Population features of biparental and uniparental forms of the oleander scale, Aspidiotus nerii Bouche, 1833 (Hemiptera: Diaspididae) on squash

Abstract

Aspidiotus nerii Bouche, 1833 (Hemiptera: Diaspididae) is a cosmopolitan pest, mainly found in tropical and subtropical regions. It has been reported from hosts corresponding to more than 100 plant families. Particularly important is the damage caused on lemon and olive trees and ornamental plants such as oleander. It has both biparental and uniparental forms. To investigate the population dynamics of both forms of pest, life tables were constructed under controlled conditions in 2016. The studies were carried out on squash in climatic cabinet adjusted to 25 +/- 1 degrees C, 65 +/- 1% RH and 16: 8 h L: D photoperiod. At the end of the study, life table parameters of both forms of pest were calculated. Namely intrinsic rate of increase (r), 0.039 and 0.042 d(-1); finite rate of increase (lambda), 1.040 and 1.043 d-1; net reproductive rate (R-0), 14.07 and 27.19 d(-1); mean generation time (T), 67.51 and 78.49 d, for biparental and uniparental forms, respectively. R-0 and T were statistically significant different between the two populations. Given these differences, it was estimated that the population size of the uniparental form may be 1.9 times higher than the biparental form.