Dithiopyr 40 WSB

5 out of 5 stars 1 Reviews | 17 Q&A

Dithiopyr 40 WSB

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5 out of 5 stars Rating: 5

1 Review | 17 Q&A

Product Overview

Dithiopyr 40 WSB is a water-soluble herbicide that can be used as an early post-emergent control crabgrass and pre-emergent control of over 40 grassy and broad-leaf weeds in established lawns, golf courses, field-grown nurseries, landscape ornamentals and more.

This product is intended for use in large areas and cannot be broken down for smaller-scale applications in home lawns.  For smaller areas please consider our other Dithiopyr products we carry in either granule or liquid.

Features and Specs

Active Ingredient Dithiopyr 40%
Target pests Crabgrass, Kikuyugrass, Goosegrass, Chickweed, Annual Bluegrass, Barnyard Grass, Oxalis, Ryegrass, Spurge
* See label for complete list
For use in Established Lawns, Golf Courses, Sod Farms, Nurseries, Landscape Ornamentals, Non-cropland, Industrial Sites
* See label for complete list
Application Rates vary depending on season and application site
See label for complete specific application instructions
Pet safe Yes, if used as directed on Label
Formulation Professional Product
NY (Restricted To Licensed Applicators Only)
Shipping Weight 1.44 lbs
Manufacturer Quali-Pro (Mfg. Number: 83014301)
UPC 072693430136
EPA Registration 53883-374



This product is not recommended for use by homeowners.

Note: In the state of New York, this product may be applied only by commercial applicators.

For control of crabgrass and other annual grasses and broadleaf weeds, use Quali-Pro Dithiopyr 40 WSB specialty herbicide in the following sites:

  • Established lawns
  • Commercial sod farms
  • Noncropland and industrial sites
  • Ornamental turf (including golf course fairways, roughs, tee boxes)
  • Landscape ornamentals, field-grown and container nursery ornamentals.

Quali-Pro Dithiopyr 40 WSB only controls crabgrass up to initiation of tillering, that is, when seedlings are first visible in established turfgrasses. Quali-Pro Dithiopyr 40 WSB will not control emerged weeds. For optimum effectiveness, apply Quali-Pro Dithiopyr 40 WSB prior to initiation of tillering, and make all other applications before germination of target weeds.

Quali-Pro Dithiopyr 40 WSB must be activated to be effective. Activation is achieved by watering-in from rainfall or irrigation (1/2 inch or more). Time applications to ensure that activation occurs before the tillering stage of crabgrass development or prior to germination of all other weeds.

Cool-Season Grasses

  • Bentgrass, Creeping
  • Bluegrass, Kentucky
  • Fescue, fine
  • Fescue, tall
  • Ryegrass, perennial

Warm-Season Grasses

  • Bahiagrass
  • Bermudagrass
  • Buffalograss
  • Carpetgrass
  • Centipedegrass
  • Kikuyugrass
  • Seashore paspalum
  • St. Augustinegrass
  • Zoysiagrass

Control of Crabgrass

Pre-emergence and Early Post-emergence Control

Quali-Pro Dithiopyr 40 WSB controls crabgrass, including the large, smooth, and southern species, when applied pre-emergence (prior to the emergence of crabgrass) in established lawns and ornamental turfs. Some early post-emergence control of crabgrass is obtained from applications of Quali-Pro Dithiopyr 40 WSB but only in the early stages of crabgrass growth after the crabgrass has emerged. Because of the difficulty in detecting the very small, early stages of crabgrass in well-established lawns and ornamental turfs, apply Quali-Pro Dithiopyr 40 WSB for early post-emergence crabgrass control only before the tillering of crabgrass. This phase of crabgrass growth is typically the time when you can first easily see the crabgrass in the lawn turf. This early post-emergence activity of Quali-Pro Dithiopyr 40 WSB gives the user an additional 2-8 weeks longer period of time to make applications while still controlling crabgrass. The exact amount of additional time will depend on the weather and how fast the crabgrass grows.

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  • 5 of 5 Stars

    The best DNA pre

    By Eric on 07/05/2019

    Great early summer product. This pre catches a few more "tougher" weeds than prodiamine.

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    9 of 9 people found this review helpful

Questions & Answers

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Does Dithiopyr 40 WSB need to be watered in after application?

Yes, Quali-Pro Dithiopyr 40 WSB does need to be watered in in order to activate the active ingredient. 

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23 of 30 people found this answer helpful

Is there a conversion table per 1000 sq ft for Dithiopyr 40 WSB?

Hi, I purchased this and read the label but I am having trouble finding how much powder should be used per 1000 sq ft and also what the annual limits are for various grass types.


How much Dithiopyr 40 WSB you use depends on the program you going to use but the amount is not easily measured out for smaller areas since it is in premeasured pouches.  The max rate on the label states: Do not apply more than 0.5 lb ai/ acre per application or more than 1.5 lb ai/acre per year using split or sequential applications.

A better option if you have less than an acre to treat would be the liquid version Dimension 2EW.  You will use .33 - .73 of an ounce of Dimension 2EW per 1,000 sq ft. The exact usage rate will depend on your location and the application program you choose. Please refer to pages 4-6 of the product label to find the exact usage rate for your needs. 

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16 of 46 people found this answer helpful

Can Dithiopyr 40 wsb be mixed with 2, 4 D and applied together?

Dithiopyr 40 WSB  and 2, 4 D can be mixed and applied together as long as they mix well in the tank. Be sure to apply during the cooler times of the day. 

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10 of 10 people found this answer helpful

Does Dithiopyr 40 WSB require the use a surfactant?

Also it is my understanding that you mix it with 10 gal of water per pouch, and it covers 1/4 to 1/2 acre.


Per the product label for Dithiopyr 40 WSB, when using as a post emergent tank mix for crabgrass: Improved control may be seen by the addition of a nonionic surfactant.  The rate will vary depending on the type of grass you have and program you are using.  Water is just the carrier so the amount of water you use is dependent on how much it takes to cover the treated area and is not set but you should a minimum of one gallon of water per 1000 sq ft.

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10 of 16 people found this answer helpful

What is the shelf life of Dithiopyr 40 WSB if it is still in the sealed packet?

Dithiopyr 40 WSB has a shelf life of 3-5 years from the date of purchase if stored at room temperature.

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9 of 9 people found this answer helpful

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Dithiopyr 40 WSB 5 out of 5 stars Rating: 5 (1 Reviews / 17 Q&A)

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