LSU Garden News: Those tiny moths you see are producing webworms that are killing your lawn | Home/Garden

Across the state, lawns are in trouble.

Sod webworms are the main culprit this year, said LSU AgCenter Extension specialist Ron Strahan.

“The numbers are biblical,” Strahan said. “We have observed nearly every house on a single street with damage in the lawn.”

The first sign that your lawn might have a problem are small moths that are light brown to dark brown with striping on the wings. They fly around as you walk through the grass or around outdoor lights at night. These moths lay eggs on grass blades.

Larvae hatch a week or so later, maturing into adult moths in three to five weeks. There can be two or more generations each year.

Larvae are amber in color but become greener as they feed on the blades of grass at night, causing damage to the lawn.

Another sign of sod webworms are yellowing and browning patches of dead lawn. Look at individual grass blades for a chewed appearance, with pieces of missing or chunks bitten out. The caterpillars are making a feast of your lawn.

Worm castings (caterpillar poop) in the ground are another clue. The castings, which are digested grass, appear as light beige pellets at the base of the plants just above the soil level.

In the early morning, when the dew is still on the ground, water droplets from the dew will be trapped in the webbing, and this is where sod webworms get their name. If you dig thoroughly in the soil, you can usually find a tiny caterpillar about ½- to 1-inch long.

Sod webworms seem to especially love St. Augustine grass.

If you see birds going into a feeding frenzy, pecking around in the grass, that’s usually an indicator sod webworm caterpillars are there.

Heavy infestations can lead to stress, causing your lawn to be more susceptible to fungal diseases such as gray leaf spot and to other insects such as chinch bugs and armyworms. A combination of these problems can lead to the death of turfgrass.

To help control sod webworms, use an insecticide with the active ingredient bifenthrin.

LSU AgCenter entomologist Sebe Brown recommends liquid rather than granular applications for better control. You will need to retreat the lawn again in seven days to kill any newly hatched eggs. Spray will not control the moths. It is most effective on the main culprit doing the damage — the caterpillar.

Treat the infested areas and extend 3 to 4 feet past where you see browning. Moths will continue to lay eggs, so continue to monitor the lawn. Eggs hatch every seven days.

The cooler weather of fall will slow down the generation interval but not kill the worms already in the lawn. Last year’s mild and short winter is likely the cause of the large populations this summer.

The good news is that in most cases your grass will recover. Water your lawn during extended periods of drought that are especially common in October here to help the grass recover before

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Your guide to keeping food moths, fruit flies, and other horrors at bay in your kitchen

I will never forget my first run-in with them. It felt sort of dirty, and not in a good way. It was a Sunday morning, The Archers on the radio, mixer lifted on to the kitchen counter, oven preheating. I lifted a plastic tub of flaked almonds down from the shelf and to my visceral and skin-crawling horror, well, the tub was crawling, moving, pulsing with tiny white larvae. The top of the container was thick with white webbing.

Do you have the enormous good fortune to be reading this somewhere in the Outer Hebrides? If so, now seems as good a time as any to ask whether you could hear the scream that pierced the calm of my London kitchen. I was surprised no one called the police. In fact, they probably should have as over the ensuing 24 hours I did thousands of utterly merciless murders (sorry-not-sorry, once again, to the man who called me speciesist when I wrote about killing clothes moths).

Food moths – Mediterranean flour moths, Indianmeal moths, Ephestia kuehniella, Plodia interpunctella, whatever you want to call them – no thank you, strictly not welcome here, and I will do everything I can, armed with vacuum cleaner, hot soapy water and bin bags, to rid myself of them. By the powers vested in me by Kilner and Ziploc, be gone from this place.

If you find even the merest hint of an infestation (you may see the tiny moths fluttering about, too), don’t waste a second. Start by taking everything out from the cupboards. Next, give cupboards – and shelves and drawers – a thorough vacuum, then toss the bin bag or empty the cylinder contents into the outside bin. Give everything a thorough wash with hot, soapy water, paying close attention to any dark, hidden places. I thought I had got rid of them all and then found some taking a nice rest cure inside the drawer runners.

Next, inspect everything before you put it back. Look carefully for webbing, larvae and pinprick holes in packaging. Examine under paper labels and packet seals, and around the rims and lids of jars. They love flour, cereals, grains, nuts, dried fruit, some dried herbs and pasta particularly, so pay close attention to them. Toss anything that shows signs of infestation into the outside bin. If you have dried goods such as flour that don’t appear to be infested but which you’re worried about, seal them in a plastic bag, and put them in the freezer for a week to kill any larvae, before decanting them into Kilner or other glass jars, or plastic tubs with tight seals.

When everything is soothingly moth-free and order is restored, stick some food moth pheromone traps up in your cupboards (Demi Diamond Food Moth Traps, £6.99 from stopmoths.co.uk). These work by attracting the male moths, which stick on to the paper and then can’t mate. They also provide a good way to monitor whether you still have an infestation –

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