Comparative Effect of Different Insecticides and Processed Kaolin on Cacopsylla pyri L. Population Reduction

Cacopsylla pyri L. (Hemiptera: Psyllidae) is one of the most serious economic pear pests in Eastern Croatia. Previous methods of pear control in the Republic of Croatia have led to the development of an insect population resistant to certain active ingredients. The objectives of this two-year study were to determine the optimal number of treatments for psylla control based on the monitoring of pest life cycle and to determine the effectiveness of processed kaolin in controlling the pear psylla in comparison with other chemical insecticides in four different treatments (T1. IPM-integrated protection program – diflubenzuron, spirotetramat, abamectin, acetamprid; T2. acrinatrin + abamectin, T3. kaolin clay, T4. control treatment). The research was conducted in 2017 and 2018 in a six-year-old experimental pear orchard on three varieties (Williams, Conference, and Abate Fetel). Monitoring of the pest population and its development was performed by visual inspection on two one-year shoots per tree of each variety in all replicates. The T1 treatment demonstrated the highest efficiency, between 84-95%, depending on the year, while the kaolin treatment had the lowest one, but it varied greatly from one year to the other (37-71%).