Effect of planting dates on the beet curly top infection and flactuation of population of leafhoppers vector
2004
Jalali, Sadegh | Bagheri, Mohammad Reza | Jahadakbar, Mohammad Reza | Hatami, Hosein Ali
Beet curly top virus has a widespread incidence in sugar beet fields in Esfahan province. Because of , short time between harvesting and replanting in another season,and long period of planting time (from Mars to May). The rate of infection is over 70% in Mahyar region. In order to effect of planting dates on rate of curly top infection, root and sugar yield, also population of leafhoppers vector, an experiment was conducted with 3 planting dates such as: early planting ( mid of April) usual planting ( early June) and late planting ( early July) in a split plot design that main factor were planting date and subfactor were six sugar beet cultivars such as : IC1 as a suscebtible cultivar to the diseases and other cultivars: T41R , 7233, H5505, PP8 and ATILA. The most infection was observed on IC1 and rate of the disease in years of 98, 99 and 2000 were 31.6% , 5.29% and 3.69% respectively. The results showed that delaying in planting date caused reduction of the curly top infection, damping off and root rot diseases, that showed significant difference with the early planting. The population of vectors (Circulifer tenellus and C.opacippennis) were the same in all sugar beet cultivars but its population in early planting were high and showed significant difference with other planting dates. Besides of vectors, other leafhopper species such as: Empoasca decipiens, Laodelphax striatellus and Macrosteles laevis were identified. In the early planting date due to high density of population of Temunorhinus tibialis and Conorhyncus brevirostris, the experimental plots were sprayed with insecticide. Delay in planting date tillandrsquoearly June , showed low infection to the curly top and root rot but showed decrease in yield in compare with early planting but significant difference was not observed.
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