Biology of the Altica viridula (Coleoptera: Chrysomelidae), an important pest of the Carpinus orientalis (Fagales: Betulaceae) in Mazandaran province

Through regular monitoring of the forests of Mazandaran province from 2022 to 2024, a destructive leaf-feeding beetle, Altica viridula Weise, was collected on oriental hornbeam (Carpinus orientalis Mill.) from the forests of Marzanabad and Royan in Mazandaran province. We studied the Cerambycid life cycle and biology in field and laboratory conditions. The results showed that the emergence of overwintering insects in nature begins in late April and peaks in mid-May. Overwintering adults were transferred to the laboratory and reared on fresh oriental hornbeam leaves. The experimental conditions included 14:10 L.D, 25±1 °C and 72±15% R.H. Studies in the laboratory were conducted based on a completely randomized design in 20 replications, and each rearing container (containing a pair of male and female) was considered a replicate. Fresh leaves were provided to larvae and adults every four days. In the laboratory, information related to the pest''''s biology was accurately recorded every day. The average length of the pre-oviposition period was 4.8±1.03 days; the average oviposition period was 6.1±0.8 days; the average number of eggs laid was 25.33±10.42; the embryonic period was 7.4±1.1 days, and the egg hatching rate was 91.1±2.18. The average lifespan of male and female was 86.2±5.08 and 86.5±4.90 days, respectively. This pest has three larval instars, and adults emerge from the pupa after six days, producing two complete generations in the laboratory. Field studies were conducted in the Marzanabad forest on Carpinus orientalis trees based on a completely randomized design with 30 replications. Each tree branch with a pair of adults was enclosed with netting and considered a replicate. To determine the mating and egg-laying time of the adults, sampling was done every four days in mid-April and then once a week to check other stages of the pest''''s life. The average pre-oviposition period is 6.7±1.3 days, the average oviposition period is 7.01±1.2 days, the average number of eggs laid is 19.5±6.44, the average embryonic period is 8.2±0.9 days, and the lifespan of male and female insects were 61.2±4.25 and 62.45±3.37, respectively. In conclusion, due to the single generation in nature and the compatibility of biological stages in the laboratory, this pest can be monitored in other areas of Hyrcanian forests where there is a host of this pest and prevent its possible outbreak.