Yucca Worms

Yucca Moths

• Yucca moths are small, white insects that blend in with the color of blossoms. Female yucca moths emerge from cocoons in the spring at the same time yuccas begin flowering. As the moth visits each flower for egg laying, she pollinates the blossom with the pollen stuck to her legs. Eggs are laid in the blossom and larvae emerge. The larvae eventually drop to the ground and build their cocoon in the soil, and the lifecycle begins again.

Yucca Weevils

• Yucca weevils have black snouts and grow to 1/2 inch long. These weevils only damage yucca plants. The larvae look like small, white grubs. The larvae burrow into the base of flowers. Eventually, these weevils make it into the plant's heart. Infested yucca plants decline in overall health. There are no treatment options except providing overall care and hoping damage isn't too significant.

Agave Snout Weevil

• Agave snout weevils are a major threat to agave plants, but also infest yuccas. Adult agave weevils are 1/2 inch in length and have brownish-black bodies. Female agave snout weevils burrow into the yucca' base and lay their eggs. You may see their larvae inside your yucca plant. They create an entryway for harmful microbes to enter. These decaying microbes cause the yucca plant to take on a wilted appearance and die.

Preventing for Agave Snout Weevils

• Treat your yucca plants once a month in March, April and May with diazinon. Diazinon is a synthetic organophosphate that alters the nervous systems of agave snout weevils, so that they die off. Use 1-1/2 gallons of diazinon for smaller yuccas or 2-1/2 gallons on larger yuccas. Dilute the insecticide with water before using. When treating your yucca plants with the insecticide, wear all of the appropriate safety gear, such as gloves, masks and long sleeves.