Background
Charcoal rot, caused by the soil-borne pathogen Macrophomina phaseolina, can be a significant threat to strawberry production. Two Huma® products, Promax® and Zap®, had previously been shown to be successful in managing soil-borne diseases in strawberries.
Objectives
The primary objectives of this study were to assess the efficacy of Promax® and Zap® in reducing the incidence and severity of charcoal rot in strawberry plants and to compare the yield of marketable fruit between treatments.
Materials & Methods
The trial was conducted at the University of Florida Gulf Coast Research and Education Center in Wimauma, Florida, using the ‘Florida Medallion’ strawberry variety. Bare-root green-top transplants of ‘Florida Medallion’ strawberries were planted on October 4 on four raised beds that were previously fumigated with Telone II (150 lb/A) and covered with black plastic mulch. Each bed represented a replication.
Inoculum of M. phaseolina was prepared on corn meal agar (CMA) plates. In order to expose the strawberry plants to the disease, three weeks after transplanting on October 24, toothpicks colonized with M. phaseolina were inserted near the plant crowns. This inoculation of plants and the Promax® plus Zap® applications formed the two treatments for this field research study.
Huma® Promax® and Zap® Decrease Charcoal Rot in Florida Strawberry, With Increased Yield and ROI of 10:1 – Table 1
Table 1 outlines the timing, frequency and the applications of Promax® and Zap® products. Charcoal rot diseased incidence (DI) scale, expressed as the percentage of the total number of wilted, partially collapsed, or dead plants in relation to the total number of plants, was employed. The DI was evaluated weekly from November 7, 2023, to January 23, 2024. Yield data were collected from November 22, 2023, to January 25, 2024.
Results
The first signs of charcoal rot appeared 28 days after inoculation. The Inoculated Control treatment exhibited the highest DI (77.5%) with the yield of 2,697 lb/acre indicating severe disease progression. The Promax® and Zap® treatment, applied by drip, was effective in reducing DI to 54% with the marketable fruit yield of 5,279 lb/acre (Figures 1 and 2). Results were significant (Fisher’s Protected LSD test [ɑ = 0.05]) when compared with the Control treatment. The combination of Huma treatment increased the yield by 96% over the Inoculated plants. No phytotoxic effects were observed with any of the treatments.
Huma® Promax® and Zap® Decrease Charcoal Rot in Florida Strawberry, With Increased Yield and ROI of 10:1 – Figures 1 and 2
Conclusions
Even though the charcoal rot (Macrophomina phaseolina) disease was not completely eliminated here, the study demonstrated that Promax® and Zap® can be effective in decreasing the effects of charcoal rot in strawberry plants. The Promax® and Zap® applications resulted in nearly doubling the marketable fruit yield when compared to the Control treatment. This significant yield increase over the IC treatment gave a net gain of several thousands of dollars per acre with the ROI of more than 10 to 1. This finding suggests that integrating Promax® and Zap® into disease management practices could enhance strawberry production by reducing the effects of charcoal rot.
