Population Dynamics of Grain Aphid, Sitobion avenue F (Aphididae: Homoptera) and Barley Thrips, Limothrips cerealium H. (Thripidae: Thysanoptera) on Wheat and Barley in Highland Balochistan

摘要

The observations on the population dynamics of Grain aphid, Sitobion avenae F. and Barley thrips, Limothrips cerealium H were taken from the fields of wheat and barley at AZRC farm and Agricultural College. Quetta during the season 2002-03. Data indicated that the population of aphid was significantly higher on wheat as compared with barley during I51 week of April and Is' week of May. The overall mean population of aphid was 1. 78/tiller on wheat and 1.25/tiller on barley. The population of thrips was also significantly higher on wheat as compared with barley during 2nd and 3rd week of April. The mean population of thrips was 2.38/lillcr on wheat and 1.44/tiller on barley. In the 2nd experiment on population dynamics of these insects on five wheat varieties, viz: AZRI-96, local, S-98, Local Zamindar and ICW, local showed significantly highest resistance against aphids than any other variety. While significantly higher population of aphids was recorded on ICW during the 2nd fortnight of April. In contrast, local proved to be susceptible to thrips as maximum number of thrips were observed on local during 2nd fortnight of April. The population of either insects (aphids or thrips) was significantly different among genotypes, among sampling dates and no statistically significant interactions were observed between genotypes and sampling dates.