Alternate host plants, hibernation sites and survival strategy of Cylas puncticollis Boh.: A new pest of cotton

摘要

Survey and field experiments from 2001 – 2005 were carried out on cotton farms and surroundings to determine the alternate host plants, hibernation and survival strategy of Cylas puncticollis Boh. (Coleoptera: Brentidae) in the Northern Guinea Savannah zone of Nigeria. Trials were also conducted on five malvaceous crops (cotton, kenaf, okra, red and white calyx roselle) in a completely randomised block design in three replications at Ngurore the ‘hot spot’ zone for the weevils. C.puncticollis was found on the following plants Astripomeoa lachnosperma, Ipomoea eriocarpa, Corchorus spp., Celeosia spp., Commelina spp., Boerhavia spp., Hibiscus spp. and Abelmoschus spp. Peak period C. puncticollis was Nov. 1st with about 12 weevils/5plants. Hibernation for the adult weevils were cotton bracts, exposed roots of cotton, thrash debris and cracked soils. Pupae and adults of C. puncticollis were found within 1 – 15cm cracked soil depths around cotton and Ipomoea weeds. Adult weevils prefers dark corners and when disturbed moves at a faster speed or fain/fake death to escape enemies.