Economic Importance of Some Soil Insects on the Potato Crop in the middle of Iraq.*

Abstract

Potato tubers (Solanum tubersom L.) attacked by some of soil insects especially the larvae of Wireworms (Agriotes spp.), larvae of Black Cutworm(Agrotis ipsilon) and Mol cricket (Gryllotalpa gryllotalpa (L.) .The damage of these insect doesn’t observed in oftentimes until the tubers pulling out. This study were conducted to evaluate the population density and percent of infection according to crop growth stage of potato. The results showed that the larvae of wireworms were accompanied the growth of crop in autumnal form planting tubers at the second half of September until harvested in the second half of January. The highest average number of larvae (2.4 larvae\ sample) were recorded at during October which synchronism with the first growth stage (sprout development),and the percent infestation of tubers was 11.11 % . In spring planting the highest average number of larvae (3.2 larvae/sample) was recorded during April which synchronism with tuber initiation and the percent of infestation was 14.13%. The black cutworm was accompanied the Crop growth during the first fourth stages only in autumnal planting. The highest average number of larvae (1.4 larvae / sample) was recorded during November when the crop was at tuber initiation .In spring planting the larvae of cutworm escort crop from the second stage (vegetative growth) and even the stage of maturation . The highest average number of larvae (2.4 larvae/sample)was recorded during April with 11.11 % infestation. Sample methods did not succeed to estimate the population density of Mol cricket, but their injures were recorded in the spring and autumn planting in the all stages of plant growth and the highest percent of infestation was 22.22% in spring planting during vegetation growth stage