Document Type : Research Paper
Authors
1
Assistant Prof., Department of conservation and protection, Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization, (AREEO), Tehran, Iran
2
Msc. Golestan Agricultural and Natural Resources Research and Education Center, Agriculture Research, Education and Extension Organization (AREEO), Gorgan, Iran
3
Research Institute of Forests and Rangelands, Noshahr Natural Resources Research Station,Mazandaran, Iran.
4
Assistant Prof., Department of conservation and protection, Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization, (AREEO), Tehran, Iran.
5
Dep. of Forest Sciences, Faculty of Agriculture, Ilam Uni. Ilam, Iran
10.22092/ijfrpr.2023.361472.1572
Abstract
Background and objectives: The Hyrcanian region is damaged every year by various factors. Pests are also one of the most important factors causing large-scale damage to the forest cover in the north of the country. Morimus verecundus, is one of the most important pests of Beech, Alder and other forest trees in Iran.
Methodology: In this research, the biology of this insect was studied on alder and beech wood specimens in laboratory and field conditions in Golestan province during 2000-2005. Studies in the laboratory were conducted based on a completely randomized design in 12 replications and each breeding cage (containing a pair of adult male and female insects) was considered as a replication. The test conditions in this research were 25±5 °C., 60±5% R.H, 14:10 L.D. Field studies in the main centers of pollution in the two stations of Derazno and Jafarabad forests started in the second half of the March. Studies in the field were conducted based on a completely randomized design in 50 replications and each tree trunk enclosed by a net was considered as a replication. To investigate the life cycle of the pest at the time of the pest's activity in the spring, a number of infected logs were taken to the laboratory every week and split with a chainsaw and the larvae or complete insects inside them were collected. Laboratory and field studies were conducted based on complete random design and the mean and standard deviation of the studied biological parameters were calculated based on common statistical methods.
Results: The results showed that the emergence of adult insects started from the early days of the April and the peak of emergence was in the middle of the May, but then at the end of October due to the emergence of new generation insects, complete insects were observed in small numbers and ended in early November. The female began to oviposit in 9±2 days after emergence and the mean of oviposition period 8.1±1.57 days, the average number of deposited eggs by each female was 99.1±12.61, the average embryonic period 8.9±2.29, White elliptical eggs hatched 95.8±4.1 days after oviposition and the average longevity of male and female insects was 77.5±16.5 and 90.5±18.2, respectively. In laboratory conditions, at the beginning of April and a few days after releasing the whole insects into the rearing cages, their feeding activity started from the bark of the thin branches of alder and beech. The average length of the pre-ovulation period is 7±4.1 days, the average length of the egg-laying period is 10.75±1.47 days, the average number of eggs laid is 51.77±0.5, the average length of the embryonic period is 75.1±1.01 9 days and the average longevity of male and female insects was 107±11.7 and 100.5±12.77 respectively. The number of larval stages was four and the fourth instar larvae formed in the deep parts of the trunk pupal chamber and pupated. The pupae emerged to adults after 2 months in December. Adults stayed in the pupation cell over winter and left them in the next spring. Therefore, the life cycle completed in two years.
Conclusion: The study of pest breeding using alder wood and completing the life of the pest in the laboratory was done for the first time. Mating and egg-laying activities were rarely observed during the day. The lifespan of complete insects of this species is long, like other species of this genus and it makes the insect able to survive the winter and survive for more than one year. To complete and optimize the pest breeding in natural areas as well as sustainable forest protection, extensive and complementary studies in this field are needed in the future.
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