Encarsia perniciosi (Tower)

Encarsia perniciosi is a monophagous, host specific, solitary ectoparasitoid of Quadraspidiotus perniciosus. It is believed to be a native of the Far East. It has been introduced into India from several places in USA, Russia and China. Most of these races are morphologically indistinguishable, but differ in certain biological characteristics such as fecundity, rate of development, presence of males and adaptability to extreme environmental conditions. The parasitoid has established in all apple growing San Jose scale endemic areas. Till recently the parasitoid along with other native natural enemies was quite effective but with the resurgence of apple scab disease the orchardists have started spraying their orchards frequently not only with various fungicides but also sometimes by mixing insecticides. This has necessitated periodic colonization of the parasitoid even in those areas where it had been well colonised.

The scale infested pumpkin is exposed to Encarsia perniciosi females in the ratio of 20:1 for 24 hrs when the scale insect is about 12 day old. The adult parasitoids are fed on honey streaks provided on butter paper. The female lays its eggs singly in the body cavities of the scales. The exposed pumpkins are either not disturbed from the original cage and the parasitoids are allowed to develop or one date of pumpkins are stacked in a rack and at least 2 days before the date of emergence, pumpkins which have been shifted to racks are placed in the cages for facilitating the easy collection of adult parasitoid. The pupation takes place inside the body of the parasitized scale which gets mummified. The parasitoids emerge within 3 weeks of ovipositing by the female parasitoid. Each female is capable of parasitising up to 90 scales. The number of pumpkins, the frequency of infestation etc. could be determined depending upon need.