Researchers at MIT figured out a way to get pesticides to better adhere to plant leaves, cutting the amount they sprayed by 90 percent and yielding similar results in fighting pests, according to Modern Farmer.
“MIT estimates in a new study, published in the journal Nature Communications, that only about 2 percent of pesticide sprays actually stick to the plants, meaning farmers have to spray many, many more times the amount of pesticides that they need. And that’s bad: excess pesticides can leach into waterways, can spread throughout the environment and cause unwanted environmental effects,” Modern Farmer said. The pesticides fail to adhere because many plants are hydrophobic, meaning they repel water.
To get the pesticides to adhere more effectively, the researchers turned to biodegradable polymers. They then divided the pesticide in half; one solution was given a polymer that lent a negative electric charge, while the other was given a polymer that lent a positive charge. When two of the oppositely-charged droplets met on a leaf surface, they formed a hydrophilic (water attracting) substance that sticked to the surface and increased the retention of further droplets.
Previous attempts relied on additives such as surfactants, soap-like chemicals that reduce the surface tension of the droplets and cause them to spread. But that only marks a small improvement unlike the polymers MIT tested. With this technique, the researchers were able to get the same pest-reduction effect with only 10 percent of the quantity of pesticides. The method is now being tested in India.