مشخصات پژوهش

The plum bud gall mite, Acalitus phloeocoptes (Nalepa) is an important pest in Miandowab region (West Azerbaijan province, Iran). The feeding activity of these mites create galls around buds that lead to tree death after few years and made fruit decrease of the host plants. Early in the spring, overwintering females migrate from the galls toward new buds where they inhabit and feed. The controlling of this pest is depended to the investigation on its biology that must be done. Regarding the study of the mite emergence in relation to duration and type of cold exposure, on early January 2017, 100 number of 1/2 year old plum branches in an orchard at Miandowab were marked with ribbon tapes as field-wintered group and another 100 branches were brought to the laboratory and stored in refrigerator with constant 3°C as laboratory-stored group. From 30 February to 24 March 2017, 12 branch sections were removed from laboratory cold-storage and 12 branches were collected from the orchard at two weeks intervals. Selected branches had the similar diameter and gall size. Three branches selected for each sides including north, south, east and west. A stickyband trap was placed near the gall on each branch and branches were placed at 15°C and 13:11 (L: D) h photoperiod. Traps were replaced on 1, 2, 3, 4, 5, 6, 10, 14, 21 and 28 days after trap placement, and captured mites were counted using magnification 10 of Leitz LABORLUX S microscope until no more mites were trapped. For each time by cold-storage combination, the cumulative distribution of the proportion of mites trapped was calculated for each branch. The number of days of median emergence for each branch in a sample was estimated by linear interpolation to the x-axis. The mean number of days to median emergence was then calculated for each time by cold storage combination, and a comparison between means for emergence from laboratory-stored and field-wintered branches at each collection date was made using MSTATC software. I