Pasture Mealybug Update - Sept 17, 2026

We are continuing to document the expansion of pasture mealybugs (PMB) being detected across the state.  The map below shows where mealybugs have been identified in dark green. The light green counties are where we expect to find pasture mealybugs. Most of the new detections are from USDA and TDA sampling and identification. They are doing a lot of field surveys to find the extent of the pasture mealybug range.

We are unsure how far north or west the mealybugs will go. In Australia, the mealybugs are found in areas with more than 19 to 23 inches of annual rainfall. The map below is from the Texas Water Development Board showing average annual rainfall from 1991-2020. The black lines are added to show roughly where 19 and 23 inches occur.

Currently, Val Verde County is the furthest west detection of PMB. I do not expect the mealybug to go much further west, but irrigation may allow it to expand beyond the range of natural precipitation.

Movement of the Pasture Mealybug

The PMB can move by means of wind, machinery, animals, and hay. We currently think wind is a primary means for moving due to how rapidly the mealybug has been found across the state. With this in mind, it is still important to prevent moving the mealybug on field equipment, animals, and hay bales.

Research by Dr. Kerns in College Station found live mealybugs in hay bales up to 42 days after baling. No live mealybugs were found at 49 days after baling. Based on this research, we suggest waiting to move hay from infested fields for as long as possible, at least 60-90 days, will help reduce the likelihood of moving pasture mealybugs to uninfested fields.

Management of Pasture Mealybug

Continue to manage your pastures and hay fields using the best agronomic practices for your location. Fertilize at appropriate rates. Irrigation can help slow the decline. 

Weed management is critical in affected fields. This week, I saw a demonstration of the effect of weed control increasing grass production in a mealybug infested pasture.  The competition from weeds like ragweed or croton may result in total grass losses.

Insecticides may help control the pasture mealybug in some fields.  Centric 40WG has a Section 18 Crisis Emergency Exemption for use at 2 to 3.44 ounces per acre. Research has shown Centric 40WG at 2.5 ounces per acre to be consistently effective in reducing mealybug populations. Pre-harvest interval is 7 days before cutting for hay and zero day for forage. 

Sefina Inscalis at 8 to 10 fluid ounces per acre offers suppression of the pasture mealybug. Research suggests that managing high populations of mealybugs with this product may not produce desirable levels of control. Its best use is when crop injury is slight, and the mealybug population is not severe. Pre-harvest interval is zero day.

Applications controlling PMB late in the season (September-October) will have less ability to increase grass growth than earlier applications, especially in fields experiencing drought conditions.

Suggestions for managing the insect include spring applications when the first injury is noticed and mealybugs are present. Including the insecticide with a herbicide application will help reduce cost.

Avoid using broad spectrum insecticides like pyrethroids. Beneficial insects including predators and parasitoids may be one of our best defenses and they are very susceptible to broad spectrum insecticides. 

• Fall armyworm control can be achieved using products containing Chlorantraniliprole (Coragen eVo, Shenzi, Osaria) and Methoxyfenozide (Intrepid, Inspirto, Invertid, Zylo)
• Grasshoppers can be controlled with Chlorantraniliprole (Coragen eVo, Shenzi, Osaria)