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Boric Acid Insecticides PDF Print E-mail
Tuesday, 27 May 2008

Boric acid and its sodium borate salts are active ingredients of pesticide products used against insects, spiders, mites, algae, molds, fungi, and weeds. They were first registered as pesticides in the United States in 1948 and reregistered in 1993. The borate salts include sodium tetraborate decahydrate, sodium tetraborate pentahydrate, sodium tetraborate (anhydrous borax), disodium octaborate tetrahydrate, disodium octaborate (anhydrous), and sodium metaborate (1).

 

Boric acid and its sodium borate salts are active ingredients of pesticide products used against insects, spiders, mites, algae, molds, fungi, and weeds. They were first registered as pesticides in the United States in 1948 and reregistered in 1993. The borate salts include sodium tetraborate decahydrate, sodium tetraborate pentahydrate, sodium tetraborate (anhydrous borax), disodium octaborate tetrahydrate, disodium octaborate (anhydrous), and sodium metaborate (1). Use of the term “boric acid” in this fact sheet refers to the acid and/or borate salts.

Boric acid is generally a white solid, but it ranges from clear to opaque. It is odorless and generally stable under ambient conditions.

Boric acid products are used on a variety of sites including sewage systems, food and non-food crops, outdoor residential areas, and indoor sites such as homes, hospitals, and commercial buildings (1). Commercial formulations of the pesticide include aerosols, liquids (solutions, emulsifiable concentrates), granules, wettable powders, dusts, pellets/tablets, and impregnated materials (baits, stakes, etc.).

How does boric acid work?

Insects die by ingesting boric acid and borate salts. Borate salts are abrasive to the insect exoskeleton.

Boron is an essential plant micronutrient, and some boric acid products are used to correct boron deficiencies in plants (1, 3). Plants require small amounts of boron but high concentrations are toxic (3). At high levels, boric acid is an herbicide that disrupts photosynthesis and causes plant desiccation.

As a fungicide, boric acid inhibits the maturation of fungi by preventing spore formation.

The mechanism of toxicity in animals is not known.

How toxic is boric acid?

Animals

Boric acid is very low to low in toxicity when ingested. The acute oral LD50 in mice is 3450 mg/kg and for rats ranges from 2660-5140 mg/kg (2). See boxes on Laboratory Testing, LD50/LC50, and Toxicity Category.

LD50/LC50: A common measure of acute toxicity is the lethal dose (LD50) or lethal concentration (LC50) that causes death (resulting from a single or limited exposure) in 50 percent of the treated animals. LD50 is generally expressed as the dose in milligrams (mg) of chemical per kilogram (kg) of body weight. LC50 is often expressed as mg of chemical per volume (e.g., liter (L)) of medium (i.e., air or water) the organism is exposed to.

Chemicals are considered highly toxic when the LD50/LC50 is small and practically non-toxic when the value is large. However, the LD50/LC50 does not reflect any effects from long-term exposure (i.e., cancer, birth defects, or reproductive toxicity) that may occur at levels below those that cause death.

For a complete report please use: http://npic.orst.edu/factsheets/borictech.pdf

 

Last Updated ( Tuesday, 27 May 2008 )
 

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