Sprayer considerations to improve spider mite control
Setting the spray boom at the proper height is important as it affects spray pattern uniformity and the velocity of the droplets entering the canopy. Nozzle companies state their boom height recommendations as the distance between the “target” and the boom. The target should be the midway point between the lowest leaves and the top of the canopy when spraying for spider mites. Follow the nozzle manufacturer’s recommendations for determining the height of the boom above the target.
The tricky part is to select a flat fan nozzle or twin, flat fan nozzle that produces the optimum droplet size under the spray volume, ground speed and pressure recommendations listed above. Nozzle manufactures publish charts and Dr. Robert Grisso, agricultural engineer at Virginia Tech University, created an Excel spreadsheet that makes this decision easier.