By Henry Wu, Technical Sales Support Representative, Chemtura AgroSolutions
Even the best products and spray schedules can be ineffective if the materials don’t reach their intended target. Proper application is key to ensuing product efficacy.
When chemicals are applied improperly, vineyard owners may face a range of costly problems, from reduced control to unintended injury from spray drift. Reducing spray drift and improving spray coverage go hand-in-hand—the same management practices that improve coverage reduce drift.
Ask yourself these questions before spraying to help ensure materials stay on target in the vineyard.
1. Is my sprayer calibrated?A properly functioning sprayer can resolve most coverage and drift problems. Test the spray volume and spray pattern when calibrating. Replace worn or improperly functioning parts before they become problematic.
2. How slow can I go?The slower you go through the rows, the better the chance for materials to thoroughly soak the target area and not get blown off course. The optimal tractor speed is between 2 and 4 mph.
3. Do I need new or different nozzles?Nozzles are designed to deliver a particular droplet size and specific pattern, so check both during calibration. Select nozzles that produce medium-sized droplets or bigger (>200 microns) because larger droplets are less susceptible to drift. Replace nozzles that do not perform within 5 to 10 percent of manufacturer recommendations.
4. Am I spraying every row?A good application leaves the target area thoroughly soaked. Reaching all sides of thick vineyard canopies requires sprays down every row. A skip-row, high spray-volume method may seem to make sprays reach farther, but it may not be enough to cover both sides of canopies adequately and increases the risk of spray drift. Also, the initial cost and time savings of skip-row applications may result in inferior pest and disease control that can be expensive and time-consuming to recover from.
5. Should I use an additive?Using additives is a good choice for two reasons. First, surfactants or oil additives help materials stay in solution in the spray tank. Second, they help materials stick to plant surfaces better, keeping products on target and reducing drift.
6. Is there an inversion?Conditions are right for inversion when soil surface temperature is lower than the air temperature. Spraying during an inversion greatly increases the chances that your application will evaporate or move to a sensitive neighboring area because your application will rise from the cooler ground to the warmer air above.
7. What’s the wind speed?Only spray when wind speeds are between 3 and 7 mph. With less wind, smaller droplets can stay suspended in the air. Conversely, wind gusts often accompany higher wind speeds and can easily blow spray droplets away from the targeted areas.
Refer to the product labels or ask your PCA or Chemtura AgroSolutions representative for additional application recommendations.