The effect of different levels of nitrogen and potassium fertilizers on the compensation of the rice stem borer, Chilo suppressalis (Lep.: Crambidae) in the field

The use of potassium fertilizer along with nitrogen fertilizer can be useful in recovering the damages of the rice plant during the attack of the stem borer, which ultimately leads to the reduction of the use of chemical insecticides in the paddy field. This research was carried out in the vegetative phase of the plant and the first generation of the pest on Hashemi cultivar rice. The following treatments were used for the experiment: T0=without the use of nitrogen and potassium fertilizer (control), T1=consumption of 46 kg of pure nitrogen per hectare with 50 kg of pure potassium oxide per hectare (100 kg of urea fertilizer+100 kg of fertilizer Potassium sulfate), T2=Consumption of 60 kg of pure nitrogen per hectare with 75 kg of pure potassium oxide per hectare (130 kg of urea fertilizer+150 kg of potassium sulfate fertilizer), T3=Consumption of 75 kg of nitrogen per 100 kg of nitrogen per hectare pure per hectare (163 kg of urea fertilizer+200 kg of potassium sulfate fertilizer) and T4=consumption of 90 kg of pure nitrogen per hectare with 125 kg of pure potassium oxide per hectare (195 kg of urea fertilizer+25 kg of sulfate fertilizer). The results showed that the most appropriate amount of fertilizer to compensate for the damage caused by the rice stem borer is the combination of nitrogen and potassium fertilizers, respectively 130 and 150 kg per hectare in two stages in the form of division and during the growth stage of the rice plant and in addition to compensation, it leads to an increase in its yield compared to the control treatment. Also, the regression relationship between dead hearts and rice crop yield due to fertilizer treatments during two years of research showed that with decreasing the percentage of dead hearts contamination in the first generation, crop yield in the treated treatments had an increasing trend. Therefore, success in stem borer management requires the development of optimal methods to compensate the damage and increase rice production.