Methods of Evaluating Pecan Cultivars for Tolerance to Feeding Damage Caused by the Black Pecan Aphid, Melanocallis caryaefoliae (Davis)

Abstract

Two aphid rearing methods were evaluated for their suitability of making biological observations on the black pecan aphid, Melanocallis caryaefoliae (Davis), and as rapid assessments of pecan cultivars for tolerance to aphid feeding damage. There were no significant differences in the biological and feeding damage data between the two experiments. In comparison, the agar method produced less aphid mortality, was easier to maintain, utilized less space, and would allow fewer samples to provide accurate results. ‘Melrose’ was the most tolerant of the nine cultivars evaluated for tolerance to feeding damage by the black pecan aphid using water agar plates. ‘Jubilee’, ‘Suprize’, and ‘82-17-680’ (Wichita open-pollinated) exhibited intermediate tolerance to feeding damage while ‘Salado’, ‘82-17-1316’ (Wichita open-pollinated), ‘Schley’, ‘Oconee’, and seedlings expressed little tolerance to damage caused by feeding. It has yet to be seen if there is a correlation between tolerance to aphid feeding defined by this experiment and actual resistance to the black pecan aphid in the field.