Sweet Potatoes & Red-Headed Azalea Caterpillars

Karen Cambre, Sharpe, Kenneth W.

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News article for October 16, 2017

I have had recent reports of something eating azalea leaves. The culprit is a caterpillar that we know as the red-headed azalea caterpillar.

As the name implies this is a very colorful caterpillar with a red head. The immature caterpillars will be magenta in color and are covered in long grey hairs. Once these caterpillars reach maturity they will have yellow and black stripes running the length of its body and that distinct red head.

We typically start seeing red-head azalea caterpillars in September but we can have several generations. Those first caterpillars that show up will pupate; a moth will emerge and then lay more eggs for more caterpillars in October.

Red-headed azalea caterpillars also like blueberry leaves so check those also when scouting. Look for missing foliage. If you see leaves chewed or missing, search for caterpillars. Mature caterpillars can defoliate a small plant in about 24 hours so do not delay treatment.

Control caterpillars with Pyrethrins, Acephate or Sevin. Biological controls would include Dipel, Thuricide and Spinosad.


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There were some really nice sweet potato exhibits at the Livingston Parish Fair. That reminded me that the sweet potato harvest is upon us. Most sweet potatoes are harvested in September, October and some into November. Their harvest date will give us a clue as to when they will reach peak sweetness for use and also indicate potato size.

Sweet potato size can be controlled by the length of time that we allow them to grow, within reason. For instance, Beauregard is a very popular sweet potato variety in Louisiana and the south. It has good yields and sweetness plus an attractive rose colored skin with orange flesh. It has a very predictable, high percentage of No. 1 potatoes if harvested at 90 days. No.1 potatoes are those that are 3 to 9 inches long, 1¾ to 3½ inches in diameter and weigh no more than 18 ounces.

The longer you leave sweet potatoes growing, the larger the potatoes will get and Beauregard will still produce very acceptable tasting large potatoes that we call jumbos. I saw a Beauregard potato recently that weighed in at an impressive 4¾ pounds.

When first harvested, sweet potatoes are not very sweet. We call those “green potatoes” and they are very acceptable for candied yams but not sweet enough for baking. It takes time for the curing process to convert starches in the sweet potato to sugars.

The first phase of curing is to heal any cuts and bruises on the potatoes created during the harvest operation. Store the potatoes at 85-90◦F and 85-95% relative humidity for 4-7 days. That will heal any defects, improve appearance and reduce diseases in storage.

Next, place the potatoes in storage to let them get sweet. Ideally they would be stored at 55-60◦F and 85-95% relative humidity for 7- 8 weeks. This is when starches convert to sugars and baked sweet potatoes will make syrup.

If you are buying sweet potatoes and do not know if they are cured, you can hold them and cure them yourselves. I like to buy sweet potatoes in October and put them in a cool room and hold them until Thanksgiving. That will insure that if the sweet potato has the potential to be sweet, it will be. Do not store potatoes in the refrigerator as they will develop a hard center. Also note that oven baking produces a much sweeter baked potato. Microwaving does not provide the time and temperature for sugar production. Once baked, you can reheat sweet potatoes in a microwave.

For more information on these or related topics contact Kenny at 225-686-3020 or visit our websites at www.lsuagcenter.com/livingston.

5/9/2018 4:13:42 PM
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