No upper threshold has been demonstrated at which scale problems will occur in spite of several years' trial work. Until this is done it could be suggested that almost any low scale leaf threshold may be adequate to give confidence to growers to omit sprays, particularly in an industry in which most growers were over-spraying because they were following the recommended calendar export spray programme designed to avoid insect damage and contamination under high risk situations. In spite of the scientific difficulties associated with validating the scale sampling technique and chosen threshold, these methods have assisted growers to move from calendar to managed spraying regimes. We would like to thank the many kiwifruit growers who have allowed their orchards to be used in both the insecticide and threshold trials. Our thanks to Mrs J.M. Kelly and Mrs N.B. Tapper for leaf and fruit assessments and to Ms B. Dow for biometrical advice.
Growers keen on kiwigreen.
Blank, R.H., Olson, M.H. and Gill, G.S.C., 1992. N.Z. J. Crop and Hort. Blank, R.H., Olson, M.H. and Lo, P.L., 1990. N.Z. J. Crop and Hort. Lo, P.L. and Blank, R.H., 1989.