ارزيابي تاثير آبياري باراني و هرس بهاره بر تراكم جمعيت تريپس توت

An Appraisal of Sprinkling Irrigation and Spring Pruning on Population Density of Mulberry Thrips Pseudodendrothrips mori Niwa (Thys.: Thripidae)

Mulberry thrips Pseudodendrothrips mart Niwa reduces the efficiency of silk production by feeding the leaf sap. In order to approach a non-chemical control measure for the pest, the effects of sprinkling irrigation and spring pruning were investigated separately in three mulberry varieties (Km, I & SI). For assessment of efficiency of sprinkler irrigation on reducing the thrips population, two half- ha. Plots were selected from each varieties and one of them was irrigated for 3 h and the other was kept as control. The number of thrips collected by random sampling was counted in each plot at four different intervals (before irrigation, 24, 48 & 72 h after irrigation). To determine the effects of spring pruning on thrips population, two plots from each variety were selected which one of them was taken under intensive pruning in mid- May. Population densities were recorded in ten different times in summer. The results indicated that the two methods as non-chemical measures donʹt show any significant effects on mulberry thrips. The data determined that only 24 h after irrigation population of thrips lowered and the density of the insect after 48 h of irrigation didnʹt show significant difference between two treatments. Also the average population of mulberry thrips in pruned treatments of SI, I and KM, were 0.28±0.17, 0.29±1.6 & 1.36±1.01 respectively. While this index in non-pruned treatments were 0.23±0.15, 0.15±0.09 & 1.56±1.3 respectively, no significant difference was observed between two pruned treatments.