Larch forests occupy 55% of the forested territory in Asian Russia and represent the major source of timber in this area. At the beginning of the 1970's hundreds of hectares of seed orchards and grafted plantations of larch were established under the state reforestation program. Over the last 69 years all of these orchards were infested by the larch bud gall midge Dasineura rozkovi Mamaev et Niolsky an indigenous species which had never caused significant damage in natural forests. Distribution of the midge coincides with the range of the main species of larches in Asia: Larix sibirica and L. dahurica. The insect forms galls in the vegetative buds of larch shoots, causing gall-bearing buds to die. During persistent and heavy infestations trees may lose up to 95 percent of their buds. Such trees commonly survive but fail to produce flower so that commercial seed production on infested seed orchards is impossible.
The nature of the interaction between larch and bud gall midge is presented along with detailed life history traits. The main factors affecting population dynamics of the midge are outlined and practical measures for pest control are discussed. This includes both use of chemical pesticides and the possiblity of developing and maintaining larch resistance to gall initiation.
Key words: Larix sibirica, Laric dahurica, Dasineura rozkovi, seed orchards, economic importance.
Correspondence: Yuri N. Barachikov, Institute of Forest, Siberian Division, Russian Academy of Sciences, Krasnoyarsk 660036, Russia
Telefax: +7-3912-433686
E-mail: yuri@for.krasnoyarsk.su