Leaf rollers (Lepidoptera Tortricidae) found on poplars (Populus spp.) in Sofia Region, Bulgaria

Abstract

In the years 1997 and 1998 investigations were performed on the
species composition and structure of a tortricid complex (Lepidoptera Tortricidae)
on poplars (Populus spp.) at three places of the Sofia region - Sofia, Kokaljane
and Jeleznitsa. Larvae and pupae of leaf rollers were collected from poplar trees
and stump sprouts and were brought in the laboratory where they were reared to
adults atroom temperature (18 - 22°C). As a result of this investigation, 14 species
of leaf rollers were recorded as follows: Archips betulana (Hbn.), A. crataegana
(Hbn.), A. padana (Scop.), A. rosana (L.), A. xylosteana (L.), Pandemis heparana
(Den. & Schiff.), P. cerasana (Hbn.), Ptycholoma lecheana (L.) (Tortricinae),
Cydia exquisitana (Rbl.), Gypsonoma aceriana (Dup.), G. dealbana (Frol.),
G. minutana (Hbn.), Hedia salicella (L.) and Pseudosciaphila branderiana (L.)
(Olethreutinae ). Eight species - A. betulana, A. padana, A. rosana, C. exquisitana,
G. dealbana, P. cerasana, P. lecheana and P. branderiana were reported for the
first time on poplars in Bulgaria. In tortricid complex studied G. aceriana (69.0%)
was the dominant species. C. exquisitana, G. minutana and P. cerasana were
subdominant and the remaining species were less numerous. C. exquisitana is
xylophagous - its larvae feed under the bark of poplar trees. The first instar of G.
aceriana develops on leaves of poplars. After the first moult larvae enter the young
twigs. The population density of G. aceriana is highest in Sofia, where an average
of 9.2 larvae/m of sprouts have been recorded in 1997. The insect infested 23.0
- 93.7% of the twigs of poplars. The larvae of G. minutana live and feed between
two òr more leaves held together by silky threads. The larvae of the remaining
species roll the leaves. With the exception of G. aceriana, all of the tortricid
species occurred in low population densities and did not reach pest status
throughout the period of this study.