What is the Pasture Mealybug?
Pasture mealybug is a small, sap-feeding insect that specializes on grasses. Adult females are covered in a distinctive white, waxy coating that gives them a fluffy appearance. Young nymphs are much smaller and can be difficult to detect without magnification.
Unlike many insect pests that remain on foliage, pasture mealybugs can be found in several locations including:
- Undersides of grass leaves
- Plant crowns and stems
- Thatch layers
- Soil surface and belowground
- Beneath dried cow patties
This behavior makes infestations difficult to detect and potentially challenging to manage.
What damage does it cause?
Pasture mealybug feeding removes plant sap and can cause significant stress to susceptible grasses. Early symptoms often resemble drought stress or nutrient deficiencies and may include:
- Yellowing of leaves
- Red or purple discoloration
- Stunted growth
- Poor root development
- Dead patches and pasture dieback
In Florida, the most severe damage has been observed on limpograss. However, infestations have also been found on bahiagrass, bermudagrass, crabgrass, and other grass species. In heavily infested fields, large areas of pasture can decline rapidly and become invaded by weeds.
Conditions that favor infestations
Research from Australia and recent observations in the United States suggest that warm temperatures, high humidity, and adequate rainfall favor population growth. Fields with dense thatch accumulation, unmanaged growth, or other plant stresses may be particularly vulnerable. Because Florida provides favorable environmental conditions for this pest throughout much of the state, there is significant concern about continued spread.
What can producers do now?
At present, early detection remains one of the most important management tools. When scouting fields, focus on areas showing yellowing, reddening, stunting, or drought-like symptoms. Carefully inspect the underside of leaves, plant crowns, thatch, and soil surface for white, waxy insects. Maintaining healthy forage stands may help reduce losses. Practices that can improve plant vigor and reduce favorable habitat include:
- Proper fertility management
- Appropriate grazing pressure
- Timely hay harvests
- Reducing excessive thatch accumulation
- Minimizing drought and nutrient stress
Producers should also take precautions to limit the movement of the pest between fields. Shared mowing equipment, hay harvesting equipment, and infested planting material are suspected pathways for spread. Cleaning equipment before moving between fields is strongly encouraged.
What about insecticides?
Currently, there are no insecticides specifically labeled for pasture mealybug control in pastures. Experience from Texas suggests that many commonly used pasture insecticides may provide limited control because mealybugs spend much of their life cycle protected within thatch and soil. Broad-spectrum insecticides may also disrupt beneficial predators and parasitoids that help suppress mealybug populations. Research is ongoing to evaluate management options and identify effective long-term strategies.
Pasture mealybug on grass. Photo credit: Dr. Nicole Quinn