Question
Our grass is dying and we suspect a worm/grub problem since we have seen some yellowish worms come up when we have raked the thatch layer. When is the best time to treat to kill the worms? What is best to kill them if we don't know exactly what species they are? How long after treatment can we prepare and plant new grass seed?
Answer(s)
You may be seeing larvae of lawn pests, most probably billbug. Here are some hints on how to scout and diagnose for billbugs and other lawn pests: Dig up a 6 by 6 inch square of your turfgrass, including 2 inches of soil. Put it in a bucket and pull it apart, looking for any insects or larvae. Collect any/all you find. Identify the insects by referring to these USU Extension FactSheets: Billbugs, at
http://extension.usu.edu/files/publications/factsheet/ENT-106-07.pdf
White grubs, at
http://extension.usu.edu/files/publications/factsheet/ENT-104-07.pdf
Sod webworm, at
http://extension.usu.edu/files/publications/factsheet/ENT-44-07.pdf
Cranberry girdler, at
http://extension.usu.edu/files/publications/factsheet/ENT-42-07.pdf
There's only one generation of billbug per year. They may be emerging as adults about now. Most of the damage is already done for the year, so if you don't find any pests in the turf sample, wait until next May to treat for the pests. Once summer cools off (highs in the 80's), you should fertilize the affected areas to promote new growth and vigor, to repair the damage. Also, be sure to check the thickness of the thatch layer in your turf. If it's thicker than one-half inch, plan to have your lawn core aerated in early fall. Aeration helps promote thatch decomposition. Thatch is a protective habitat for the billbug, so it's best to minimize it.
Other Questions In This Topic
- When should I be pruning my roses?
- I've noticed lots of caterpillars eating the leaves of my Birch trees--they look like inchworms. I've also seen them in neighbor's trees. Is there an infestation, and what can I do about it?
- When is the best time to seed native grasses such as streambank and western wheatgrass into an existing Kentucky Bluegrass lawn? Some of what I've read leads me to believe that it would be best to seed in late fall so the seed will germinate in the spring. But I wonder if it would be better to seed in early fall after stressing the KBG. I will also be seeding sheep fescue, but I've seen conflicting information on whether that is native or introduced. My goal is to have a lawn that can survive with no water, and stay green with very little water.
- How do I prevent aspen sprouts from coming up in my lawn?
- I have a lawn with necrotic ring, it has been treated with f:stop. Question; Future construction will remove much of the sod. Should I treat the soil before I lay new sod.
- How late in the fall season can you lay sod in northern Utah?
- How can I tell when my pears are ripe?
- I notice groups of about 4 or 5 pine needles buried into the flower beds and am wondering what type of bug is pulling them into the ground in the fall. They do not get ther naturally because of the way they are sticking out of the ground. Half buried. I am just wondering what creature this might be and do I need to do something about it?