sSEASONAL ABUNDANCE AND HOST PLANT PREFERENCE OF CERTAIN APHIDS SPECIES INFESTING SOME CITRUS TREES ORCHARDS

Abstract

These studies were carried out in El-Mansoura district, Dakahlia Governorate during the two seasons of 2004/2005 and 2005/2006 on different citrus trees (Navel orange, Mandalin and Valencia orange). The present study illustrated that Aphis gossypii Glover, Aphis citricola (V.D. Goot) had two peaks at April and August during the two seasons of investigation. While, Myzus persicae (Sulzer) and Aphis craccivora Koch had one peak occurred during March and April for the two seasons. Each aphid species showed different degrees of preference for the different tested citrus trees. A. gossypii exhibited higher population on Mandarin trees. While Navel orange receive the highest population of A. citricola and M. persicae. The weather factors play a great role on the population density and seasonal abundance of the tested aphid species.

Toxicity of Certain Chemical Compounds Against Aphids, Leafhoppers AND Related Predators on Faba Bean Fields

“…Aphis craccivora and Aphis faba are the most important insects which affect the plant growth of faba bean and caused yield losses depending on the intensity of infestation (El-Dessouki et al, 2014). Both nymphs and adults of leafhoppers inject a toxin in the foliage during feeding causing down-curling of leaf edges, which turn yellow at first, then become brown and die (Nielson,1995;El-Gindy, 2002). The leafhoppers also transmit pathogenic organisms: spiroplasma, viruses, mycoplasma, and bacteria.…”