Summer might not be just around the corner, but once gardens are in full bloom safe insect and pest control will become a necessity. As a NY green contractor that specializes in green roofs and gardens it’s part of our job to ensure that the spaces we create can be enjoyed to their fullest potential.
Mosquitoes and other bugs will exist naturally within any green space and it is important to be able to control their populations. The best option is to use safe and natural methods so as to reduce diseases spread by mosquitoes and maintain a clean and healthy setting. It’s much easier for our clients to enjoy their urban landscape when they are free from worry regarding insects and pests.
With this article we aim to provide a deeper understanding of how one of the most annoying and dangerous pests, mosquitoes, finds a host and the current scientific advancement in safe pesticide production and application.
The focus here is on the mosquito species Aedes Aegypti AKA the Asian Tiger mosquito; most well known for being a royal nuisance but also very importantly responsible for spreading yellow fever. When mosquitoes hunt for a meal they detect a number of chemicals, including carbon dioxide, lactic acid, ammonia, and octenol.
Octenol, in particular, is emitted by all mammals and is a carbon-based compound that has a molecular structure that can take on a “right-handed” or “left-handed” form. Both the right and left forms are a mirror image of the other and the “handedness” of either form determines how its molecular bonds are assembled.
A test performed by Agricultural Research Service (ARS) entomologists concluded that mosquitoes are more likely to be attracted to the right-handed form of octenol emitted by mammals. Information regarding compounds that most attract mosquitoes can be crucial in determining effective pesticide and repellent use.
Traditionally, a variety of man-made chemicals are applied to the body or a garden to repel insects. These chemicals are known to have harsh smells and negative health effects especially when applied directly to the skin. Folk and homeopathic remedies have long been used by indigenous cultures and many are coming under current scientific review.
The USDA and their chief scientific research agency the ARS along with a few collaborators have recently found that the ancient Pacific folk remedy of using breadfruit (Artocarpus altilis) to repel mosquitoes actually holds scientific weight.
Three chemicals within male inflorescences of breadfruit have been identified as being more effective at repelling mosquitoes than the leading repellent known as DEET. These chemicals – Capric, undecanoic and lauric acids (or C10, C11, and C12 saturated fatty acids) – have been recorded as being entirely successful in repelling the malaria carrier.
A separate study that examined the effectiveness of a variety of saturated and unsaturated fatty acids as mosquito repellent found that participants wearing a cloth treated with these compounds were protected against mosquito bites. Dried clusters of the flowers can be burned, as is done in native pacific cultures, to release the chemicals and stave off harmful mosquitoes as well. This is the first scientific research validating the effectiveness of the folk remedy.
In the same respect, ARS scientists studied the effectiveness of the Indian and African method of burning Jatropha curcas seed oil to repel insects. Jatropha curcas is a versatile plant with all parts having homeopathic functions.
In an effort to validate the folk remedy, Natural Products Utilization Research Unit (NPURU) chemist Charles Cantrell extracted the smoke from the plant and analyzed its repellent properties concluding that the free fatty acids and triglycerides present were effective at preventing mosquitoes from biting. Fatty acids have previously been observed to have mosquito repelling properties, but this study is the first to include triglycerides in its findings.
Folk remedies are regarded as safer methods of repelling mosquitoes due to the toxicity of modern pesticides. Chemical pesticides often have a strong negative impact on humans due to the similarity in physiological systems shared by humans and pests.
In further scientific advancement, ARS scientists have tested a new form of mosquito control that they have concluded to be safe for humans, yet detrimental to insect populations. This nonchemical approach involves using a molecular pesticide technology that prevents mosquitoes from producing essential proteins necessary for their survival. The protein present in this pesticide is a nucleic acid such as DNA or RNA that interrupts specific genes within pests.
Due to the gene technology involved, this method can be designed to target a specific pest species and is even effective against species that are resistant to certain chemical pesticides. It is important to use caution with any technological advancement, however this alternative to modern pest control is reported by the USDA to negatively affect only the species towards which the method is directed. This new, nonchemical approach to preventing mosquito bites could serve as a model system for developing new, safer pesticides.
When enjoying your days and evenings in your Brooklyn green roof or garden you probably won’t be using natural pesticides like jatropha curcas seed oil or breadfruit to stave off pesky mosquitoes. But we are looking at these ingredients and many more as possible natural mosquito control. We’ll be sure to keep you posted as our research continues!