EFFECT OF 4 FUNGICIDES ON BARLEY NET BLOTCH CAUSED BY DRECHSLERA-TERES

The effect of four fungicides (benomyl, carbendazim, triadimefon and s ulphur), used in intensive barley cropping on the epidemiology of Drec hslera teres f. maculata and f. teres, was investigated under a contro lled environment. Two fungicides (benomyl and carbendazim) increased d isease development, especially al the recommended held rate, sulphur h ad the same effect at lower concentrations and triadimefon promoted ne t blotch caused by D. teres f. teres. At the recommended field rate, c arbendazim enhanced sporulation in the two pathogen forms, whereas ben omyl and sulphur enhanced 14 sporulation only on the maculata form. Th e results showed that, under controlled conditions, most of the fungic ides promoted net blotch development and that sporulation increased ei ther as a result of the pathogen form or of the concentration of the a ctive ingredient.