Population Density of Empoasca Spp.;Liriomyza trifolii (Burgess) and the Common Natural Enemies on Faba Bean Plants in Relation to Sowing Dates in Kafr El-Sheik Governorate

Abstract

Leafhoppers, Empoasca spp. (Homoptera: Cicadellidae) and The serpentine leafminer, Liriomyza trifolii (Burgess) (Diptera:Agromyzidae) are important harmful insect pests of faba bean, Vicia faba L.( Sakha 1 variety ), which causes considerable loss in yield. So, population density of these insects and the common natural enemies in relation to sowing dates were studied on faba bean during two successive growing seasons, 2016/17 and 2017/18 at Kafr EL-Sheikh Governorate. The obtained results revealed that population densities of Empoasca spp. were higher in mid- October plantation than mid- November plantation in first and second season, respectively with two peaks during both growing season. Population densities of L. trifolii larval recorded two peaks of abundance for the first and second sowing date during the two study seasons. The rate of emerging (Opius sp.) parasitoids synchronized with high parasitism. Statistical analysis cleared that the positive higher relation between rate of parasitism and population of leafminers larvae in second plantation in first season also, between rate of parasitism and emerged parasitism in second season.The population of L. trifolii in (first season) mid- November was significant than first one. The rate of parasitism as well as the emerging parasitoids was significantly higher in mid –November than mid- October (second season )Statistical analysis cleared that the population of leafhoppers; rate of parasitism and associated predatorswere insignificant differ during the two planting dates, while leafminers were significant in first seasons on contrast in the second one. On the other hand, the common predatory were significantly higher on mid-October than mad-November in the second one synchronized with the highest levels of leafhoppers and leafminers. These results could be useful in developing programs of integrated insect management in faba bean fields to reduce insecticide.