Armoured scale, hemiberlesia lataniae and h. Rapax (hemiptera: Diaspididae), infestation of kiwifruit rejected for export at two packhouses from 1987 to 1991

Abstract

Kiwifruit rejected for export because of armoured scale contamination were collected from a packhouse in Kerikeri and another in Whangarei, New Zealand from 1987 to 1991. A subsample of up to 50 scale infested fruit from each orchard was examined for scale. The 5 640 fruit which were examined yielded 14 390 scale. Latania scale, Hemiberlesia lataniae (Signoret), comprised 84% of the scale from Kerikeri and greedy scale, Hemiberlesia rapax (Comstock), 96% of the scale from Whangarei. No other scale species was found. First and second instar were the most common stages, except for the last 3 years at Kerikeri, when mature third instar predominated. The mortality of all scale stages ranged from 60 to 91%, except in 1988 at Kerikeri when a high proportion of live first instar reduced mortality to 44%. Of the supposed scale infested fruit, 56% had a single scale, 15% had no scale, and the remainder had multiple infestations. Most multiple infestations (82%) had at least one mature scale associated with immature scale indicating the survival of the first generation scale through to reproduction. Over the 5-year study period 34% of Kerikeri and 15% of Whangarei orchards submitted crop with >20 scale/ 1000 trays. Mature scale were responsible for the greatest proportion of reject fruit and are therefore the most important stage to try and control. These findings highlight the need to prevent the establishment of the first generation scale after fruit set and the second generation scale before harvest. © 1992 The Royal Society of New Zealand.