Brock: Controlling summertime pests

Published 12:00 am Wednesday, April 8, 2020

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With the global pandemic, many offices and businesses have been closed by government orders. Agriculture is deemed a vital industry, so LSU AgCenter employees are still working, albeit remotely. Our office is closed and no one (including employees) is allowed in. BUT we’re doing our best to serve the public, and we are available by email. Mine is located at the end of this article.

Tomato Field Day has been optimistically scheduled for Thursday May 28, at the Millet farm in Paulina. Please monitor for updates. We are hoping to have the St. James Parish Garden Contest, but only if we see lots of changes in the pandemic by mid-May.

People have been thinking of self-sufficiency by the recent uptick in the interest in vegetable gardens, orchards, and even backyard chickens. I’ll be happy to field emails on these topics, and the LSU AgCenter has lots of information for beginners and experts alike. An Internet search for your topic with “LSU AgCenter” will yield results.

Thrips and whiteflies are coming out now, “not as single spies, but in battalions.” They’re not very close, entomologically speaking, but their damage, timing, location, and control measures are similar, so let’s throw them together. Several species of both exist, and most will be ¼ inch or smaller. Get out your reading glasses. They’re considered soft-bodied insects with piercing/sucking mouthparts.

Whiteflies are fairly obvious to spot. They’re white, but more elongated than a typical fly, looking more like tiny moths.

They fly around an infested plant, or rest on its leaves. Preferring to infest the underside, in major infestations, they will get up top too.

They aren’t very threatening so far, producing typically minor damage. High populations can cause damage by sucking a lot of juice out of the leaf tips, especially in new growth, where you’ll notice wilting, or possibly browning of leaf margins. As summer goes on and numbers increase, they’ll exude a large amount of “honeydew,” which is what soft-bodied insects “let out” as they process plant juice. The sugary exudate provides a growing substrate for sooty mold, which does not penetrate plant cells, though enough of it can hinder photosynthesis.

Thrips are trickier to find, as they hide in the interior of flowers, buds, and leaf petioles. Damage includes stunting new growth, stippling of leaves and flowers, distorted fruit, and (worst yet) the viruses they transmit. Thrips are often gone by the time we notice symptoms, so shake a branch tip over a white piece of paper to check. Many tend to fall off and you’ll see them.

Chemical control of these pests includes solid organic options like neem oil, light horticultural oil, and horticultural soaps. Getting them to the bugs can be tricky since whiteflies fly and thrips hide. Systemic insecticides like spinosad and acephate are better options if coverage is a challenge, and they can be mixed with horticultural oil. Check the label for regulations on flowering plants, as persistence can be an issue for bees.

If you want to know more about gardening, landscaping, or anything horticultural, contact the St. John & St. James Parishes County Agent André Brock at Also, LSU Ag Center’s website can be accessed at with lots of user-friendly information.