Comparative Effect of Different Insecticides and Processed Kaolin on Cacopsylla pyr i 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 resistan 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%). Cacopsylla pyri L. (Hemiptera: Psyllidae) jedan je od najozbiljnijih gospodarskih štetnika kruške u istočnoj Hrvatskoj. Dosadašnje metode suzbijanja štetnika u Republici Hrvatskoj dovele su do rezistentnosti kruškine buhe na pojedine insekticide. Ciljevi dvogodišnjega istraživanja bili su odrediti optimalan broj tretmana s ciljem suzbijanja štetnika na temelju praćenja životnoga ciklusa te utvrditi učinkovitost kaolina u usporedbi s drugim kemijskim insekticidima u četiri različita tretmana (T1: integrirane zaštite bilja (IPM) – diflubenzuron, spirotetramat, abamektin, acetamprid; T2: akrinatrin + abamektin, T3: kaolinska glina, T4: kontrolni tretman). Istraživanje je provedeno 2017. i 2018. godine na pokusnome nasadu kruške starosti šest godina, na tri sorte (Williams, Conference, Abate Fetel) Praćenje populacije štetnika i njezinih razvojnih stadija obavljeno je na dva jednogodišnja izbojka po stablu svake sorte u svim ponavljanjima. Tretman T1 pokazao je najbolje rezultate, s najvećom učinkovitošću od 84 – 95 % ovisno o godini istraživanja, dok je tretman s kaolinom imao najnižu učinkovitost, koja je varirala u odnosu na godinu (37 – 71 %).