Water Dispersible Granules (WDG)

Water dispersible granules are a pesticide formulation that has been around since the 1960s. WDGs have proven to be an excellent method of pesticide alternative to liquid-based formulations.

On this page, you will learn about water dispersible granules, how the granules are formulated, and how to properly apply water dispersible granules around your home to treat for pests.

What is a Water Dispersible Granule? 

Pesticides can come in many forms one of which can include water dispersible granules. This granule is a formulation where rather than being in liquid form and needing to be sprayed, the pesticide is reduced to a paste and blended with an organic material that will dissolve in water.

In the case of water dispersible granules (which are also referred to as dry flowables), water-dispersible granular formulations are very similar to wettable powder formulations with the difference being that instead of being dust-like, the product is compressed into dust-free, granule-sized particles.

Most WDGs come with a product-specific measuring device, with dry ounce (or pound) increment marks based on product density (weight per unit volume). Because of this and the fact that they readily flow or pour out of their containers, they are easier to measure and cleaner to handle than WPs. Similar to wettable powders, water-dispersible granules need to be mixed with water and applied as a spray suspension. Once in the water, the granules break apart into fine particles like powder.

WDGs tend to flow easily, which allows them to be poured, rather than scooped out of a package. The ease of dispersion is highly formulation-specific, and well-designed WDGs should disperse fairly quickly.

The percentage of the active ingredient in WDGs are high, sometimes being has high as 90% by weight. Water-dispersible granules bind to the soil after exposure to moisture, and function as a limited soil treatment.

Conditions for Using WDG

Water-dispersible granules perform well as herbicides as well as insecticides.

They settle out quickly unless they are constantly agitated to keep them suspended. They can be used for more pest problems and in most types of spray equipment where agitation is possible.

Benefits of WDG

The benefits of a water dispersible granule are very similar to the benefits brought by wettable powders with the exception of one added benefit: reduced exposure risk. WDGs are easier to mix and measure and because they are less dusty, they are less of an inhalation hazard.

Water dispersible granules are also the most economical formulation of pesticides due to the high percentages of the active ingredient and the fact that they are lightweight reducing freight and storage costs.

WDG Drawbacks

Though WDGs are usually not as dusty as WPs, there can be smaller particles present, sometimes due to attrition (breaking up) of granules during transportation/handling. A well-designed system should be devoid of this problem.

WDGs usually take more time to fully disperse in water than other formulations, so good mixing practices are important.

Water dispersible granules also require a fair amount of agitation. This is because they would very quickly clog your nozzles and they would also settle out very fast in your spray tank or have very poor suspensibility. To prevent this, you would have to grind the active ingredient by agitation to reduce its particle size.

Our Recommendations

Prodiamine 65 WDG - Prodiamine 65 WDG is an excellent pre-emergent herbicide that is activated by water. It is easy to use, safe and effective. It provides excellent control for broadleaf and grassy weeds with a long-lasting residual to contain susceptible weeds and prevent new growth from occurring. Same Exact Active as Barricade but for less. Get the same effectiveness and save money doing it.

Tools Needed

To use a water dispersible granule product you will need to dilute and mix the granules with water into a handheld sprayer. Please use the necessary PPE for safety before mixing and applying.

User Guide

Step 1: Check the Label

The WDG chemical will either come with a dosing spoon or be in individual use packets. Follow label directions for proper dosage of WDGs and proper application instructions.

Step 2: Mix WDG Product in Sprayer

Shake the insecticide container well before spraying to agitate the WDG and to make sure it doesn’t settle.

Step 3: Apply Product

Spray around your exterior windows, the eaves of the house, and other areas where there are cracks and crevices. If it is a herbicide WDG, apply to the target weeds, spraying evenly.

Key Takeaways

• Water Dispersible Granules are a granule that once in water, will break apart into fine particles like powder.
• WDG products usually have an excellent residual and depending on the type of WDG, perform well against: weeds, fungi and insects.
• Keep in mind that water dispersible granules take more time to disperse in water than other formulations, so good mixing is important.