of non-target organisms coming from treated fields: cytochrome P450, catalase, total glutathione, and malondialdehyde, TM, TEB, DM, LCT and Cu. Our results highlighted a partial accumulation of different chemicals, the involvement of two important mechanisms of defence, and some cellular damages after exposure to the considered pesticides. In details, 1) LCT and DM were not accumulated in lizard muscle, copper remained at basal levels, whereas TM and TEB were uptaken with a partial metabolization of TM; 2) the cytochrome P450 and the catalase were involved in lizard biochemical responses to pesticides-mixtures used for "conventional" farming treatment; 3) "conventional" treatment with pesticides caused damage to lipids, besides DNA, probably related to the excess of hydroxyl radicals.

Topics: Animals; Catalase; Glutathione; Lizards; Pesticides; Thiophanate

Cotton hardlock caused by Fusarium verticillioides (Sacc. Nirenberg) can reduce cotton, Gossypium hirsutum L., yields > 70% in the southeastern United States. The spores infect flowers on the day of pollination, resulting in hardlock, which is the failure of the fiber to fluff as the boll opens at maturity. Frankliniella spp. Thrips (Thysanoptera: Thripidae) inhabiting the flowers are hypothesized to increase hardlock by spreading the conidia or by creating entranceways for the germinating Fusarium conidia. Experiments were conducted at Marianna and Quincy in Florida in 2006 and 2007 to determine whether there was a relationship between the number of adult and larval thrips inhabiting the flowers of cotton and the incidence of cotton hardlock. Frankliniella tritici (Fitch) was > 98% of the adult thrips in the samples at both locations each year. The adults of Frankliniella bispinosa (Morgan) and Frankliniella occidentalis (Pergande) also were collected. There were no significant regression relationships between weekly mean densities of thrips in the flowers and the incidence of cotton hardlock at harvest in any of the experiments. Additional experiments were conducted at each location in 2006 and 2007 to determine whether weekly applications during flowering of the insecticide lambda-cyhalothrin, the fungicide thiophanate methyl, and the combination of the two reduced the incidence of cotton hardlock at harvest. Applications of the insecticide significantly reduced the numbers of adult F. tritici, the number of thrips larvae, and the incidence of hardlock at harvest. Applications of the insecticide were as affective as applications of the insecticide plus fungicide. In one experiment, applications of the fungicide reduced the incidence of hardlock at harvest. Applications of the insecticide usually significantly increased the number of adult F. occidentalis. None of the pesticide treatments significantly affected the numbers of the key thrips predator Orius insidiosus (Say). We conclude that insecticidal control of the adults and larvae of F. tritici during flowering reduced the incidence of cotton hardlock. However, there were no significant regression relationships between the incidence of cotton hardlock at harvest and the number of thrips in the flowers.

Topics: Animals; Fungicides, Industrial; Fusarium; Gossypium; Host-Parasite Interactions; Insect Control; Insecta; Insecticides; Nitriles; Plant Diseases; Population Density; Pyrethrins; Regression Analysis; Southeastern United States; Thiophanate