Author : Agustin, Jenny M.

Summary : The effects of hirsute, glabrous, glandless, glanded, nectaried, and nectariless characters of six selected cotton strains on H. armigera were tested under laboratory, cage, and field conditions. In the laboratory, H. armigera moths generally preferred to oviposit on growing tips. Growing tips of Alcala Glandless and Nectariless 1215-SR-2 were the most and the least preferred for oviposition, respectively. On the other hand, squares were the most preferred for larval feeding, where Alcala Glandless was the most preferred while Nectariless 1215-SR-2 the least. In cage test, the growing tips offered the most favored sites for oviposition, followed by the squares. In the field, Sea Island (hirsute) was the most preferred host for oviposition followed by Alcala Glandless, Stoneville 213 (nectaried), Deltapine 16 (normally glanded), Nectariless 1215-SR-2, and REBA P279 (glabrous) (in this descending order) but Nectariless 1215-SR-2 and REBA p279 exhibited the least damaged squares and bolls, respectively. On the other hand, Sea Island had both the highest damaged squares and bolls, indicating that glabrous and nectariless characters of cotton strains were outstanding resistant factors against H. armigera. H. armigera moths preferred to oviposit on 68-day-old Sea Island than at 83-day-old REBA P279. Seventy-nine-day-old Sea Island and 99-day-old REBA P279 harbored the highest and the lowest number of larvae, respectively. Glabrous REBA P279 gave the highest yield while hirsute Sea Island produced the lowest. There was an inverse relationship between or among seed cotton yield and number of bollworm eggs and larvae, and percent damaged squares and bolls. Direct relationship existed between or among number of eggs and larvae, and percent damaged squares and bolls.