Utjecaj hrastove mrežaste stjenice Corythucha arcuata na visinu biljaka hrasta lužnjaka ovisno o načinu podmlađivanja

Abstract

Oak lace bug Corythucha arcuata represents a new pest of oaks in Europe, introduced from North America in year 2000. Damage is caused by adults and larvae that feed on the underside of leaves. The paper presents the results of investigation of impact of Corythucha arcuata on pedunculate oak growth. The two variant experiment was established in 2019 and included the evaluation of the effect of oak lace bug on the height of the seedlings (i) grown under the shade of the adult trees after the intermediate felling and (ii) seedlings grown unshaded after the final felling. Both variants included eight plots of which four were treated with the insecticide thiamethoxam, while other four were untreated. Assessment of the intensity of the attack was performed in June, July and August in 2019, 2020 and 2021, while the height of the plants was measured at the end of the vegetation period in 2019, 2020 and 2021.The results indicate significant decrease in the intensity of the attack on seedlings grown unshaded by the old trees. After first year, there was no difference in average height of the treated and untreated seedlings grown after the intermediate felling, while the difference was evident after second and third year. Such results indicate cumulative effect of the oak lace bug attack on the seedlings of the penduculate oak. On the other hand, during whole experiment, the differences between treated and untreated plant average height after the final felling were not evident.