In East Africa and other regions, potato crops are currently threatened by a worm known as the potato cyst nematode. There could be new hope for protecting the plants, however, in the form of biodegradable paper made from banana waste.
Presently, one of the main methods of controlling the nematodes involves applying pesticides to the soil. Unfortunately, such chemicals aren't cheap, plus they can potentially harm the environment.
Seeking a less expensive and more eco-friendly alternative, scientists at North Carolina State University looked to waste generated at banana plantations. More specifically, they were interested in the fibrous rachis – or stalks – from which the actual bananas are picked. Although some uses for rachis are being explored, the stalks are usually just discarded or utilized in fertilizer.
For the study, rachis from Cavendish banana trees were ground into a slurry, which was then spread out into a thin sheet and allowed to dry. The resulting "banana paper" – which consisted mainly of lignin and cellulose from the rachis – was subsequently cut into small square pieces. Some of those pieces were left as is, while others had a trace amount of the nematode-killing pesticide abamectin added to them.
Both types of paper were then wrapped around individual potato seeds (basically just small potatoes), which were planted in separate test plots in Kenya. As a control, additional seeds were planted without the paper in plots sprayed with abamectin, and in plots that hadn't been sprayed.
Over the course of two growing seasons, it was found that potato plants grown from seeds wrapped in the paper (both treated and untreated) experienced virtually no nematode infestation. This was likely due to the fact that the paper adsorbed and trapped exudate chemicals produced by the plants' roots – ordinarily, these chemicals are released into the soil around the plant, where they attract nematodes to the roots.
The effect was particularly pronounced in the plants grown from seeds wrapped in the abamectin-doped paper. Because they were the most protected from the nematodes, their potato yields were up to five times higher than those of the plants grown without the paper. And importantly, because the paper allowed the abamectin to be delivered right where it was needed, the amount of pesticide required was about one one-thousandth the amount recommended for spraying the plot.
"The beauty of this approach is that it is straightforward, inexpensive and sustainable; farmers can adopt it on a smaller scale," said postdoctoral research scholar Tahira Pirzada. "No chemicals are used in the paper-making process. This is the way forward."
A paper on the research was recently published in the journal Nature Sustainability.
Source: North Carolina State University
