Impact of treatment with plant extracts from Reynoutria sachalinensis (F. Schmidt) Nakai on intensity of powdery mildew severity and yield in cucumber under high disease pressure

Efficacy of plant extracts from Reynoutria sachalinensis (F. Schmidt) Nakai against powdery mildew in greenhouse-grown cucumbers ( Cucumis sativus L.) was investigated over 3 years under high disease pressure in Greece. In most trials efficacy of the resistance-inducing extracts from R. sachalinensis reached about 90% and was comparable with that of fungicide treatments. In all trials extract-treated cucumbers yielded as many or more fruit per plant as fungicide-treated plants. R. sachalinensis extract applications enhanced yield up to 49% over the control. The results demonstrate the potency of R. sachalinensis plant extracts as effective plant protecting agents even under the high disease pressure prevailing in the Mediterranean region.