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                          Billbugs/Chinch bugs: A Hidden Lawn Menace
 

 
 

 

 

 

 

 

 

 

 

 

 

There are several strategies for controlling billbugs. We feel it’s best applied before major damage occurs...

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Cultural Practices

• Maintain healthy turf: Proper watering, fertilizing, and mowing will help grass become resist and recover quicker from damage if it’s attacked by billbugs. And a healthy lawn is less vulnerable to insect feeding.

• Choose resistant grasses: Some fescues and ryegrasses show better tolerance to billbug feeding.

 

Timing Is Key

• Early monitoring in late spring before eggs hatch is the best way to detect billbugs before they cause serious damage.

 

Chemical Control

• Preventive insecticides applied in spring and early summer can target adults or newly hatched larvae. The Home & Garden Store recommends applying Ferti-lome Above/Below around the 15th of March on the 1st application and around the 15th of June for the 2nd application.

 

Professional Help

• There are several pest control specialists in the Boise area who can certainly diagnose billbug issues and recommend specific treatments timed for peak effectiveness for those of you who prefer to have a pest control specialist perform the work for you.  We recommend contacting them prior to March if you go that direction.

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The culprit
The adult billbug (weevils) measures from one-quarter to three-quarters of an inch long and the head of the larva are brown to near black in color.  They are fairly easy to recognize since their snouts are long and their mandibles (jaws) are quite strong for their size.  The distinctive snout is what gives the adult billbug its name.  There are four species of billbugs found in the Treasure Valley and its thought that there is perhaps a fifth one here now.  Probably the one that causes the greatest amount of damage here in Idaho is the bluegrass billbug, although all of them do sufficient damage.  Many of the lawns in our area are either bluegrass or a combination of bluegrass, ryegrass and perhaps a fescue blend.  Billbugs typically attack only bluegrass, so if you have ryegrass or a fescue, you’re probably not going to be bothered with billbugs, although they sometimes attack these types of sod also.  
 
An adult billbug will survive the winter by burying deep into the soil and as the weather warms, they come up in the soil and consume the roots of sod.  Female billbugs lay their eggs in the soil and when they hatch, they too start consuming the roots.  Adult billbugs lay their eggs in the stems of bluegrass.  Unlike some insects such as the coddling moth, billbugs typically lay only one generation each year.  Although the adult billbug can create havoc to a lawn, it’s the larva that most often causes devastation in lawns as they feed on the crown and roots of sod.  Adult billbugs do damage above the soil and the larva does its damage to the root system.  The billbug larva looks like what most people think of as grubs, however they are legless and much smaller (about three-eighths of an inch long) and are typically found rolled up in the lawn soil.  The head of the larva is bright orange in color.  Damage is often not recognized as a billbug problem.  As we stated in the sub-heading “Final Thoughts”, many folks believe that the lawn is simply not getting enough water.  What’s really happening is that the larva are eating the roots of the sod, making it difficult for sod to survive as the weather warms up.
 
Just a thought worth keeping in mind. Another insect, the chinch bug creates the same appearance as the billbug.  This insect chews the sod off at or near soil level, thus creating the same appearance as the billbug, both often fooling the homeowner into thinking it’s a watering problem.  A quick way to tell if either of these insects is causing damage to the lawn is by simply lifting up on the sod.  If it pulls up easily, most likely you have either billbug, chinch bugs or both. As you saw earlier in this blog post, The Home & Garden Store recommends Ferti-lome Above/Below to control billbugs and it works equally well on chinch bugs.  However, if it’s only billbugs you’re after, Hi-Yield has several products such as Grub Free Zone III that costs a little less and is quite effective at controlling billbugs.
 
Billbugs become most active when soil temperatures reach about 65 degrees, but we have found billbug larva actively eating the roots of sod as early as March.  To control billbugs, apply Hi-Yield ‘Grub-Free Zone III’ twice each year, once in mid-March and again in mid-June.  The bag states that a bag will last all season.  Some folk’s think that means all summer, but that’s not the case.  There are four seasons, spring, summer, fall and winter!  Now you know why it takes two applications.  One application will last approximately 3 months and billbugs actively feed from early spring through mid to late fall.  Hi-Yield ‘Grub-Free Zone III’ must be watered in before the product becomes active.  Watering can occur either by a sprinkler or rainfall.  By doing so, it places the insecticide in the area where the billbug larva is feeding.  There are other products that state they control billbugs, however we have found over the years that Ferti-lome Above/Below works far better than any other means of controlling both billbugs and chinch bugs. 

We should also note that it’s important to always check the label of all chemicals before applying, first to make sure the product is listed for controlling the insect you identified and second, to make sure you are following all precautionary measures listed on the container.  It should be safe to allow pets and children back on the lawn within a day or two after thoroughly watering the product into the soil. 
 
Some folks rely on beneficial nematodes which can kill around 200 +/- damaging, soil dwelling insects.  And beneficial nematodes won’t kill or damage good insects such as ladybugs.  The soil temperature must be 52 degrees or better for this to be an effective option. 
 

Final Thoughts

While billbugs are small, their impact on lawns can be significant. Billbugs are often found in soil conditions that have been neglected.  Even in the best of conditions, they often get their start near a walkway or driveway where the sod tends to dry out the quickest.  If billbug damage is allowed to go unchecked, repair to the sod may be needed.  Because their damage often masquerades as drought, many homeowners don’t realize they have a billbug problem until it’s advanced. Sod repair can be accomplished by overseeding or re-sodding in the fall. Remember, regular inspection, understanding their life cycle, and taking preventive action can save time, money, and a lot of lawn heartache.

If your lawn shows signs of stress and doesn’t respond to watering, it may be worth investigating the problem to see whether billbugs are the hidden culprit. The Home & Garden Store can help you diagnose the problem and would be happy to help you if you like. 

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The Home & Garden Store has the products to control billbugs, chinch bugs and a host of other insects.  Stop by and see us.  We can help you with all your gardening questions.  The general manager of The Home & Garden Store has been solving insect problems for over 50 years right here in the Treasure Valley.

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