The effect of increasing mating delay on the reproductive performance and population growth rates of the vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), was investigated under laboratory conditions. Virgin females were mated at 1, 3, 5, 7, 14, 21 and 28 days after emergence and reproductive and life table parameters were estimated. The pre-oviposition period (number of days between mating and the onset of oviposition) significantly decreased in females mated within 7 days, whereas females mated at older ages showed equivalent pre-oviposition periods (<4 days). The length of the oviposition period did not vary with increasing age at mating. Female longevity significantly increased in females mated at 21 and 28 days, as a consequence of a longer pre-reproductive period. Fecundity and sex ratio were not affected by the female age at mating, whereas fertility was higher in mealybugs mated at older ages. Additional field observations highlighted that young and old virgin females were equally able to attract males, as both mated on the same day as the field release. Mating delay also affected the life table parameters of P. ficus, as the intrinsic and finite rates of increase did not differ in mealybugs mated within 7 days and significantly decreased in females mated at older ages. The mean generation time and the population doubling time were overall similar in females mated at 1–7 days, and increased significantly in females that experienced longer mating delays. In terms of the mating disruption control of P. ficus, our findings indicate that this method would be effective if mating is delayed >7 days, as shorter delays in mating did not reduce the population growth rates.

The use of pheromones to disrupt mating behaviours is perhaps the most promising method for controlling the sugarcane pest Dasylepida ishigakiensis Niijima et Kinoshita, also known as the white grub beetle. Herein, based on laboratory observations of mating, oviposition and hatching behaviours in the white grub beetle, we suggest guidelines for the timing and length of sex-pheromone release in the field. In the present study, we collected virgin female adults early in the mating season (4 February) in sugarcane fields in Okinawa, Japan and mated them in the laboratory after different time intervals with males collected at the same time. We investigated the effects of delayed mating on mating success, timing of oviposition, female longevity after mating and progeny hatchability. Mating success – defined as the proportion of mated females that produced progeny – and hatchability were not significantly affected by mating delays of less than 31 days, although further delays dramatically decreased these parameters. Female life span and the time between mating and oviposition were unaffected by mating delay. Similar results were obtained for laboratory-reared adults mated on day 45, 60 or 80 after adult emergence. Based on these findings, we propose that releasing synthetic sex pheromones between mid-January (i.e. shortly before the start of the mating season) and late March would be optimal for disrupting the mating behaviours of this beetle in the field.