Oxalic Acid’s Sublethal Effects

Treating bees with oxalic acid damages honeybees. Peter Borst, at Bee-L, writes:

Sublethal effects of oxalic acid on Apis mellifera are hardly investigated. However, permanent damages of the digestive organs of adult workers are described. This can influence the nutrient supply and the feeding behaviour of the bee. In cage-experiments the food ingestion of A. mellifera after a treatment with oxalic acid was investigated …

The treatment with 3.5% OA resulted in sublethal effects on A. mellifera: reduced food ingestion and vitality. The less requirement of food can indcate changes in the metabolism which are also reflected in the low activity. It has to be investigated in further studies whether these results are caused by organ damages or other effects like dehydration or symptoms of poisoning. Sublethal effects of oxalic acid on Apis mellifera: changes in food ingestion. S. Schneider, E. Rademacher (Freie Universität Berlin, Institut für Biologie, Neurobiologie, Königin-Luise-Straße 28/ 30, 14195 Berlin)

This shouldn’t be any surprise to a natural beekeeper. Feeding bees  oxalic acid is sugar syrup just isn’t natural.  🙂

It’s known that vaporizing oxalic acid is less harmful than the syrup. But it’s not natural either.

My own oxalic acid experience indicated oxalic is one of the least harmful and most effective mite treatments available. It:

  • wasn’t as invasive as powdered sugar dusting
  • didn’t leave toxic residues or by-products like the synthetic pesticides
  • didn’t interfere with colony function like essential oils and formic acid

But that’s not to say or even think that oxalic is benign. Who knows what it does to the beneficial bacterial balance in the hive?