عنوان مقاله [English]
Chemical spraying is one of the important field operations in wheat production. Farmers usually use lance sprayers, micronair sprayer and atomizer sprayer (motorized knapsack mist blower) in order to control the sunn pest when wheat plant is reach to a desire high. Sunn pest damaged on wheat plant lead to a serious problem in which when targeted plants spray with chemical, the sunn population keep protecting themselves by moving down ward to the lower parts of plant stem. The above mentioned sprayers can not be used to spray with in wheat canopies, while it has been shown that a modified atomizer sprayer is capable of targeting the lower portion of wheat canopies. In this study a conventional atomizer sprayer was manipulated with an boom type to provide a modified atomizer sprayer. Then the modified atomizer sprayer was used to compare with lance atomizer and micronair sprayers in relation to chemical spraying efficiency for controlling the sunn pest damaged in wheat production. The experimental design was setup randomized completed block design (RCBD) with three replications. Results showed that modified atomizer and lance were the first and last sprayers which had lethal effects of 92.6% and 46.5% respectively on the sunn pest at the 5% confidence level. Amount of drifting were 43.1% and 8.3% mioconair and modified atomizer sprayers respectively, at the 1% confidence level. The least amount of solution consumption (11.4 lit/ha.) and the best spraying uniformity were occurred under micronair sprayer operation.VMD and NMD were 388 µm and 286 µm for micronair sprayer respectively. When plant stand was evaluated, there was not any significant difference among sprayer systems in regard to crop lost, except for the lance sprayer which has showed 5.6% crop damaging at the 1% confidence level. Findings in the present study indicated that modified atomizer sprayer is capable of covering more spaces at the middle and bottom of plant canopies with high density (droplets / square cm) than other sprayers. Boom modified atomizer sprayer is strongly recommended as the sunn pest controller in wheat crop, when the plants reached to desirable height.