Is neem oil safe for bees?

Last updated: October 2026

Only with precautions. The National Pesticide Information Center rates neem oil as practically non-toxic to bees because insects must eat treated plants to be harmed¹, but University of California IPM lists evidence that neem oil is toxic to honey bee brood and advises against spraying flowering plants except between sunset and midnight where the label allows². Laboratory work also found azadirachtin reduced bumblebee reproduction⁴.

What do pesticide experts say about neem oil and bees?

Neem oil is pressed from the seeds of the neem tree (Azadirachta indica), and its most active component, azadirachtin, reduces insect feeding and interferes with insect hormone systems, making it harder for insects to grow and lay eggs¹. The National Pesticide Information Center (NPIC) describes neem oil as practically non-toxic to bees and reasons that, because insects must eat the treated plant to be killed, bees and other pollinators are not likely to be harmed¹.

Other university sources are more cautious. University of Georgia Extension states that most neem products are toxic to bees⁷. University of California Statewide IPM gives neem oil and azadirachtin a bee precaution rating of II, which means they should not be applied to, or allowed to drift onto, flowering plants including weeds, except between sunset and midnight when the label and regulations allow². The ratings reflect reported toxicity to adult and developing honey bees².

In North America, searches about neem oil and bees peak in June and are lowest in December, so the advice on keeping sprays off flowering plants while bees forage matters most in early summer. In the Southern Hemisphere the same peak falls around December.

Is neem oil harder on bee brood than on adult bees?

The UC IPM database records evidence of toxicity to honey bee brood for neem oil products, not just to adult workers². A semi-field trial in the Czech Republic exposed small honey bee colonies in tunnel tents to flowering oilseed rape treated with neem formulations containing 1% azadirachtin³. A spray applied at full flower caused some reduction in foraging activity and brood development, while granules added to the soil at sowing did not adversely affect bee mortality, foraging or brood development³.

The authors called the trial a pilot with tentative results, because the treatments were not replicated³. They concluded that the spray could be applied to flowering rape during periods of low or no honey bee activity³.

Does neem oil affect bumblebees and other pollinators?

Bumblebees have been studied more closely in the laboratory. When microcolonies of the buff-tailed bumblebee (Bombus terrestris) were fed azadirachtin in sugar water for 11 weeks, mortality ranged from 32 to 100% across concentrations of 3.2 to 320 mg per liter, and no reproduction occurred above 3.2 mg per liter⁴. At 3.2 mg per liter, egg laying and drone production were significantly reduced, and when bumblebees had to forage for food, drone numbers fell at 0.64 mg per liter⁴. Azadirachtin also repelled bumblebee workers in a concentration-dependent way⁴.

Stingless bees show a similar pattern of hidden effects. Workers of Nannotrigona testaceicornis exposed to an azadirachtin product at strawberry crop concentrations had low mortality, but their midgut lining was damaged and brain cell chromatin changed⁵. A review of azadirachtin risk notes that chronic laboratory exposure also harmed the stingless bee Partamona helleri, but that azadirachtin's instability and low residual persistence make such chronic exposure unexpected under field conditions⁶. The same review reports that azadirachtin was selective to the Asian honey bee, Apis cerana, under standard risk assessment criteria⁶.

How long does neem stay active on plants?

Azadirachtin breaks down quickly. Microbes and light degrade it in soil, water and on plants, and the other components of neem oil are broken down by microbes in most soil and water environments¹. University of Georgia Extension makes the same point for gardeners: neem does not last long once it is applied, which is why thorough, targeted coverage matters⁷.

How do you spray neem oil with bees in mind?

Follow the product label first. UC IPM stresses that its ratings are not the pollinator statements printed on labels, and that the label and applicable laws always apply². Within the label, these steps reduce exposure for bees^2,7:

• Do not spray, or let spray drift onto, flowering crops or flowering weeds while bees are active².
• If plants nearby are in flower, apply in the evening or early morning when bees are not foraging⁷; UC IPM allows the window between sunset and midnight for rating II products where the label permits².
• Keep spray out of water that bees can reach, including puddles².
• Read the active ingredient: neem oil products act mainly as contact insecticides, repellents and feeding deterrents, while azadirachtin products act mainly as insect growth regulators⁸.
• Spray only plants where the target pest is present and listed on the label⁷.

Does neem oil harm other beneficial insects and wildlife?

For predatory insects and parasitoids, the azadirachtin review describes slight to moderate toxicity, with immature stages of beneficial insects more susceptible than adults in laboratory tests⁶. It recommends attention to which stage of a natural enemy is present and to application timing⁶.

Water is the other concern. NPIC rates neem oil as slightly toxic to fish and aquatic organisms and azadirachtin as moderately toxic to them¹. The review cites a European Food Safety Authority finding of moderate to high toxicity of azadirachtin to aquatic organisms⁶. Keeping spray out of ponds, drains and puddles protects both bees and aquatic life².