Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Effect of seasonal augmentation of Leptomastix dactylopii How. on Planococcus citri (Risso) population.

Abstract

Releases of Leptomastix dactylopii were made in 1991 and 1992 in a coffee plantation in Karnataka, India, following infestations by Planococcus citri. A total of about 9750 adults of the parasitoid were released in 6 batches in January-March,1991, and March-April, 1992. Parasitized pests were recorded about 30 days after the first release. In 1991, parasitism increased to a maximum of 52.03% by June and in 1992, to a maximum of 22.22% by July. Before the releases, in January 1991, the population of P. citri was 4.44 healthy individuals/node. This decreased to 0.59 healthy and 0.64 parasitized individuals/node by June. In March 1992, 3.78% of pests were parasitised, indicating that a small population of the parasitoid had persisted. The numbers of healthy and parasitised P. citri fell from 13.22 and 2.17 individuals/node, resp., in April 1992 to 0.25 and 0.07 individuals/node, resp. in July 1992. It is concluded that L. dactylopii can reduce a population of P. citri if it is released when the pest population is small and if augmentative releases are subsequently used.