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Night Spraying Herbicides

Farming Smarter Project

Timeline: 2012 – 2015

Project Lead: Ken Coles



Zero-tillage systems require timely pesticide applications to control weeds & diseases. A southern Alberta farmer tried spraying at night and had some success. Farming Smarter wanted to find if night spraying could provide a feasible alternative to poor daytime conditions and potentially improve efficacy due to greater absorption. Night spraying might provide farmers with the option to cover the same acres in a shorter time frame or to cover more acres with the same equipment.


  1. Determine if applying pesticides at night is a practical option for producers.
  2. Generate unbiased data on the efficacy and tolerance of night applications of pesticides.
  3. Uncover possible issues/complications associated with night spraying.


Collaborators: Farming Smarter; Smokey Applied Research & Demonstration Association; Alberta Crop diversification Centre South; Agriculture and Agri-Food Canada
Alberta Locations: Lethbridge, Brooks, Lacombe, Falher
Research plots were established at three locations across Alberta: Lethbridge, Bonnyville and Falher.

In preseed burndown (PSBD) trials, plots were sprayed at label-recommended and three quarter-label rates with four herbicides: Prepass (Florasulam), Rounndup (Glyphosate), Aim (Carfentrazone) and Heat (Saflufenacil) according to the experimental design using hand held sprayers equipped with two meter booms and CO2 propellant at three different timings, day (12-2 pm), night (12-1 am) and early morning (4-5 am).

In-crop trials plots were sprayed at three quarter-label rate with the herbicides, Liberty (Glufosinate-ammonium), TM Muster + Select (Ethametsulfuron-methyl + Clethodim), Vantage™ Plus MAX II (glyphosate), Odyssey (Imazamox, Imazethapyr), Select (Clethodim), OcTTain (fluroxypyr, 2,4-D LV ester), Everest (Flucarbazone-sodium), Axial + Infinity (Pinoxaden + Prasulfotole, bromoxynil) and Barricade (Thifensulfuron, methyl, tribenuron methyl) depending on the target crop and experimental design, using similar equipment and spray timing as mentioned above in the PSBD trials.


Final Reports

The major conclusions drawn from our study are:
  1. The herbicides in PSBD and in-crop trials performed most effectively when applied in the day time (12-2 pm). Night time (12pm-1am) gave better results than the least effective Dawn time (4-5 am). We saw a substantial advantage of Day and Night time applications over the Dawn time application
  2. Although, Night time application performance was less often effective than Day time application, it performed better more often than Dawn time and, therefore, it could be useful as an alternate spray application timing when opportunities for Day time application are limited
  3. The results also suggest that moisture-stressed plants or a major rainfall event shortly after herbicide application could also reduce efficacies potentially rendering the herbicides totally ineffective, upsetting the performance patterns most often seen in our study

Project technicians actually got out at midnight to test the theory.

Read/download the final reports

Night Spraying Herbicide Report

Night Spraying Fungicide Report

Project Videos

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