Efficacy and selectivity of vegetation-applied herbicides and their mixtures with growth stimulator Amalgerol premium at oil-bearing sunflower grown by conventional, Clearfield and ExpressSun technologies

G. Delchev
Abstract. During the period 2010 – 2012, on the experimental field of the Field Crops Institute – Chirpan was carried out a field experiment with oil-bearing sunflower (Helianthus annuus). A total of 18 variants from the three technologies for oil-bearing sunflower growing were investigated – conventional (hybrid Arena), Clearfield (hybrid Alego) and ExpressSun (hybrid P64LE20). Vegetation-applied herbicides Goal, Raft and Pledge combined with the soil-applied herbicide Pelican provide good control of annual broadleaved weeds in conventional technology for sunflower growing. Combinations of herbicides Stomp, Wing with herbicide Pelican can be applied to mixed weeding from annual grassy and some broadleaved weeds, but with the absence of Xanthium strumarium, Cirsium arvense and Convolvulus arvensis. Herbicide combination Modown + Pelican should be used in secondary weeding primarily from annual broadleaved weeds, but with the absence of Xanthium strumarium. Herbicide tank mixtures Pulsar + Stomp by Clearfield technology and Express + Stratos ultra by ExpressSun technology completely destroyed all annual and perennial grassy and broadleaved weeds. Vegetation use of herbicides by conventional technology causes high phytotoxicity on sunflower. Phytotoxicity was the highest by herbicide Goal, followed by Pledge. Phytotoxicity is weaker by herbicides Stomp, Raft, Wing and Modown. Treatment of growth stimulator Amalgerol premium with herbicides Goal, Raft, Wing, Pledge and Modown as tank mixtures increases the selectivity of these herbicides.