Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Requirement of dormant spray oil for the suppression of San Jose scale, Quadraspidiotus perniciosus (Comstock) on apple.

Abstract

Studies to determine the requirement of using miscible oil as a tree spray oil on the basis of fruit infestation revealed that apple orchards in Himachal Pradesh, India, with 11% fruit infestation with Quadraspidiotus perniciosus before treatment during 1989 showed no infestation during 1990, whereas 27.5% of fruits were infested on untreated trees. During 1991, some regeneration (1.6%) of the pest was recorded from fruits of treated trees while untreated trees had sizeable infestation (36.2%). A repeat spray given during 1992 considerably reduced the diaspidid infestation on fruits, suggesting that sprays applied in alternate years help to minimise the cost of treatment and also keep diaspidid populations in check.