the effect of sowing date and plant density on population and infestation of chickpea pod borers in lorestan province

the effects of sowing date and crop density of chickpea on population and infestation of pod borers were studied in a randomized complete block design by factorial arrangement with three replications in the chickpea growing region of greet, khorramabad in 2007 until 2009. experimental factors comprised of sowing dates (march 14, march 30, and april 21) and crop density (25, 50 and 75 plant.m-2). population of larvae on plants during the growing season and final yield and 100 seeds weight at harvesting time were determined. pod borers low population in first year was attributed to the extremely cold winter (occurrence of 14.6°c) during the growing season. the second year results showed that although pest population in early date of planting was 1.35 times higher than other dates and infestation percentage was more than 5 times, but the yield was 61.6% higher in early sowing treatment. infestation percentage was 5 and 4 times higher in plots sowed on march 14 and 30, respectively than those plots sowed on april 21. the average chickpea yield in march 14 and 30 were 61.6 and 52.4% higher than april 21, respectively. higher plant density increased population and pod borers damage in chickpea. the highest seed yield was obtained from the highest plant density. when plant density increased from 25 to 50 and 75 plant.m-2 chickpea grain yield increased 13.3% and 37.7%, respectively.