Effects of Plant Extracts on Crop Diseases, Two-Spotted Spider Mites, and Weeds

This research was conducted to evaluate the controlling effects of various plant extracts obtained from ۳۸ agricultural materials of traditional agriculture against rice blast (Pyricularia oryzae) in rice plants. We also evaluated the inhibition rates of other crop pathogens, two-spotted spider mites (Tetranychus urticae), and weeds by three selected plant extracts. Rice blast was completely suppressed by ۳% ethanol extracts of Rheum palmatum roots, and suppressed by ۹۷% and ۷۷% in response to treatment with ۱۰% ethanol extracts of onion (Allium cepa) bulbs and pine tree (Pinus densiflora) leaves, respectively, under in vitro conditions. Moreover, a seedling bioassay revealed that rice injuries of two cultivars (Ilmibyeo and Hopyeongbyeo) caused by rice blast were reduced by ۴۰-۷۱, ۲۹-۶۳, and ۲۳-۶۳% in response to treatment with ۵% and ۱۰% ethanol extracts of R. palmatum roots, A. cepa bulbs, and P. densiflora needles, respectively, compared with non-treated controls. The selected R. palmatum extract also controlled crop diseases caused by Phytophthora capsici, Bortytis cinerea, Rhizoctonia solani, and cucumber powdery mildew (Sphaerotheca fuliginea). R. palmatum extracts at ۱۰% reduced two-spotted spider mites by ۴۶% when compared with each control. A broad leaf weed, Quamoclit coccinea Moench and a grass weed, Echinochloa oryzicola were inhibited ۴۶-۵۵% by R. palmatum roots, A. cepa bulbs, and P. densiflora needles at ۱۰%. Thus, the selected plant extracts may be used for control of crop diseases and weeds in organically cultivated crop fields.

کلیدواژه ها:

Agricultural organic materials ، Pyricularia oryzae ، Rice blast ، Traditional agriculture.