Developmental rates and times , thermal thresholds and thermal constants for the lack bean aphid A. craccivora were studied in relation to field conditions during winter, spring , summer and fall to provide a data over a variety of temperature conditions.
Using both days and degree-days time scales, the developmental times for different stages were decreased as the temperature increased from winter through spring, fall early summer and mid summer, but higher temperatures in late summer resulted in a slower rate of development and a longer developmental times. The biophysical model predictions based on the regression equations describing the relationship between temperature and developmental rates , provided estimates of lower and upper temperature thresholds to be 6.8 and 34.0 C for the complete generation . Degree-day (DD) accumulations of 88.0, 8.2, 96.0 and 77.0 DD were required for completion of nymphal stages, pre reproductive period, aphid generation and reproductive period. A total of 163 DD was required for development from birth to death.
Although the model under estimated developmental rates in the field, it was consistent enough in its predictions to be useful on an empirical basis. The model should prove valuable for both research and pest management applications.
Species 1: Homoptera Aphididae Aphis craccivora (black bean aphid)
Keywords: DEGREE DAY, Egypt
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