The Block Island Times

Asiatic garden beetle is lawn problem culprit

By Fred Nelson | Nov 16, 2011

Last month I reported a problem with grubs in my lawn. Crows decimated the turfgrass as they were feeding on grubs that were feeding on the grass roots. Since these areas are virtually bare they will have to be reseeded.

Normally, we associate grub damage to turf with Japanese beetle grubs, but as I mentioned I had seen only one Japanese beetle all summer. So I dropped off samples of the grub at the University of Rhode Island Extension Center for identification. Within two days I received the report that the offending critters are the larval stage of the Asiatic garden beetle.

While I initially thought that I might be the only victim of these beetles, I have had numerous folks report that they too had this problem — some up on Corn Neck Road, others around the West Side.

The Asiatic garden beetle is about 3/8 inch long and is reddish brown in color. If you leave an outside light on in the summer you most likely will find some of them clustering around the light. They feed on some ornamentals and flowers during the night and return to the soil during the day.

The adults lay eggs in the soil and the resulting grubs develop and feed on the roots of turfgrass. To control the grubs, the URI folks suggest applying a pesticide called Merit in late May to early June. As with any pesticide, be sure to read the label. Before applying, measure and mark out the area to be treated so that your application will comply with the directions. To be most effective, the material should be watered or applied just before a rain. This ensures that the material gets into the soil where the grubs are developing.

An alternative control for beetle grubs in lawn areas is the use of milky spore bacteria. This material is a long lasting control but it will take several years to become really effective. It is applied in a specified manner: Apply one teaspoon every four feet in rows spaced four feet apart. The areas in between will become inoculated naturally as grubs feed upon the inoculated areas and migrate away from the original source, thus spreading the milky spore disease. One application is sufficient for years to come. It is essential that no other pesticide is applied to control grubs as this will defeat the spread of the bacteria by live grubs.

Where large patches of lawn have been devastated and reseeding is necessary, it is recommended that fine leaf fescues be planted. Apparently they are more tolerant to grub infestations than Kentucky bluegrass varieties. I’m going to try to make a dormant seeding this fall in hopes that the seed will be ready to germinate as soon as the soil warms up in the spring. Just as soon as our weather starts to become more like winter, I shall lightly rake in some seed and fertilizer and hope for the best. If this doesn’t succeed I can always follow up with a spring seeding.

Seaweed mulch

The past couple of weeks, the seaweed has been collecting along the shore from the Surf Hotel up to the area opposite the Beachead. I have made a few trips using trash barrels, recycling bins and five gallon pails, and have completely covered my vegetable garden along with my blackberry arbor.

History has shown that seaweed provides a multitude of nutritional elements, facilitates growth of plants and adds organic matter without any introduction of weed seed. Some folks are concerned that the salt content might become a problem, but I haven’t seen any evidence of this. Seaweed applied in the fall has ample time for what little salt might be present to be diluted into the soil throughout the winter and spring. Further, if this were a problem, there would be historical precautions cited and I have not seen any evidence pertaining to this. There is still time to get over to the beach to collect and make the most of this valuable garden resource.

“The frost hurts not weeds.”

—Thomas Fuller, “Gnomologia” (1732)

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