Entomologist Robert Van Den Bosch coined the term “pesticide treadmill” in his 1978 book The Pesticide Conspiracy to describe how the insecticide industry cannot keep pace with pesticide resistance. We still see this phenomenon today.
A New and Revealing Study
The scientific journal Oecologia published a study in Costa Rica that compares mosquito populations in orange plantations with those in natural rainforests. Scientists focused on bromeliads, plants that live on trees and catch and retain rainwater in their broad leaf bases. Mosquito larvae and other aquatic organisms live in these rainwater reservoirs. Bromeliads in orange groves are treated with the pesticide dimethoate, while those in the surrounding forest are not. The results are startling.
Mosquitoes Survive, but Their Predators Do Not
While dimethoate kills most mosquito larvae, a few individuals persist, growing more robust without competition for food in the absence of their siblings. Furthermore, damselfly larvae, which feast on mosquito larvae, perish completely from chemical treatments.
What this means put simply? The next generation of mosquitoes is mostly pesticide resistant and thrives in pools devoid of predators. Rainforest bromelidads, with intact aquatic ecosystems, maintain fewer mosquitoes.
More Unintended Consequences
Insufficient knowledge of malaria-transmitting mosquitoes during World War II led to a pest control boondoggle in the South Pacific. Two species of Anopheles mosquito occupied the region. One thrived in cool, shaded waters, so vegetation was hacked away. Unfortunately, the other Anopheles species thrives in warmer, sunlit water. It was also a vastly better vector (aka carrier) of malaria. Thus, the attempts to control malaria actually led to a worse disease situation.
Similarly, efforts to eradicate the boll weevil from cotton plantations in south Texas and neighboring states to the east, using DDT, carbaryl, and azinphosmethyl, succeeded in suppressing the beetle only to liberate the Pink Bollworm in the early 1950s, making the bollworm the worst cotton pest.
What to Do
Clearly, chemical pesticide applications have varying degrees of success and are fraught with complications such as insecticide resistance by the target pest, eradication of natural predators and parasites of pest species, and emergence of new pests in the absence of those targeted enemies. How best can we cope with mosquitoes, then?
- Repellents, especially those such as Ben’s products with DEET as the active ingredient, continue to be your best weapon against mosquitoes, other biting flies, and ticks.
- Eliminating water-catching containers and draining birdbaths, puddles, and other standing water on your property prevents mosquitoes from breeding in large numbers.
- Maintaining a yard and garden that closely matches the natural habitats in your region helps guarantee a healthy ecosystem that keeps pest insects in check.
- Decreasing or suspending entirely your own pesticide use prevents decimation of insects and spiders that prey on mosquitoes and other pests.
Watch this blog for more information about evolving pest control strategies that are compatible with human health and the health of our environment. Meanwhile, consider the above suggestions.