The influence of abiotic factors on the development of caterpillars of the chestnut transient moth (Cameraria ohridella Deschka & Dimic) in laboratory conditions

Goal. To investigate the effect of abiotic factors on the duration of development of the caterpillars of the chestnut transient moth, and the ability of the caterpillars to penetrate another leaf of bitter chestnut in laboratory conditions. Methods. In laboratory conditions, experiments were conducted to determine the duration of development of moth caterpillars at temperatures of 15, 20, 25, 30°C, with and without illumination. Chestnut moth caterpillars of different ages were previously selected in natural conditions. In the laboratory, they were placed in thermostats according to their age (10 specimens each), and kept at the appropriate temperature until pupation. To test their ability to re-penetrate the leaves, caterpillars of different ages were removed from the primary leaf and planted on another. Artificial lighting was applied (round the clock) using 4 fluorescent lamps PHILIPS TLD18W/54-765 with a power of 18 W. The experiment was repeated 10 times. Accounting was carried out daily. Statistical processing of data was carried out according to generally accepted methods. Results. During the experiment, it was determined that moth caterpillars are not able to re-enter another chestnut leaf. During the study of the influence of abiotic factors on the duration of the development of caterpillars, it became known that under a temperature regime of 15°C and without lighting, their survival is significantly lower than with lighting. In conditions of complete darkness, 24.4% of the pest was frightened, and with lighting — 58.8%. At the same time, the results of the experiment also showed the importance of the effect of the temperature regime on the maintenance of these insects. Thus, the greatest death of caterpillars was recorded at a temperature of 15°C, when the temperature increased to 20—25°C, this indicator gradually decreased, but when the holding temperature increased to 30°C, the death rate increased again. Thus, we came to the conclusion that it is possible to keep the chestnut moth in laboratory conditions only during the period of its seasonal activity in nature. It is at this time that it becomes possible to study it more thoroughly, and to search for ecological means to reduce the number of chestnuts. Conclusions. Chestnut moth caterpillars are not able to re-enter another chestnut leaf, and their full development is possible only inside mines, where there are optimal conditions for this. The greatest mortality of young caterpillars in laboratory conditions was observed at storage temperatures of 15 and 30°С. The optimal temperature regime for this stage of pest development is 20—25°C. Therefore, keeping these caterpillars in laboratory conditions is effective only during the period of their seasonal activity in nature.