Field trialRatnanagar, Bagmati Province, Nepal
Mustard-Oil Barriers Against Ant Infestation in Beehives
Whether a mustard-oil barrier can keep ants out of honey bee hives without chemical ant chalk.
01 / The question
Can vegetable oil serve as a non-toxic physical barrier against ants?
02 / The context
Ants are among the most common predators of honey bee colonies; they attack hives in mass, taking adult bees, brood and honey (Sanford, 1987; Sarwar, 2016).
Beekeepers often respond with “ant chalk” containing deltamethrin and cypermethrin, synthetic pyrethroids that are toxic to non-target insects, including bees.
In a local apiary, 5 of 20 hives were infested, and the beekeeper reported recurring ant problems despite using ant chalk.
03 / The method
Sample: 20 Apis mellifera hives, 5 of them infested (3 moderately, 2 heavily)
- Newton-type hives on metal-rod stands
- Ants removed by hand from infested hives before treatment
- Bowls of mustard oil placed under each leg of the hive stands
- Daily observation for seven days: ants present or absent on the stands and inside the hives, and how many
04 / The findings
- No ants returned to the three moderately infested hives during the seven days.
- In the two heavily infested hives, a few ants remained inside but no new ants reached them; these were removed by hand.
05 / The implications
- Suited to small-scale and resource-limited beekeepers: mustard oil is cheap, easy to find and familiar in Nepal, and needs no special equipment.
- Avoids exposing bees and hive products to pyrethroid ant chalk.
Limitations
- Heavy infestations need manual cleaning before the barrier works fully.
- Oil must be refilled and cleaned to stay effective.
- It does not address flying ants.
- Rain and wind can change the oil level.
06 / Research record
- Type
- Field trial
- Location
- Ratnanagar, Bagmati Province, Nepal
- Sample
- 20 Apis mellifera hives, 5 of them infested (3 moderately, 2 heavily)
- Status
- Field trial, reported in the Journal
- Cited in the source
- Sanford (1987); Sarwar (2016); Hebbar, Hebbar & Patwardhan (2015)