A Test for Chemical Effect Using Cucumber Fruit to Multiple-Host Fungi

Abstract

A method was developed for testing chemical effect by using cucumber fruits to multiplehost fungi, Botrytis cinerea Persoon, Sclerotinia sclerotiorum (Libert) de Bary, Corticium rolfsii (Saccardo) Curzi and Rhizoctonia solani Kühn. Each fungus was seeded on PSA medium in petri dish, 9cm in diameter, and incubated for 3 days at 25°C until the fungus developed to whole petri dish. Cucumber fruits were cut to pieces 4-5cm in length and dipped in test solutions of chemicals for 1-10 minutes. After being dried, the cucumber fruit pieces were placed on the above fungus. After incubating for 72-96 hours in a high moisture at 20-25°C, the height of colored parts or mycelial growth on cucumber fruits was measured. The height of colored part on chemical-treated cucumber fruits was compared with that on nontreated ones. The method is very simple for testing chemical effect to the fungi described above. The result obtained by the method on testing chemical effects to B. cinerea corresponded to the effect of chemicals practically used by spraying for protection of cucumber gray mold in a vinyl house. The method is, therefore, able to be used practically for screening effective chemicals.