Bacterial diseases remain among the most persistent and economically damaging problems facing commercial growers. "Pathogens such as Pseudomonas spp. and Xanthomonas spp. are especially challenging because they rapidly colonize natural openings or damaged plant surfaces, leading to leaf and fruit lesions that can spread quickly through dense production environments," says Chris Rose, Product Manager at BioWorks. "Repeated reliance on traditional bactericides has also contributed to the emergence of resistant bacterial populations, leaving growers with fewer effective tools."
A biological mode of action without resistance risk
Chris shares that BotryStop® WP, a biological pesticide recognized for its activity against Botrytis, is now demonstrating meaningful efficacy against bacterial pathogens as well. "The product's active ingredient, Ulocladium oudemansii strain U3, functions by colonizing dead or senescing plant tissue, the same sites typically sought by Botrytis spores." This competitive exclusion prevents Botrytis establishment, but its benefits extend further.
Research has now shown that the colonization mechanism also helps protect plants from bacterial entry. By occupying susceptible tissue before pathogenic bacteria can invade, BotryStop WP reduces opportunities for infection. "The biological activity of this strain creates a protective barrier at key infection sites. It's a mode of action that bacteria can't adapt to, which eliminates the risk of developing resistance."
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Jenny Nacmanson (Crop Health Advising & Research) and Suchismitha Sahoo (Truly Green Farms) visit Michael Brownbridge, Bioworks at the 2025 Canadian Greenhouse Conference
Performance in greenhouse and field trials
Extensive third-party trials have validated BotryStop WP's capacity to manage both Pseudomonas and Xanthomonas in ornamental crops.
In University of Florida testing on Impatiens challenged with Pseudomonas, applications of BotryStop WP resulted in a dramatic reduction in foliar symptoms: from an average of 17.7 leaf spots in the untreated control to just 1.2. Chase Agricultural Consulting observed similarly compelling results on Hibiscus, where disease severity caused by Pseudomonas was reduced by 72% relative to untreated plants.
BotryStop WP also demonstrated impact under high pressure from Xanthomonas on Geranium, reducing leaf spotting by 55%. "When you see a consistent response across different species, growing conditions, and disease pressures, you know you're looking at a tool with broad utility for commercial growers," Chris notes.
Regulatory progress and expanded opportunities for growers
"Based on its strong bacterial control data, BotryStop WP has received 2(ee) approval for use against Pseudomonas in several states including Georgia, Texas, Washington, and Idaho. It is already labeled for Xanthomonas control on ornamental and bedding crops."
BioWorks has also submitted amendments to the EPA seeking formulation updates and label expansions that will formally incorporate both Xanthomonas and Pseudomonas control claims across a wider range of crop groups. "Our goal is to make BotryStop WP as easy and practical for growers to adopt as possible. Growers want a single solution that fits into their existing programs and provides reliable, resistance-free protection against multiple destructive diseases."
"This isn't just about solving a single disease problem. It's about giving growers a durable tool they can depend on year after year, even as disease pressures shift."
For more information on BotryStop WP, including product specifications and availability, visit BioWorks' official product page.
For more information:
BioWorks
Chris Rose, Product Manager
[email protected]
bioworksinc.com
