Temperature thresholds and thermal requirements for development of Nasonovia ribisnigri (Hemiptera: Aphididae).

Abstract

Early detection of Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) on lettuce is of primary importance for its effective control. Temperature thresholds for development of this pest were estimated using developmental rates [r(T)] at different constant temperatures (8, 12, 16, 20, 24, 26, and 28 degrees C). Observed developmental rates data and temperature were fitted to two linear (Campbell and Muñiz and Gil) and a nonlinear (Lactin) models. Lower temperature threshold estimated by the Campbell model was 3.6 degrees C for apterous, 4.1 degrees C for alates, and 3.1 degrees C for both aphid adult morphs together. Similar values of the lower temperature threshold were obtained with the Muñiz and Gil model, for apterous (4.0 degrees C), alates (4.2 degrees C), and both adult morphs together (3.7 degrees C) of N. ribisnigri. Thermal requirements of N. ribisnigri to complete development were estimated by Campbell and Muñiz and Gil models for apterous in 125 and 129 DD and for both adult morphs together in 143 and 139 DD, respectively. For complete development from birth to adulthood, the alate morph needed 15-18 DD more than the apterous morph. The lower temperature threshold determined by the Lactin model was 5.3 degrees C for alates, 2.3 degrees C for apterous, and 1.9 degrees C for both adult morphs together. The optimal and upper temperature thresholds were 25.2 and 33.6 degrees C, respectively, for the alate morph, 27 and 35.9 degrees C, respectively, for the apterous morph, and 26.1 and 35.3 degrees C, respectively, for the two adult morphs together. The Campbell model provided the best fit to the observed developmental rates data of N. ribisnigri. This information could be incorporated in forecasting models of this pest.