How Garden croton, Tawa-tawa and Lemon grass can be used to kill Aedes Aegypti Mosquito Larvae

There is currently no cure for the Zika Virus or any Virus for that matter.

So much of the focus of researchers in on killing the vector, namely the Aedes Aegypti Mosquito that carries the disease as noted in my blog article entitled “How Ministry of Health and IAEA using Radioactivity to reduce Aedes Aegypti Mosquito Population”.

Jerouen Paul Lumabao, a 10th Grade student at Daniel R. Aguinaldo National High School in Davao City in the Philippines, has discovered three (3) plants that can kill the Aedes Aegypti Mosquito as reported in the article “Common plant could help fight Zika virus”, published MAY 26, 2016 BY Sid Perkins, Student Science.

The 17-y-o discovered that the extracts from the following three (3) plants can be used to kill the larvae of Aedes Aegypti Mosquito:

1.      Garden croton (Codiaeum variegatum)

2.      Tawa-tawa (Euphorbia hirta)

3.      Lemon grass (Cymbopogan citratus)

His results, which he presented at the Intel International Science and Engineering Fair on Thursday May 12^th 2016, were quite impressive and a very competent example of the scientific process at work. The Intel International Science and Engineering Fair was sponsored by Intel and brought together more than 1,750 students from 75 countries around the world.

Jerouen Paul Lumabao demonstrates that not only is he a promising biochemist, but the discovery is very significant to the fight against the Aedes Aegypti Mosquito, the insect that spreads Dengue Fever, Chikungunya and the Zika Virus.

So how can these plants extracts kill the larvae of Aedes Aegypti Mosquito?

Jerouen Paul Lumabao's mosquito larvae insecticide - How to extract essential oils using evaporation and solvent extraction

To extract the active organic ingredient, he used an evaporation and solvent extraction technique.

He first left the leaves dry for a week in a warm drying chamber. He most likely avoided direct sunlight, as radiation could damage the molecules of the active ingredient, which is the Evaporation part of his process. Then he masticated the leaves and soaked them in ethyl-alcohol or isopropyl alcohol, which is basically solvent extraction.

The extracted oils from each of these plants leaves, allowing the alcohol to naturally evaporate over several days until an oily mixture was left behind. These mixtures contain all of the organic substances that were present in the leaves of the Garden croton (Codiaeum variegatum), the Tawa-tawa (Euphorbia hirta) and the Lemon grass (Cymbopogan citratus).

By using this method, he helped to preserve the chemical structure of the active and inactive compounds found in the leaves, as direct heating would cause some of the more volatile compounds to evaporate or break down into smaller compounds.

These oily mixtures were then tested on the larvae of the insects, with a control group so as to verify his results. Based on his observations, the Tawa-tawa (Euphorbia hirta) and the Lemon grass (Cymbopogan citratus) caused the Aedes Aegypti mosquito larvae to have stunted growth, resulting in them not developing into fully grown mosquitoes.

But the results of are a bit more astounding; within a 24 hour period, the extracts from the Garden croton (Codiaeum variegatum) had killed all of the mosquito larvae.

So is this mosquito larvae insecticide the mosquito killer we've been looking for all this time?

Toxicological assay needed - Potential insecticide to kill Aedes Aegypti mosquito

Not exactly.

This is far from an effective solution, as the extracts from these plants may be toxic to animal, plant and human life in body of water is sprayed. After all, the extracts, albeit natural, are chemicals; at certain concentrations, they could be toxic to humans. This is especially true of the Garden croton (Codiaeum variegatum), whose bright colours indicate that the leaves contain alkaloids, which I suspect is the main killing ingredient.

 A toxicological assay would have to be done on these plant extracts to determine the exact elements and compounds in the extracts that actually kill the mosquito larvae. Killing mosquito larvae can also be achieved using DDT, a banned chemical known to cause birth defects in animals and humans, so we have to determine if these chemical extracts are equally dangerous. It would also be used to identify if there are active compounds in the mixture that are toxic to plants, animals and humans and in what concentrations.

This toxicological assay could then be followed up by trials on the active compounds in the mixture to determine the effective dosage level of the active ingredients to stunt and kill the Aedes Aegypti mosquito larvae. It is during these trials that a delivery mechanism that is a lot more targeted e.g. using a time release floating capsule instead of manual spraying, can be developed for commercial purposes.

Still, even in its current form, which is a mixture of different chemicals and oils, the extracts from the discovery can be used to kill the Aedes Aegypti mosquito larvae, after doing a bit of experimentation. Given that these plants are common in the Caribbean, making this insecticide from plant extract isn't difficult.

Combined with a homemade insect repellant as described in my MICO Wars blog article entitled “How to make DEET-free mosquito repellant from Essential Oils and iso-propyl alcohol”, this discovery can potentially be a very powerful and practical home-made weapon to combat  the spread of Dengue Fever, Chikungunya and the Zika Virus.

All spread by the Aedes Aegepti Mosquito!