Journal of Pest Science (2007) 80, 217-223

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Stanislav Trdan, Nevenka Valic and Dragan Znidarcic (2007)
Field efficacy of deltamethrin in reducing damage caused by Thrips tabaci Lindeman (Thysanoptera: Thripidae) on early white cabbage
Journal of Pest Science 80 (4), 217-223
Abstract: Our research assessed how the number of sprayings with deltamethrin influenced the efficiency against onion thrips, Thrips tabaci, on early white cabbage. The study was performed in 2002 and 2005 using the early white cabbage cultivar Parel, which is very susceptible to the attack of onion thrips. The cabbages were planted in a block-design experiment, with percentage of damage on the exterior leaves recorded according to the positions of the leaves (i.e. outer to inner). Although the attack of thrips was much greater in 2002 than in 2005, nevertheless, control plants in both years showed much more damage than plants with at least one insecticide spraying. In 2002, there was little difference between one and two sprayings, but three sprayings showed a significantly improved result. However, three sprayings of this insecticide is generally not permitted in farming practice. In 2005, no differences in efficacy among one, two and three sprayings were recorded. We also assessed a high threshold (up to 10% damaged leaf surface) and low threshold (up to 1% damaged leaf surface) for the removal of damaged leaves. In 2002, both thresholds were exceeded for control plants, but in 2005, the attack of thrips was mild enough that neither threshold was exceeded. In this case, one spraying was sufficient to reduce leaf damage below the higher (more tolerant) threshold, but three sprayings were needed to reduce leaf damage below the lower (more stringent) threshold. Therefore, in Slovenia or other parts of the world with similar climatic conditions, we recommend one spraying as broadly effective and recommend the more tolerant threshold for leaf removal.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Stanislav Trdan

Research topic(s) for pests/diseases/weeds:
control - general

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Thrips tabaci Cabbage (Brassica oleracea) Slovenia