Reflective mulches for management of aphids and aphid-borne virus diseases in late-season cantaloupe ( Cucumis melo L. var. cantalupensis)

Abstract

A complex of aphids and several mosaic virus diseases can cause major losses in cucurbitaceous crops grown in the inland valleys of California. Three field experiments were conducted to test and compare the effectiveness of reflective polyethylene and biodegradable, synthetic latex spray mulches for management of aphids and aphid-borne virus diseases of late-season cantaloupe ( Cucumis melo L. var. cantalupensis cv. Primo) in the San Joaquin Valley. Beneficial responses were obtained from the reflective mulches, under conditions of high aphid populations and virus inoculum potential, during each of the experiments. Aphid numbers on leaves of plants growing over mulches were consistently lower than on those growing over bare soil. Onset of symptoms of cucumber mosaic cucumovirus, and watermelon mosaic and zucchini yellow mosaic potyviruses, were delayed 3–6 weeks in plants growing over the mulches, which was critical for initiation of normal flowering and fruiting. High virus disease incidence (100% incidence of foliar symptoms) reduced cumulative, marketable melon yields (number of fruit, fresh weight, and size) in the control plots to near zero in two of the three experiments. In each of the experiments, polyethylene or spray mulch treatments which completely covered each planting bed provided at least 9.5- and 2.5-fold increases in marketable yield, respectively. In the first two experiments, reflective mulches would have provided the difference between salable crops and total crop loss. Partial bed coverage with spray mulch, and alternate row applications of polyethylene film mulches, were less effective than complete coverage of every planted row.