Temperature requirements and generation number estimates of croton mealybug reared in Rangpur lime

Abstract

The objective of this work was to determine the temperature requirements for the development of croton mealybug (Praelongorthezia praelonga) and to estimate the number of year generations at the state of São Paulo, Brazil, counties of Bauru, Barretos, São José do Rio Preto, Bebedouro, Avaré, Araraquara, Itapetininga and Limeira. In order to determine stage durations of egg and nymph stages, and their temperature requirements, the insects were reared on Rangpur lime (Citrus limonia) seedlings at 18, 20, 22, 25, 28, 30 e 32°C, under 70±10% relative humidity and a 14-hour photofase. Developmental stages and biological cycle (egg–adult) durations were affected by temperature, and higher values of these parameters were obtained at lower temperatures. The lowest temperature development threshold (TT) and thermal constant (K) for egg and nymph stages and for the egg–adult period were 6.16°C and 398.40 degree-days (DD), 12.10°C and 374.50 DD, and 10.28°C and 735.29 DD, respectively. Based on the air temperature average values from the evaluated counties, the number of generations per year varies from 4.99 to 6.60.