EFFECT OF SEEDLING TRANSPLANTATION AND POST-EMERGENCE HERBICIDES APPLICATION ON FIELD DODDER (CUSCUTA CAMPESTRIS) CONTROL IN SUGAR BEET

In order to control field dodder (Cuscuta campestris Y.) in sugar beet, experiments were done in greenhouse and field of Sugar Beet Research Institute, Karaj, Iran. In greenhouse test, the impact of direct seed sowing, transplanting of seedlings at two and eight-leaf stages (factor A) and dodder seed sowing with no distance and at 7 cm distance from the host (factor B) on control of the weed was studied in a factorial experiment based on completely randomized design with three replications. In the field test, the effects of direct seed sowing and transplanting of sugar beet seedlings (factor A) and application of four post-emergence herbicides (factor B) on control of the weed were evaluated in a factorial experiment based on randomized complete block design with four replications. In the greenhouse experiment, percentage of infection was decreased by increasing the distance between the parasite and the host. In the field experiment, the degree of host infection by dodder was recorded before and after application of the herbicides. Fresh and dry weight of dodder and root yield of sugar beet was measured. The method of cultivation was significantly effective on the ability to deploy of dodder on the host so that in direct sowing of sugar beet seed, the ability of dodder to colonize the host was found to be 3.5 times higher than that of transplanting method. Root yield was significantly influenced by the sowing method and showed 2.5 times increase in transplanting method. The biomass of the parasite established on the host demonstrated 7.5 times decrease compared to the direct seed sowing method.