Primary selection of essential oil from some medicinal plants to inhibit Didymella bryoniae, causal agent of gummy stem blight disease of watermelon

บทคัดย่อ

The objective of this study was conducted to select of an essential oil from some medicinal plant for inhibiting Didymella bryoniae, causal agent of Gummy Stem Blight of watermelon. The essential oils from 9 speciesof tested plants were extracted by using water distillation method. The essential oils from tested plants were mixedto PDA medium at 0.6% final concentration for fungal inhibition test. The results showed that the essential oils from7 species consists of, wild ginger: Boesenbergia pandurata Holtr., ginger: Zingiber officinale Roscoe, Siameseginger: Alpinia galanga (L.) Willd., lemon grass: Cymbopogon citratus Stapf., leech lime: Citrus hystrix DC., hairybasil: Ocimum americanum L. and sweet basil: O. basilicum Linn. could inhibit the mycelial growth of D. bryoniae up to 100% on PDA medium. In addition, there was no significantly different when compared with using benomyl fungicidal. Whereas an essential oil from curcuma: Curcuma longa Linn. showed partial inhibition to the mycelialgrowth of D. bryoniae on PDA, and tangerine: C. reticulata Blanco. did not inhibit this fungal.