tants can be used at very low rates ranging from as low as 0.10 percent to 0.25 percent volume/volume basis.
Stickers make the pesticide solution adhere to the plant foliage to a greater degree as compared with solutions that do not contain a sticker. By increasing the adherence to the foliage, runoff of the spray mixture, wash-off during rain or irrigation and/ or the evaporation of the pesticide from the target surface are reduced. By minimizing pesticide losses, the effectiveness of the pesticide application will increase.
Compatibility agents are utilized when two or more products are incompatible with each other and are added to the same spray mixture. This could be a physical or chemical incompatibility which causes uneven distribution in the spray tank. The compatibility agents will aid in suspension of the pesticide into the spray solution.
ACIDIFIERS AND BUFFERS
The pH of the spray solution will vary greatly depending on the water source as well as products being mixed into the spray tank. Well water pH from underground sources will usually range between 7.0 (neutral) to 9.0 (alkaline). The pH can vary significantly with season and source.
Most pesticide applications are recommended to be applied at a pH of 5.5 to 7.0. As the pH increases above 7.0, some pesticides are subject to degradation. In most cases, the buffers should be added to the solution to reduce the pH to the desired range before adding the pesticide. As each pesticide is added to the tank, the pH should be rechecked to ensure the modified solution is still within the recommended pH range.
Acidifiers are added to the pesticide spray solution when the mixture is alkaline (pH > 7.0) and the need exists to neutralize the solution to a lower pH. Buffers will change the pH of the water solution, which will be maintained even if the pH of the solution changes.
In the case of Aliette, the label states that buffering to pH 6 or higher is recommended to avoid phytotoxicity when copper has been used prior to, with or following the application of Aliette. Other products may also have information on the label as to the target pH of the spray solution.
ANTI-FOAMING AGENTS AND SPRAY COLORANTS
Anti-foaming agents are used to reduce air entrapment in the spray mixture that may occur during agitation or spraying. Foaming of the spray solution can create problems in mixing or application. Colorants are used to cause the treated area to be colored to ensure complete coverage of the spray solution over the desired target area. In citrus, colorants are frequently added to the spray mixture when treating stumps of trees that have been removed due to various reasons. The colorant will remain on the cut surface to indicate that the stump has been properly treated with herbicides to inhibit regrowth.
DRIFT CONTROL AGENTS
Drift control agents will increase the average droplet size when the solution is sprayed. Larger droplets are less likely to drift (move away from the target site) as compared with smaller droplet sizes. The use of drift control agents can be very important if applying products that may impact sensitive crops or plants which may be located near the application site. There are no drift control agents available to completely eliminate drift.
When mixing any two or more products together to create a tank mix, it is always wise to make sure this new pesticide solution will not damage the crop or create a combination that will not mix evenly in the tank. The pesticide mixture should not create clumps or separations in the spray tank, causing an uneven application of the spray mixture.
Common causes of incompatibility could include impurities in the spray tank or water, order in which the pesticides were mixed into the tank, types of formulations being used, water pH and/or amount of time the mixture has been in the tank.
When mixing pesticides together into the spray tank, follow the W-A-L-E mixing order:
- add enough water to fill the tank about one-half full or one-half of the desired spray volume. Any water-conditioning agents should be added to the tank at