Pesticide-free protection of white cabbage against Thrips tabaci Lindeman

Abstract

In autumn 2002 field screening tests were carried out at the National Institute for Agricultural Quality Control in order to assess the susceptibility of 52 white cabbage varieties to Thrips tabaci. The evaluation based on the degree of damage occurring on the head leaves. In case of each variety, all the damaged leaves of 10 mature cabbage heads were marked with the appropriate value of the six-degree damage rating scale created for the procedure. The ratings for each leaf expressed the size of the damaged surface proportional to the surface of the whole leaf. Varietal resistance was represented by the sum of these values (proportional to the surface of the first head leaf) expressing the damage observed on the whole head. The number of damaged leaves was also counted. All varieties suffered smaller or greater damage. However, 'Bariton', 'Bently', 'Desmond', 'Avalon', 'Masada' and 'Transam' were the least damaged and described as resistant varieties, therefore recommended for late autumn cabbage production. The damage decreased from month to month from September till December.