Application Considerations

How the pesticide is applied will determine how effective it is. The following tips will help in good application.

• Water source.The water source can affect the effectiveness of the pesticide application. Water pH and softness can adversely affect some pesticides depending on their chemistry. Be sure to read the label for precautions. Also, if water is obtained from streams or ponds, there may be soil particles that can absorb some pesticides or plug up spray nozzles. Again, be sure to read the label to determine if this will be a problem. Protect nozzles with screens to keep them from clogging up.
• Droplet size. The droplet size will determine how driftable the spray will be. Droplet sizes of less than 200 microns in size are highly driftable, and if a pesticide drifts away from the spray target, it won't be able to control pests. Using a drift reduction adjuvant will reduce problems with spray drift.
• Adjuvants. These are non-pesticides that are added to a pesticide spray mix to improve the pesticide's performance. These can include surfactants, oils, buffering and conditioning agents, defoamers, deposition agents, drift control agents, and others. Some insecticides require a spreader-sticker. Be sure to read the label to determine adjuvant requirements. Improper use of adjuvants may result in phytotoxicity, so only use if needed.
• Sprayer calibration. Consistancy of application through each field is important. Some pesticide rates are on a per acre basis. If that is the case, then you must determine first how many gallons per acre will be used. High pressure sprayers can be calibrated to determine how many gallons per minute are sprayed. Airblast mistblowers should also be calibrated to determine spray volume.
• Spray coverage. Target the spray to where the pest is found. For instance, elongate hemlock scale is on the underside of needles. Twig aphids are primarily on the most current growth. Balsam woolly adelgid can be on the trunk, branches, and buds. Creating more of a mist from the spray nozzle will get more spray back to the 2nd or 3rd year needles. Use water sensitive cards to determine what portions of the trees are being sprayed adequately. These are especially helpful in adjusting airblast mistblower to determine which rows are receiving adequate coverage.