Roots, Shoots, Fruits & Flowers: Common Chickweed, Juvenile Beetles, Citrus Caterpillar, and Fire Blight


Common chickweed choking out grass. Photo: Mary Cook, Vernon Parish.

Common Chickweed

Mary was complaining about “moss” growing near a barn and sent an image with weeds that look like chickweed and wanted to know how to control it.

Dan Gill, retired horticulture specialist, addressed this problem in one of his articles, “This is chickweed. It has been growing in your lawn over the winter, and this is late to begin control efforts. First, you need to begin to mow it. It has been blooming and setting seeds. If you allow seeds to be produced, it means worse problems next year.

Typical lawn weed killers like Weed B Gon™, Weed Stop 2X™, Weed Free Zone™, Speed Zone™ and others will control chickweed. As it gets hotter, the chickweed will disappear whether you do anything or not.

In the future, spray with one of the above weed killers in January or February to control this weed when it is younger and has not spread so much.”


Juvenile form of a long-horn beetle. Photo: Dorine Bearden, DeRidder, LA.

Juvenile Beetles

Dorine, near DeRidder, discovered a juvenile insect, “I found these…in a water oak we cut down. Can you identify them? I have searched the internet but cannot find a picture that resembles these. They are between two and three inches long.”

Ms. Victoria Bayless, Curator of the LA State Arthropod Museum (LSAM) made an identification, “This is a pupa of a longhorn beetle. Which one though I could not say.”

A blog from Texas A&M Agrilife Extension titled, “Wood-boring Insects of Trees and Shrubs” describes longhorn beetles, “Adults are called long-horned beetles because their antennae are occasionally longer than their bodies. Larvae tunnel underneath bark and into the heartwood. The tunnels are oval to round in cross section because of the round shape of the larvae. Larvae of some species are legless, but most have three pairs of small legs on the first three segments behind the head capsule. While tunneling, larvae continually pack their tunnels with excrement (frass), which looks like compressed wood fibers, or push frass out of the holes they produce. This excrement, along with the sap exuded by the plant in response to the damage, is often visible on the outside of infested trunks or branches. Many species of beetles belong to this group, but most are secondary invaders.”


An orange dog caterpillar on a citrus leaf. Photo: Peggy Kessler, Master Gardener, Dry Prong, LA.

Citrus Caterpillar

Peggy, a Master Gardener in Dry Prong, share this image with this note, “his caterpillar - and several of his friends - are on one of my citrus trees. Can you identify it please?”

AHA shared these thoughts, “This is an orange dog caterpillar (ODC), and it becomes a giant swallowtail butterfly. In general, I recommend tolerating the damage by the ODC on citrus. If the citrus is a small tree, then move the ODC to a large citrus.”


Characteristic "shepherd's hook" on blighted ornamental pear. Photo: Carol Pinnell-Alison, LSU AgCenter.

Fire Blight

Walton sent an email regarding a pear tree, “[My] pear’s tree leaves will leaf out beautifully - then some of the leaves will die - it happens every year. [What is happening] ???”

Walton’s pear tree has a bacterial disease called “fire blight”. Dr. Raj Singh, The AgCenter’s “Plant Doctor” makes these recommendations for managing fire blight, “The management of fire blight requires the use of a combination of disease management practices, since no single practice is sufficient to control this disease. In areas where fire blight is common, choose only resistant varieties when establishing new plantings, but remember resistance is not the same as immunity. Disease can still develop on these varieties to some extent. Once the plants are established, employ cultural practices that promote a vigorous plant to reduce the damage caused by this disease. Keep in mind, however, that overfertilization and overwatering tend to promote lush, succulent growth that is susceptible to disease. The natural resistance of the plants can be further enhanced by applications of fosetyl aluminum (Aliette™) or one of the phosphite fungicides. Careful pruning to remove infected branches also will help to reduce the amount of inoculum present in the spring. When pruning, be sure to cut back far enough into healthy tissue to ensure infected tissues are removed completely. Also be sure to clean and disinfest cutting tools frequently using a 10-percent-bleach solution (or other suitable disinfectant) to prevent the accidental spread of the bacterium. A weak solution of a copper fungicide may be applied during the bloom period to reduce infection of the flowers, but such applications must be made every 4-5 days during the bloom period to be even moderately successful. As an alternative, streptomycin sulfate may be used, but repeated use of this antibiotic eventually will lead to the development of resistance in the bacterial population.”

If you want to contact Roots, Shoots, Fruits, and Flowers, please send your questions and pictures to Keith Hawkins, Area Horticulture Agent (AHA), 337.284.5188 or or

“Before you buy or use an insecticide product, first read the label, and strictly follow label recommendations. Mention of trade names or commercial products in this article is for informational purposes only and does not constitute endorsement by Louisiana State University AgCenter.”

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

5/11/2022 1:05:10 PM
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