Kim, S.B., & Kim, D. 2013 Temperature-dependent fecundity of overwintered Unaspis yanonensis (Hemiptera: Diaspididae) and use of degree-days for the prediction of first crawler. Crop Protection 43: 60-64

Notes: The longevity and fecundity of the overwintered arrowhead scale, Unaspis yanonensis (Kuwana) (Hemiptera: Diaspididae), was examined at constant temperatures. The total fecundity increased up to 24
C and declined thereafter. Total fecundity reached a maximum of 260.9 eggs per female at 24
C. Females demonstrated periodic oviposition activity but the pattern differed with temperature. The first cycle of fecundity was not significantly different between 16 and 28
C. However, fecundity in the latter cycles, measured at rearing temperatures of 16, 20 and 32
C, was lower than at 24 and 28
C. The preoviposition period ranged from 49.0 d at 16
C to 19.7 d at 32
C, and was shortest (19.4 d) at 28
C. The longevity was found to be greatest (87.3 d) at 16
C and was as short as 48.9 d at 32
C. Regression of the mean development rate vs. temperature provided a low-threshold temperature estimate of 8.7
C for the pre-oviposition stage and a thermal constant of 358.4 degree days. The theoretical low threshold temperature and thermal constant applied to the calculation for the completion of the U. yanonensis pre-oviposition period predicted the appearance of first crawlers in the field.