Pink Hibiscus Mealybug Overview

Invasive Pest

The invasive pink hibiscus mealybug (Maconellicoccus hirsutus) is a small pest that has made its way to California and has the potential to cause significant damage to both agriculture and landscapes.

Feeding

The pink hibiscus mealybug feeds on the sap of a wide range of plants, including grapevines, maples, black walnut, and other important agricultural and environmental plants. It causes severe damage to the plants it infests, leading to symptoms such as oozing sap, wilting, dieback, and even plant death. The pest also excretes a sugary substance called honeydew, which can attract other insects and encourage the growth of black sooty mold, further weakening the plant.

The preferred host of the pink hibiscus mealybug is the hibiscus, which can be found in gardens, parks, and public landscapes, as well as in residential yards.

Pink Hibiscus Mealybug Lifecycle

Although the pink hibiscus mealybug has a limited presence in California, it's important to detect and control this pest as early as possible. Proper identification and reporting of the mealybug at different stages of its life cycle are crucial for effective management.

The pink hibiscus mealybug has a life cycle that includes

Ovisacs/Eggs: The life cycle of the pink hibiscus mealybug begins with the female laying eggs on the plant's leaves or stems. The eggs are laid in a cottony mass and are pale yellow in color. They usually hatch within 5 to 10 days, depending on temperature and humidity.

In regions with colder temperatures, the pink hibiscus mealybug may overwinter as egg masses. The female mealybug lays her eggs in a cottony mass, usually under the bark or in the crevices of the plant. The eggs overwinter and hatch the following spring, starting the life cycle anew.

Nymphal Stages: After hatching, the pink hibiscus mealybug goes through three nymphal stages. During this period, the mealybug molts and gradually develops the characteristic white, waxy coating that covers its body. The first instar is approximately 0.3 mm in length and has no waxy coating. The second and third instars are larger and have a thin layer of wax. In the fourth and final instar, the mealybug grows to about 2-3 mm in length and develops a thick, white, waxy covering.

Adult Stage: Once the mealybug reaches adulthood, it no longer molts and develops further. The adult female mealybug is approximately 3 mm in length, has an oval-shaped body, and is covered in a white waxy coating. The adult male mealybug is smaller, approximately 1-2 mm in length, and has wings. Unlike the female, the male does not feed on plants.

Preferred Host: Hibiscus 

The hibiscus plant is a flowering shrub or small tree that is native to warm temperate, subtropical and tropical regions of the world. There are many different species of hibiscus, but the most commonly known and cultivated for ornamental purposes is the Chinese hibiscus (Hibiscus rosa-sinensis).

In California, hibiscus plants are grown in gardens, parks, and public landscapes, as well as in residential yards. They are often used to add color and visual interest to outdoor spaces and are appreciated for their tropical appearance and ability to attract pollinators like butterflies and bees.

Flowers: Hibiscus flowers are easily recognizable with a wide variety of colors, five petals, and a long column of stamens extending outside of the bell-shaped calyx. They bloom prolifically throughout their growing season, which can last from spring to fall in temperate regions and year-round in tropical regions, but only last a day or two before falling off.

Leaves: Hibiscus is evergreen, meaning it maintains its leaves throughout the year. The leaves are dark and glossy, ovate or lanceolate in shape, and can vary in size from 3 to 18 cm in length, while the petiole is reddish. Leaves are simple and alternately arranged with finely serrated edges. Foliage is dense, often obscuring the main stem.

Stems: Hibiscus stems vary in thickness, color, and texture depending on the age and species of the plant. Younger stems are green and smoother while older stems become woody and rough. Nodes on the stems serve as the points for leaves and branches to emerge, and may develop into new leaves or flowers. The stems grow upright from the base of the plant and can branch out into a bushy or tree-like shape depending on the species.

What you can do

The pink hibiscus mealybug is an invasive pest that can cause significant damage to hibiscus plants and other crops. To combat this pest, it is important for individuals and communities to take action. Here is what you can do: 

1. Learn to recognize pink hibiscus mealybug and its feeding damage
2. Inspect hibiscus for evidence of pink hibiscus mealybug infestation and feeding damage   
3. Collect and report a suspected sighting
   1. Snag it-collect the specimen in an air-tight container
   2. Snap it-take a photo of where you found it, include landmarks
   3. Report it-report suspected sighting to the CDFA Pest hotline

Sources

Maconellicoccus hirsutus (pink hibiscus mealybug), CABI Digital Library, n.d., https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.40171

Pests in Gardens and Landscapes, Hibiscus, University of California Integrated Pest Management, n.d., https://ipm.ucanr.edu/PMG/GARDEN/PLANTS/hibiscus.html

Pink Hibiscus Mealybug, United States Department of Agriculture, n.d., https://www.invasivespeciesinfo.gov/terrestrial/invertebrates/pink-hibiscus-mealybug

The Jepson Herbarium-Hibiscus, Univeristy of California Berkeley, n.d., https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=9572