Insect pests and their effect on yield, oil content and dry matter weightof sunflower

In the study of' insect pests infesting sunflower at Peshawar, field cricket(Gryllus bimaculatus Deg.) thrips (Thrips tabaci Linn.), hairy caterpillar(Diacrisia obliqua Wlk.). whitefly (Bemisia tabaci Genn.), jassids (Amrascadevastans Dist.), green stink bug (Nezara viradula Linn.). seed bugs (Nysiusinconspicuous) and different species of grasshoppers, including surfacegrasshopper (Chortogenus trachypterus trachypterus Blan.), shorthorn,grasshopper (Truxalis exalta Wlk.); longhorn grasshopper (Tettigona spp.) wererecorded. In order to evaluate the losses due to the insect pests on sunflowertwo insecticides namely Sundaphos.50 WSC at the rate of a 1.23 -lit./ha andSunmerine 5 EC at the rate of 1.11, lit./ha were applied to control all theinsect pests attacking sunflower crop against the plots which were left opento the natural infestation of all the insect pests. Maximum seed yield (2124kg/ha) was obtained from plots treated with insecticides (Sundaphos andSunmerine) for the control of all the insect pests. From the plots where noinsecticide was applied and the crop was allowed to the natural infestation ofall the insect pests the seed yield was 1929 kg/ha. 1n the plots where all theinsect pests were controlled with insecticidal treatment, the seed yield wassignificantly higher than the plots which were left open to the naturalinfestation of all the insect pests. The loss in seed yield of sunflower due tothe attack of various insect pests was 195 kg/ha or 9.18 percent. The averageoil content from the seed of sunflower was 897.70 kg/ha from the plots whereall the insect pests were controlled with the insecticides while in plots whereno insecticide was applied, the average yield of sunflower oil was 795.64kg/ha. The loss in yield of sunflower oil due to the attack of various Insectpests was 102.06 kg/ha or 11.36 percent. The average weight of sunflower drymatter was 3634 kg/ha from the plots where all the insect pests werecontrolled with insecticidal treatment, while in the plots which were left opento the natural infestation of insect pests, the average weight of sunflowerplant dry matter was 3131 kg/ha. The loss in weight of dry matter ofsunflower due to the attack of various insect pests wits 503 kg/ha or 13.34percent. In short the loss in sunflower seed yield, oil content and dry matterdue to all the insect pests was respectively 9.18, 11.36 and 13.34 percent.