New Zealand Journal of Crop and Horticultural Science abstracts
Armoured scale (Hemiptera: Diaspididae) distribution in kiwifruit blocks
with reference to shelter
R. H. BLANK
G. S. C. GILL
The Horticulture and Food Research
Institute of New Zealand Ltd
Whangarei Research Centre
Private Bag 9003
Whangarei, New Zealand
email: rblank@hort.cri.nz
B. W. DOW
The Horticulture and Food Research
Institute of New Zealand Ltd
Ruakura Research Centre
Private Bag 3123
Hamilton, New Zealand
Abstract Armoured scale insect (Hemiptera: Diaspididae) leaf
infestations were monitored from rows of kiwifruit
(Actinidia deliciosa
(A.Chev.) C.F. Liang et A.R. Ferguson var.
deliciosa) vines in three
blocks at each of 11 sites, at 3-8 times from December until May. The
relationship of scale leaf infestation with distance across kiwifruit blocks
(scale distribution) was analysed using different regression models. Scale
distributions were best described using linear models for 26 kiwifruit blocks
and for seven blocks using quadratic models. Scale distributions derived using
live scale followed similar patterns to those derived from total scale. Overall
53% of sites or blocks had significant linear or quadratic scale distributions.
Kiwifruit blocks with high scale infestations invariably had significant scale
distributions whereas those with low infestations had non-significant
distributions. The finding of significant relationships using regression models
with parallel lines or curves for different sampling times at some sites,
showed scale distributions hold throughout the season. In the simplest
situation scale infestations were highest in kiwifruit rows adjacent to
alternative host plants and declined linearly away from the scale source. These
findings were consistent with the hypothesis that scale distributions were
caused by the aerial dispersal of crawlers from alternative host
plants.
Keywords armoured scale; Diaspididae; kiwifruit;
distribution; Hemiberlesia rapax; Hemiberlesia lataniae;
Aspidiotus nerii; Actinidia deliciosa
H98020
Received 11 May 1998; accepted 14 September 1998
PDF file of entire paper: medium quality (766K); (scanned from paper original: notes about this process)
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