Protecting peppers from aphid-borne viruses with aluminum foil or plastic mulch

Aluminum foil and plastic mulch, covering 57-83% of the ground in peppers from emergence, effectively protected the crop against aphid-borne cucumber mosaic and potato virus Y by repelling winged aphids. Aluminum foil and grey plastic sheets gave the best results, followed closely by white plastic on black. The mulches were most efficient during the first 3 weeks in the field, after which they lost some of their reflectance. Trappings of winged aphids from the aluminum-covered plots during the first 3 weeks were only 2 and 5% of the control, and those in the grey-plastic-covered plots were between 6 and 12%.Myzus persicae was especially sensitive to reflection, and trappings in the aluminum and grey plastic plots during the first 3 weeks were less than 0.6 and 2% of the control, respectively. Repellence of winged aphids was correlated with virus incidence, especially during years with high natural virus spread; infection rates in the mulched plots at harvest time reached only 4.5-6% compared with 45% in the controls. As a result, yields were markedly higher except in the aluminum-mulched plot where in one season growth of plants was retarded, perhaps due to lower soil temperature.