Field biology of the cotton mealybug, Phenacoccus solenopsis (Hem.: Pseudococcidae) on Chinese hibiscus shrubs in Ahvaz, Iran

The cotton mealybug, Phenacoccus solenopsis Tinsley is an invasive pest species in tropical and subtropical regions and recently has caused severe infestations on Hibiscus rosa-sinensis L. in southern Iran. In the present study, field biology of this pest was investigated on Chinese hibiscus shrubs as its important host plant in Ahvaz during 2013-2014. Results indicated that P. solenopsis has completed 11 generations per year. The shortest generation times were 3rd, 4th and 5th from early May to early July which lasted 21.63±0.84, 21.48±1.01 and 23.11±1.55 days, respectively, with no significant difference. The 11th generation was the longest and occurred from early December to late March for 90.20±19.61 days. The reproduction mode in all generations was bisexual and none of unmated females did parthenogenetic reproduction. The highest fecundity was calculated as 432.15±35.00 offspring / female for 8th generation in September and the lowest belonged (10.58±1.33 offspring / female) to 10th generation in winter. The highest and lowest sex ratio of females in total population were obtained in 11th generation (%96) and 9th generation (%69), respectively. According to present results, the cotton mealybug has high reproductive potential on Chinese hibiscus shrub and is able to develop well in unfavorable hot summers of Ahvaz. These results can be used in control management of this pest.