Rose Rosette Disease, Slime Mold, Leaf-footed Bug & Citrus Leaf Miner

A rose with rosette disease. Photo: AgCenter

Rose Rosette Disease

Denise sent an email regarding her roses, “One of our roses has contracted rose rosette, in case y’all are documenting this disease.”

Rose rosette disease (RRD), as described by Dr. Raj Singh, Plant Pathologist with the AgCenter, in “infected roses produce a cluster of new shoots from a single point on the parent canes. The new shoots elongate rapidly and appear like a ‘witch’s broom,’ Singh said.” RRD is a viral disease spread by eriophyid mites so miticides will help prevent the spread of RRD.

Denise is providing an important service by reporting RRD. Dr. Singh will gather reports of RRD and attempt to find trends. He will also share this information with other agencies to implement control measures.

Slime mold is a harmless, fugus-like organisms. Photo: Terri Linzay

Slime Mold

Terri sent an email with some images, and she wrote, “I have some more weird stuff growing in my yard. I think it’s a fungus again. It started out tiny and yellow like someone threw paint on the ground. Then it turned orange. And when I scratched it with a stick it was dark brown black dirt looking. Thanks for your help.”

According to Louisiana Home Lawn Series, “Slime molds are harmless, fungus-like organisms that use grass blades as a substrate for structural support during reproduction….They are non-pathogenic and do not obtain any nutrients from the turfgrass.”

“Slime mold control is not necessary as most fruiting bodies disappear two to three days after first appearing. However, if desired, slime molds can be physically disrupted or removed from leaf blades through sweeping or lightly hosing off the leaves with water.”

Leaf footed bug is a vegetable pest. Photo: Kathy Serenbetz

Leaf-footed Bug

Kathy also sent an email with a very clear image, “Sir, I have an infestation of the attached bug in my garden. Can you identify it and possibly tell me how to get rid of them?”

Figure 3. Leaf-footed bug, a vegetable pest. Photo: Kathy Serenbetz

The insect in the photograph is a leaf-footed bug (LFB) and can sting green and ripe fruit and pecan leaving damage. Be advised, these are members of the stink bug family. If held too long or crushed, they emit a foul odor. Common insecticides like Sevin® or Malathion® can suppress LFB.

A citrus leaf with old damage by a citrus leaf miner. Photo: Melissa Jeane

Citrus Leaf Miner

Mr. Don came into the office with these samples of his white grapefruit tree. He would like to know what is going on with them and what to spray to get rid of it.

Mr. Don had citrus leaf miner (CLM) and the image to the left shows old damage. CLM, during a juvenile stage, feeds between the top and bottom surfaces of a tender, new leaf and makes tunnels. The Louisiana Insect Pest Management Guide prescribes spinosad to treat for CLM. Treatment must occur when leaves are new and tender.

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.”

6/6/2019 7:49:06 PM
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