Effect of Planting Date, Plant Spacing, and Weed Cover on Populations of Insects, Arachnids, and Entomophthoran Fungi in Potato Fields

Abstract

The average daily abundance of arachnids, carabids, coccinellids, ants, staphylinids, mummified aphids, and entomophthoran fungi was the same in 15- and 36-cm within-row seed spacings and over a wide range of weed cover. Carabids were significantly less abundant in herbicide-treated plots. The tests confirm previous observations that late plantings can significantly reduce populations of Macrosiphum euphorbiae and Aphis nasturtii. Of the other arthropods monitored, only the carabids showed a tendency for increased populations in early-planted potatoes.