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- Author or Editor: D. R. Sumner x
Field studies were conducted in 1973 and 1974 to determine the effects of various reflective film mulches, vegetal barriers of millet (Pennisetum americanum (L.) K. Schum), and soil- and foliar-applied pesticides on yields and control of the watermelon virus complex (WMV), insects, nematodes, and soil-borne pathogens affecting yellow summer squash (Cucurbita pepo var melopepo L. Alefi, ‘Dixie’). All film mulches used (aluminum; white and blue plastic; brown paper) significantly reduced WMV in both fruits and plants. The millet barrier caused a significant reduction in WMV infected plants. In 1974, the systemic insecticide, carbofuran (Furadan) and/or sprays of mineral oil, significantly reduced WMV in non-mulched plots. Brown paper mulch significantly increased infestation of pickleworms, Diaphania nitidalis (Stoll) and all mulches significantly reduced infestations of serpentine leafminers, Liriomyza munda Frick. Leafminers were also controlled with carbofuran. Film mulches had no significant effect on populations of plant-parasitic nematodes and plant-pathogenic fungi. Both groups of pests were controlled with DD-MENCS (a mixture of 1,3-dichloropropene, 1,3-dichloropropane, methylisothiocyanate), but not with carbofuran or sodium azide. Film mulch increased squash yield 70 to 610% over the unmulched control. Plants in non-fumigated plots covered with aluminum and white plastic mulches produced significantly greater yields than plants in plots covered with blue plastic and brown paper mulches. Soil pesticides significantly increased yields over the non-fumigated control, and, averaged across main plots, DD-MENCS = DD-MENCS + carbofuran > carbofuran + sodium azide > sodium azide = nontreated check. The effects of film mulch were greatest in the non-fumigated check. Conversely, the effects of soil fumigation were negligible under film mulch and one could be substituted for the other.
This study was designed to determine the effect of pest control intensity on net returns in multiple cropping systems. The study is tempered with an evaluation of risk. The cropping system encompasses: turnip greens (Brassica rapa L.) for processing, field corn (Zea mays L.), and southern peas [Vigna unguiculata (L.) Walp. ssp. unguiculata] for processing. Within the ranges of pest control intensities studied, less intensive control resulted in higher net returns. Further, the level of greatest pest control intensity consistently yielded negative net returns. This level, however, was less risky in terms of gross returns. Risk did not differ significantly between the other levels of pest control.
Cover crops relay-cropped with vegetables with conservation tillage were compared with fallow conventional production for 10 years. Conservation till-relay received no pesticide and only one-quarter the recommended fertilizers. Winter cover provided significantly better weed control than conventional. Weed problems in relay occurred only in the rows where vegetables were planted. Legume winter covers increased soilborne organisms but did not influence root disease severity or postemergence damping-off. Thrips, aphids, and whiteflies were most frequent. These pests remained below the economic threshold with winter cover crop-relay. However, infestation of these pests and Colorado potato beetles was severe in conventional plots. Winter cover crops provided habitat for more than 14 beneficial insects.