Orange tortrix on grapes in Salinas Valley
The orange TORTRIX, Argyrotaenia citrana (Fernald), caused considerable damage to grapes in vineyards near Soledad in the Salinas Valley during 1968 and 1969. This insect is morphologically identical to the “apple skin-worm” which is a pest of several deciduous fruit trees and other plants in several northern California coastal counties. So far, it has not been found on grapes in Napa, Sonoma, or Mendocino Counties. In addition to contaminating the grape bunches, the principal damage is caused by the larvae feeding on the berries and stems within the berry clusters. Stem feeding in the cluster causes berry drop and, in some cases, when the stem is cut or girdled, portions of the cluster below the injury are killed. Larval feeding on berry clusters may also provide an avenue for infection by spoilage microorganisms.