| Effects of cypermethrin, dichlorvos, kaolin and ash, and their combinations on cowpea weevil Callosobruchus maculatus F. (Col.: Chrysomelidae) |
| Paper ID : 1285-3IICE (R1) |
| Authors: |
|
Roghaiyeh Karimzadeh *1, MinaMina Javanshir1, Mir Jalil Hejazi2 1Department of Plant Protection, Faculty of Agriculture, University of Tabriz, Tabriz, Iran 2University of Tabriz |
| Abstract: |
| Reduction in chemical residues in stored food commodities through the use of reduced dosages of less toxic chemicals is one of the main goals of post-harvest pest management programs. In this study the individual and combined effects of cypermethrin, dichlorvos, ash and kaolin was assessed on adults of Callosobruchus maculatus F. under laboratory conditions (30 ± 2° C, 65 ± 10% R.H. and 14: 10 (light: dark) h). The insects were exposed to the studied compounds on concrete surface prepared in plastic Petri dishes (9 cm in diameter). Dose ranges for different treatments were determined based on the preliminary experiments as follows: 760-2400 mg ai/L of cypermethrin, 700-3000 mg ai/L of dichlorvos, 25-70 gr/m2 of ash and 30-70 gr/m2 of kaolin. Bioassays consisted of five doses and a control, and were repeated three times at different days. Twenty adults of cowpea weevil (< 24 h) were released in each Petri dish, and their mortality was recorded 72 h after treatment. LC50/LD50 values estimated for cypermethrin, dichlorvos, ash and kaolin were 1286.96 mg ai/L, 1350.55 mg ai/L, 36.64 gr/m2 and 45.18 gr/m2, respectively. In order to evaluate the combined effects of treatments, LC25 of cypermethrin or dichlorvos was applied with LD25 of ash or kaolin. Percent mortalities of cypermetrin + ash, cypermetrin + kaolin, dichlorvos + ash and dichlorvos + kaolin were 80%, 76.66%, 43.33% and 35% respectively. These results indicate that the effect of simultaneous exposure to cypermethrin and ash or kaolin is more than sum of the individual effects of them. It means the toxic effect of cypermethrin was synergized by ash and kaolin. If similar treatments performed at larger scales give comparable results, it may be concluded that cypermethrin, dichlorvos, ash, kaolin and combination of cypermethrin with ash or kaolin can be used in cowpea weevil management programs. |
| Keywords: |
| Cypermethrin, Dichlorvos, Ash, Kaolin, Cowpea weevil |
| Status : Paper Accepted (Poster Presentation) |
