Tuttle mealybug is a significant issue in zoysia japonica species, particularly in EmpireTM Zoysia, but we have also found it in IconTM and ZeonTM lawns.
A Tuttle mealybug is very small (less than 2mm in length), and difficult to find in low numbers. In addition, it feeds in concealed locations, commonly beneath the leaf sheath or between grass blades and the stem. These insects have pink, oval-shaped bodies and secrete a white, waxy substance that covers their body and parts of leaves. Adult females are larger and often covered with more wax than nymphs. The white wax is often the best indicator of infestation.
When looking for these insects, you must closely inspect the plant material in and adjacent to several areas exhibiting damage. A 10–40X hand lens or field microscope will be helpful. Insects will be found concealed in the leaf sheath and near the base of the plants, so close examination is critical. Look for the white, waxy substance as well as the presence of black sooty mold.
Tuttle mealybug primarily feeds on plants in the grass family (Poaceae). It is most often found feeding on and damaging zoysiagrass, particularly EmpireTM zoysia lawns, although it can also a pest of bermudagrass.
Heavily infested areas of turfgrass appear generally unhealthy, usually resembling drought stress. Damage can be widespread in lawns and become severe rather quickly due to the insect’s non-descript nature and the insect’s obscure behavior.
As with every other turfgrass species, everything begins with cultural practices. If you have the right plant, planted correctly in the right area, being maintained (cut) at the right height, with the right amount of sunlight, water, and fertilizer, then the turfgrass will be healthier and more likely to fend off infestation.
The keys to more effective control appear to be:
- 1. Thatch management. Verticutting (removing thatch) in the spring. One of the biggest factors that seems to facilitate Tuttle outbreaks is thatch buildup. Zoysia lawns that have accumulated a dense thatch layer typically have higher mealybug infestations and those infestations are much more difficult to get under control. These insects are very well equipped to hide in the thatch, avoiding direct contact with insecticides and other predators or adverse environmental conditions. The thatch can also prevent insecticides from getting down to the lower plant tissue and roots, where some of the systemic products need to be taken up and spread throughout the plant. Thatch management is key to zoysia management AND Tuttle management.
- If there is a known infestation, immediately (within 2 weeks) after verticutting, make an insecticide application.
- Use a systemic insecticide that the mealybugs will ingest as they feed on the plant sap. Do not rely solely on contact insecticides.
- Rotate chemical classes between insecticide applications. This is very important because mealybugs are highly likely to develop resistance to insecticides. Another major issue is that our most commonly used and affordable systemic products are neonicotinoids (Class 4A). Although there is no confirmed evidence of resistance anywhere in the state, repeat applications of the same chemical class is setting the stage for insecticide resistance and the loss of a control tool. Dr. Dale at UF recommends using other chemical classes, like Ference (Cyantraniliprole, Class 28) or even azadirachtin (class 18B). Though insecticides are limited in options, everything possible should be done to avoid resistance.
For more information on Tuttle mealybug, see https://edis.ifas.ufl.edu/in989