Do Chrysoperla carnea and Adalia bipunctata influence the spread of Cucurbit aphid‐borne yellows virus and its vector Aphis gossypii?

Abstract

AbstractThe effects of two aphidophagous predators, the larvae of Chrysoperla carnea and the adults of Adalia bipunctata, on the spread of Cucurbit aphid‐borne yellows virus (CABYV) transmitted by the cotton aphid Aphis gossypii were studied under semi‐field conditions. Aphids and natural enemies were released inside insect‐proof cages with a CABYV‐infected cucumber plant placed in the centre of the cage and surrounded by 48 healthy cucumber seedlings. The spatiotemporal dynamics of the virus and vector were evaluated in the short (7 days) and long term (14 days) in the presence and absence of each predator. The spatial analysis by distance indices methodology, together with other indices measuring the dispersal around a single focus, was used to assess the spatial pattern and the degree of association between the virus and vector.The presence of C. carnea larvae and A. bipunctata adults induced A. gossypii dispersal after 14 days but not after 7 days. The reduction of the initial aphid population established in the plant located in the centre of each cage was always higher for C. carnea than for A. bipunctata. There was some evidence that the natural enemies affected the spread of CABYV, though more so for C. carnea than for A. bipunctata.This study suggests an influence of both predators on the spread of the aphid, mainly in the long term, but only weak effect of predators in the spread of the viral disease was demonstrated.