Effects of plant essential oils on spore germination of several fruit anthracnose pathogens.
Hsieh T. F., Chen C. H., Tsai J. N.
Author Affiliation: Floriculture Research Center, Taiwan Agricultural Research Institute, COA, GuKeng, YunLin, Taiwan.
Plant Pathology Bulletin 23 : 31-41
Abstract : Seven plant essential oils extracted from cassia, clove, eucalyptus, anise, lemongrass, lemon eucaly, and thyme were collected and evaluated for their suppression of spore germination of Colletotrichum species including C. gloeosporioides isolated from papaya, mango, pomelo, apple and Indian jujube and C. musae isolated from banana in Taiwan. The plant essential oils were diluted for 62.5 to 2000 µl/L to test the inhibitory effectiveness of spore germination on water agar plate. Among those tested essential oils, cassia, clove and lemon eucalyptus essential oils were the best three oils to inhibit the spore germination of six isolates of Colletotrichum species. The cassia essential oil showed the best inhibitory effect on spore germination with IC50 less than 98.7 µl/L. The harvested banana fruits were soaked in the 500-µl/L solution of cassia and clove essential oils for 10 min, respectively, to evaluate the effect of essential oils on control of anthracnose disease caused by C. musae. Data showed that the disease severity rating by percentage of lesion area was markedly decreased by treatment of cassia oil after 6 days of incubation, but the disease severity was obviously increased by treatment of clove oil. These results could provide valuable information in formulating the natural plant protectants in the future.