Howard (Hymenoptera: Encyrtidae) are larval parasitoids of the cassava mealybug, Phenacoccus herreni Williams & Cox (Sternorrhyncha: Pseudococcidae). To control epidemic outbreaks of this cassava pest in South America, they were used in successful mass release programs (Bellotti et al., 1999). It was shown in a previous study (Bertschy et al., 1997) that both encyrtid wasps are attracted to infested cassava plant odors and preferred these significantly over healthy plant odors. As yet, it is unclear whether this
