Tips from Your Denver Tree Service to Prevent Fall Pests
americanarbor September 28, 2016

Along with the leaves changing, the start of fall can come with some unwanted pests in your yard and typically consist of webworms and Japanese beetles. Take advice from your local Denver tree and landscape service and make sure you know how to identify and properly deal with these insects before they create too much damage.


Webworms consist of 20 different species that infect turf grass throughout the country. Adults are beige colored, around a half inch long, and have folded wings once mature. As the sod webworms grow, they start to leave large areas of brown sod. They like to choose sunny and dry locations and can kill a lawn in a matter of days. To determine your lawn is being damaged by webworms, you can dig into the patch and look for their telltale silk lined tunnels (or have your local landscape service do that for you!)

Japanese Beetles

Another pest that can wreak havoc on your lawn are Japanese beetles. They live in the soil and feed on the grass roots. Once the grubs (young Japanese beetles), chew off grass roots, it makes it hard for the grass to absorb enough water to survive any hot or dry weather. The way you can tell you have grubs in your grass is simply by looking for patches of dead or brown grass. These patches can be rolled back to show the lack of turf roots. However, you won’t find the grubs here as they have most likely already moved on. In most cases, they can be found in the patches of green grass adjacent to the brown patch.

If you catch them early, it’s fairly easy to prevent further destruction. If your turf is not irrigated, the greater chance that a population as small as 7-15 grubs per square foot can cause some damage. However, if your turf is irrigated, it can help withstand larger numbers of them. The best times to apply insecticide is from mid-July to late September as that is when the most grub root feeding occurs. It’s best to treat Japanese beetles when they are young. At stage 5 of their life cycle, they lay their eggs in turf and soil until up to 60 eggs are laid. This starts in the fall and so it’s crucial to start treatment right away.

The beginning of fall is prime breeding time for both webworms and Japanese beetles. Here are some important things you can do to protect your lawns from these pests:

  • Consistent and regular nutrient feeding to make your lawn strong enough to protect itself
  • Water your lawn frequently and deeply
  • Identify the problem early so it can be controlled as soon as possible

Not sure what’s damaging your lawn? Visit our lawn care and fertilization services page to find out how American Arbor Care, your Denver lawn specialist can help.

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