What Is Boric Acid Powder?

Boric acid, also known as orthoboric acid or boracic acid, is generally considered a “safe” insecticide of relatively low human toxicity. It occurs naturally in plants (including vegetables), and small quantities are necessary for proper plant development.

Chemistry

Boric acid is a white, crystalline solid of chemical formula H?BO?, which is sometimes written B(OH)?. It is only sparingly soluble in water. It melts at 170 degrees Celsius, at which temperature it will decompose into water and metaboric acid (HBO?).

Production

Boric acid is manufactured by the combination of borax (sodium tetraborate decahydrate, Na?B?O??10H?O) with muriatic acid (hydrochloric acid, HCl).

Applications

Boric acid is commonly found in insecticides. It purportedly works through an unusual mode of action by penetrating the exoskeleton and killing insects by dehydration, although the exact mechanism is not well understood.

Toxicity

The acute toxicity of boric acid is reportedly about the same as that of sodium chloride (table salt). In large doses, however, it is known to cause sterility in male test animals.

Fun Fact

In 1943, the original Silly Putty was synthesized from boric acid and silicone oil.

References

• National Pesticide Information Center: Boric acid--General fact sheet
• Journal of Pesticide Reform: Pesticide fact sheet--Boric acid and borates
• Beyond Pesticides: Chemical watch fact sheet--Boric acid