Effect of strip-management on the population of the aphid, Aphis craccivora Koch and its associated predators by intercropping faba bean, Vicia faba L. with coriander, Coriandrum sativum L.
Experiments were conducted at the experimental farm of the Environmental Studies and Research Institute, Minufiya University, El Sadat Branch, Minufiya Governorate, Egypt to investigate the effect of strip-management and intercropping system with Coriander, Coriandrum sativum on infestation with the cowpea aphid's (Aphis craccivora Koch) and its associated predators, on five faba bean varieties, during the two successive seasons 2007/08 and 2008/09. Susceptibility of the five faba bean varieties to the aphid's infestation was also estimated. Results showed a significant positive effect of C. sativum intercropping with the faba bean varieties, as it caused significant decreases in aphid's population, significant increases in the numbers of associated predators and increases in the seed yields in both seasons. The lowest mean numbers of aphid (263.77 and 254.97 individuals/tiller) were scored in the plot of Giza-843 variety, intercropped and surrounded by the strip management of coriander, while the highest ones (597.37 and 523.57 individuals/tiller) were recorded in the plot of Giza-3 imp. without intercropping in both seasons, respectively. Highest mean number of predators (24.8 and 24.07) were recorded in the plots of Giza-3 imp. intercropped with coriander. However, the lowest means (3.10 and 3.03 individuals) were recorded in the plots of Giza-843 variety alone in the two seasons, respectively. Highest seed yields (1.87 and 1.90 ton/fed.) were recorded in the plots of Nubaria-1 and Giza-843 varieties, intercropped with coriander, while the lowest ones (1.17 and 1.20 0 ton/fed.) were found in Giza-3 imp. plots alone in both seasons, respectively. Results showed significant positive correlation coefficient between mean number of predators and seed yield/plant in the two seasons and a significant negative correlation between seed yield/plant and mean number of aphid/tiller.