| Popis: |
Colarado potato beetle resistance to organophosphorous insecticides has been resistered in Croatia in 1986, to pyrethroids – in 1988. The field experience was confirmed in laboratory tests indicating a spot resistance pattern due to constant use of the same insecticides in same regions. Out of safer insecticides the insect growth regulators (IGR) and Bacillus thuringensis subsp. tenebrionis (Btt) were tested. The both groups of products show initial action, but differ in their residual activity: the IGR – up to 22 days, the Btt – up to 10 days. Optimum timing of the application for both groups is when 20-30% eggs have hatched and the first second instar larvae are present. |
