ANTIXENOSIS COMPONENT OF RESISTANCE TO SORGHUM MIDGE, CONTARINIA-SORGHICOLA COQ IN SORGHUM-BICOLOR (L) MOENCH

Sorghum midge, Contarinia sorghicola Cog. (Diptera: Cecidomyiidae) is the most destructive pest of grain sorghum, and host-plant resistance is an effective method of controlling this insect. We studied the anti xenosis component of resistance to sorghum midge using multi-, double- and no-choice cage tests, and under multi-choice field conditions to quantify and understand the nature of antixenosis component of resista nce to this insect in Sorghum bicolor (L.) Moench. Midge response towa rds sorghum panicles was influenced by panicle size and cage type used to study the orientation behaviour. Maximum number of midges were rec orded at 30 and 60 min after initiating the experiment. Antixenosis sh own by C. sorghicola under multi-choice field conditions to ICSV 197 a nd TAM 2566 was not confirmed under cage tests, while DJ 6514, AF 28 a nd IS 3461 were non-preferred both under field and cage conditions. Mi dge-resistant female parents (PM 7061 and PM 7068) were less preferred than the midge susceptible (ICSA 42 and 296A) female parents. Male-st erility did not influence host finding and acceptance by the midge fem ales, although in one out of two tests, the maintainer lines (B-lines) were preferred over the male-sterile lines (A-lines).