Effect of ultraviolet-reflective mulches on tomato yields and on the silverleaf whitefly

Field studies were conducted for three seasons, Fall 1994, Spring 1995, and Fall 1995, on the effect of ultraviolet (UV)-reflective films (mulches) on the silverleaf whitefly (Bemisia argentifolii Bellows and Perring), the in cidence of tomato mottle virus (ToMoV), and on fruit yields of staked, fres h-market tomatoes (Lycopersicon esculentum Mill.). The UV-reflective mulche s were metallized aluminum (aluminum) and painted aluminum (silver) on eith er black or white plastic film, The aluminum and silver mulches were evalua ted with and without a white (fall) or black (spring) 25-cm-wide painted ba nd in the bed center. Controls were the conventional white (fall) or black (spring) polyethylene mulches. Highest reflected energy (mu mol.m(-2).s(-1) ) to the plants at 15 cm from the mulch surface was measured on the aluminu m mulch with or without a white painted band, Lowest energy was reflected f rom the white or black controls and from silver on black mulches with or wi thout a black painted band, Whitefly populations in the fall were lower (P less than or equal to 0.05) on the aluminum than on the silver mulches. In the spring, when whitefly populations were low, whiteflies were more numero us on the black control and silver on white, than on the aluminum mulches. In the fall seasons, the proportion of plants with symptoms of ToMoV transm itted by the silverleaf whitefly were higher on the controls than on the al uminum mulch. In the spring, the proportion of plants with symptoms was not affected by mulch treatments, Yields in the fall were similar with UV-refl ective or white control mulches. In the spring, fruit size and marketable y ields were greater (P less than or equal to 0.05) on plants with silver on white mulch than on the control black mulch.