As she helped her family grow produce each year, Kalia learned how to protect her home garden from weeds, rabbits, and deer. But no amount of weed-whacking or fence-building could keep the insects away.
To try to solve this problem, 13-year-old Kalia embarked on a project to find out whether it was possible to avoid synthetic insecticides—and associated environmental and health risks—without compromising the harvest. For her investigation into green gardening, Kalia received a 2011 Young Naturalist Award.
Kalia sought a natural option for protecting her homegrown plants by turning to other plants. “Organic, plant-based pesticides that rely on plants’ natural defenses against insects may not only be effective and inexpensive for protecting crops,” wrote Kalia in her essay, Plant Extracts as Natural Insecticides, “But also safer and more environmentally friendly.”
She decided to test green chili and garlic—which both have track records as effective insecticides—as well as Eastern hemlock, which she hypothesized might repel insects much like the cedar, its relative. Using a food processor and some water, Kalia created three mixtures per plant and tested each by spraying them on greater wax moth larvae and recording the larvae’s survival rates over two weeks. To reduce potential errors—which Kalia details at length in her essay—she maintained a control group that she sprayed with water.
As Kalia had anticipated, the green chili, which contains a potent irritant called capsaicin responsible for its spiciness, was the most effective, killing 95 percent of the larvae within 10 days of spraying. All of Kalia’s plant extracts performed better than her control group.
The young naturalist feels confident that plant-based insecticides offer a safer alternative to chemical pesticides, and perhaps as importantly, they can be prepared easily and cheaply in the kitchen. Kalia started her project by asking: “Do we want organic produce or plentiful produce?” Thanks to her investigation, Kalia’s family won’t have to choose.
The Young Naturalist Awards is a nationwide, science-based research contest for students in grades 7 through 12 presented by the Museum. To learn more and to submit your own project, visit amnh.org. The deadline for the 2012 contest is March 9, 2012.
The Young Naturalist Awards are proudly supported by Alcoa Foundation.