Field studies were conducted for three seasons, Fall 1988 and Spring and Fall 1989, on the effect of six mulch colors: blue, orange, red, aluminum, yellow, and white (fall) or black (spring), on fruit yields and on insect vectors of Sunny' tomato (Lycopersicon esculentum Mill.). Plant growth and yields were inconsistent with mulch colors during the three seasons. In Fall 1988, in a once-over harvest, extra-large (≥ 70 mm diameter) and marketable fruit yields were higher (P ≤ 0.05) on blue than on the conventional white mulch. In Spring 1989, early marketable yields on red mulch were higher than on black mulch, and in Fall 1989, under high stress from tomato mottle virus (TMoV) transmitted by silverleaf whitefly [Bemisia argentifolii (Bellows and Perring)], seasonal yield of extra-large fruit was better on orange than white mulch. In Fall 1988 and 1989, fruit size and marketable yields were reduced on yellow mulch. Aphids (Aphididae), thrips (Thripidae), and whiteflies were counted monthly in traps placed on the mulched beds. Aphids were least numerous on the aluminum and yellow and most numerous on the blue mulch. Where differences occurred, the fewest thrips were captured on aluminum and the fewest whiteflies were captured on the yellow, aluminum and orange mulches. Although differences were not always significant, the fewest adult whiteflies also were observed on foliage of tomato plants grown on these latter three mulches. Later in the seasons, as plant foliage covered the mulch, differences in the number of insects captured were similar for all mulch colors. Low numbers of whiteflies on the orange and aluminum mulches early in Fall 1989 delayed virus symptom development and increased yields. Virus symptom development was not delayed and yields were low on the yellow mulch, in spite of the low number of whiteflies. When averaged over all mulch colors, extra-large and marketable fruit yields increased linearly with delayed symptom development. It is proposed that, under high insect stress, mulches should be selected for their effects on insects in addition to their effects on soil temperature and plant morphology.

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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 incidence of tomato mottle virus (ToMoV), and on fruit yields of staked, fresh-market tomatoes (Lycopersicon esculentum Mill.). The UV-reflective mulches were metallized aluminum (aluminum) and painted aluminum (silver) on either black or white plastic film. The aluminum and silver mulches were evaluated with and without a white (fall) or black (spring) 25-cm-wide painted band in the bed center. Controls were the conventional white (fall) or black (spring) polyethylene mulches. Highest reflected energy (μmol·m–2·s–1) to the plants at 15 cm from the mulch surface was measured on the aluminum mulch with or without a white painted band. Lowest energy was reflected from the white or black controls and from silver on black mulches with or without a black painted band. Whitefly populations in the fall were lower (P ≤ 0.05) on the aluminum than on the silver mulches. In the spring, when whitefly populations were low, whiteflies were more numerous 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 transmitted by the silverleaf whitefly were higher on the controls than on the aluminum mulch. In the spring, the proportion of plants with symptoms was not affected by mulch treatments. Yields in the fall were similar with UV-reflective or white control mulches. In the spring, fruit size and marketable yields were greater (P ≤ 0.05) on plants with silver on white mulch than on the control black mulch.

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