EFFECT OF ADJUVANTS, SPRAY VOLUME AND NOZZLE TYPE ON METCONAZOLE ACTIVITY AGAINST LEPTOSPHAERIA BIGLOBOSA AND L. MACULANS DURING LATE SPRING TREATMENTS IN WINTER OILSEED RAPE

In two seasons 2005–2006 the metconazole (Caramba 60 SL at the dose of 0.75 l/ha) was applicated by spraying at the begin-ning of flowering against phoma stem canker (Leptosphaeria biglobosa and L. maculans) in winter oilseed rape. The effect of water volume (200 and 400 l/ha), adjuvant type (Break Thru S 240 – 0.1 % and Atpolan 80 EC – 0.5%), and nozzle type (XR11002 – fine droplet size and DB11002 – course droplets at pressure 0.4 MPa) on the biological efficacy of fungicide spraying was investigated in the studies. The results showed that adjuvants did not significantly influence biological efficacy of fungicide treatments against L. biglobosa and L. maculans. Generally, control of both pathogens on the leaves and stem did not depend on spray characteristics (nozzle types-droplet size). However, positive effect of air induction nozzles DB 11002 (course spray quality) on fungicide treatments against L. biglobosa, particularly with addition of adjuvant Atpolan 80 EC was observed. Two different volumes of water tested (200 and 400 l/ha) did not influence efficacy of metconazole in control L. maculans and L. biglobosa. The above suggests a possibility of decrease the volume of water used with fungicide to 200 l/ha, without a negative biological effects on fungicidal activity.