engleski

Implementation of pheromone traps in detecting click beetles population level in East Croatia

Wireworms as a larval stage of click beetles are serious underground pest in agricultural production. For that reason pheromone traps become more interesting not only for detecting population level, but for prediction of timing for insecticides implementation in order to reduce the amount of insecticides. The trials were carried out during 1998, 1999, 2000 and 2001, at the locality of the Agricultural Institute in Osijek, in eastern part of Croatia. Traps were baited with the pheromone composition for seven species from genus Agriotes. During 1998 and 1999 only traps type VARb was used. They are suitable only for flying species. In year 2000, traps type VARb and YATLOR were used. YATLOR traps are suitable for crawling species. In year 2001, traps type YATLOR funnel were used. Those traps were designed for both, crawling and flying species. For each investigated species two traps were operated from the beginning of March until the end of August. The check of traps was done once weekly. Replacement of sex pheromones capsule was once every month. Traps were put in the field under winter wheat. Analizing of the trap type showed that VARb traps captured more male click beetles of A. ustulatus, A. sputator, A. lineatus and A. rufipalpis, which is presumed because of their biology. Traps type YATLOR and YATLOR funnel were captured six different species of click beetles. Except above mentioned species they include A. brevis and A. obscurus. The most dominant species in eastern Croatia was A. ustulatus. The greatest number of A. ustulatus were recorded in 1998 (1159), followed by 2001 (587), 1999 (487) and 2000 (463) on VARb trap. The very first species appeared at the beginning of June (1999 and 2001), second decade of June in 1998, and at the end of May in 2000. The peak of flying was in the middle of the summer (July), while last specimens were captured at the end of August, except in 2001 when two beetles were captured on the 4th of September. In all investigated periods, traps baited for A. litigiosus did not capture any species. Wireworm population caught on sex pheromone traps seemed to be correlated with number of larvae caught by soil digging. Soil analyses showed also the greatest number of A. ustulatus larvae in all three years of investigations. Similar number of A. ustulatus was caught in 2000 and in 2001 although precipitations were very different. In 2000 dry period was in opposite with very moisture period in 2001. In all years of conducting studies, pheromone traps prove to be sensitive tool for detecting present wireworm population. YATLOR and YATLOR funnel traps caught six species of wireworms while VARb caught four species. This investigation showed that the sex pheromone traps type YATLOR funnel can be used to predict wireworms populations of the most wireworm species.

pheromone traps ; click beetles

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