مطالعات زیست شناسی کک چغندرقند ‭(.Chaetocnema tibialis ILL) ‬و تعیین میزان آلودگی در تاریخ های مختلف کاشت

‭Sugar beet flea beetle (Chaetocnema tibialis Ill.) (Coleoptera: Chrysomelidae) has been one of the main pests in sugar beet fields in Fars province in recent years. Its adult stage damages the seedlings soon after their emergence. To study 1- the biology ofthe pest in the nature, 2- the effect of 3 different sowing dates of sugar beet on the infestation level of the plants and 3- comparison of infestation levels between two different types of sugar beet seeds (polygerm and mono germ) in the different sowing dates, field experiments were conducted in main sugar beet plai1ting areas with different climates in Fars province during 1998-99. The selected areas were Kavar (Cold weather), Marvdasht (Mild weather) and Darab (Hot weather). The sowing dates were second half of March, April and May. The two seed types were 7233 (a monogerm cultivar) and 85505 (a polygerm cultivar). The planting area for each cultivar was 1000 m2. Observations and sampling were conducted regularly (7-10 days intervals) to record the flea beetle population and infestation changes during the growing season. To study the biology of the. sugar beet flea beetle, the seeds were planted in the pots, each covered by a cage, wherein a few pairs of the adult fleas were released. The results showed that the adult fleas are overwintering 8-10 cm deep in the soil and under plant derbries. Re-emergence and reactivation of adult fleas in the next season depends on the weather condition, in cold and mild regions of Kavar and Marvdasht, it is first half of April, but in hot region of Darab it happens in late Februry. As an average, the egg-laying period of the fleas lasted 4-9 days, embryonic period 6-12 days, larval period 2129‬ص ‭days, pupal period 6-10 days, and developmental period to complete one generation was 35-52 days. The adults of the first generation appeared in the nature in the late May and early June in all the three regions. Late sown fields faced higher infestation levels in both cultivars and in all the three regions. Maximum adult fle.a beetle populations were recorded in the late June and early July. There was no difference in infestation level between polygerm and monogerm cuItivars in all the three sowing dates. To prevent the.‬

Keywords:

چغندرقند , کک , آلودگی , تاریخ کاشت , کوار (فارس) , مرودشت , داراب