Population dynamics of spotted stem borer, Chilo partellus (Swinhoe) and its interaction with natural enemies in sorghum

K Divya

doi:10.17485/ijst/2010/v3i1.3

Abstract

Sorghum stem borer, Chilo partellus Swinhoe is one of the serious pests of sorghum and maize crops in Asia and throughout East and South Africa. In India, it is becoming as the most damaging insect pest particularly in Dharwad region of north Karnataka by causing economic losses during kharif and rabi seasons. The observations on population dynamics of egg masses, larvae, pupae, number of plant damaged and parasitic interactions of natural enemies with larvae and pupae of C. partellus were recorded at weekly interval at Dharwad (Karnataka). The stem borer population was significantly higher in kharif than in rabi-summer crop. The larval parasitoid, Cotesia flavipes was found to be very active in kharif season and maximum parasitization of 29% was recorded in November whereas Sturmiopsis inferens was prevalent during rabi-summer crop and maximum parasitization of 28% was recorded during February. A population of 2% pupal parasitoid, Tetrastichus sp., was also recorded during kharif season. Keywords: Biological control, Chilo partellus, population dynamics, stem borer.

Highlights

Sweet sorghum, Sorghum bicolor (L.) Moench is grown in the rainy as well as post rainy seasons, generally by resource poor farmers in the semi-arid regions of the world Asia, East and SouthAfrica
Sorghum crop is being attacked by nearly 150 insect species causing an annual loss of over $1 billion in the Semi Arid Tropics (ICRISAT, 1992) and the most damaging species are Chilo partellus, Busseola fusa and Eldana saccharina (Songa et al, 2001)
In India, a number of stem borer species have been reported as serious pests of sorghum crop of which spotted stem borer, Chilo partellus (Swinhoe)

Summary

Introduction

Sorghum bicolor (L.) Moench is grown in the rainy as well as post rainy seasons, generally by resource poor farmers in the semi-arid regions of the world Asia, East and SouthAfrica. Partellus on variety HC-136 and JS-20 during rabisummer and kharif and larvae and pupae populations was found to be high during kharif season crop than in rabi-summer. (0.2-4%) at Hissar and these parasitoids remained active during 3rd week of Aug to 1st week of Sep. Keeping the above problems and prospects in view, the present investigations was undertaken to study the population dynamics of C. partellus and its interaction with natural enemies in sorghum ecosystem at Dharwad region in kharif and rabi-summer seasons in the year 2005-06.

Results

Conclusion