Bio-control of Stem Rot in Jerusalem Artichoke (Helianthus tuberosus L.) in Field Conditions

Abstract

Stem rot is a serious disease in Jerusalem artichoke (JA). To reduce the impact of this disease on yield and quality farmers often use fungicides, but this control method can be expensive and leave chemical residues. The objective of this study was to evaluate the efficacy of two biological control agents, Trichoderma harzianum T9 and Bacillus firmus BSR032 for control of Sclerotium rolfsii under field conditions. Four accessions of JA (HEL246, HEL65, JA47, and JA12) were treated or notreated with T. harzianum T9 and B. firmus BSR032 in a 4 × 2 × 2 factorial experiment in two fields (environments), one unfertilized and one fertilized. Plants were inoculated with S. rolfsii and disease was evaluated at 3-day intervals for 46 days. T. harzianum T9 and B. firmus BSR032 reduced disease incidence by 48% and 49%, respectively, whereas T. harzianum T9 + B. firmus BSR032 reduced disease incidence by 37%. The efficacy of T. harzianum T9 and B. firmus BSR032 for control of S. rolfsii was dependent on environments and genotypes. The expression of host plant resistance also depended on the environment. However, HEL246 showed consistently low disease incidence and severity index in both environments (fertilized and unfertilized). Individually, T. harzianum T9, B. firmus BSR032, or host plant resistance control stem rot caused by S. rolfsii in JA. However, no combination of these treatments provided more effective control than each alone.

Vermicompost in combination with Trichoderma asperellum isolate T13 as bioagent to control sclerotium rot disease on vegetable soybean seedlings

“…They were maintained and multiplied on PDA at 25±2 °C. For the laboratory experiment, Trichoderma species aged 3 d were used in fungal confrontation assays (Junsopa et al, 2021). For the greenhouse experiment, this species was multiplied in steamed rice according to Charoenrak and Chamswarng (2016), while sclerotia were collected from the culture on PDA (Fig.…”

“…Even though augmentation in controlling Rhizoctonia solani disease has been reported from the use of vermicompost and T. harzianum in the growing media (Ersahin et al, 2009), there has been no report on this effect on sclerotium rot disease. Since several Trichoderma spp., such as T. asperellum (Chamswarng and Intanoo, 2002;Charoenrak and Chamswarng, 2016;Pacheco et al, 2016), T. harzianum (Ozbay and Newman, 2004;Pacheco et al, 2016;Kamel et al, 2020;Junsopa et al, 2021) and T. koningii (Trutmann and Keane, 1990;Woo et al, 2014;Pacheco et al, 2016;Kamel et al, 2020) have been examined as effective biocontrol agents against soilborne plant pathogens, T. asperellum could be used for soil amendment together with vermicompost to control sclerotium rot disease.…”