Pick Your Battles With The Pepper Weevil
The pepper weevil, a black beetle that is oval in shape with a long curved proboscis, is smaller than a cardboard match head but is a big enemy of peppers. In fact, it is an enemy of all pepper varieties — from bell to jalapeño. This pest tends to be more of a problem in small, hot pepper varieties simply because there are more peppers available to feed on and greater chances for the weevils to reproduce.
Mainly a pest in southern states such as Florida, Texas, New Mexico, California, and Arizona, pepper weevil also feeds on the weed nightshade, which can be a concern to growers if weed plants are near pepper fields, explains Phil Stansly, a professor of entomology at the University of Florida. Because adult pepper weevils are very mobile and can fly, growers need to be wary that the pest will migrate to their fields.
The Life Cycle Of The Pest
To successfully control pepper weevil, Stansly says it is important to understand its life cycle. The adults feed on flower buds and fruit, drilling a hole often near the calyx of the fruit to deposit their eggs. Eggs hatch in a few days and the larvae work their way down into the fruit toward the seeds.
“They feed in the fruit and make a mess,” explains Stansly. “Depending on the size of the pepper and how many weevils are inside, the fruit may fall off the plant before it is harvested, which actually is a good thing.” Fruit on the ground, he says, is a sign to the grower that he has a big problem.
The larva goes through three molts until it is finished feeding. It then pupates inside the fruit where the adult eventually emerges and sits until it is strong enough to chew its way out — whether the fruit is still on the plant or has fallen to the ground, explains Stansly.
In addition to seeing fruit lying on the ground, another way for growers to recognize a pepper weevil infestation is to check the calyx of the fruit. If the calyx is yellow, there may be a weevil inside.
Stansly also suggests growers use an aggregation pheromone trap to determine the presence of the pest. Because pepper weevils come in from the margins of the field, it is helpful to station the pheromone traps in those areas to determine when the weevils arrive.
“Scouting is very important to determining the presence of pepper weevil,” he says. “It is important to know early in the game that they are in the field.”
Why is it so critical to know the first signs of pepper weevil? Because the adult is the only life stage that is susceptible to insecticidal control. “Once the weevil has laid its eggs,” says Stansly, “it’s too late.”
To knock down the adults, growers have a few choices. Those options include the neonicotinoids Belay (clothianidin, Valent USA Corp.), and Actara (thiamethoxam, Syngenta Crop Protection). However, the grower should always rotate a neonicotinoid with an insecticide having a different mode of action. A carbamate, Vydate (oxamyl, DuPont Crop Protection) is another tool available to growers.
Growers’ best line of defense against pepper weevil, however, is being proactive in the field, Stansly concludes. “It is important to clean up crop residue, limiting the length of time a pepper crop is in the field and reducing pepper weevils’ access to the crop.”