By Jeannette Warnert
While tending your landscape and garden this spring, keep an eye out for pink hibiscus mealybug (PHM), an invasive insect that has already been found in parts of Southern California. PHM could make its way to the Central Valley and cause significant damage to crops, landscape plants and the natural environment.
The California Department of Food and Agriculture believes that early detection and rapid response will be the best way to prevent its spread and is calling for residents and professionals to report suspected sightings on its website or to local officials.
UC Integrated Pest Management advisor Eric Middleton – an entomology expert who serves San Diego, Orange and Los Angeles counties – is raising awareness about PHM by training California nursery workers, farmers, landscape professionals and Master Gardeners about the pest's lifecycle, feeding habits, damage and identification.
Originally from Southeast Asia, PHM made its way to Hawaii in 1983, most likely on imported plants. In 1999, it was found and successfully eradicated from Imperial County. A decade later it popped up in Riverside County, where officials had to destroy 30,000 pounds of dates to stop its spread. Still, as of 2014, populations of PHM have been found in parts of Southern California, and in several other U.S. states.
“PHM can be moved on plants by nurseries or people sharing backyard plants,” Middelton said. “It can also be moved by wind or by animals, sometimes birds and even ants will pick up and move the pest from one place to another.”
As its name suggests, PHM favors hibiscus, the tropical perennial popular in California for its attractive foliage and showy red, orange, pink or white flowers. However, the pest will feed on the leaves, buds, stems and roots of more than 200 plant species, from vegetable crops to trees.
Pink hibiscus mealybugs are difficult to identify. One sign of an infestation is plant damage, such as crinkled or twisted leaves, distorted shoots, shriveled flowers and tiny deformed fruit. The mealybugs excrete honeydew when feeding, which can lead to an accumulation of sooty mold on leaves, inhibiting plant growth.
One trick to tell PHM from other mealybugs is its pinkish-to-reddish color across all of its life stages. In addition, PHM secretes a pinkish color when crushed, as opposed to the yellowish or orangish color when many other types of mealybugs are crushed.
In any event, identification of PHM must be confirmed by an expert under a microscope.
“If you find suspected pink hibiscus mealybugs, don't try to manage them on your own,” Middleton said. “CDFA needs to know about it. Contact the local agricultural commissioner's office, UC Cooperative Extension or CDFA.”
Resources:
Report suspected invasive species on the CDFA Report-a-Pest website