Male response to sex pheromone emission in Mediterranean populations of the long-tailed mealybug (Hemiptera: Pseudococcidae).

A new pherotype for Mediterranean populations of the long-tailed mealybug Pseudococcus longispinus (Targioni Tozzetti) has been recently identified as producing the new compound 2-(1,5-dimethyl-4-methylenecyclopent-2-en-1-yl)ethyl acetate. To study the effects of sex pheromone emission on males, the attractant efficacy of different emission rates of this compound has been studied under field conditions. For this purpose, experimental pheromone dispensers were designed, and their release profiles were studied by gas chromatography to obtain their mean release rates. Male trap captures were correlated with the corresponding pheromone release rates to explore the existence of an optimal emission value or range that maximizes the captures. The resulting correlation fitted a quadratic model, with a relative maximum of captures corresponding to a theoretical optimal emission rate of 66 μg/d. Nevertheless, no significant differences were found in male captures among emission rates between 2 and 147 μg/d, which indicates a wide range for effective trapping. The highest pheromone emission studied (502 μg/d) obtained the lowest captures, suggesting a possible repellent or male impairment effects to locate the source of the sex pheromone at high doses. The application of the results obtained for control techniques such as monitoring, mass trapping, or mating disruption is discussed.