- The Beaufort scale is a measure that relates wind speed to observed conditions at sea or on land.
- Pest control operators need to be aware of wind conditions at the time of application, as some conditions are not ideal for spraying pesticides.
- Ideal spraying conditions are at wind speeds of 6–19 km/hr, which equates to a Beaufort number of 2 or 3.
The Beaufort scale is a measure that relates wind speed to observed conditions at sea or on land. It can be used in place of a wind-measuring instrument to assess the suitability of the weather conditions for spraying.
Pest control operators need to be aware of wind conditions at the time of application as some conditions are not ideal for spraying pesticides.
Table 1 outlines different wind speeds and their corresponding Beaufort number, and how these conditions relate to pesticide spray application.
Wind speed and pesticide spray advice
Table 1: Beaufort scale and pesticide spraying conditions
Calm: smoke rises vertically
Avoid fine sprays,
especially on warm, sunny days
Light air: wind direction shown by smoke drift, not wind vanes
Light breeze: wind felt on face, leaves rustle, wind vanes move by wind
Ideal spraying conditions
Gentle breeze: leaves and twigs in constant motion, wind
extends a light flag
Moderate breeze: raises dust and loose paper, small branches move
attempt to apply
pesticides under these conditions
Fresh breeze: small trees sway, crested wavelets form on
Strong breeze: large branches move, umbrellas hard to use
Near gale: whole trees move, breaks twigs off trees,
difficulty walking against the wind
Gale: breaks twigs off trees, generally impedes progress
Strong gale: slight structural damage (e.g. chimney pots and roof tiles removed)
Storm: seldom inland, trees uprooted, considerable
Reviewed 03 November 2021