Pasture Mealybug
The Pasture Mealybug has the potential to be a very serious problem for all livestock producers and anyone that depends on grass. This pasture mealybug is completely new to us and has the potential to have a major impact on anyone that grows grass. Unfortunately, while researchers are working diligently, currently there are little to no control options.
The pasture mealybug was officially identified in south Texas this past September. It has already proved to be a devastating pest in areas where it has been found. The insect’s larva is the stage in which it feeds. These larva feed on the juices from the plant but in doing so they inject a toxin into the plant that kills the plant. It not only kills the top growth, but the entire plant including the roots. In cases where it was found in south Texas, the plants were totally dead all the way down to the roots and the plants did not resprout. Obviously, we are not looking at damage like we might see with armyworms or even stem maggot; this pest actually kills the whole plant.
Many of you may have seen mealybugs before. We see them mostly on ornamentals and house plants, however, this is a totally different mealybug. It only feeds on grass and appears to feed on all types of grass. Thus far, there have been no bermudagrass or other grasses including annual hay grazers and sorghums that it will not feed on. One of the researchers was in a field infected with the insect and went home and accidentally infected his San Augustine lawn and they killed his whole yard. You think your native grasses and oldworld bluestems will be safe, think again. Reports indicate that at a native seed repository in Texas City the pasture mealybugs killed every variety of native plant they had at the location.
The insect itself does not move long distances. Most of the movement appears to have been mechanical. Unintentionally and probably unwittingly, custom hay balers and roadside shredders seem to be the primary mode of transportation for the pest at this time. Researchers do believe it can be moved in and on hay bales so that is another means of transporting the insect over long distances. Moving cattle from an infested field will transport the insect as the adults will stick to their legs.
The darned bug appears to be extremely hardy. It goes quite deep into the soil to lay eggs as a result it is thought our winters, even the hard ones, will not kill out the pest. Thus far, researchers have had very limited time to research products to kill the insect, but there is some hope. Using our normal grasshopper, armyworm, and stem maggot products have shown to have no effect and probably cause more harm than good due to the damage they do to beneficials. Beneficial insects look to be very important in controlling the pest. I have seen no research to prove it, but I think healthier strands of grass with good roots may be able to withstand infestations better than weak stands. That will mean having phosphorus and potash levels correct according to soil test. Most thin and weak strands of grass I see are due to low levels of these two nutrients.
This is all very new information, and researchers are focusing on the pest and conducting many trials to learn how to manage the pest. It is important to watch for the insect and let me or someone know if you think you see it in your fields. I am happy to come and check or sample your fields if you think you might have an infestation. It will be much easier to treat a field or two to potentially slow its spread, rather than to wait until it has spread across the county. As of today, the closest reported finding of the insect is in Bell and Falls Countiesnot that far away. I fear it is just a matter of time until we find it in our area. We do have an updated pasture mealybug publication with more information available at the office. Feel free to call or come by and we will get you a copy.