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.