Temperature-dependent Development of the Cycad Aulacaspis Scale, Aulacaspis yasumatsui (Hemiptera: Diaspididae)

Ronald D. Cave, Cora Sciacchetano, Rodrigo Diaz

Abstract


Egg duration period, immature development time, and pre-oviposition period of the cycad aulacaspis scale, Aulacaspis yasumatsui Takagi, were measured at 9 constant temperatures in the laboratory. Egg duration period ranged from 15 d at 20°C to 7 d at 30°C. First instar development time was 30 d at 18°C but only 4 d at 35°C. No first instars completed development below 18°C or above 35°C. Development time of second instar females ranged from 19 d at 18 and 20°C to 9 d at 30°C. Development time of male second instar + pupa ranged from 15 d at 20°C to 9–10 d at 25–32°C. Pre-oviposition period averaged 14 d at 20°C to 8 d at 25– 32°C; no females laid eggs at 18 and 35°C. The lowest temperature threshold for all stages ranged from 8 to 12°C and 538 degree-days were required for female immature development in a linear model. Development rates of the scale are compared to those of 3 of its natural enemies, Cybocephalus nipponicus Endrödy-Younga, Rhyzobius lophanthae (Blaisdell), and Coccobius fulvus (Compere and Annecke).Translation provided by the authors.

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