Interactive effect of nitrogen and insecticide on jassid,amrasca devastans (Dist.) population and photosynthetic capacity of okra abelmoschus esculentus (L.) moench

Infestation of phloem feeding insects reduce crop yield with or without reducing photosynthesis,however,in the present research,we report for the first time that jassid,amrasca devastans (dist.) infestation rate reduces crop yield by reducing photosynthesis. we assessed the interactive effect of nitrogen and a. devastans abundance on photosynthesis activity of okra abelmoschus esculentus (l.) moench. insecticide spray reduced the jassid abundance on okra thereby improved growth of okra. although increasing supply of n also improved the growth of insecticide sprayed or non-sprayed okra plants by enhancing photosynthetic pigments and photosynthetic efficiency,numbers of jassids increased significantly. however,this improving effect of n on growth was more in insecticide sprayed plants. jassid infestation greatly reduced chlorophyll contents and photosynthetic rate,which is positively associated with jassid infestation-induced reduction in growth. moreover,reduction in photosynthetic rate in okra plants due to jassid infestation may have been due to stomatal and some metabolic perturbations. copyright 2014 zoological society of pakistan.