Another Myth Debunked: Concrete-Eating Termites

Termites eat through concrete! This claim has been repeated so often that many PCOs believe it. Not exactly eating a hole "just enlarging a crack in the foundation," according to quite a few reputable PCOs.

If this idea is sometimes also entertained by entomologists, there is good reason. An eminent termite researcher, Dr. Nan-Yao Su, looked for the basis of the claim and found it in an obscure journal, The Philippine Journal of Science, published in October 1919. In it, an early researcher on termites in Formosa, Dr. Masamitsu Oshima, wrote: "It is said that the soldier of Coptotermes formosanus attacks lime mortar by dissolving the lime with acidulous secretions."

According to Dr. Su, "When Dr. Oshima used the expression `It is said ...' he was using a direct translation of a Japanese expression that actually means `I speculated that ... .'"

This "entomythological" notion that the glandular secretion from the fontanelle of a subterranean termite soldier is acidic would never have been accepted by the academic community if it had known that Dr. Oshima had in fact said that this was speculation.

EVIDENCE NONEXISTENT. To determine what the actual pH level was in the secretion from the fontanelle opening in the head of Formosan termites, Dr. Su and his associate Dr. Rudolph Scheffrahn tested several species in their laboratory at the University of Florida Research and Education Center in Fort Lauderdale. They found no evidence of acidic content in the secretion.

Dr. Su quotes two more sources. According to A.E. Mills (1983, Physiological Entomology), "The tacky secretions used by Coptotermes and Reticulitermes are simply adhesive entangling agents with no apparent toxic or pheromonal properties." And according to J.M. Pasteels et al. (1983, Annual Review of Entomology), "Coptotermes produce mucopolysaccharides and hydrocarbons from homologous glands ... ." Dr. Su adds that the hydrocarbons in the secretions are something like starch glue, and mucopolysaccharides are something like sticky protein-based fluid.

According to Dr. Su, of the termite species in the United States that do produce the secretion, that of R. flavipes is extremely minimal compared to that of its Formosan cousin.

In Biology of Termites, Kumar Krishna and Frances Weesner write that termites are unable to penetrate concrete, but that hidden cracks and other openings could be penetrated. It may be possible that with a poor mortar mix, sand particles might be loosened and a tiny crack enlarged. It is a Myth Conception that subterranean soldiers can dissolve mortar with the discharge from their fontanelle gland.

Termite teeth and jaws are sharp and strong enough to eat through ¹/₈-inch-thick walls of PVC pipe. (Termites, after all, receive four sets of new teeth in their lifetime; we only get two.) I have a sample of this pipe, with a hole having mandibular scrapings, sent to me by Jim Russell of American Exterminating Co., Springfield, Mass.

PCOs can expect calls from above-ground pool owners this summer. Termites often eat holes in the plastic liner at the rounded edge. Foragers are attracted to moist areas, especially during dry spells. They bite into anything softer than their teeth. For more information on pool liners and termites, see my Myth Conceptions columns in the August 1991 and July 1993 issues of PCT.