Frank McDonough, of the Los Angeles County Arboretum, shares his expertise on the identification, treatment and prevention of the top three lawn pests. Besides being used generically to describe most insects, bugs is also a term for a specific group of insects that includes some of the world's most destructive pests. Besides using their snoutlike mouthparts to pierce, suck and chew plants, some varieties such as chinch bugs inject plant-killing toxins that can rapidly destroy a lawn. Testing for these pests is imperative. Chinch bugs: - Indications: Soapy-water test
- Treatment: Pesticides
- Prevention: Mowing to proper height; dethatching
If it's late spring, summer, or early fall and your St. Augustine lawn is dying off, you'd better test for chinch bugs. Push a bottomless coffee can about an inch into the sod that you're testing and fill it about one-third full with a soap-and -water solution -- a tablespoon or two of soap to a gallon of water (figure A). Wait several minutes. If chinch bugs are present, the tiny black pests will soon be seen swimming on the surface of the water. Just one chinch bug is an indication that you need to spray with Orthene, Sevin or imidachloprid. Prevention is simple : keep your lawn well watered and don't fertilize too heavily before the warm season . Chinch bugs prefer hot, dry, overfertilized and stressed-out lawns. Billbugs, another lawn-destroying member of the order of bugs, are treated in the same manner as our next group of pests, the grubs. Grubs: - Indications: Damaged grass; grubs in soil
- Treatment: Nematodes
- Prevention: Nematodes; aeration, fertilization; dethatching
Grubs belong to an almost equally destructive group, the beetles. Unlike bugs, the adults of which usually do most of the damage, it's the beetles' larvae that destroy patches of lawn, by feeding on the roots. Otherwise healthy-looking patches of lawn that pull up as if they have no roots are an indication of beetle damage. To test for grubs, pull up on a patch of grass; if it comes up fairly easily, it could indicate grub damage. Your next xtep is to cut a flap of sod about 1' by 1 ' by 6" deep. Pull the sod back like a trapdoor and poke through the soil to find the comma-shaped white grubs (figure B). Count them: if you count between three and five, you need to treat the lawn. Use parasitic nematodes, or if the infestation is large, imadachloprid, one of the safer synthetic insecticides. Go to your local nursery or county extension agent and get the grub identified. Knowing a grub's life cycle can tell you the best time to spray. Keeping a healthy lawn is the best prevention for grubs, and you can also apply parasitic nematodes on a regular basis. Gophers: - Indications: Holes in lawn; dirt piles
- Treatment: Traps; poison
- Prevention: Good luck
Mounds of fresh dirt are a dead giveaway for gophers, a notoriously lawn-damaging rodent. There are two effective -- and many not-so-effective -- methods for controlling gophers. The most effective are traps (figure C) and poison; all the rest fall into the second category. They type you use depends on several considerations : the season (each seems to work best at different times of the year); safety (if you have children or digging dogs, don't use poison); and personal preference (some people detest the job of throwing away a trapped gopher, while others aren't too keen on the idea of poisoned gopher corpses rotting away in their lawns). Prevention isn't easy, but here are some tips: - Don't plant tender annuals, vegetables, bulbs and other things that gophers love to eat around your lawn.
- Put perches on your barn (if you have one) or the second story of your house to accommodate one of the major predators of gophers: owls.
- If you have dogs, make sure they spend a lot of time in the areas where gophers are a problem.
Tips: Host Jessie Mack Burns shares a couple of final tips for keeping your lawn healthy - Cut back your trees so the lawn will get enough sun.
- Mow often enough that you never have to remove more than a third of the height of the grass. Then leave the clippings, which will degrade back into the lawn and feed it.
Web site resources for bugs, grubs, and gophers: Symptoms of Chinch Bugs in a Lawn Grub Control Getting Rid of Gophers
GUESTS :
Frank McDonough
E-mail: frank.mcdonough@arboretum.org
Website: www.arboretum.org
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