[Population density of wheat aphids and their control in Yemen Arab Republic [Diurophis noxia; Rhopalosiphum maidis; Coccilenedae]]
1989
Al-Nassiri, M.S. | Al-Zabidi, A. (Central Highland Research Station, Dhamr (Yemen, D.))
Wheat is one of the most important crop in Yemen. But, the yield of wheat is very low for several reasons. One of them is the high susceptibility of local varieties to pests and diseases. Aphids is the most dangerous insects on wheat. Yield lose could reach up to 30 %. Diurophis noxia and Rhopalosiphum maidis are the most wide spread Aphid species on wheat in the country. The objectives of this paper are to study Aphids population density, and to evaluate the proper method of their control. Yellow traps and direct counting on infested plants were used to determine the Aphid density. Four chemicals were applied to field grown wheats to study the efficacy of this chemicals in controlling Aphids and to identify their negative effects on Aphids natural enemies. The results show that the highest Aphid population density reached one week before heading stage. Therefore, this time was considered the best time for chemicale applications. All the chemicals were highly efficient in controlling wheat aphid, but they have negative effects on Aphids natural enemies with the exception of Primor treatment. Reducing the chemical dosages and using specialized chemicals could keep a good balance between Aphids and their natural enemies
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