MONITORING OF SAWFLY POPULATIONS (Hymenoptera, Symphyta: Hoplocampa spp.) IN PLUM AND APPLE ORCHARDS USING VISUAL TRAPS

The investigation of hoplocampa minuta (christ, 1791) (black plum sawfly), hoplocampa flava(linné, 1760) (yellow plum sawfly) and hoplocampa testudinea (klug, 1816) (apple sawfly) populationsusing white sticky traps rebell®bianco was carried out in conventionally and organicallymanaged apple and conventionally managed plum orchards of the institute of horticulture oflithuanian research centre for agriculture and forestry in 2010 and 2011. temperature sums forpredicting sawfly spring emergence were determined: 120 ± 5 degree-days for apple sawfly, 85 ±26 degree-days for black plum sawfly and 95 ± 28 degree-days for yellow plum sawfly. however,more years of the study are needed to confirm these temperature sums. the average densities ofsawflies during the flight period were: h. minuta — 14.8 ± 7.3 sawfly trap-1 in 2010 and 54.2 ±35.9 sawfly trap-1 in 2011; h. flava — 13.3 ± 5.2 sawfly trap-1 in 2010,and 16.6 ± 6.9 sawfly trap-1in 2011; and h. testudinea in organic orchard — 38.3 ± 26.2 sawfly trap-1 in 2010 and 5.0 ± 2.8sawfly trap-1 in 2011, in conventional orchard — 14.8 ± 8.1 sawfly trap-1 in 2010 and 9.3 ± 4.3sawfly trap-1 in 2011. conditions for development of both plum sawfly species were better in2011, when abundance nearly reached the economic threshold. population density, cumulativetrap catches during the flight period, and damage caused by apple sawfly varied significantly betweenthe study years and apple cultivars. in 2010, apple sawfly was more abundant and causedmore serious damage than in 2011. the economic threshold of 30–40 individuals per trap wasreached in 2010 due to the better conditions of development. the various apple cultivars suffereddifferent damage levels: cv. ‘aldas’, ‘vitos’ and ‘rubinola’ suffered the highest damage in the organicorchard, but no significant differences were observed. in the conventional garden, cv. ‘auksis’had the most damaged fruits.