Our Florida summers feature relentless heat, intense humidity, and constant afternoon thunderstorms. These three elements affect every applicator from homeowners to row-crop farmers. They determine whether an application will be safe and effective, a waste of time, or possibly even dangerous. Understanding their impact and timing your work around peak Florida heat and storms ensures safer, more effective applications. Read on to see Best Practices for Pesticide Applications During Florida’s Summer.
Heat and Pesticides
High temperatures have several important effects on pesticides.
- Volatilization occurs when heat causes a pesticide to vaporize after application and move away from your intended target as a gas. These vapors can drift to and damage nearby sensitive plants and non-pest organisms away from the application site. Avoid applications during peak heat hours, usually 10 A.M. to 4 P.M.
- If the pesticide you’re using relies on residual performance, both UV rays and heat can cause the breakdown and shorten the time span of your pesticide. This may impact how often you need to reapply!
- Just like us, plants can suffer from heat stress. Plants close their stomata during the day to prevent water loss; however, this also reduces the absorption of pesticides applied to their leaves. Again early morning applications tend to perform better. Example of herbicide drift towards non target crops.
Rain and Wind
Florida averages 80-100 thunderstorm days per year, with most taking place on summer afternoons. We all know storms can develop within an hour after a clear sky.
- Read your label specifically. Some labels require a rain-free period that can range from a few hours to over 24 hours.
- Avoid applying if rain is forecast before the rain-free period ends.
- Rainfall before a product is fully absorbed can wash it off target surfaces and into nearby bodies of water.
Wind helps create pesticide drift. This is the movement of droplets or vapors away from the target site. Thunderstorms raise wind speeds which can drastically decrease the effectiveness of your pesticides. A good recommended range to apply within is 3-10 mph.
To further reduce drift, use coarser nozzle settings, lower your boom height, and apply during the calmest part of the day. Typically, during the morning hours.
Humidity
High humidity slows the evaporation process. This is a dual-edged sword for pesticide applicators. High humidity can improve absorption of certain products; however, wet leaf surfaces also reduce the effectiveness of contact pesticides.
More importantly for us, high humidity limits the body’s ability to cool itself and raises the risk of heat illness for anyone working outdoors in full PPE.
PPE and Heat Safety
Wearing full PPE in Florida summer heat significantly increases heat illness risk. Know the warning signs:
- Heat cramps: muscle spasms
- Heat exhaustion: heavy sweating, weakness, pale or clammy skin, nausea
- Heat stroke: body temperature above 104°F, hot dry skin, rapid pulse
To reduce risk:
- Apply early in the morning before temperatures rise
- Drink water frequently; before, during, and after an application
- Take regular shade breaks
Quick References of Best Practices
- Read the label every time. Follow the legally required instructions specific to each product.
- Try to apply early in the morning to avoid peak heat, afternoon storms, and gusty winds.
- Check the forecast before every application.
- Calibrate your equipment regularly to ensure the proper rate.
- Keep records of application timing, weather conditions, and products used.
Conducting pesticide applications during Florida summers demands more planning than any other season. Although not always possible, most risk factors can be reduced by early morning or late evening work. Hopefully you all now feel better prepared for Pesticide Applications During Florida’s Summer.
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