Abstract
As we observed in the fruit inspections in the station of orange for export, pest population have increased in yield since they abandoned organic fertilizations and adopted synthetic fertilizers. By the entomologists information's about the effects of fertilization types and rates on pests, a controlled trials were performed to elucidate there interaction. Peach fly Bactrocera zonata (Saunder), injury level, characteristics changes were compared with normal synthetic fertilizers used in the experiments. Orange orchards treated with potassium sulphate fertilizer applied for at least two seasons hosted fewer peach fly, than orchard treated with normal rate of potassium sulphate (0.3 kg./tree) This variation seems to high and total content of foliar potassium sulphate in fruits in plots, with high rates (1.5 kg./tree). There were positive significant amount yield differences among applications. These study revealed that the optimum rate is ranged between 1.0 to 1.5 kg./tree. The main results observed from the study are summarized in the decrease in the number of infected fruits with an increase in the number of healthy fruits and thus increase the amount of fruits for exportation processes. This study may be useful index in large scale screening of orange for fruit fly resistance.