بررسی تأثیر رطوبت نسبی روی تغییرات جمعیت زنجرک Psammotettix alienus روی محصول ذرت در شرایط آب و هوایی شهرستان شهرکرد

Maize crop in recent years has widely cultivated in Shahrekord province. This crop has two types of foraging and seedy maize in the region, that most of the area under cultivation is foraging maize, because this region is pole of animal husbandry in the country and need of this crop is so prevalent, also extensive research in the field of pest of it is necessary in the region. Leafhopper Psammotettix alienus is one of the most important sucking pests of maize, that it has both direct and indirect damage (with transmission of viral diseases and etc.). Recently the population of this pest in the Shahrekord area has gone up and has reduced crop yields so that farmers have to choose a way to control it. The amount of this pest activity related with fluctuations in temperature and relative humidity, that in this study to investigate the effect of relative humidity on the population of leafhopper, three fields were selected and sampling in these regions was conducted by sweeping net. Meteorological data and other collected data were recorded in special tables and analyzed by SAS statistical software. The results showed that there is two peak populations for this leafhopper, respectively, in the third week of July and the third week of September, that both of them have occurred in conditions that, relative humidity was at its lowest level during the maize growing season. Study of graphs of population changes with relative humidity, showed that the leafhopper population decreases with increasing humidity. Also data analysis showed that the effect of daily relative humidity on this leafhopper population dynamism were significant in five percent level. Also relative humidity and rainfall showed a negative correlation with the population of this leafhoppers. According to the results of this research and also, due to damage of this pest and huge increase of its population in maize fields in recent years, can recommends to farmers to use of sprinkler irrigation method to reduce the population and finally reduce the damage of this pest, because this method of irrigation increases the relative humidity that it causes to reduce the population and thus damage of this leafhopper.