Roots, Shoots, Fruits & Flowers: AgCenter access, “3+3” Plan, Carpenter Bees and Loquat Ailments

Even though the AgCenter is closed to walk-in visitors due to the viral pandemic, citizens can still contact their local offices by phone or by email. Here is a link to find the phone numbers and email addresses of your local AgCenter office.

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Figure 1. St. Augustine turf, a popular warm season grass in Louisiana. Photo: LSU AgCenter.

In last week’s edition of RSFF, Anthony shared images of annual bluegrass and of crabgrass. He later conveyed to AHA that he wants his St. Augustine grass to thrive in his landscape. A couple of management practices will make St. Augustine to have fewer weeds without herbicides. The “3+3” plan will help with St. Augustine lawn: Set mower at 3 inches, and fertilize 3 times per season: April, June & August. Both practices will solve many problems with St. Augustine turf.

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Figure 2. An image comparing a bumblebee and a carpenter bee. Image: LSU AgCenter.


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Figure 3. A closeup image of a native mason bee. Photo: Michael Warriner.

Sherry made this inquiry, “I have some big black angus looking bees boring holes into painted wood on my back porch. First, I don't know what kind of bees they are, but they liked the azalea shrubs I bought that are now blooming. Are these bees the kind that would take to living in bee houses made from bamboo?”

Sherry is probably asking about carpenter bees attacking the wood in her porch. Carpenter bees are different bees from those that inhabit bamboo bee houses. Native mason bees tend to visit the bee houses for nurturing their brood.

The AgCenter’s website recommends these practices to prevent carpenter bees from damaging wood, “Prevent damage form carpenter bees by painting exposed wood. Though not a guaranteed remedy it works most of the time. A preventative treatment may be made by applying two applications of a borate formulation (Timbor) on existing structures and using pressure treated wood when rebuilding or replacing damaged wood. Professionals can use Astro and Tempo Scultra with 8.0 ounces liquid soap added per gallon to both insecticide mixtures.”

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Figure 4. A closeup image of a fungal leaf spot on a loquat leaf. Photo: Keith Hawkins.


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Figure 5. A loquat leaf with drought symptoms. Photo: Keith Hawkins.


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Figure 6. A pear branch with classic fire blight symptoms: the shepherd’s hook and scorched leaves. Photo: University of Georgia Extension Service.

Mickey brought in some loquat leaves earlier in the month and wanted to know what is happening. His loquat seedlings are in containers and kept in a greenhouse.

The image in Figure 4 shows a fungal leaf spot and occurs when standing water drops persist on a leaf surface. According to plant pathologists, a fungal spore requires about 8 hours in a drop of water to penetrate a leaf surface.

The leaf in Figure 5 shows a totally different symptom. The edge of the leaf shows drought stress. So, what is going on here? One leaf has too much moisture, but another leaf has too little moisture. The answer to this paradox probably lies in how the loquat is watered. If some of the foliage is watered, then those leaves would be susceptible to fungal leaf spots, and the lower leaves may be staying dry. The soil has inadequate moisture so some of the leaves show dry conditions. The solution for watering loquats in a greenhouse is to water the soil in the containers and to avoid watering the leaves.

While AHA was researching diseases of loquats, he learned that one disease is the most common for this plant. Fire blight (FB) attacks loquats most frequently, and it is caused by a bacterium. Other plants are susceptible to FB including pear, apple, crabapple, quince, loquat, mayhaw, hawthorn, Indian hawthorne, cotoneaster and pyracantha.

According to an article on the LSU AgCenter website, “It is important to pay attention to fire blight now because the bacteria overwinters in wounds in the branches that are left from the previous year’s infections. As the trees start to flower you will see a liquid oozing from those wounds and both sugars and bacteria are in the liquid. Honeybees are particularly attracted to the sugars and therefore will spread the bacteria as they go about pollinating flowers. The bacteria can also be spread by splashing water from rain showers.

While spraying the tree is not a sure cure, it can help to prevent the spread to other susceptible plants which include pear, apple, crabapple, quince, loquat, mayhaw, hawthorn, Indian hawthorne, cotoneaster and pyracantha.

The control method would be to spray either streptomycin or a copper fungicide. Copper can be purchased as Kocide, Tri-Basic Copper Sulfate and Bordeaux mixture. Streptomycin can be found in products such as Agri-Mycin and Bonide Fire Blight Spray.

Start your spray when 10% of the pear blooms are open. Repeat your spray every 4-7 days until the blooming period is complete but pay attention to and follow the number of sprays allowed and interval between sprays that are listed on the individual product label.

Your only other choice for fire blight control is to prune out the dead limbs making sure to dip your shears in a 10% Clorox solution between cuts. This type of pruning will make a mess of the form and shape of the trees but will help control the disease if visual appeal is not a goal.”

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.”

3/23/2020 8:25:04 PM
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