Beauveria bassiana strain GHA
Beauveria bassiana is a fungus that occurs naturally in soil and kills insects. It is sold as BotaniGard and Mycotrol, and the spores are sprayed on to the pest. It works by contact, not by being eaten: spores stick to the insect, germinate and grow through its skin, and the fungus kills it from inside. The label says to expect control 7–10 days after the first spray, and it works best when started early, before numbers build. It is a greenhouse and nursery tool for whiteflies, thrips and aphids. It is not selective, though. It kills Aphidius wasps and the mealybug destroyer, it infects ground beetles and some spiders, and the label warns it is potentially pathogenic to honeybees.
At a glance
- Mode
- Fungal spores; kill on contact
- Label rate
- ½–2 qt per 100 gal (ES); ½–2 lb per 100 gal (22WP)
- Speed
- Control 7–10 days after the first spray
- Repeat
- Every 5–10 days; 2–5 days for heavy whitefly or aphids
- REI / PHI
- 4 hours / 0 days
- Store
- 40–85 °F (4–29 °C)
- Harms
- Aphidius, mealybug destroyer, ground beetles, some spiders; bees
How it works
The products contain live spores of B. bassiana strain GHA: at least 10 trillion viable spores per quart of BotaniGard ES or Mycotrol ES, and the same per pound of BotaniGard 22WP. The label describes the sequence: the spores attach to the pest, germinate and penetrate the cuticle, and the fungus then grows rapidly inside it. UConn adds that infected whitefly nymphs turn brown or pink, and that the white fungal growth is often not seen in a greenhouse. Because it works by contact, it only kills what the spray actually hits. Label directions are to spray to wet, but not to the point of runoff.
It is live, so it is fragile. The label says spores die after more than 24 hours in water, so mix only what you will use that day. Store the product between 40 and 85 °F. Fungicides may kill the spores, and UC IPM advises waiting 48 hours after a Beauveria spray before applying one. Speed is the other limit. UMass and UConn both say applications must start before whitefly numbers are high. Against heavy outbreaks the label itself suggests combining it with a compatible insecticide. Field results are weaker than greenhouse ones. In Quebec field onions, Beauveria sprays did no better than leaving the crop untreated. In Penn State's spotted lanternfly trial, the spores did not persist on the foliage.
Applying it
The figures below come from the EPA-accepted master labels for Mycotrol ES / BotaniGard ES (EPA Reg. 82074-1, April 2024) and BotaniGard 22WP (EPA Reg. 82074-2, March 2025). Follow the label on the product you buy.
Shake, then mix on the day
Shake to suspend the spores, add to half the water with agitation, then top up. Do not mix the day before; spores in water for more than 24 hours die.
½–2 qt per 100 gal
Whiteflies, mealybugs and aphids ½–1 qt; thrips 1–2 qt; up to 3 qt in high-volume sprays, which the label gives as 2–6 tsp (⅓–1 fl oz) per gallon. 22WP: ½–2 lb per 100 gal.
Wet the pest, not the ground
Spray to wet but avoid runoff, covering all the infested foliage. Test a few plants first, and use caution on open blooms.
Every 5–10 days
Every 2–5 days under heavy whitefly or aphid pressure. The label sets no limit on the number of applications.
REI 4 hours; PHI 0 days
Crops can be picked the day of spraying. Avoid areas where honeybees are foraging, and keep it out of water: the label says it may be toxic to fish.
Pesticide sensitivity
It is a general insect pathogen, so some beneficials are at risk. It can kill more than 55% of adult Aphidius colemani in lab and greenhouse work, and cut wasp emergence from parasitised aphids by up to 83% in related species. BotaniGard significantly reduced survival of the mealybug destroyer in University of Minnesota tests. UC IPM warns it infects soil-dwelling predators such as ground beetles and certain spiders, and gives it a bee rating that means no spraying on flowering plants except between sunset and midnight. It was far gentler on minute pirate bugs (80–100% survived) and Macrolophus, and residues from cutting dips barely affected Encarsia or Eretmocerus. Check a product →
When to choose something else
Beauveria suits a greenhouse or conservatory where you can spray thoroughly and repeatedly, early on. Choose something else when:
- You rely on Aphidius wasps for aphids — the fungus kills the adults; use the aphid midge or lacewing larvae on hot spots instead
- You are releasing the mealybug destroyer — BotaniGard reduced its survival
- Greenhouse whitefly is on a crop that stays in for five months or more — UMass says releases of Encarsia formosa work better there
- The pest is spotted lanternfly — Penn State does not recommend it; see the spotted lanternfly page
- The crop is field onions — sprays did no better than untreated in Quebec trials; flower strips cut thrips by up to 50%
- Numbers are already high — the label expects 7–10 days to control, and says intense outbreaks may need it combined with a compatible insecticide
Where to buy
These are the registered products whose EPA labels we checked. They are not ranked. helpfulbugs takes no commission and does not sell either one.
- Certis BotaniGard ES / Mycotrol ES (EPA Reg. 82074-1)Liquid, 11.3% strain GHAUS · GREENHOUSE & HOME
- Certis BotaniGard 22WP (EPA Reg. 82074-2)Wettable powder, 22% strain GHAUS · GREENHOUSE
Beauveria bassiana strain GHA by target
Rate and timing differ by what you are releasing it against. Each page below is the program for one pest.