Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Effect of Insecticides on Soil Microorganisms and Natural Enemies in Rice Field

Dr. Mainul Haq
CSO and Head
Entomology Division, BRRI, Gazipur-1701

Md. Nazmul Bari
SSO
Entomology Division, BRRI, Gazipur-1701

Md. Shahjahan Kabir
SSO
Plant Pathology Division, BRRI, Gazipur-1701

Abstract/ Executive Summary:

Three commonly used insecticides, i. e., carbofuran 5G, diazinon 10G, chlorpyriphos 20EC were applied in BRRI farm Gazipur during T. Aman 2007 and Boro 2008-09 to see the insecticidal effect on natural enemies and soil microorganism. Application of insecticides at 45 DAT affected natural enemy population. Azotobacter colony varied with sampling time and the highest colony was found at 60 DAT.

Keywords: Insecticide, Soil microorganism, Natural enemy, Azotobacter

Location: BRRI, Gazipur

Start Date: 01-07-2007

End Date: 30-06-2008

Program Area: Pest Management

Commodity: Rice

Objectives:

To determine the effect of insecticides on soil microorganisms present in soil and on natural enemies of rice insect pests.

Methodology:

Two experiments with three commonly used insecticides, carbofuran 5G, diazinon 10G, chlorpyrifos 20EC and an untreated control were designed in RCB with four replications during T. Aman 2007 and Boro 2008. The unit plot size was 5m X 8m. The insecticides were applied at recommended rate. Two applications of insecticides at 30 DAT and 45 DAT were administered in each season. Natural enemy population was estimated by direct hill count (20 hill/plot) before and after three days of insecticide application. Soil sample were collected five times at 29, 33, 48, 60 and 75 DAT from the treated and untreated plots (control) covering 0-15 cm soil depth. During Boro 2007. Azotobacter colony was counted by dilution plate method using Jensesen’s medium (Nitrogen free medium).

Source of Information: Proceedings of BRRI Annual Internal Review, 2007-08

Article Link (Online Journal):

Funding Source:

1. Government

Budget:

Total Budget (Tk.) :

Achievement/Findings:

Effect on natural enemies: Overall populations of natural enemies were very low. Most commonly found natural enemies were spider, ladybird beetle, damsel fly and staphylinid beetle. Ladybird beetle and staphylinid beetle were not found at 30 and 45 DAT respectively in Boro season. Damselfly and spider population were found highest at 30 and 45 DAT respectively in T. Aman season. Natural enemies were not affected after application of insecticides at 30 DAT in both the season. But population decreased after application of insecticide at 45 DAT in both the season. Effect on soil microorganisms: Average number of Azotobacter colony was 7.8 x 1012, 5.02 x 1012, 9.1 x 1011, and 1.1 x 1012 per gm soil in carbofuran, diazinon, chlorpyrifos and untreated control respectively. Only chlorpyrifos showed less number of colonies than the untreated treatment. Colony number varied with the sampling time. Colony number was higher in all treatment at 60 DAT.

Knowledge Management: Report/Proceedings