Aug 5 2015


We’ve put together our top ways to save you money and get the most out of your inputs when spraying; whether you are spraying for weeds, insects/pests, or diseases/fungus, we have you covered!


1.) Find Your Economic Threshold [1]:  An Economic Threshold refers to the density of the pest vs. the economic return you would get from the controlled treatment.

There are four factors that affect the Economic Threshold:

  • Cost of Spraying AKA Dollar Value of Treatment
  • Pest Density
    • The physical number of pests per area.
  • Growth Stage of the Pest
    • i.e. If a weed is in its seedling stage vs. reproductive stage, will it take significant resources from your crop if it’s not treated?
  • Yield Loss
    • The yield that is expected to be lost if your field is left untreated.

There are many online calculators to determine Economic Thresholds, below is an example of a Green Foxtail calculation [2].

Economic Threshold Calculator

Image Source


2.) ID Your Pests:

  • Use your resources, whether it be your agronomist, or even a few quality mobile applications to identify the pest causing problems on your field.
    • Ag Weed ID: This app allows you to take a photo and compare your problem weed to a database of others.
    • BASF Cereal Diseases App: This application gives you all pathogens that affect Cereal crops and their corresponding symptoms, life cycle, etc.
    • AgPhD:  This is a handy little app that can help you ID both insects and weeds, in addition it provides you with ways to best control them.

Spray Apps

3.) Think Timing:

  • Treat the pest before it becomes a major problem that competes heavily with your crops for resources and optimally before it reaches its peak reproductive growth stages.
  • Spray when wind is blowing consistently in one direction at a speed of between 2 – 15 km per hour or 1.5 – 10 miles per hour [4].
  • Spraying is best when temperature is low (below 25° C or 77° F) and relative humidity is high (40 percent humidity and above) [4].
  • Read the pesticide/herbicide labelling carefully to determine if rain will either be helpful or hurtful to your spray application.


4.) Add Fertilizer when you Spray: 

You can add both Macronutrients and Micronutrients at the same time you spray your pesticide/herbicide application, all in one pass.  This may save you some dollars and some labour.


5.)  Adapt an Integrated Pest Management plan

An IPM involves learning more about your pests, their behaviour, life cycles, and interactions. Understanding the pest will help you learn more ways to better control it or treat it. The Environmental Protection Agency provides more information on how to make your own plan at this link [5]:

Written and Published by Jessica Kohls, BSc, PgCE – Dutch Biologist