Investigation of the Effects of Some Plant Activators Against Verticillium Wilt (Verticillium dahliae Kleb.) on Cotton

Abstract

Wilt disease caused by Verticillium dahliae Kleb. is one of the stress factors affecting yield and fiber quality traits in cotton cultivation. Plant activators provide resistance by stimulating genes that activate the resistance mechanism in the plant. The aim of this study is to determine the effect of plant activators such as auxiGRO, Green Miracle, Maxicrop, ProAct Plus and Sojall Vitanal against verticillium wilt under both in vitro and in vivo conditions. Firstly, the effect of various concentrations of plant activators (0, 1, 5, 25, 100, 250, and 500 ppm) on mycelial growth two fungal isolates of V. dahliae (PHCVd3-non-defoliating pathotype and PHCVd47-defoliating pathotype) in potato dextrose agar media was investigated in vitro. The effect of plant activators on V. dahliae was determined in tolerant cotton plants (cv Carmen) and in susceptible cotton plants (cv Acala SJ2) in two different ways as seed coating and foliar application in vivo. In vitro experiments were carried out with three replicates, and in vivo experiments were with five replicates depending on a completely randomized plots design. 500 ppm dose of all plant activators inhibited mycelial growth of both isolates by approximately 90%. The lowest disease index (DI) against PHCVd3 was determined as 1.43 in the tolerant cv Carmen with seed coating of auxiGRO. The lowest DI against PHCVd47 was found in Sojall Vitanal and ProAct Plus as 2.09 and 2.12, respectively. The lowest DI against both isolates were found as 1.42 and 2.18 in cv Carmen by foliar application of ProAct Plus, respectively. Plant activators did not show any inhibitory effect on disease severity against both isolates in cv Acala SJ2. The combination of tolerant cultivar + plant activators can be suggested against verticillium wilt disease as alternative control.