Evaluation of selected herbs for biocontrol of Rice Blast Disease

Abstract

Rice blast disease caused by Pyricularia oryzae is the most destructive disease of rice worldwide. It kills seedlings or plants up to the tillering stage. The most common practice controlling method is using chemical fungicide, however there are several negative impact of using synthetic chemicals to the human consumption as well as to the environment. In order to solve this problem, this study was conducted to find other alternative methods to control blast disease by using plant extracts from family Zingiberaceae which are Alpinia galangal, Curcuma longa and Zingiber officinale. Screening for antifungal activities of these plant extracts were done in vitro on Potato Dextrose Agar (PDA). After 7 days of treatment, result showed that crude extracts of Alpinia galangal hexane crude extract exhibited strong inhibitory against Pyricularia oryzae with the highest percentage of inhibition 52.9%, followed by Curcuma longa hexane crude extract with 49.1% and Zingiber officinale methanol crude extract with 43.5% inhibition. The antifungal activities may be due to the presence of some chemical compounds such as alkaloids, saponins, tannins, phenols, gylcosides, flavonoids and terpenes that been proved thru phytochemical test. However, further trial such as field trial is necessary to be done to evaluate the effectiveness of these extracts to control rice blast disease under field condition.

Phytochemicals as alternative fungicides for controlling plant diseases: A comprehensive review of their efficacy, commercial representatives, advantages, challenges for adoption, and possible solutions

“… [ 46 ] Alpinia galangal (rhizomes) Curcuma longa (rhizomes) Zingiber officinale (rhizomes) P. oryzae (rice blast disease) In in vitro assay , A. galangal hexane crude extract exhibited strong inhibitory effect against P. oryzae with the highest percentage of inhibition (52.9%), followed by C. longa hexane crude extract with 49.1% and Z. officinale methanol crude extract with 43.5% inhibition. [ 47 ] Combretum erythrophyllum (leaves) Quercus acutissima (leaves) Melia azedarach (leaves) Fusarium proliferatum F. oxysporum F. subglutinans F. verticilloides F. semitectum F. chlamydosporum F. solani F. equisite F. graminearum (maize seeds spoilage) In in vivo assay, M. azedarach acetone extract obtained by ultrasonic extraction showed strong antifungal activity (97% inhibition) against F. proliferatum while combined acetone extracts from C. erythrophyllum and Q. acutissima exhibited 96%, 67% and 56% inhibition against F. verticilloides , F. proliferatum and F. solani , respectively. [ 48 ] Saposhnikovia divaricata (roots) Allium sativum (bulb) Juglans regia (green husks) Embellisia astragali (Standing milkvetch yellow dwarf and root-rot) In in vitro assay using poisoned food technique, extracts of the three plants obtained by 95% ethanol totally inhibited mycelial growth of E. astragali and significantly inhibited spore germination with inhibition rates ranging from 86% to 88%.…”