ABSTRACT
Of the various species that make up the family Pseudococcidae, Planococcus citri, known as the white mealybug, has been reported as an important pest afflicting various crops. Considering the great environmental variability to which this insect is submitted, this study was aimed to investigate the biological aspects of this bug on coffee trees (Coffea arabica) at different temperatures and to determine its heat requirements. The experiment was conducted in chambers acclimatized at 70 ± 10% UR, 12-hour photophase, and temperatures of 15, 20, 25, 30 and 35º C. The results obtained showed that temperature influenced the nymphal development of P. citri,except the second instar of males. The duration of the nymphal period of females ranged from 77 to 30 days when temperature was raised from 15 to 30º C, and longevity of females was longer for the extreme conditions (15 and 30º C). In the nymphal period, there was 100% of mortality when exposed to 35º C, and 30% at 25º C. The development velocity as related with temperature fit the linear hyperbolic model. Analysis of the heat-requirement data revealed that the lower limit of temperature (Tb) was lower for the different instars of males in relation to females. The results indicated that low temperatures prolonged the insect’s development and that the most favorable temperature was 25º C, while the most unfavorable were 15 and 35º C.
KEY WORDS
Coffea arabica
; Coccoidea; biology; temperature