Seasonal occurrence of Liriomyza bryoniae (Kaltenbach) and their parasitoids on cucumber crop

Abstract

The results of this study revealed a steady increase in population density of leaf miners Liriomyza bryoniae (Kaltenbach) from 1.33 larvae/leaf at the beginning of the season to 3.3, 6, and 7 larvae/leaf with the progression of the agricultural season until 10 November, a slight drop in population occurred at the end of the season. The results revealed that the leaf miner population showed a significant negative correlation (-0.74) with maximum temperature and a non-significant negative correlation with minimum temperature. The maximum percentage of factor role was 55% for maximum temperature and ( 18 %) for the minimum temperature. Two species of insect parasitoids (Diglyphus isaea and Opius sp ) Hymenoptera order were recorded on the leafminer Liriomyza bryoniae larvae and pupae. Diglyphus isaea was the most common species. It was active throughout the growing season and increased in number as the leafminer populations increased. The rate of % parasitism was 4.3 % on 7 Aug. increased to 7.8, 12.8, 20.3, and 38.2% on 1 Sept., 7 Sept., 7 Oct., and 21 Oct respectively, while the rate of % parasitism of Opius sp ranged from 2.6% to 5.9% from 14 Sept to 21 Oct.