Effect of Bacillus and Trichoderma species in the management of the bacterial wilt of tomato (Lycopersicum esculentum) in the field

Abstract

Background Bacterial wilt caused by Ralstonia solanacearum is one of the most devastating diseases in tomato cultivation. This study aimed to evaluate the effect of Bacillus and Trichoderma isolates to manage the bacterial wilt disease. Main body of the abstract Field experiments were conducted in a randomized complete block design at Mwea and Kabete sites in Kenya. The treatments included 3 Trichoderma; 2 Bacillus isolates; a mixture of T1, T2, and T4; chemical standard; and distilled water as control. Trichoderma and Bacillus isolates were grown on sterilized sorghum grain and cow manure carriers respectively. Antagonist’s inoculation was carried out by dipping tomato plants for 30 min in each treatment suspension. Each treatment was then applied at a rate of 150 ml/plant hole and this was repeated after 35 days. All the treatments significantly reduced bacterial wilt incidence and severity at P ≤ 0.05 than the control at both sites. Trichoderma isolate T1, followed by Bacillus isolate CB64, was the best in reducing the disease incidence by more than 61.66 and 53%, respectively at both sites. Treatment CB64 and T1 had the highest reduction of R. solanacearum population in the soil by 93.17 and 92.07%, respectively. However, control had a pathogen increase of 20.40%. CB64 and T1 performed significantly better compared to the standard, while the mixture of isolates T1, T2, and T4 performed the poorest in all parameters. The treatments also increased the yield of tomato. Short conclusion Results from this study showed that Trichoderma and Bacillus isolates are effective biological control agents for use in management of bacterial wilt.

Evaluation of Biocontrol Agents Against Bacterial Wilt in Tomato Using Seedling Screening

“…Eighteen out of twenty-five isolates reduced wilting significantly on both varieties L390 (highly susceptible) and L180 (moderated resistant) compared to the negative control (Table 1). Previous studies have reported different fungal and bacterial isolates that were able to control bacterial wilt in tomato [16][17][18]. Wilting percent on L390 was higher than on the moderately resistant cultivar L180 treated with biocontrol.…”

“…Further, DNA sequencing identified distinct species: isolate 52-86 was a Talaromyces sp., 26-81 was a Trichoderma sp., 106-85 was a Bacillus sp., and 106-86 was a Variovorax sp. Distinct species of BCA might differ in the mechanism of action yielding differences in biocontrol efficacy [6], and genetic variation within the same species of BCA that might cause variability in control efficacy [16,21]. Higher W% was observed in some biocontrol treatments compared to the negative control suggesting an interaction between the biocontrol pathogen and the plant [6,22].…”

Early Growth Performance of In Vitro Raised Melia volkensii Gürke Plantlets in Response to Beneficial Microorganisms under Semi-Arid Conditions

“…Cow manure was used as a carrier for Bacillus subtilis and Trichoderma isolates. Following guidelines by [ 24 ] with minor modification, 50 mL of colonized cow manure solution containing 1.5 × 10 13 CFU. g −1 of B. subtilis and 4.71 × 10 8 CFU.…”

Potassium Phosphite Enhances the Antagonistic Capability of Bacillus amyloliquefaciens to Manage Tomato Bacterial Wilt

“…First, approximately 75 ml of sterilized water was added to 4.5 kg of dry soil to wet the soil. A total of 450 ml of R. solanacearum cell suspension (approximately 8×10 8 cfu ml -1 ) was sprayed onto the soil and mixed (final cell concentration of 8×10 7 cfu g -1 soil) (Kariuki et al 2020), and then 300 g of soil amended with R. solanacearum was collected in sterile plates (diameter: 20 cm) by sterile weighing spoons for each treatment. K-Phite or strain F8 was applied to each treatment according to the treatment design.…”