Effects of Feeding by Monelliopsis nigropunctata, Monellia caryella, and Melanocallis caryaefoliae on Growth of Pecan Seedlings in the Greenhouse1

Abstract

The foliar-feeding aphids, Monelliopsis nigropunctata (Granovsky), Monellia caryella (Fitch), and Melanocallis caryaefoliae (Davis) seriously affected the main stem and root growth of potted pecan seedlings in the greenhouse. All three species reduced the dry weight of roots and main stems and the chlorophyll content of the foliage. M. nigropunctata had the greatest effect on seedling growth and, in addition, reduced the size of the foliage. M. nigropunctata and M. caryaefoliae exhibited the greatest reduction in chlorophyll content. Starch content of the roots was reduce, but there was no difference among the three species. Starch and total carbohydrate content of the stems also was reduced by the three species, although it was not as severely reduced as in the roots. Honeydew produced by each of the three species was composed of fructose, glucose, inositol, and sucrose.