00000caa a22000003i 4500 UP-1685594773862388093 Buklod 20210226185458.0 m | | ta 210226s1985 xx r |||| u|eng d (iLib)UPBAG-00039347583 STII-DOST BAG rda eng ARTICLE-2353 Santos, Flora L. author. DDT resistance in three local populations of rice weevils by Flora L. Santos and Clara Y. Lim-Sylianco. 1985. pages 151-164 illustrations 26 cm text rdacontent unmediated rdamedia volume rdacarrier This Article/Publication is available upon request to NAST/the Author Address: 3rd Level Philippine Science Heritage Center DOST Complex, Bicutan, Taguig, 1631 Metro Manila Direct Lines: (632) 838-77-39/66/92 Trunklines: (632) 837- 2071 to 82 ext. 2170-75 FAX No.: (632) 837-3170 E-mail: secretariat@nast.ph Includes bibliographical references (page 157) and index. The relationship between DDT resistance and dehydrochlorination of DDT by three local populations of rice weevils was studied. In-vitro studies showed that DDE formation increased with increasing resistance to DDT. Variation in the amount of DDE fromed from a fixed dose of DDT was also observed in the presence of several modifier compounds. Treatment with phenobarbital could activate as well as inhibit the transformations of DDT to DDE in the rice weevils tested. The most pronounced effect on DDT dehydrochlorinase activity was the activation of the enzyme in both the A and the F strains of rice weevils exposed for 22 hours to the DDT-phenobarbital mixture. Inhibition by phenobarbital was alos observed in weevils pretreated for 24 hours with the modifier compound. Piperonyl butoxide and carbaryl exerted predominantly inhibitory effects on DDT dehydrochlorinase although a slight increase in enzyme activity was detected in weevils with piperonyl butoxide 24 hours before DDT application. At 18 hours treatment with DDT-modifier compound mixture, only small changes in DDT dehydrochlorinase activity were obtained. At 27 hours treatment with the modifier compounds, the inhibitory effects of piperonyl butoxide and of carbaryl were still observed. In phenobarbital-treated weevils, however, enzyme activity had returned to normal levels. Agriculture. Rice weevils Pesticide resistance. Lim-Sylianco, Clara Y. author. The Philippine Journal of Science Vol. 114, nos.3-4, July-December 1985. Request full-text access via UPB University Library through https://forms.gle/KZjBv7aRtY6jiL5E9 (viewed 26 February 2021) FI UPBAG UPBAG-MAIN ARTICLE-2353 Analytics