BIOLOGY OF BYCTISCUS POPULI (L.) (COLEOPTERA, ATTELABIDAE). PART I. LAST YEAR’S IMAGOES.

The biology of Byctiscus populi (L.) was studied on Populus tremula L. in Forest District B?lovice nad Svitavou (former district of Brno-venkov) in the period 2007 to 2009. Last year’s imagoes occurred there from the third decade of April until the end of July. Females lived in the laboratory on average 1.5 months and damaged 7.2 to 19.2 cm2 leaves. In nature, females live on average two months. They produce 20 to 30 leafrolls and lay 30 to 41 eggs. Every day, they roll up 0 to 4 (on average 0.4) leafrolls and lay 0 to 6 (on average 0.8) eggs. They lay 0 to 4 (on average 1.3) eggs into one leafroll, in the laboratory 0 to 8 (on average 2.2) eggs. In 67% leafrolls, leaves are rolled up by their adaxial face outwards, in 32% inward and in 1% towards both faces. The production of rolls (from the beginning of biting out holes into petioles to leafroll sticking) takes on average two hours. Two thirds of rolls persist on shoots for the period of 1 to 4 weeks. At one third of rolls, females bite out the petioles immediately a er rolling up the leaf blades and rolls fall to the soil surface.1