Effect of Planting Dates and Certain Insecticides on the Lima Bean Pod Borer, Etiella zinckenella (Treit.) (Lepidoptera: Pyralidae) and Productivity of Cowpea Plants in Qalyoubia Governorate.

Abstract

Field experiments were carried out in Tahla village, Qalyoubia governorate during two successive seasons, 2014 and 2015. The first experiment was conducted to study the effect of four planting dates of cowpea seeds (March, 20 th ; April, 10 th ; May, 1 st and May, 22 nd .) on infestation levels of cowpea pod borer, Etiella zinckenella (Treit.), and effect on yield of this crop. The degree of infestation by E. zinckenella significantly increased by delaying planting date. Cowpea plants cultivated in the earliest planting date (March, 20 th) was attacked by few numbers (2.3 & 1.5 larvae/10 pods during the two successive seasons, respectively), with the high weight of cowpea seeds (27.7 & 28.9 kg/ 100 m 2 during the two seasons, respectively). However, it was given the lowest number of both damaged pods and seeds. In contract the plants of the latest planting date (May, 22 nd) was more liable to insect infestation (9.0 & 15.3 larvae/10 pods during both two seasons, respectively), with the low weight of cowpea seeds (20.2 & 19.3 kg/ 100 m 2 during 2014 and 2015, respectively), Also, it was given the highest number of damaged pods and seeds. Therefore, it was concluded that the plant date was effective on infestation rate by this pest and yield of cowpea seeds and can be avoided by planting it as early as March, 20 th. The second experiment was studied the effect of some insecticides and their efficacy against lima bean pod borer, E. zinckenella of cowpea. The present results showed that the mortality percentage were arranged descending as Sumithion 50% EC (62 %), Tracer 24% SC (55.3%), Radiant 12% SC (53.4%), Neemix 4.5% EC (35.7%) and finally Dipel 2x 6.4% WP (33.7%), with significant differences between the tested treatments compared with control. Also, Sumithion was the superior compound in this respect being registered 53.8 % increasing in the yield over the control value followed by Tracer (43.2 %), Radiant (40.8 %), Neemix (19.7 %) and Dipel 2x (12.7%).