Aluminosilicate clay suspension treatment as a migrant aphid dissuadant for management of nonpersistent viruses in commercial melons.

Commercial melons in California are subject to infection by several viral pathogens that are transmitted by various aphid species in a nonpersistent manner. In this system, insecticides are relatively ineffective at reducing virus incidence since any probing aphid, including casual and migrant species, can initiate new infection centers. It may be possible to interfere with visual cues from potential host plants in order to reduce the incidence and density of aphid vectors. An aluminosilicate clay suspension which alters the reflection of light from the plant surface was applied to plots within large commercial melon fields in California at regular intervals and at several sites over two years and compared to no treatment in order to determine if aphid density and related virus incidence could be reduced. Aphid density in treated plots was significantly reduced at some sites and at several levels of pest pressure. Aphid species composition was also significantly different between the two treatments. A melon pest species, Aphis gossypii, was proportionately more common in treated plots while casual and migrant aphid species were proportionately more common in untreated plots. The results are discussed in terms of potential virus transmission, pest management, and economic feasibility.