Coverage – Page 5 – Sprayers 101

Crop-Adapted Spraying (CAS) and an Apple Orchard Case Study

The ultimate goal of CAS is to adapt the amount of active ingredient per unit ground area such that the amount of active ingredient per unit target area (usually the leaf area) remains constant for canopies of varying shape and density. When this is achieved with sufficient accuracy, the pesticide efficacy is maintained. These three plants are all significantly different in size. When calibration is appropriate to each plant, the foliar coverage “experienced” for each plant will be the same, in spite of differences in the amount of solution expelled per ground area.

Posted on February 24, 2021 (February 7, 2022) by Jason Deveau (Spray Guy)

An orchard spraying scenario Here’s a common situation: An orchardist following IPM identifies a pest that poses an economic threat. It’s an annual pest and spraying is really a matter of when, not if. The operation is 150 acres and runs three airblast sprayers; two have a tower and one does not. Multiple varieties are […]

Perspective on rates, volumes and coverage

Posted on July 23, 2020 (November 18, 2024) by Jason Deveau (Spray Guy)

This short article is a thought exercise designed to give some perspective on chemical rates, carrier volumes and the foliar area we expect them to protect. Imagine we are spraying the fungicide Captan on highbush blueberry. In Canada, the label rate is to apply 2kg/ha (28.5oz/ac) of planted area. Captan is 80% active ingredient, so […]

Rainfastness of Insecticides and Fungicides on Fruit

Posted on September 24, 2019 (May 23, 2025) by Wendy McFadden-Smith

This article was co-authored by Kristy Grigg-McGuffin, OMAFA Horticulture IPM Specialist In view of the frequent heavy rains in many regions this season, understanding rainfastness, or the ability of a pesticide to withstand rainfall, is important to ensure proper efficacy. All pesticides require a certain amount of drying time between application and a rain event. […]

What’s with dew? – Tips with Tom #9

Posted on July 5, 2019 (June 20, 2025) by Jason and Tom

When warm air is cooled, it loses some of its moisture-holding capabilities. This change often occurs at night, when plants (and other objects) cool. Once the temperature of the surface of the leaves, for example, drops below the dewpoint, it causes water to condense, forming the shiny dew that causes so many to question early […]

How Airblast Spray Droplets Behave (or Misbehave)

Posted on January 21, 2019 (September 22, 2025) by Jason Deveau (Spray Guy)

Some pesticide labels require or prohibit certain droplet sizes to reduce the potential for drift. But, even when labels are silent about size restrictions, operators should be aware of the potential for droplet size to affect coverage. In the case of airblast, droplets should be: Once spray leaves the nozzle, the operator has no more […]