In Vitro Antifungal Activity of Different Plant Hormones on the Growth and Toxicity of Nigrospora Spp. on Date Palm (Phoenix dactylifera L.)

Objective: The profound negative impact of chemical fungicides on human and animal health, as well as, the whole agroecosystem encouraged tremendous efforts to find alternative approaches to suppress the growth of plant pathogens. Method: Recently, plant hormones have been considered to reduce fungal severity. Five different plant hormones namely 2, 4-D (2,4-Dichlorophenoxyacetic acid); BAP (6- Benzylaminopurine); Dicamba (3,6- Dichloro-2-methoxybenzoic acid, 3,6-Dichloro-o-anisic acid); IAA (Indole-2-acetic acid) and SA (Salicylic acid) were selected to examine their antifungal activity against the growth of two species of date palm fungal pathogenNigrosporaspp. Results: Results showed that SA at 50 ppm was sufficient to inhibit the mycelium growth ofN. oryzaecompletely, while withN. sphaerica; the treatments of 2, 4-D (40-50 ppm) and SA (40-50 ppm) led to similar complete inhibition results of mycelium growth. The data of BAP and IAA indicated no toxic effect toward mycelium growth of the pathogens. Similar trends of results have been obtained for phytotoxicity bioassay which performed on detached date palm leaves, 2, 4-D and SA at 30 ppm led to a complete inhibition for the production of toxins in the culture ofN. oryzaeandN. sphaerica. Conclusion: 58% significant reduction in toxin production was obtained with Dicamba 30 ppm. Results presented here reveal the antifungal activity of different plant hormones inin vitroexperiments, and are important to examine their efficiency in farther field studies on date palm.