A specific beetle known as the agave snout weevil is causing distress for gardeners in the region who cultivate amoles, yuccas, and agaves. This insect belongs to the broader group of beetles, which are the most successful animal group on Earth. With 400,000 identified species and estimates suggesting up to 33 million exist globally, beetles comprise 25 percent of all known animal species. Their hard outer wings, called elytra, protect them from environmental extremes and allow them to inhabit diverse ecosystems, including soil, wood, and human homes.
The agave snout weevil is a particular concern for succulent growers. The female weevil uses its snout, or rostrum, to drill deep into plant tissue. During this process, she injects a bacterium that rots the plant's core. She then lays eggs in these holes using a retractable ovipositor. The hatched larvae feed on the decaying underground material, weakening the plant from the inside out.
This pest affects a wide range of plants, including tree grass, desert spoon, mangaves, dragon trees, ponytail palms, and columnar cacti such as saguaro and organ pipe cactus. The weevil has been an evolutionary companion to agaves for millions of years. While it is a pest in gardens, it serves an ecological function in the wild by targeting weakened plants, often those stressed by drought. This process creates moist organic matter for desert animals and ensures that only the most drought-resistant offspring survive.
Homeowners can identify the adult weevil by its jet black color and half-inch length. It is a slow-moving herbivore that is initially found on the leaf bases of host plants. When threatened, the beetle practices thanatosis, or playing dead, by retracting its snout and constricting its body to resemble a small pebble. The most effective non-chemical control method is to remove the beetle manually when it is first spotted on the plant.
Not all succulents are equally vulnerable. Species with tough, fibrous leaves, such as sharkskin agave, Queen Victoria agave, and Parry agave, are generally resistant to the weevil's snout. However, growers of Agave tequilana, the source of tequila, should be vigilant, as an infestation can prevent the plant from producing usable spirits.
A plant sale is scheduled for this weekend, November 6 through 8, at Cal State University Fullerton. The event will feature 70 California native and 60 non-native, drought-tolerant species. The sale takes place at the Cal State Fullerton Arboretum and Botanical Garden, located at 1900 Associated Road. It is the largest botanical garden in Orange County, spanning 26 acres.
The sale operates on Saturday from 9:00 a.m. to 3:00 p.m. and on Sunday from 10:00 a.m. to 2:00 p.m. The arboretum is open daily from 9:00 a.m. to 4 p.m., excluding holidays, with a suggested admission fee of $5. For more information, interested parties can visit arboretum.fullerton.edu.
Among the plants available at the sale is the red osier or creek dogwood, a California native. This species requires more water than most indigenous plants and needs protection from afternoon sun. It is noted for its bright wine-red stems, which can grow up to 15 feet tall in a spreading clump. The leaves display fall colors before dropping, and the white bracts are often mistaken for flowers. A Silver and Gold variety is also available, featuring variegated foliage and golden yellow stems.
Gardeners are encouraged to monitor their succulents for signs of distress, such as bending leaves or loose growth. If the base of a plant turns black and soil-dwelling beetles are observed, it may indicate an agave snout weevil infestation. Early detection and manual removal remain the primary strategies for managing this persistent pest in residential landscapes.
