Pasture Insects 5-15-26

Other than looking for fall armyworms and bermudagrass stem maggots, I have to admit that I have not looked closely at the insects in pastures until this past year. From using a sweep net scouting for armyworms, we know there are many different insects in the field. But until we began looking closer into the grass canopy, I didn't think there was much to see.

What we have found is there are more insects feeding on the grass than we knew were there. Some of these include at least three different mealybugs, two aphids, and the predators of these. While our knowledge of these insects in incomplete, it is important to identify what is being found and what could cause damage symptoms in your pastures. 

Of the mealybugs, the most concerning is the pasture mealybug, which has been found across much of the southern half of Texas. In addition to this mealybug, the rhodesgrass and bermudagrass mealybugs have been found.

Yellow Sugarcane Aphids
(Photo by S. Biles)

One difference between the pasture mealybug and the other two is where they are likely to be found. The rhodesgrass and bermudagrass mealybug have been noticed more at ground level in the thatch layer and on lower stems while the pasture mealybug is usually found on the leaves. Of these, the pasture mealybug is the one of concern right now. Read more on the rhodesgrass mealybug HERE. 

When scouting a pasture, I tend to look for red leaves which are often give away the location of the pasture mealybugs. This spring I have also found an aphid which will cause red leaves.

The yellow sugarcane aphid is a historical pest of seedling grain sorghum causing death to the leaves it feeds on. It can be found on the underside of lower leaves, often causing the leaf to yellow or redden. 

A white insect being found in some pastures is the wooly aphid. The wooly aphid has been found in clumps as large as 12-18 inches across. They have a white "wooly" appearance that can be confused with mealybugs, but they produce a lot more white stuff near the ground and in the lower plant canopy.

Wooly Aphids (Photo by S. Ross)

So far, I have not seen these aphids causing enough damage for concern.

To add more confusion, some of the lady beetle larvae feeding on the aphids can look similar to mealybugs. I have found scymnus lady beetle larvae on bluestem infested with yellow sugarcane aphids and sorghum aphids on johnsongrass. This is an aphid predator and not a pest. They may also feed on mealybugs.

Scymnus lady beetle larvae and sorghum aphids
(Photo by S. Biles)

If you have any of these, or other, insects you want identified, send me some pictures of the insect in focus, to me via email at biles-sp@tamu.edu or text to 361-920-1138.