Within-plant distribution of squash bug (Heteroptera: Coreidae) adults and egg masses in vegetative stage summer squash

Within-plant distribution of squash bug, Anasa tristis (De Geer), adults and egg masses on spring plantings of summer squash was determined by making whole-plant visual examinations. A significantly greater percentage of adults was found on the soil surface than on plants in early stages of crop phenology (>10 leaves per plant). On plants with greater numbers of leaves, squash bugs were found predominantly on plants. Studies of distribution of egg masses indicated that >90% of squash bug oviposition occurred on abaxial leaf surfaces. A significantly greater percentage (90%) of egg masses was deposited on leaves in the lower one-half of plants during vegetative plant growth. Average weighted mean egg mass location on plants was found to be highly correlated (P < 0.01) with the number of leaves per plant. Results of this study suggest that sampling procedures should be developed separately for adults and egg masses. Monitoring for adults should include examination of both the plant and soil surface, whereas sampling for egg masses should concentrate primarily on the lower foliar canopy.