Uses of some cotton agronomic traits to decrease insecticide spraying
1986
Yodsaporn Chantachume
The results indicated that thrips, aphids and larvae of American boll worm tended to be larger in number and caused more damage in a hairy leaf variety comparing to a glabrous leaf variety. However, for jassids, a glabrous leaf variety was destroyed heavily. The number of thrips was small in the red leaf variety compared to the normal green leaf variety, but the latter one gave more yields. Jassids and spiny boll worm (Earias fabia Stoll) could decrease yields of the crop depending on the amount of insects. A number of jassids and plants damaged by jassids and spiny boll worm decreased when cotton was grown under normal spraying which resulted in an increase in yields of the crop compared to a lower level spraying condition. For the experiment at Suphan Buri Field Crops Research Center in the 1983 rainy season, the data showed that there was no significant difference in yield between the normal and low level spraying conditions at Supan, in the number of insecticide spraying should depend on the agronomic traits of cotton variety and the environments of the planting area having different kinds and amount of insects. Among the varieties tested, DI 5.5-278 which does not have nectary glands was the most interesting variety, because it gave a high yield in both conditions of insecticide spraying.
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