Field screening of cotton cultivars and germplasm against cotton stem weevil (Pempherulus affinis Faust) (Curculionidae: Coleoptera).

摘要

There were 14 cultivars viz., MCU 3, MCU 5, MCU 7, MCU 10, MCU 11, MCU 12, SVPR 1, SVPR 2, SVPR 3, LRA 5166, K11, KC 11. KC2, Surabi and five hybrids RCH 2, RCH 20, RCH 134, RCH 144 and Sakthi 9 selected for screening at Padisonputhur pudupatty village Karumathur in Madurai district, Tamil Nadu for two seasons during 2003. The variety MCU 5 was used as standard check. It was a multiple cross derivative, long staple and the average yield was about 20 q/ha. From the investigation, it was revealed that in both the seasons, cultivar MCU 3 was found to be resistant to stem weevil. The possible reason was the production of gummy exudates which flooded the tunnel made by the grub thereby suffocating the grub and finally leading to the death of the grub.