PLANT-POPULATION INFLUENCE ON SQUASH YIELD, SWEET-POTATO WHITEFLY, SQUASH SILVERLEAF, AND ZUCCHINI YELLOW MOSAIC

Zucchini squash (Cucurbita pepo L.) fruit yield and the incidence of s weetpotato whitefly (SPWF) [Bemisia tabaci (Gennadius)], squash silver leaf (SSL) disorder, and zucchini yellow mosaic virus (ZYMV) were mea sured during Spring and Fall 1991 in experiments containing various pl ant populations. In both experiments, as the within-row spacing increa sed from 30.5 to 76.2 cm or the number of plants per hill decreased fr om three to one, the number of marketable fruit per hectare decreased, and the marketable fruit per plant increased. Adult SPWF populations increased with decreased within-row spacing in the spring but not the fall experiment. The incidence of SSL or ZYMV infection was not affect ed by plant population in either experiment. The results indicate that increasing zucchini squash plant population can increase yield withou t affecting the incidence of SSL or ZYMV.