New Zealand Plant Protection 53 (2000), Efficacy and timing of insecticides for the control of San José scale on apple

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New Zealand Plant Protection 53 (2000): 13-17

Efficacy and timing of insecticides for the control of San José scale on apple

P.W. Shaw, S.J. Bradley and J.T.S. Walker

ABSTRACT

Applications of lime sulphur, mineral oil, neem and the insect growth regulator, fenoxycarb were compared to diazinon and chlorpyrifos for control of San José scale. Lime sulphur, fenoxycarb and neem significantly reduced fruit infestation by scale insects at harvest relative to untreated trees but not to the same extent as the organophosphate insecticides, diazinon and chlorpyrifos. Mineral oil (1%) gave a level of control intermediate between these two groups of treatments. A second trial compared November applications of two rates of oil with chlorpyrifos. The only treatment to significantly reduce scale incidence on fruit in late January was the 2% rate of oil. A third trial examined the effectiveness of two dates of oil application in late summer. Application on 24 February reduced the incidence of scale infested fruit more than applications on 8 March. This was possibly due to dead scale still being present on the fruit.

Keywords: San José scale, mineral oil, fenoxycarb, neem, application timing.