Most Potted Flower Growers have clear spring production goals: achieving full, vibrant blooms on schedule, optimizing plant health for retail appeal, and controlling input costs to maximize profitability.
But even before plants begin their most active growth phase, thrips may already already lurking among your cuttings. Early infestations can quickly escalate, with a single adult female capable of producing up to 90 offspring in just four short weeks. These rapidly growing populations can prove difficult for biological and chemical control measures to tackle, while their impact can threaten margins and relationships with key customers.
But what if you could start your spring production with a clean slate, dramatically reducing pest pressure throughout the growing cycle? What if you could cut your pesticide costs, minimize labor expenses, and deliver the premium blooms your customers demand?
The solution lies in mastering a simple, but often-overlooked technique: strategic dipping of cuttings and young plants. This powerful first line of defense against thrips can set the stage for a successful, profitable growing season. Let's dive into the advanced strategies that will help you perfect this crucial skill and safeguard your spring production.
Know Your Enemy: The Thrips Menace
Before we explore advanced dipping techniques, let's quickly identify our key adversaries, and where different life stages may be hiding on incoming plant material:
Thrips Species | Eggs | Larvae | Adults | |
Western Flower Thrips Frankliniella occidentalis | Foliage | Foliage | Growing Media | Foliage |
Echinothrips americanus | Foliage | Foliage | Foliage | Foliage |
Onion Thrips Thrips tabaci | Foliage | Foliage | Growing Media | Foliage |
Thrips parvispinus | Foliage | Foliage | Growing Media | Foliage |
Early infestations of these 4 common thrips species can wreak havoc on high-value spring varieties like chrysanthemums, geraniums, begonias, gerberas, petunias, and many more.
Advanced Dipping Techniques: Your Shield Against Thrips
Solution Preparation: Mix an approved insecticide according to label rates. Consider using reduced-risk products like oils, soaps, or microbial insecticides.
Temperature Control: Ensure the dipping solution is at room temperature. Cold solutions can shock plants and reduce efficacy.
Immersion Time: Submerge cuttings for 5-10 seconds. Longer isn't better and can lead to phytotoxicity.
Complete Coverage: Use mesh trays to ensure all plant parts, including the growing medium, are fully submerged.
Draining: Allow excess solution to drain back into the dipping tank to prevent waste and maintain solution concentration.
Drying: Place treated plants in a well-ventilated area to dry before transplanting or spacing. This prevents water-logging and reduces the risk of fungal issues.
Solution Management: Monitor and adjust the dip solution regularly. Replace it when visibly dirty or after treating a large volume of plant material.
Phytotoxicity Prevention: Test new dip solutions on a small batch of plants and observe for 24-48 hours before large-scale application.
Product Selection and Efficacy
Oil-based insecticidal products are particularly effective against thrips:
Mineral oils can reduce thrips populations by 75% to 95%.
These oils are effective against several life stages.
Lower concentrations (0.1% - 0.5%) of oils can be effective while minimizing phytotoxicity risks.
Avoiding Phytotoxicity
While dipping is highly effective, it's crucial to avoid plant damage:
Test products on a small scale before widespread use.
Avoid high concentrations of oils (exceeding 0.5 - 2%) on sensitive varieties.
Consider plant variety and growth stage when selecting dip solutions.
Beyond Dipping: Next Steps for Sustainable Thrips Management
After dipping, implement these strategies to maintain thrips control:
Predatory Mite Application:
Use sachets containing predatory mites like Amblyseius swirskii, or Amblyseius cucumeris.
Place 1-2 sachets per plant within the crop, avoiding direct sunlight.
Scouting and Monitoring:
Implement weekly scouting using blue or yellow sticky cards placed just above the crop canopy.
Inspect undersides of leaves, flowers, and growing points for thrips damage or presence.
Establishing Predatory Mite Populations:
Maintain greenhouse temperatures above 20°C (68°F) and 60% relative humidity to support optimal establishment of Amblyseius swirskii or Amblyseius cucumeris.
Provide supplemental food, such as supplementary feeder mites, if thrips are in low numbers.
For Stratiolaelaps scimitus, apply them directly to the surface of the growing media and maintain soil moisture for a favorable environment.
Environmental Management:
Optimize temperature and humidity to discourage thrips reproduction.
Use vent screens to deter thrips entry.
Sanitation:
Regularly remove plant debris and maintain a clean growing environment to eliminate potential thrips breeding sites.
Properly bag and dispose of infested plant material.
Conclusion: Dip for Success
For spring production, a clean start isn’t just a best practice, it’s essential for protecting plant health, profit margins, and customer trust. A well-executed dipping protocol, combined with a strong IPM strategy, does more than control thrips; it safeguards your entire growing season.
When it comes to thrips, prevention is far more cost-effective than reaction. Before your spring cuttings enter production, ask yourself:
“Have we dipped yet?”
Finding effective strategies for reducing thrips management costs this spring doesn't have to be challenging. Schedule a Call today with our Technical Consultants and learn key insights that can help you sustainably save more of your production from thrips.