Evaluation of Some Reproductive and Developmental Parameters of Paracoccus Marginatus (Hemiptera: Pseudococcidae) Under Laboratory Conditions

Abstract

The papaya mealybug Paracoccus marginatus Williams and Granara De Willink (Hemiptera: Pseudococcidae) is an invasive insect species attacking a diverse range of host plants. It causes an enormous damage to crops including those of very great economic importance including the papaya, being its main host. Considering its potential threat to fruit and crops of economic importance throughout Togo, this study, which was carried out in the laboratory under conditions of 28 ± 2°C, 75 ± 5% RH, 12 : 12 LD, made it possible to determine some biological parameters of P. marginatus, essential for the implementation of management programmes for this species. The results showed that a female of P. marginatus had three periods of reproductive activity, namely pre-oviposition, oviposition and post-oviposition periods which last on average 7.74 ± 1.26; 6.13 ± 3.02 and 7.45 ± 4.27 days respectively. During oviposition, a female P. marginatus lays an average of 25.262 ± 11.16 eggs per day, for an average total of 224.32 ± 29.99 eggs during her lifetime, which averages 18.44 ± 3.31 days. During the post-embryonic development of P. marginatus which lasts on average 25.98 ± 4.47 days for the female against 29.70 ± 5.58 days for the male and which passes through three larval stages, the important mortality rates of the first and second larval stages were noted. They are estimated to an average of 61.40 ± 0.05 and 52.8 ± 0.025 respectively. However, at the third stage, the rate is 35.02 ± 0.03 for the female and zero for the male. These results provide a better understanding of the biology of P. marginatus under local conditions and thus provide a basis for controlling the population of the species and the damage it causes in Togo.