The role of fungus Beauveria bassiana in reducing the number of Pissodes castaneus (Col., Curculionidae) in young forests

Small banded pine weevil Pissodes castaneus is one of the most dangerous pests of Pinus sylvestris plantations and thickets. The lack of effective and environmentally safe methods of limiting the number of the pest justified to undertake the studies aimed at the laboratory and field evaluation of biological activity of entomopathogenic fungus Beauveria bassiana used to reduce the numbers of small banded pine weevil. In laboratory, the beetles were reared on the sections of fresh Scots pine twigs that were treated with five suspensions containing from 1 × 10 to 1 × 10 conidia of B. bassiana in 1 ml. During the 3-week rearing, insect mortality was determined and median lethal concentration LC was calculated. The field treatments consisted of spraying 4-year-old P. sylvestris trees with two formulations of fungus containing 1 × 10 conidia ml of suspension. Treatments consisted of spraying 4-year-old P. sylvestris trees with two fungus formulations containing 1 × 10 conidia ml High insecticidal activity of B. bassiana was found because the pathogen caused the death of 14-94% of P. castaneus beetles, LC = 6.51 × 10 conidia ml . Field treatments did not result in the reduction of plant damage caused by small banded pine weevil; therefore, the spraying of trees with B. bassiana cannot be recommended to protect the young stands of P. sylvestris against pest.