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ARS Home » Research » Publications at this Location » Publication #90756
Title: METHIONINE-RIBOFLAVIN MIXTURE REDUCES POWDERY MILDEW INFECTION IN STRAWBERRY PLANTS

Author
item Wang, Shiow
item TZENG, DEAN - CHUNG HSING UNIV, TAIWAN

Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/29/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Powdery mildew is a serious fungal disease in strawberry plants. Its control requires periodic application of fungicides. Because the use of chemicals poses potential harmful effects on the ecosystem, the application of various agricultural pesticides to control plant diseases has become an issue of great concern to the general public. Therefore, it is important to find an effective alternative way to control powdery mildew in strawberry plants and reduce dependency on fungicide use. Methionine and riboflavin are essential nutrients for most living cells and pose minimal danger to the environment. Mixtures of methionine and riboflavin, in the presence of light, can generate various active oxygen radicals, including hydroxyl radical and singlet oxygen, which are strongly biocidal to a wide spectrum of microorganisms. We found that foliar application of a mixture of methionine and riboflavin was effective in reducing the severity of powdery mildew. The disease control efficacy was enhanced by supplements of copper, iron, and surfactants. These results suggest that treatment with mixture of methionine and riboflavin is beneficial to strawberry plants and may serve as an alternative to fungicides for controlling powdery mildew. This study has potential to benefit strawberry growers and consumers.

Technical Abstract: Foliar application of a mixture of methionine (1 mM) and riboflavin (26.6 uM) reduced the severity of powdery mildew [Sphaerotheca macularia (Wallr. ex Fr.) Jacz. F. sp. Fragariae] infection in 72 strawberry (Fragaria x ananassa) progenies and over 110 clonal genotypes. The disease control efficacy was enhanced by supplements of copper, iron, and surfactants [sodium dodecyl sulfate (SDS), Triton X-100, Tween-20, or oxyalkylenemethylsiloxane (Silwet L-77)]. Free radical scavengers (n-propyl gallate, thiourea) and antioxidants (alpha- tocopherol, beta-carotene) on the contrary reduced the efficacy of this mixture. Plants treated with a mixture of riboflavin (26.6 uM), D,L-methionine (1mM), copper sulfate pentahydrate (1mM) and SDS (1 mg.ml -1) or MR formulation (29% SP) showed decreased powdery mildew infection. Results in this study suggest that treatment with a mixture of methionine and riboflavin is beneficial to strawberry plants and may serve as an alternative to fungicides for controlling powdery mildew.