Invasion of greedy scale crawlers (Hemiberlesia rapax) onto kiwifruit from taraire trees

Abstract

Taraire (Beilschmiedia tarairi) trees arc commonly found in association with kiwifruit orchards on the free draining volcanic soils in Northland. Greedy scale Hemiberlesia rapax (Comstock) (Hemiptera: Diaspididae) were monitored from taraire leaves in 1985-86. A small stand (100x250 m) of taraire adjacent to a kiwifruit (Actinidia deliciosa) orchard was estimated to contain 1-4 million mature scale. Greedy scale crawler activity on the taraire was assessed using sticky tape traps. Aerial dispersal of crawlers was monitored in the kiwifruit orchard adjacent to the taraire using sticky glass traps. Potted kiwifruit trap plants, which had been kept free of scale, were placed in the orchard to measure crawler dispersal and settlement. Two main periods of crawler release, aerial dispersal and settlement occurred in November-January and March-May. These results show that greedy scale can invade kiwifruit orchards in high numbers from adjacent host plants such as taraire.