Consumption of Black Cherry Leaves by Phytophagous Insects

Abstract

Black cherry (Prunus ser?tina Ehrh.) was the third most prevalent tree (11% of the total stems, 15% of the total importance value) growing in a 40-year-old, intermediate tree stage of an old-field sere in the Youngstown State University Arboretum. Leaf drop of black cherry comprised 42, 42, 64 and 76% of the aboveground primary production of dry matter, energy equivalents, nitrogen and ash, respectively. Fruit drop accounted for 3.5, 3.5, 4.7 and 2.6% and twig drop 1.7, 1.8, 2.3 and 2.2%, respectively, for dry mass, energy equivalents, nitrogen and ash of the aboveground primary production. Total leaf consumption by phytophages was 2.9, 3.0, 5.1 and 2.1% of the leaf fall for dry mass, energy, nitrogen and ash, respectively. Low consumption early in the growing season is contrary to comparable studies. Decreasing leaf cyanide levels, leaf water content, pr?dation, increasing parasitism and leaf toughness are suggested as causes for the observed seasonal changes in phytophage densities. The movement of energy, nitrogen or minerals through the phytophage component is low relative to the total movement in a black cherry tree system. The importance of normal phytophage densities is not their contribution to energy flow and material cycling but is related to their ameliorating effects on disruptive phytophage densities by maintaining an innoculum of parasites and predators that respond to phytophage outbreaks.