Virulent aphid population dynamics in Kentucky winter wheat: a land use analysis

Winter wheat is a major commodity worldwide and in the state of Kentucky alone, the annual revenue exceeds $200 million. However, wheat is frequently infested by aphids (Aphididae: Hemiptera) which cause yield loss through feeding damage and as vectors of plant viruses. Two aphid species, Rhopalosiphum padi and Sitobion avenae, act as vectors of Barley Yellow Dwarf Virus (BYDV) and winter wheat becomes infected with BYDV when aphids, moving from host plants, migrate into uninfected crop fields. In Kentucky, BYDV causes over $30 million in yield loss annually. Therefore, understanding the temporal and spatial dynamics of aphids vectoring BYDV is important for integrating pest management to ultimately reduce yield loss. To study these dynamics, replicated field plots were planted in western Kentucky for sampling of aphids populations. Specially designed aerial aphid traps were used for weekly sampling of migrating aphids into the field. Aphids were removed from the traps, counted and screened for BYDV using enzyme linked immunosorbent assay (ELISA). Additionally, in an effort to look at any effects by bordering crops, Geographic Information System (GIS) was used to analyze the landscapes surrounding the field sites. We used 636 traps to capture over 5600 aphids during the growing season; of these, 2500 were screened for BYDV. Research revealed that the majority of the migrants come during the fall, bringing the virus. The landscape pattern and border vegetation play a significant role in aphid migration and subsequently the movement of BYDV. This information is crucial in the successful implementation of an integrated pest management program targeting aphid pests in Kentucky winter wheat.