Field Crops News

Generalist Predators Reduce Aphid Establishment and Spread of Beet Yellows Virus in Sugar Beet

Beet yellows virus (BYV) is found throughout the world where sugar beets are produced. It is transmitted from infected to healthy plants primarily by the feeding of green peach and black bean aphids. Migrating aphids arrive in beet fields and transmit the virus to plants which develop a systemic infection. The virus is then spread by the movement and feeding of subsequent aphid generations.

By excluding predators from certain plants researchers were able to study the ability of generalist predators to reduce establishment of aphid colonies and thus limit the spread of the virus. In field trials, a combination of predators, including soldier beetles and lady beetles, reduced aphid numbers by 80% in 24 hours. Over 90% of those aphids protected from predation survived during the same period. In a second study, it was shown that protecting aphids from ground dwelling predators (ground beetles, spiders, rove beetles, etc.) for four weeks early in the season, significantly increased the number of plants developing initial BYV infections. At season end, where predators had been excluded, the overall infection was about one-third greater.

These studies, conducted in the Netherlands, demonstrate the potential of naturally occurring predators to limit aphid populations in field crops and thus help in the management of virus diseases.

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