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Grumblings about grubs

August 02, 2008|By BOB KESSLER

Last year's drought certainly had a impact on the number of grubs that were able to survive because of our dry turf.

This year it looked like it could be the same, but last week's rains will certainly help the eggs that have been laid as well as eggs that will be laid in the next few weeks. That's if they should find enough moisture to survive.

This means we will likely see more Japanese Beetles next year as the population builds.

When the Japanese beetle lays her eggs she looks for areas that have moisture. If the eggs don't have enough to hatch right away, they can stay dormant for several weeks until there is enough moisture.

A female can lay four to five eggs at a time and then re-mate and lay more eggs. This can continue until she lays up to 50 to 60 eggs. Most egg laying is done by mid-August but you can find adults well past that time. Irrigated lawns will be more likely to attract the females because it's a desirable egg-laying site.


It is difficult to make a general recommendation on controlling grubs. Most lawn services will apply a product to control the developing grub. If you have seen plenty of beetles in your yard since late June, you might be at risk to have a grub population high enough to experience damage. Usually our grass can tolerate up to six to seven grubs per square foot of grass and not show any damage.

Once we get eight or more you might have damage. What you do depends on what you're willing to risk. When you go to the store to look for grub-control products look closely at the active ingredients. Some products state that they control grubs but not all products will control the grubs in our areas. Just because it is on the shelf doesn't mean it should be used in our area.

Products that only contain lambda-cyhalothrin, bifenthrin, deltamethrin, cyfluthrin or permethrin will not work on our grubs when applied to the soil surface. The active ingredient will become bound to the organic material and will not get down into the soil surface where the grubs are located. You should have used imdacloprid (Merit), halofenozide (Mach 2) until the end of July.

If you choose to wait and see if you have a problem you can use a couple of different product to correct the problem. Both trichlorfon (Dylox) and carbaryl (Sevin) will work well in the fall to control grubs. Be sure to water any of these products in well especially the Dylox and Sevin. Read the label of any material you use to be sure you apply the proper amount and apply it properly. Follow all safety instructions.


Hardscape is defined as the areas of your landscape made from wood, concrete, stone, brick and plastic. With high gas prices, people are staying around home more and are creating changes in the landscape such as a patio or deck or a new sidewalk or garden path.

I like hardscape because it adds a lot to the yard and expands how you can do more outside. If you are planning one of your own projects fall is a great time to do it. Right now you can make up your plans and get the information you need to do it.

Then when it cools off in late August you have plenty of time to get it done before winter. The Internet is a great source of ideas and tips on how to do most of the hardscape projects you might want to tackle. Also watch for project ideas in gardening and landscaping magazines. Building supply stores also have a lot of how to books that contain good plans.

We have a lot of places in our area to rent the tools you need for your project, which may be cheaper than buying. Another tip is ask your neighbors and friends if they are planning a project. Perhaps you can help them to learn some new skills and then they can help you with your project. Two sets of hands make projects go a lot easier than one set. Finally, don't try a huge job all at the same time. Projects always take a lot longer than you think. Break your plans down into smaller jobs that you can get done in a couple of weekends

Fewer tomatoes

The recent weather - 95 to 98 degrees in the day time, 70s at night - will cause the tomato blossom to not fertilize or "set" properly. We recently went through five to six of those days at a time when our tomatoes have a lot of flowers. The result will be noticed in a few weeks with fewer green tomatoes. This will only be temporary because we had a great rain and it cooled off.

Bob Kessler specializes in consumer horticulture and energy for Penn State University. He can be reached weekdays at 717-263-9226 or by e-mail at

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