Greedy scale, <i>Hemiberlesia rapax</i> (Hemiptera: Diaspididae), phenology on kiwifruit leaves and wood

Abstract

Abstract Greedy scale ( Hemiberlesia rapax (Comstock)) populations at Whangarei, New Zealand were monitored at regular intervals on unsprayed kiwifruit ( Actinidia deliciosa (A.Chev.) C.F. Liang et A.R. Ferguson var. deliciosa ) wood and leaves from 1984 to 1989 to obtain detailed stage‐specific phenological information. The relationship between relative abundance of each scale stage and Julian day or degree‐day accumulation (&gt;9.3°C) were determined using a Bayesian smoothing programme. Two scale generations, summer and winter, were readily discernible. There was close agreement between the phenology of scale on wood and leaves. However, because of senescence and abscission in autumn there was only a partial winter generation of scale on leaves. Synchrony of stage‐specific events was enhanced using degree‐day accumulations rather than Julian days, particularly for the winter generation. Estimates of stage‐specific peaks and troughs for crawlers, white caps (first instar), yellow caps (second instar), black caps (third instar), and mature scale are given in the paper and have a mean standard error (SE) of 10 Julian days or 38 degree‐days (&gt;9.3°C). Mean generation intervals for scale on wood and leaves were 1022 (SE 18) and 1114 (SE 53) degree‐days respectively.