Any substance added to a spray tank, separate from the pesticide, that will enhance the properties of spray solution so it can deliver the formulation faster and more efficiently. Agricultural spray adjuvants have been known as wetting agents, spreaders, stickers, or surfactants. An “adjuvant” is a substance added to a prescription to aid the operation of the main ingredient. A spray adjuvant performs this function in improving the safety and effectiveness of an agricultural chemical application. The proper use of spray adjuvants can contribute substantially to safer and more effective pest control and understanding their many properties and functions is important to their proper use.

Soil surfactants, or soil wetting agents, alter the property of rainfall and irrigation water to allow enhanced infiltration into soils while rendering run-off and evaporation. Soil surfactants are an effective water management tool that can be used to reduce irrigation watering times and prepare soils in advance for follow-up to soil applied crop protection products such as soil sterilants. Soil surfactants are effective at reducing soil repellency resulting in greater soil moisture content for growing crops.

An adjuvant can overcome issues with the:

• Barriers posed by the properties and quality of the water in the solution.
• Structure and composition of target plant surfaces
• Application equipment and conditions.
• Environment in which spray application is made.

Surfactants (surface active agents) are a type of adjuvant designed to improve the dispersing/emulsifying, absorbing, spreading, sticking and/or pest-penetrating properties of the spray mixture. Adjuvants, specifically surfactants, generally improve the effectiveness of post-emergence herbicides.

Locate the product’s SDS document and look for the Specific Gravity measurement in Section 9. Multiply this number by the weight of a gallon of water (one gallon of water weighs 8.34 lbs.), this will provide you with the weight of your adjuvant per gallon.

Spray drift is the physical movement of a pesticide through air at the time of application, or soon thereafter, to any site other than that intended for application (often referred to as off-target). Consider these best management practices for managing spray drift: pay attention to wind speed and direction; plan to spray when wind is blowing away from sensitive areas; select proper nozzle size and type with correct pressure to manage desired spray droplet size; keep spray boom as low as possible; factor for relative humidity and air temperature; use a drift control adjuvant. You cannot totally control drift. KALO has products that significantly reduce the number of driftable fines in the spray pattern to help manage drift to acceptable limits. Drift mitigation or drift management are more accurate terms than drift control.

A nonionic surfactant significantly reduces the surface tension of a spray droplet, allowing it spread more evenly across the surface of the targeted area. Nonionic means that the surfactant has a neutral charge and has less tendency to interfere with other tank mix ingredients.

Consult the crop protection chemical label and be sure to follow label instructions for using a tank mix adjuvant. If the crop protection chemical label is void of information regarding adjuvant use, consult a local ag extension agent or crop protection chemical supply representative for recommendations regarding the adjuvant use. Always consider conduct inga jar test to confirm tank mix compatibility.

The spray application functionality is the more important consideration when comparing various competitive adjuvant products. Focus on end-result functionality in place of chemical descriptions. CPDA certified adjuvants and adjuvants registered with the states of Washington and California have been reviewed to meet the quality standards for product performance

Wetting of foliage and/or pest. Adequate wetting is required to provide good retention and coverage of the spray solution. A suitable adjuvant, at the proper concentration, will provide improved wetting of the plant or pest surface.

Modifying rate of evaporation of spray. The need for reducing the rate of evaporation of a spray solution applied at 2-3 gallons per acre in a hot dry area is obvious. The need, however, may be equally great in the application of a concentrate spray in an orchard. Once the spray has been applied, it may be desirable to have the spray dry as rapidly as possible. Both functions can be performed by a proper adjuvant.

Improving weatherability of spray deposit. Resistance to heavy dews, rainfall, and sprinkler irrigation can mean the difference between successful control and failure of an application. The proper adjuvant can greatly improve the weatherability of the spray deposit under these conditions.

Enhancing penetration and translocation. Many chemicals perform most effectively when they have been absorbed by the plant and transported to areas other than the point of entry. “Systemic” pesticides have this ability. Their absorption can be enhanced and certain non-systemic chemicals can be made to penetrate plant cuticles through the use of a suitable adjuvant.

Adjusting pH of spray solution and deposit. Many pesticides (primarily organic phosphates and some carbamates) degrade rapidly under even mildly alkaline conditions found in some natural waters and on certain leaf surfaces. Buffering adjuvants can prolong the effective life of alkaline sensitive chemicals under these conditions.

Improving uniformity of deposit. It is well accepted that, with non-systemic pesticides, the quality of performance of a pesticide can be no better than the quality of the spray deposit. This is particularly true of most fungicides which require complete and uniform coverage. The proper adjuvants can provide this kind of coverage.

Compatibility of mixtures. With the savings in labor costs to be obtained from doing more than one job with a single application, the effort is made frequently to mix various combinations of pesticides, and pesticides with liquid fertilizers, in the same spray tank for simultaneous application.

The resulting compatibility problems can frequently be corrected with the proper adjuvant.

Safety to crop. Phytotoxic chemicals can harm the crop which we are trying to protect. The hazard can be increased through the use of the wrong adjuvant or substantially reduced through the choice of a proper one.

Drift reduction. The use of special viscosity building or droplet altering adjuvants applied through nozzles, often from conventional aerial or ground equipment, is one of the most promising approaches to drift reduction.

Water hardness is associated with increased levels of solubilized minerals contained in spray water. Calcium, magnesium, and iron are each considered “hard water” minerals that can have negative impact on spray performance. These minerals impact performance by interacting with crop protection products, antagonizing the ability of the pesticide to perform. Opposites Attract - Glyphosate is antagonized by hard water minerals when cationic (positively charged) calcium, magnesium, and iron minerals in hard water seek out and attract anionic (negatively charged) glyphosate herbicide mixed into spray solution.

This antagonistic connection is made immediately when glyphosate herbicide is mixed into “hard water” spray solution, rendering the resulting spray mixture less effective.

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Adjuvants are products added to the spray tank for the purpose of modifying and enhancing the spray solution.

Spray water quality can be managed with the use of spray adjuvants to adjust pH and mitigate the antagonism of hard water minerals.Spray adjuvants that reduce the pH of spray solution are called acidifiers; others that adjust and hold spray pH to a desired level are called spray buffers.Many different types of adjuvant products are available for managing spray pH and hard water minerals, these adjuvant products are generally called spray conditioners. Spray conditioners perform by offering hard water calcium, magnesium, and iron, a more attractive connective site in the spray tank solution than the pesticide being mixed and sprayed. Water conditioning adjuvants do not remove the hard water minerals from the spray solution, but rather tie them up to prevent and mitigate pesticide antagonism.

pH is a measure of water alkalinity represented on a logarithmic scale of 0 to 14. Water with pH greater than 7.0 is considered alkaline while water less than 7.0 pH is described as acidic. Some pesticides, mostly insecticides, miticides and fungicides, are broken down chemically by high pH water. This degradation is called alkaline hydrolysis. Some pesticides are sensitive to loss in low pH water; this degradation is called acid hydrolysis. Accordingly, it is important to have a general understanding of the spray water pH and the sensitivity of pesticides to it. In general, a pH of 5.0 to 6.5 (slightly acidic) is optimum for most spray applications.

Ammonium sulfate disrupts hard water antagonism and conditions spray water in two ways:

• 1. The weakly bonded ammonium ion disassociates from the sulfate, leaving the double-negative sulfate wide open for attraction to the double-positive hard water minerals, such as calcium, magnesium, and iron.
• 2. The disassociated single-positive ammonium ion is attracted to the single-negative glyphosate molecule, becoming more readily accessible to targeted plant.

AMS treated water prevents hard water mineral antagonism of glyphosate. Ammonium ion attaches to glyphosate for enhanced uptake. Ammonium sulfate disrupts hard water antagonism of herbicides, fungicides and insecticides.

Proper mixing of crop protection products is critical to ensure the products are applied uniformly. Mixing can sometimes make the difference between acceptable and unacceptable performance.

DALES is an acronym for tank mixing order of dry products: Dry - Agitate - Liquids - ECs - Surfactants

WALES is an acronym for tank mixing order of liquid products: Wettables - Agitate - Liquids - ECs - Surfactants

These acronyms have been around for some time and have served the industry well over the years.

Unless otherwise specified by directions on the pesticide manufacturer’s label, the following tank mix sequence more accurately addresses newer formulations.

Unless otherwise specified by directions on the pesticide manufacturer’s label, the following tank mix sequence more accurately addresses newer formulations.

• 1. Fill the spray tank 1/3 to 1/2 full with clean water and start the agitation.
• 2. Water-soluble bags • Water-soluble granules • Water-dispersible granules(Some product labels will require pre-slurry.)
• 3. Wettable powders
• 4. Water-based suspension concentrates• Water-soluble concentrates
• 5. Suspoemulsions• Oil-based suspension concentrates
• 6. Emulsifiable concentrates• Surfactant • Oils • Adjuvants • Soluble fertilizers • Drift retardants
• 7. Continue filling with remaining water.

TESTING FOR PRODUCT COMPATIBILITY IS IMPORTANT! Since formulations sometimes change and are not all created equally, users should perform a jar test to determine the physical compatibility of the products being introduced into the spray tank and to determine water volume proportional to the water volume of the planned spray tank. NOTE: If the tank mix is not compatible, a higher water volume, reduced rate of tank mix partners, reduced number of tank mix partners or a compatibility agent (such as KALO’s Compex or Compex Extra) may be needed.

JAR TEST INSTRUCTIONS

• Pour 1 pint (16 ounces) of water into a 1 quart (32 ounce) jar.
• Add the correct proportion of fertilizer and wettable powders to the water and ensure that the materials are uniformly mixed. Add aqueous components individually, again ensuring each is mixed uniformly.
• Add emulsifiable concentrates (EC) compounds last. Invert (DO NOT SHAKE) the jar 10 times to mix and let stand for at least one hour.
• Inspect for unusual signs such as participates, clumping or layering in the mixture.
• It is important to remember that a jar test will only show physical incompatibilities and not phytotoxic incompatibilities.To check for the latter, test by spraying an inconspicuous spot.