Roots, Shoots, Fruits & Flowers: Chinch Bugs on Corn, Lawn Slime Mold, Quince Rust, and Grape Tomatoes

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Chinch bugs infesting a cornstalk. Photo: Ronnie Zaunbrecher.

Chinch Bugs on Corn

The Inbox runneth over. Readers of this blog have frequently sent their emails and images and have brought relevant content to share with gardeners.

Ronny sent his question and picture, “A friend sent these pictures a few weeks ago. These insects migrated from a dying ryegrass field to his sweet corn. He applied permethrin and had good control. Any ideas on what it is?”

AHA consulted with Dr. Sebe Brown, an insect specialist with the AgCenter, and he replied, “Those are chinch bugs. A pyrethroid works very well controlling them, bifenthrin works best out of the pyrethroid class of chemistry.”

Chinch bugs usually attack lawn grass and prefer hot dry conditions. Corn is in the grass family and is susceptible to chinch bug infestation. An AgCenter publication on chinch bugs in corn makes this point, “Chinch bugs damage crops by removing plant sap with their piercing and sucking mouthparts. Their damage is often compounded by dry weather conditions.”

One of the brand names of bifenthrin is “Bifen™”. The label will list the active ingredient of any insecticide.

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Slime mold in the lawn. Photo: Susan McReynolds, Master Gardener.

Lawn Slime Mold

Susan saw something unusual in her yard and sent this email, “I noticed three spots like this on our yard today. Do you know what it is?”

Susan has a type of slime in her yards. A very recent article about slime molds from the LSU AgCenter shared this passage, “LSU AgCenter plant doctor Raj Singh said slime molds appear as crusty or powdery coating on any surface, including wooden planks used for making raised beds, garden mulch, lawns or even the leaves and stems of all different kind of garden plants. ‘The encrusted cover is usually a powder buildup that wipes off easily,’ he said.” Slime molds are harmless and require no chemical treatment. A homeowner can use a garden hosepipe to rinse away this sooty type of slime mold in the lawn.

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A pear with quince rust, a fungal disease. Photo: Sara Swain.

Quince Rust

Sara wrote to AHA, “I was given your email and was told to share pictures of my pear trees with you. I've searched and cannot find anything on why some of the pears look like they do.”

Sara has a fungal disease called “quince rust”. A couple of AgCenter horticulture agents wrote about quince rust in an article about mayhaws, “Fruits in the pome fruit group (apples, quince, pear and mayhaw) are susceptible. A unique aspect of this disease is that the eastern red cedar and some junipers are essential for the continuation of the disease from year to year. The fungus completes part of its life cycle on the cedar and junipers and part on the mayhaw.”

These agents recommended these practices for managing quince rust, “If you already planted a susceptible selection, then the elimination of cedar and junipers close to the mayhaw would reduce the number of fungal spores that could cause an infection. This may not be very practical. A fungicide application from the time the flower buds begin showing color through bloom would help manage the disease. Fungicides available for homeowners are sulfur or myclobutanil. Copper fungicides may be used but not during bloom.”

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Varieties of grape tomatoes. Photo: Cornell Agritech.

Grape Tomatoes

Kathy simply asks, “Can you recommend a small, grape tomato to me?”. AHA consulted with Dr. Kiki Fontenot, our vegetable specialist, and she replied via email, “I have not conducted a grape only tomato trial. But I have grown a few that I really like.

Juliet, Jellybean and Odat are good producers with nice taste. Odat was amazing from Morova seed in the Czech Republic but I just looked on their website and did not see it listed anymore. The other two should be easy to find in American seed companies.”

Bart Joffrion, retired AgCenter agent, wrote about the difference between grape and cherry tomatoes, “At first glance, they don’t look that different from red cherry tomatoes. On closer inspections you see they are more elongated than the cherry and shaped like a grape or like an olive. Grape tomatoes combine several desirable tomato qualities including very sweet flavor, firm texture and at least a resemblance of having been ripened on the vine.

There are several varieties available now to choose from. The original that is found from most of the stores now is the hybrid “Santa F1” variety.”

If you want to contact Roots, Shoots, Fruits and Flowers, please send your questions and pictures to Keith Hawkins, Area Horticulture Agent (AHA), 337-463-7006 or khawkins@agcenter.lsu.edu. Also, you can be on the “green thumbs” email list by emailing your request to the address above.

“This work has been supported, in part, by the USDA National Institute of Food and Agriculture, Renewable Resources Extension Act Award, Accession Number 1011417.”

5/27/2020 8:20:38 PM
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