CHARIS J. BAES, KRISTINE CLAIRE P. LEDESMA, HANNA O. OLIVARES (FEBRUARY 2007)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
Rice fungal diseases are one of the reasons of low rice production Although there are available resistant varieties, not all are present in one locality and not everybody can afford them. Since indiscriminate use of chemicals can cause environmental hazards organic fungicides are now used as alternative preventive measures.
The study aimed to evaluate the antifungal effects of the aqueous extracts of Allium plants garlic (Allium sativum), onion (Allium cepa), chives (Allium schoenoprasum), leeks (Allium ampeloprasum var. porrum) and scallions (Allium fistulosum) on rice pathogens Helminthosporium oryzae that causes brown spot and Gibberella fujikuroi which is the causative fungus of bakanae.
The poisoned food technique was used to determine the percent inhibition of the aqueous extracts of the test plants on the said pathogens. The rice pathogens were incubated at 25°C for five days.
One-way ANOVA and LSD were used to compare the mean percent inhibition of the different extracts (p≤0.050, a = 0.05).
Aqueous extracts of chives inhibited Helminthosporium oryzae by 12% and Gibberella fujikuroi by 46%. The aqueous extracts of garlic had inhibited the growth of Helminthosporium oryzae by 30% and that of onion against Gibberella fujikuroi by eight percent. Extracts of scallion and leeks were not able to control the growth of the fungi tested.
The aqueous extracts of chives have a significantly higher inhibition on Gibberella fujikuroi than the aqueous extracts of onion (p = 0.00).
The aqueous extracts of chives and garlic have an equal inhibition on Helminthosporium oryzae (p = 0.03).