تاثیر اسیدیته آب بر سمیت برخی از حشره‌کش‌های متداول روی کنترل کرم ساقه‌خوار برنج(Chilo suppressalis (Walker) ) در شرایط مزرعه‌

Rice (Oryza sativa L.) is one of the most important crops in Iran, and its cultivated area is about 900 thousand hectares. One of the serious problems of rice cultivation in Iran and the world is the rice stem borer, Chilo suppressalis (Walker). Water is the most important carrier of insecticides, and plays an important role in creating favorable conditions for the effectiveness of insecticides. In the present study, the effect of water acidity reduction on the toxicity of three conventional insecticides was investigated. Experiments were conducted in the form of randomized complete block design with four replications in Hashemabad village of Gorgan city, Golestan province with longitude 54.346068 and latitude 36.891402 degrees and altitude 174 meters above sea level. The treatments included hexaflumoron 10% EC, hexaflumoron with reduced acidity, acetamiprid 20% SP, acetamiprid with reduced acidity, deltamethrin 2.5% EC, deltamethrin with reduced acidity, and control (water). In order to reduce the acidity of the consumed water, the fixator was used as a water acidity reducer. After the water acidity reduced from 7.5 to 5.5, the solutions were prepared with the desired concentrations of insecticides and sprayed with a back pump sprayer. Sampling of each plot was done by counting the number of infected and healthy stems and claws, as well as the percentage of sprouting damage and white head of clusters. Sampling of the larvae population was recorded one day before and two, six, and ten days after foliar application. The results of this study showed that insecticides at 5.5 acidity were more toxic than at 7.5 acidity. So, the amount of infected stems one day before foliar spraying (5.28%), two days after foliar spraying (4.39%), six days after foliar spraying (3.53%), and ten days after foliar spraying (2.92%) was reduced. Also, the highest yield was obtained by hexaflumoron with 5.5 acidity. Therefore, it can be concluded that the reduction of water acidity can increase the efficiency of hexaflumoron, acetamiprid, and deltamethrin on rice stem borer.