Pasture Mealybug Update 5-22-26

This week we were able to set up and spray an insecticide control test near Cuero, TX.  This test has products we have hope will be successful in controlling the insect, but there is still some uncertainty until we get the data in a week or two.  The other factor is that none of these products are labeled for control of mealybugs in pastures.  

Yellow Sugarcane aphids and
Pasture mealybug nymph

There have been some challenges finding the mealybugs in the fields.  In the field with this study, the majority of mealybugs found are very small nymphs.  We have several observations regarding scouting for the mealybug. 

1) Time of day may be important for scouting pastures. It seems we can find more before noon than after the day has heated up.

2) Larger mealybugs may drop off the plant when disturbed so being careful when handling the plants may increase your chance of finding the insects.

Moving the mealybug from infested fields to un-infested fields has been a point of discussion with several people this week.  It is important to clean any kind of equipment that is driven through an infested pasture.  This includes haying equipment, tractors, trucks, sprayers and people, to the extent possible. 

I proved last year the mealybug can be moved on clothing from the field to my home, infesting my front yard. Keep this in mind when traveling to fields where the mealybug has not been found. Enter the field clean of pasture mealybugs.

Products lacking research.  Anytime there is a new or concerning pest, there are "new", untested products that may be sold claiming to be able to control the insect. This has already begun with the pasture mealybug. Some of these products make claims that are not supported by field research.

I am a natural skeptic of any new products until I see research demonstrating the products effectiveness. If possible, choose products with a proven track record. Products that do not have independent research may indicate a product that does not work well enough for the company to justify the research.

Good research is conducted comparing the treatments in question to untreated plots. The research tests generally have four or more replications of the treatments. This is accepted research practices for determining the effect of different treatments.

Simply comparing one field to another, or the east side to the west side is not adequate to demonstrate the how effective a product works. It may sell a product that may not really work.

If you choose to spray anything you haven't used before, I encourage you to leave untreated strips in the field and mark them well so you can find them later to compare untreated to what ever treatment you make. Then when you recheck the field in 5-7 days, compare what you find in the treated areas to the untreated.

The untreated areas can be small (20 ft by 50 ft) but should be in an area that can be compared to the treated part of the field. Comparing the inside of the field to the other side of the fence is not the same as having an untreated area in the field. 

If you have any questions, email, text or call me at biles-sp@tamu.edu or 361-920-1138