August is awful. Its heat makes one miss the relative cool of July. Its rain is so sporadic that it invokes nostalgia for the rainy afternoons of early summer. But if there is a silver lining in August for gardeners, it is the simplicity that it brings. The weaker spring crops, tomatoes, squash and the rest, are all gone now, destroyed or rendered fruitless by insects, disease, and heat. This leaves only the hardened, usually pest and disease-free survivors Okra, Pepper, Sweet Potato and Eggplant. I say usually because, this year, my eggplant bed is under attack by a new-to-me pest, the False Potato Beetle!
I’ve dealt with Colorado Potato Beetles (CPB) before. Those orangish, black-striped terrors often attack my spring potato crops and occasionally bother early tomatoes. However, I’ve never seen them in late summer on Eggplant. This raised suspicion. Also, I spotted unusual, round, whitish purple creatures munching on leaves from the same plants; these appeared to be the larval stage of the unidentified beetle. A little digging led me to identify these garden pests as the lesser known, lookalike cousin of CPB, the False Potato Beetle.
False Potato Beetle munching on an Eggplant leaf in the author’s garden.
False Potato Beetle (FPB) looks nearly identical to its cousin in the adult stage. They are similarly shaped and colored, though a close look reveals subtle differences between species. While both have yellowish-orange heads and pale-yellow backs with dark stripes, the FPB’s back is slightly lighter hued, more of a whitish, cream color. Also, the CPB’s underside and legs are a very dark orange to brown, with the False Potato Beetle having lighter colored legs and underside. If you’re saying, “These old eyes will never be able to tell the difference, County Agent. Cream and light-yellow look the same to me.”, I get it. Fortunately for those of us with poor vision, the larval stage (babies) of the two beetles looks very different and is the key to correct ID! FPB larvae are larger and have a whitish coloration. CPB larvae, in contrast, are a similar burnt orange color to the adult beetle. I promise, the difference is very distinguishable!
False Potato Beetle is considered a minor garden and agronomic pest as they typically only bother Eggplant, and they don’t usually destroy entire plants. However, if you get a FPB outbreak in your Eggplant garden, they can still be pretty destructive. These beetles feed in the same manner as caterpillar pests, chewing away entire sections of leaves and stems. Unchecked infestations can defoliate entire sections of plants. So, if you find these little beetles eating away at your eggplant garden, what can you do?
False Potato Beetle larvae. Photo courtesy of the author.
First, if you scout regularly, you’ll notice the beetles and their larvae in relatively small numbers before outbreaks become widespread. I had pretty good success this year just catching infestations early and picking off the beetles I saw and squishing them. Continue scouting and squishing for a few days and pretty soon, the population is reduced to a manageable level. However, if squishing makes you squeamish, you also have some common pesticide options at your disposal. I normally encourage clients to start their chemical pest control strategy with “softer” products like Pyganic, a pyrethrin make from an extract from the Chrysanthemum plant. Pyganic works great but is a little harder to find; you may have to order online or ask your local retailer if they can get it for you. If you are unable to find Pyganic or it doesn’t perform for you, the old standby products with carbaryl or pyrethroids (Sevin, Ortho Bug-B-Gone, and others) also work well.
False Potato Beetle can be a late summer garden pain, but with regular scouting, proper insect ID, lots of squishing, and maybe a timely pesticide application or two, you should be able to continue to harvest eggplant deep into fall! If you have FPB in your garden or have another horticultural question, give your local UF/IFAS County Extension office a call! Happy Gardening!
I know this is going to come as a shock to some readers, but not all bugs are bad. In fact, while there are over 1 million species of insects worldwide, less than 1% are problem pests! This problem 1%, composed of common garden pests, including aphids, stinkbugs, nuisance caterpillars, and scales, get all the attention and for good reason; they can be extremely destructive to home and commercial crops. However, the good guys, beneficial predatory insects, are out there too, providing valuable pest control day and night and should be considered in part of a quality garden pest management strategy.
Beneficials come in many shapes and sizes. Some are commonly known predators, such as spiders, Lady Beetles and Praying Mantids, while others are lesser known pest nemeses, like Paper Wasps, Pirate Bugs, and Lacewings. Regardless, gardeners should do their homework and be able to identify beneficials when they see them and allow them to do their jobs. The presence, or not, of a handful of Lady Beetles or Lacewings on the attack can be the difference between needing to treat with insecticides for an aphid outbreak or just letting nature take its course. Studies have shown that just one individual Lady Beetle in the larval stage can consume as many as 500 aphids; adult Lady Beetles are even hungrier aphid eaters! Paper Wasps, you know the ones who make the large “papery” nests around eaves of house and other structures, play an important beneficial role, frequently preying on caterpillars. If their nests aren’t near highly trafficked areas around your home and you don’t have family members allergic to wasp stings, your garden will thank you for leaving a few paper wasp colonies as caterpillar insurance!
Lacewing eggs on a Jade plant in close proximity to the author’s vegetable garden.
In many instances, beneficial insects can keep pest insect infestations at bay, allowing gardeners to spot treat outbreaks when they get out of hand or even prevent the problem from needing chemical intervention altogether.
As helpful as they are, beneficial insects in the garden won’t totally negate the need for chemical treatment entirely. From time to time, garden pest populations outpace the beneficials’ abilities to kill them and intervention from humans is needed. In these times, it is advisable to use a couple of best practices to limit exposure to beneficial insects. First, try to use selective insecticides that only target specific pests and are nontoxic to other bugs, like the product Bt for caterpillar pests (sold under many brands like Dipel, Garden Safe Bt Worm and Caterpillar Killer, Thuricide, etc). However, if a nonselective, general insecticide, like the Pyrethroids (many common homeowner insecticide brands) and carbamates (Sevin and others), is needed, timing these broad spectrum sprays for early in the morning and late in the evening when many beneficials are not very active can help reduce friendly fire casualties. Care should also be taken to only spot treat infested plants and not the entire garden, this helps reduce beneficial exposure to these broadly toxic pesticides.
Every gardener should have a plan for pest control and beneficials can play an important role in this overall strategy. Gardeners can help ensure that nature pulls its weight in controlling problem pests by taking a little time to scout for beneficial insect populations, keeping a close eye on developing pest outbreaks, using selective insecticides when you can, and only spraying broad spectrum products as spot treatments when necessary and timing those applications for very early or late in the day. If you have a question about whether or not a garden insect is a good guy or a pest or want more information on garden pest control strategies, contact your local UF/IFAS County Extension Office! Happy Gardening!
The following resources were used in the development of this article:
Do you notice a large number of bees or wasps visiting your magnolia tree? Do you see “bumps on the twigs”? Are the leaves and branches turning black? It is probably Magnolia or Tuliptree scale.
Photo by: Rebecca Bolestra
These scale belongs to a group of insects referred to as soft scales. Scale insects feed by inserting their piercing-sucking mouthpart into the plant’s vascular system and removing sugar and water from the tissue. As the insects feed the fluids become concentrated in the gut of the scale, forcing them to excrete a clear, sticky liquid called honeydew. The honeydew drips onto the leaves, stems and anything else below. Honeydew serves as a growth media for sooty mold, the thin layer of black fungus that forms on the surface. The honeydew is a food source for other insects, like bees and wasps. But, the sooty mold prevents sunlight from reaching the leaf surface, preventing photosynthesis from occurring.
Scales are identified by their body covering. Magnolia scale (Neolecanium cornuparum) is one of the largest soft scale, measuring up to ½ inch in diameter. They range from pink-orange to dark brown in color and are often covered with a white wax at maturity. Tuliptree scale (Toumeyella liriodendri) is a similar appearing scale that can infest magnolia species. But, it does not form the white wax.
Magnolia and Tuliptree scale reaches maturity in August with one generation per year. The female lays her eggs, which hatch internally and form crawlers that move from under the body covering and migrate to the underside of small twigs, where they will spend the winter. Once settled in, the young scales begin to feed and never move again, growing larger in the same spot.
Now is the time to take action. For small trees, the scales can be removed by hand with a soft brush. Horticultural oil will smother adults and crawlers, if the trees to be treated are larger or time is limited. Systemic insecticides can be applied for lasting effects. Imidacloprid is a pesticide that can be applied as a soil-drench, reducing the potential for harm to pollinating insects. In the fall, insecticidal soap can be applied to control the crawlers that hatched. Plan on treating the tree again next year. Scale population suppression usually requires at least two years of pest management. For more information on scale insect management go to: https://edis.ifas.ufl.edu/pdffiles/MG/MG00500.pdf
On a daily basis, it is not unusual for our Extension Office to get calls, emails, and walk-ins with questions about insect identification. Sometimes we even get questions about imaginary insects! The overwhelming opinion by our clientele is that the insects in question are harmful to their landscapes and gardens. This is not always the case since there are more than 100,000 species of insects found in the United States, but less than 1% are harmful.
Recently I received a call about an abundance of bugs in a client’s newly installed sod. He was concerned that the insects were taking over his yard. Luckily, he was able to submit some good quality photos so the University of Florida/IFAS Extension Service could help him identify the insects.
An adult ground beetle (Mochtherus tetraspilotus). Photo Credit: Michael C. Thomas, Florida Department of Agriculture & Consumer Services
The photos were sent to a University of Florida Entomologist for identification verification. It turns out the insects were ground beetles (family Carabidae). Adult ground beetles are slender and range between 1/4″ and 3/8″ in length. Their head and thorax are much narrower than their abdomens. Ground beetles are beneficial insects that feed on moth eggs and larvae. They are known predators of soybean loopers, cabbage loopers, and velvetbean caterpillars. It is suspected that the beetles found by the client came from the sod farm and were living in the thatch layer of the sod. They were possibly feeding on sod webworms or other moth larvae.
Accurate identification is the first step of integrated pest management (IPM). In this case, the insect found wasn’t a pest at all. If you need help identifying an insect, feel free to contact your local Extension Agent. For more information on beneficial insects, visit these publications found at edis.ifas.ufl.edu.
Pesticide labels are not exciting reading materials but they contain necessary details about the specific product. The label information helps you with many decisions to use the product correctly and protect yourself and the environment during the product use. Beth Bolles with UF IFAS Extension in Escambia County will share information about a readily available product and why you should always read through the complete pesticide label.
North Florida vegetable gardeners have made it to summer and now the plants and gardeners are starting to give in to the heat and humidity. The squash has likely succumbed to squash vine borers, many of the tomato varieties are having trouble setting fruit, stink bugs are all over, and gardeners easily wilt by noon. This is a good time to use our oppressive heat to your advantage in the vegetable garden by solarizing the soil.
We have reached the peak of heat. Use it to your advantage in the garden. Source: National Weather Service.
Soil solarization is a method of pest control that creates a greenhouse to heat up the soil in an effort to drive away pests. Pests that can be reduced with soil solarization include weeds, various soil-borne fungal pathogens, and nematodes. Weed seeds can actually be killed by the increased temperatures, sometimes as high as 140 degrees Fahrenheit, while fungi and nematodes are merely driven deeper into the soil layer as they try to escape the heat. Although they are not killed, this can help vegetable gardeners as it may take these organisms 3-4 months to repopulate in high enough numbers to cause damage. Soil solarization can be considered another tool in your integrated pest management (IPM) toolbox, along with other cultural, physical, and chemical means of pest control.
A raised bed being solarized over the summer. Source: Evelyn Gonzalez, UF/IFAS Master Gardener Volunteer.
To properly execute soil solarization, the site should be in full sun and the existing vegetation removed, either by hand or with a tiller or other implement. Tilling can help loosen the soil surface and allow heat to penetrate deeper in the soil horizon. Before being covered with plastic, the area should receive rainfall or be irrigated, as the water will help conduct heat to greater depths. The next step is to cover the area with plastic. Note that this can also be done over raised beds! Clear plastic is best for maximum solar radiation penetration. Black plastic will heat up mostly on the surface and opaque plastic sheeting may not let enough light in to get temperatures high enough. The plastic should be slightly larger than the area covered, as the edges will need to be buried to create an air-tight seal. It’s recommended to leave the plastic in place for at least six to eight weeks, just in time to begin fall gardening preparations.
It’s important to monitor the site while it’s “cooking” to look for any holes that might appear. Small holes can be repaired with duct tape, while large holes or rips in the plastic may require starting over. Overlapping strips of plastic is not recommended since too much heat will be lost.
You may be wondering what happens to all of the good soil microbes. Well, unfortunately, they are also either killed or suppressed. Fortunately, researchers have found that they are able to repopulate quicker than the pest organisms, especially in soils with a good amount of organic matter.
Much more information on soil solarization can be found in these two documents:
