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How to apply BioCeres® WP (Beauveria bassiana) for best results

Published on: | Created by: Roxanne S. Bernard

Tags: beauveria bassiana, bio-insecticide, bioceres, thrips

Beauveria bassiana infecting an aphid Anatis Bioprotection

Beauveria bassiana is a species of fungus naturally found in the soil. This living organism acts like a parasite, infecting different types of invertebrates (insects, mites, etc.). There are several Beauveria bassiana strains. The advantage of commercialized strains is that they better target pests like aphids, thrips and whiteflies (e.g. our ANT-03 strain in BioCeres® WP).

When the conidia (spores) come into contact with the insect’s cuticle (skin), they spread into the hemolymph (blood), which they feed on. This causes small insects like thrips to die within three to five days and larger insects to die within five to seven days.

This fungus can be very virulent when applied in optimal conditions, using the right mixing and application techniques.

For best results in applying Beauveria bassiana :

1 Always follow the safety rules for applying chemical pesticides

Étiquette sur un sac de BioCeres bio-insecticide
Apply BioCeres® WP (Beauveria bassiana) using the safety equipment recommended for chemical pesticides.

Even if BioCeres® WP’s active ingredient is natural, the same safety rules apply. During the entire process, from pre-mixing to spraying, it is important to wear safety goggles, a NIOSH-approved respirator, long sleeves and pants, waterproof gloves and shoes with socks.

2 Use Beauveria bassiana (BioCeres® WP) preventatively

Beauveria bassiana should be used as prevention rather than a cure. Due to the infection incubation period, it takes several days to kill pests.

The best practice is to start foliar applications at the beginning of the season, when you receive the plants, or on cuttings before pests first appear. You can even do soakings.

3 Always check BioCeres® WP’ date of manufacture before starting

Étiquette sur un sac de BioCeres® WP bio-insecticide
Label indicating the date on which the product was manufactured

BioCeres® WP can be kept for 12 months at 4 ºC and for 6 months at 21 ºC.. Beauveria bassiana spores are living beings and therefore highly sensitive to heat, low humidity and poor storage conditions.

Always check the date of manufacture on the bag before spraying. Dead spores cannot infect pests.

If you cannot find the BioCeres® WP date of manufacture or have doubts, don’t hesitate to contact us.

4 Apply Beauveria bassiana  in the late afternoon, in the evening or on a rainy day

Beauveria bassiana spores are very sensitive to UV rays. For this reason, we advise you to apply this product in the late afternoon or evening. You can also do foliar application on cloudy or rainy days.

5 Make sure the atmospheric humidity is favourable for application

Beauveria bassiana is a fungus, it prefers a humid environment. We recommend maintaining the relative humidity at 60% or higher during foliar applications.

With the right level of humidity, once the infected insect is dead, the fungus’ mycelium will emerge from the pest’s different sutures. The white filaments look a bit like cotton fluff. If a healthy insect comes into contact with the mycelium, it will also get infected and die.

Note that poor conditions (e.g. not humid enough, too hot, UV exposure) can stop the mycelium from developing outside the contaminated insect.

6 Make sure the ambient temperature is favourable

High temperatures can reduce the viability of the spores. Optimal application temperatures are between 18 and 29 ºC. Spores develop more slowly below 15 ºC and become inactive above 33 ºC.

7 Pre-mixing Beauveria bassiana properly is one of the most important steps

Beauveria bassiana spores are hydrophobic and can therefore be difficult to mix with water. It is important to premix using the correct technique (and the right container – see below)! This step makes all the difference. An improper premix will leave excess residue on the leaves and fruits and uneven concentrations of conidia in your solution.

8 Use the right container

It is very important to premix in a hermetically sealed container, like a mason jar, blender or industrial paint mixer.


Never mix with hot water!
Never pre-mix in a pail or bucket using a stick or whisk.

This will add too much air to the water and the solution will not mix properly.

Once you have weighed your dose (2 to 4g/L):

  • Transfer into a hermetically sealed container
  • Add cold or room-temperature water (2 L of water for a 100 L tank)
  • Mix well for 30 to 45 seconds
  • Pour your premix into the spray tank
  • Rinse the premix container with water three times and add the rinse water to the spray tank
  • Prepare a fresh batch for each application

9 Apply the mixture as soon as possible

Apply your Beauveria bassiana solution as soon as possible. Exposure to direct light or heat for an extended period can kill the spores before you have a chance to apply them. Do not keep the solution to apply the next day.

10 Apply where you see pests

Aleurodes ou mouches blanches
Whitefly colony under a rose leaf

Beauveria bassiana spores need to come into contact with the target pest, which is why it is important to achieve complete foliar coverage. Thrips, whiteflies and aphids are mainly found under the leaves or on the terminal buds.

Additional information

  1.   - The rise of microbes offers growers some important new IPM tools
  2.   - Compatibility of the parasitoid Aphidius matricariae with BotaniGard for the control of greenhouse aphids
  3.   - Biological control in greenhouse IPM systems: Where we’ve been, where we are, and where we need to go?

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