Monday, August 17, 2015

Fall Army Worms and Preemergent Products for Winter Weeds

This is what I wrote two weeks ago after I had sprayed my beds with herbicide mix for three hours and I was then hit by a pop up thunderstorm:

“While spraying in my beds, I did notice a huge number of moths, which usually indicates a worm attack is not too far away. Time to get out a little preventive worm killer it looks like. If you have ever experienced worm damage, you know it hits your lawn hard and fast, so preventative applications will keep you from having any surprises if you go out of town or even take a long nap! The worm season so far this year has been weird – very spotty.”

Well, I got busy with other things. Sure enough, I went out to check on what vines I was going to attack Sunday and there was a small fall army worm outbreak in my yard.

A friend of mine that grew hay used to say he could hear army worms munching on the pasture as they crossed the fields. Since army worms eat the green leaves off the plant, he would lose big hay dollars to this worm. Athletic fields, Golf Courses, and home lawns lose the aesthetic value of the green grass, and the worms thin the canopy of the grass where weeds will move in if given a chance. Prostrate growing weeds like spurge, lespedeza and Florida Betony seem to come in the fastest.

What bothers me the most is you work all summer on your grass to have it looking nice, and once it starts to slow down for the winter, fall army worms and then sod web worms attack the grass. Look for areas that appeared to have been mowed low and with a dull blade. You can see that the leaf blades have been chewed. Also thatch type debris will be churned up on the surface. Birds and low flying wasps are also predators of army worms. Thanks to cell phones last year, I took a cool picture of a wasp attacking the head of an army worm.

Since army worms are in direct contact with the ground, they are very easy to control. Bug Blaster, Bifen, Sevin, Cyonara and Acephate will all put a hurting on army worms. Thuricide (Bt) and Spinosad are organic products that will also work well if you get them while the worms are small. Since the population of worms is so high and hit so hard, keep your eye out for a second hatching.

For those of you with St. Augustine and Centipede, keep your eye out for the sod web worm. Watch for moths in your yard around dusk. If you begin to see a moth that gets out of the grass, flies for 6-10 feet then lands again (like a bobwhite quail for you bird hunters) you may want to consider using one of the above mentioned products. Usually sod web worms would not come out until September / October; however, with the crazy weather we are having, scouting for them could not hurt.

Now is the time to put out preemergent products in the lawn and beds to prevent those small seeded annual weeds. Henbit, chickweed, Poa annua (annual bluegrass), cudweed and lawn burweed are a few of the winter weeds that would like to occupy your lawn and flower beds. Poa annua (the green grass that is very visible in February and March) and lawn burweed (the prostrate growing weed that develops a sticker) are usually the most hated of the winter weeds. Some people use profanity while describing them at the counter of Possum’s! 

If your yard has thatch, drainage, or compaction issues, now is a great time to aerate your lawn (and beds where possible) before you apply your fall preemerge. Aeration is a great cultural practice, which will among other things help your roots grow throughout the winter giving you a head start for the spring. 

In my travels this week, I saw brown patch (large patch) fungus in several yards, and the “nasty rascal the chinch bug” is still sucking the life out of many lawns. Gray leaf spot is still alive and doing well.

Always read, understand and follow product label. The product label is a Federal Law.