A monitoring technique for resistance to biodegradable insecticides in the tobacco budworm (Lepidoptera: noctuidae) and the boll weevil (Coleoptera: curculionidae), and mechanisms of resistance to these insecticides /
A procedure involving the use of glass vials coated on their
| Main Author: | |
|---|---|
| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1994.
|
| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=741965601&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | A procedure involving the use of glass vials coated on their inner surface with insecticide was developed to monitor field populations of adult tobacco budworms, Heliothis virescens (F.) and the boll weevil, Anthonomus grandis grandis (Boheman) for resistance to biodegradable Residues of organophosphorus (chlorpyrifos, profenofos), grandis grandis (Boheman) for resistance to biodegradable insecticides. Residues of organophosphorus (chlorpyrifos, profenofos), carbamate (methomyl), and cyclodiene (endosulfan) insecticides in glass vials were depleted in 2 d at room temperature 25 ︢30C in daylight or in the dark. (methomyl), and cyclodiene (endosulfan) Residues of these compounds remained Residues of these compounds remained much longer (> 70 d) in vials pretreated with organic acids (benzoic or decanoic) or held in the freezer at temperature below -100C. The loss of toxicity was shown to be due mainly to hydrolytic degradation of the insecticide rather than to the volatilization.temperature below -100C. Holding the vials in the freezer eliminated breakdown by removing water vapor from the air. The addition of organic acid to the vials significantly extended stability of insecticide residues. Holding the vials in the Field monitoring data indicate that resistance to organophosphorus, carbamate, and cyclodiene insecticides is present among field populations of tobacco budworm and boll weevil in several agricultural areas of the United States and Mexico. Diagnostic concentrations needed to distinguish susceptible individuals from those that were eterozygous and homozygous for resistance were established. Comparative studies on profenofos toxicity with or without synergists indicated that enhanced metabolism was not an important mechanism of resistance to this insecticide. Differences between resistant and susceptible tobacco budworms in the inhibition of acetylcholinesterase by tetrachlorvinfos, methomyl, and carbaryl indicated that target site insensitivity was a major mechanism of resistance to organophosphorus and carbamate insecticides. The high correlation (r > 0.98) of survival of field tobacco budworm populations exposed to diagnostic concentrations of endosulfan and dieldrin suggested the same mechanism (target site) conferred resistance to both insecticides. Measurements of penetration of radiolabeled profenofos indicated that a decrease in insecticide uptake may be an additional resistance factor in the tobacco budworm. |
|---|---|
| Item Description: | Vita. "Major Subject: Entomology". |
| Physical Description: | xiv, 123 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |