Researchers have uncovered a new and unexpected weapon in the fight against the sweetpotato weevil: color.
For years, Montana State University's Gadi Reddy has been searching for a solution to the sweet potato's greatest threat, and in particular one that avoids the use of toxic pesticides.
Sweetpotato weevils are especially crafty, living out their larval stage within vines and tubers. The adults, meanwhile, are nocturnal. Current methods hinge on trapping the pests via synthetic pheromones designed to lure them in. But while the technique has succeeded in suppressing populations in a handful of countries, it has largely failed to significantly limit the amount of damage inflicted.
In the past, studies have shown that the insect prefers red over other colors, with light red being their favorite shade. Knowing this, Reddy set about determining whether the same held true under indoor conditions. If so, he reasoned, the color could be used to improve the effectiveness of the pheromone traps.
As it turns out, the sweetpotato weevil's favorite color is a fickle thing. The researchers arranged eight different colored traps for the insects to pick from, with green turning out to be the most popular indoors. In all, the color attracted nearly double the number of weevils than the standard traps currently being used by growers.
"Sweetpotato weevils responded to pheromone baited traps of different colors differently in the field and indoors," Reddy said. "In the field, sweetpotato weevils preferred red, and particularly light red, over the other colors, but indoors, green traps were favored. We have no explanation for the difference."
Reddy said new studies are needed to explore the reason behind the switch in color preference, but that regardless, he and his team recommend that growers switch to green-colored traps for sweet potatoes grown indoor based on the results.
"If we use proper color...we can see a 40% increase in catching the weevil," Reddy told Nature World News in an email.
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