APHIS CRACCIVORA KOCH. AND PREDATORS ON FABA BEAN AND COWPEA IN NEWLY RECLAIMED AREAS IN EGYPT

Abstract

The population density of the cowpea aphid, Aphis craccivora Koch. and its associated predators on faba bean and cowpea fields were studied at El-Khattara district, Sharkia Governorate, Egypt in 2010-2011 and 2011-2012 seasons. A. craccivora had three peaks on faba bean for each season the first peak was during the fourth week of December , the second one was in the second week of February, where the last peak was in the first week of March (2010–2011 season), The three peaks of 2011-2012 were recorded in the first week of January, the fourth week of February and the second week of March 2012. There was one peak only on cowpea in the third and fourth week of July in 2011 and 2012, respectively. The common predators observed in faba bean and cowpea fields were: Coccinella undecimpunctata L., Chrysoperla carnea Steph., Paederus alfierii (Koch.), Orius sp., Syrphus sp. Scymnus sp. and Cydonia vicina isis (Muls.) Regarding predators on faba bean, two peaks were found in the first weeks of February and second week of March (37 and 79 predators/ 100 plants) during the first season 2010-2011, also, two peaks were found in the third week of February and second week of March (61 and 58 predators / 100 plants), respectively in 2011-12 season. On cowpea, however, also two peaks were found in the fourth week of July and second week of August (89 and 69 predators/ 50 plants), respectively in 2011 season, while, one peak was found in the third week of July (78 predators/ 50 plants) in 2012. Statistical analysis showed that temperature and relative humidity had different effects (significant or insignificant) on insects under investigation.