At War with Termites: A History
In non Western cultures today termites are often still consumed and considered a delicacy. Rich in protein and fat, a 100 gram serving of the insects provides 75 percent more calories than an equivalent serving of steak.Human beings have had a long and complicated history with termites. When prehistoric man was a hunter and gatherer, massive termite mounds were a source of plentiful and easily obtainable protein and an important part of the natural bounty that allowed early man a fairly laid back lifestyle.
The advent of farming as a cultural development however, brought termites into a more confrontational relationship with man and resulted in the very earliest DIY (do it yourself) termite extermination efforts. Crops in the fields became a prime target of swarms and colonies and as ancient man built more permanent habitation structures, the insect became increasingly seen as an invasive pest in shelter dwellings.
The History of Extermination
The history of warfare between man and termite is a long one and marked by great victories in the long term by the pernicious insects. Early efforts at neutralizing the destructive potential of termite colonies included labor intensive activities such as digging into the colony, and locating and removing the queen. Early efforts at fumigation included the burning of grass, wood, cow dung; other methods employed by ancient man and right up until fairly recent times include flooding the nest with water, pouring heated liquids into the nest (including melted paraffin). Burial of the offal of dead animals, or animal carcasses themselves in or near termite colonies, pouring collected urine into mounds and colonies are also other old time approaches to exterminating termites.
All too often, the battle between termites and man was won by the insects. In the days before effective pesticides were developed to deal with infestations, all too often the unhappy homeowner waged a losing battle against the implacability of mature colonies. In termite prone areas just as often as not entire structures could be lost to the voracious appetites of the invading insects.
Arsenic as a Termite Extermination Method
The earliest efforts at a chemical approach to termite extermination were centered on the use of arsenic. Arsenic is a compound that is highly toxic to termites, but also to humans and all other multi-cellular life forms. Only a few known organisms on earth, specifically some strains of single celled bacteria are known to be able to metabolize the compound and survive.
The use of arsenic as a termiticide continued well into the age of professional extermination; arsenic trioxide dust was long a tool in the arsenal of professional exterminators, although its use has fallen into disfavor in recent years. Arsenic also figured prominently in the treatment of building materials against termite susceptibility. It has only been in the last decade or so that the manufacture of pressure treated wood has ceased utilizing arsenic in its process amid fears of arsenic leaching into soil and poisoning ground water.
Over the decades an industry began to build around the need for effective pest control, the eradication of termite invasions being a prime motivator in the establishment of the field. Chemical advances over the years resulted in a growing array of effective pesticides that could be used to battle termite infestations.
Methyl Bromide: 40 Years of Effective Use
One of the earliest and most effective agents for exterminating termites was methyl bromide. An organic substance produced both naturally (by the oceans) and artificially It was widely used for decades as a soil sterilizing agent, commonly utilized to prepare fields for foodstuff cultivation (including use in commercial strawberry fields). For well over forty years in the United States, methyl bromide in gas form was the main fumigant pesticide used by termite exterminators. Its use was so prevalent for this purpose that of an estimated 71,500 tons of methyl bromide produced in 1999, over 95% was used for extermination by fumigation. Owing to the toxicity of the substance, and its long term ecological impacts, including its detrimental effect on the ozone layer, methyl bromide has been phased out on a worldwide basis under the Montreal Protocol of the Vienna Convention for the Protection of the Ozone Layer. The termite extermination fumigant Vikane gas (sulphur fluoride) has been the primary replacement for the use of methyl bromide, even though its toxicity and environmental impact are still an unfolding question.
Natural Approaches to the Problem
The question of how to exterminate termites—and how best to get the job done—remains a central one in pest control. As more and more chemical pesticides have fallen under fire for toxicity to humans and the environment, increasing attention has been given to more natural termite extermination methods.
Increasing pesticide research and development has concentrated on the formulation of insecticide which inhibit natural metabolic processes within the individual termite or which disrupt the production of physical features necessary to the survival of the insect. These types of insecticides tend to work best in bait systems which rely on the enticement of workers to feed and return the termiticidal compound to the colony.
Beneficial nematodes are an example of naturally occurring organisms being used to exterminate termite populations. Nematodes are parasitical, microscopic worms that attach to termite workers and inject them with bacterium that pre-digests the termites from within. The death of the worker form of a termite colony means the end for the entire population as workers feed and maintain the reproductive, soldier and brood forms of the insects.
An increasingly promising method of exterminating termites has been pesticides such as diflubenzuron which was used first in forestry and crop applications. Diflubenzuron inhibits the production of “chitin” which makes up the exoskeletons of insects such as termites. An inability to form a healthy exoskeleton means that an insect has no protection from the elements, parasites and other hazards and renders movement impossible.
As the termite extermination methods become more sophisticated and safer for humans, animals and the environment, termite extermination costs are likely to become increasingly high. Even so, when contrasted against the enormous economic impact that termite infestation can have on human populations and their livelihoods, every dollar spent finding the most effective method of exterminating termites is well spent.