POSSIBILITY OF USING ENTOMOPATHOGENIC FUNGI BEAUVERIA BASSIANA FOR CONTROLLING THE ASH WEEVIL (STEREONYCHUS FRAXINI)

Jasenova pipa spada među najopasnije štetnike jasena, a štete čini i na drugim vrstama. Dosadašnje suzbijanje svodi se na primjenu kemijskih pesticida u stadiju ličinke. Kako se primjena kemijskih pesticida ograničava, prednost se daje pripravcima na biološkoj bazi. Entomopatogena gljiva Beauveria bassiana u znatnoj mjeri napada prezimljujuća imaga jasenove pipe, a pozitivni rezultati ispitivanja na drugim vrstama iz porodice pipa (Curculionidae) opravdavaju istraživanja mogućnosti primjene ove gljive za suzbijanje jasenove pipe. Ovim istraživanjem htjelo se utvrditi potencijal B. bassiana kao biološkog sredstva za suzbijanje jasenove pipe. S tim u svezi uspoređena je efikasnost eksperimentalnog soja BB1 iz Mađarske i autohtonog soja dobivenog iz uginulih zaraženih imaga iz Lipovljana. Pokus s eksperimentalnim sojem BB1 iz Mađarske nije pokazao utjecaj na mortalitet imaga, dok je pokus kontaminacije sporama s uginulih zaraženih imaga iz Lipovljana pokazao ugibanje 83 % imaga jasenove pipe od mikoze koju je uzrokovala B. bassiana. Ujedno je ojačana pretpostavka o koevolucijski razvijenom soju gljive patogenom za lokalne populacije kukca te utvrđen potencijal gljive B. bassiana kao biološkog sredstva za suzbijanje jasenove pipe. Daljnja istraživanja treba usmjeriti prema masovnoj proizvodnji spora i terenskom ispitivanju u šumi.Ash weevil (Stereonychus fraxini) is one of the most dangerous pests of ash, it also damages olives, and some other tree species. So far, suppression has been conducted by mainly using chemical pesticides during the developmental stages of larvae, which has not prevented major damage resulting from beetles (regeneration devouring?). Because of environmental concerns, the use of chemical pesticides is restricted and development of selective biological pesticides is proposed. A significant effect of the entomopathogenic fungi Beauveria bassiana on overwintering adults of ash weevil, together with the positive results of tests on other species of the weevil family (Curculionidae), suggest that the possibility of applications of the fungus to control ash weevil should be studied. This study was carried out in order to determine the potential of B. bassiana as a biological agent for the control of ash weevil, and to compare the efficacy of an experimental strain BB1 from Hungary and native, yet undefined, strain from fungus-infected dead beetles from Lipovljani. Trial with the experimental strain BB1 from Hungary showed no effect on mortality of adults, while contamination by spores from dead infected beetles from Lipovljani showed a significant effect on mortality caused by the entomopathogenic fungi (83%). This strengthened the assumption of the coevolutionary developed strain of fungi, pathogenic for the local population of insects and strengthened the potential of B. bassiana as a biological control agent to control ash weevil