2020 has not been the most pleasant year in many ways. However, one positive experience I’ve had in my raised bed vegetable garden has been the use of a cover crop, Buckwheat (Fagopyrum esculentum)! Use of cover crops, a catch-all term for many species of plants used to “cover” field soil during fallow periods, became popular in agriculture over the last century as a method to protect and build soil in response to the massive wind erosion and cropland degradation event of the 1930s, the Dust Bowl. While wind erosion isn’t a big issue in raised bed gardens, cover crops, like Buckwheat, offer many other services to gardeners:
Buckwheat in flower behind summer squash. Photo courtesy of Daniel Leonard.
Covers, like Buckwheat, provide valuable weed control by shading out the competition. Even after termination (the cutting down or otherwise killing of the cover crop plants and letting them decompose back into the soil as a mulch), Buckwheat continues to keep weeds away, like pinestraw in your landscape.
Cover crops also build soil. This summer, I noticed that my raised beds didn’t “sink” as much as normal. In fact, I actually gained a little nutrient-rich organic matter! By having the Buckwheat shade the soil and then compost back into it, I mostly avoided the phenomena that causes soils high in organic matter, particularly ones exposed to the sun, to disappear over time due to breakdown by microorganisms.
Many cover crops are awesome attractors of pollinators and beneficial insects. At any given time while my Buckwheat cover was flowering, I could spot several wasp species, various bees, flies, moths, true bugs, and even a butterfly or two hovering around the tiny white flowers sipping nectar.
Covers are a lot prettier than bare soil and weeds! Where I would normally just have either exposed black compost or a healthy weed population to gaze upon, Buckwheat provided a quick bright green color blast that then became covered with non-stop white flowers. I’ll take that over bare soil any day.
Buckwheat cover before termination (left) and after (right) interplanted with Eggplant. Photo courtesy Daniel Leonard, UF/IFAS Calhoun County Extension.
Now that I’ve convinced you of Buckwheat’s raised bed cover crop merits, let’s talk technical and learn how and when to grow it. Buckwheat seed is easily found and can be bought in nearly any quantity. I bought a one-pound bag online from Johnny’s Selected Seeds for my raised beds, but you can also purchase larger sizes up to 50 lb bags if you have a large area to cover. Buckwheat seed germinates quickly as soon as nights are warmer than 50 degrees F and can be cropped continuously until frost strikes in the fall. A general seeding rate of 2 or 3 lbs/1000 square feet (enough to cover about thirty 4’x8’ raised beds, it goes a long way!) will generate a thick cover. Simply extrapolate this out to 50-80 lbs/acre for larger garden sites. I scattered seeds over the top of my beds at the above rate and covered lightly with garden soil and obtained good results. Unlike other cover crops (I’m looking at you Crimson Clover) Buckwheat is very tolerant of imperfect planting depths. If you plant a little deep, it will generally still come up. A bonus, no additional fertilizer is required to grow a Buckwheat cover in the garden, the leftover nutrients from the previous vegetable crop will normally be sufficient!
Buckwheat “mulch” after termination. Photo courtesy of Daniel Leonard, UF/IFAS Calhoun County Extension.
Past the usual cover crop benefits, the thing that makes Buckwheat stand out among its peers as a garden cover is its extremely rapid growth and short life span. From seed sowing to termination, a Buckwheat cover is only in the garden for 4-8 weeks, depending on what you want to use it for. After four weeks, you’ll have a quick, thick cover and subsequent mulch once terminated. After eight weeks or so, you’ll realize the plant’s full flowering and beneficial/pollinator insect attracting potential. This lends great flexibility as to when it can be planted. Have your winter greens quit on you but you’re not quite ready to set out tomatoes? Plant a quick Buckwheat cover! Yellow squash wilting in the heat of summer but it’s not quite time yet for the fall garden? Plant a Buckwheat cover and tend it the rest of the summer! Followed spacing guidelines and only planted three Eggplant transplants in a 4’x8’ raised bed and have lots of open space for weeds to grow until the Eggplant fills in? Plant a Buckwheat cover and terminate before it begins to compete with the Eggplant!
If a soil building, weed suppressing, beneficial insect attracting, gorgeous cover crop for those fallow garden spots sounds like something you might like, plant a little Buckwheat! For more information on Buckwheat, cover crops, or any other gardening topic, contact your local UF/IFAS County Extension Office. Happy Gardening!
Whitefly adults and eggs. Photo Credit: James Castner, University of Florida, IFAS.
Whiteflies are a pest we typically see in the fall but if you look around, you’ll notice high densities of them now. Despite their name, whiteflies are more closely related to an aphid or scale insect than a fly. They are 1/16 of an inch long (about the size of a gnat) and resemble small moths. They can be found on the undersides of host plant leaves and their behavior is easily recognizable as they scatter from the leaves when they are disturbed.
Silverleaf Whitefly. Photo by Lyle Buss, UF/IFAS
You’ll find whiteflies on a variety of plants ranging from ornamentals such as ficus, poinsettia, hibiscus, and ivy to vegetables like tomato, pepper, eggplant and okra. Some species feed on sweet potatoes, vegetables in the cabbage family, and citrus.
There are several species of whiteflies in Florida but the three main species of agricultural and horticultural concern are the silverleaf whitefly (also known as the sweet potato whitefly), citrus whitefly, and the ficus whitefly. Whiteflies have piercing-sucking mouthparts with which they feed on plants. The top side of leaves on infested plants may become pale or spotted due to whiteflies feeding on the undersides of leaves. It’s not uncommon for an infestation of whiteflies to go unnoticed until leaves turn yellow or drop unexpectedly. Some whitefly species can cause greater damage by transmitting plant viruses.
Whiteflies, along with aphids, scales and mealybugs excrete a sugary substance known as honeydew. This honeydew coats the surface of the plant where the insect feeds and facilitates the growth of a black fungus called sooty mold. Ants and wasps also feed on the honeydew secreted by these insects and may serve as an indicator that a plant is infested with whiteflies or other honeydew secreting insects.
Adult female whiteflies can lay anywhere from 200-400 eggs in her lifetime. The eggs are laid on the undersides of leaves. These eggs hatch into nymphs (also known as crawlers) after 4-12 days. From there, the crawlers will insert their mouthparts into the leaves of host plants where they will molt, pupate and then become adult whiteflies. This process takes anywhere from four weeks to six months, depending on temperature and humidity.
Whiteflies are difficult to control due to their prolific reproductive cycle. It is difficult to get rid of whiteflies once there is an infestation. As with dealing with most insects, proper plant selection, irrigation, and fertilization are critical for managing whiteflies. Removing sources of infestation such as weeds around the garden or old plant debris around the yard can help prevent whitefly populations from carrying over to the next season. Natural predators such as lady beetles, lacewings and predatory mites can help keep whitefly populations in check.
Insecticides such as insecticidal soap or horticultural oil can be used to help reduce whitefly populations. Be sure to always read the label for instructions. For more information on whiteflies, please contact your local UF/IFAS Extension Office.
In late July, Larry Kinsolving, a Jackson County Master Gardener, noticed an insect pest in the beautiful, large azalea bushes that frame the front entrance to his home in Marianna, Florida. The azalea caterpillar is found in Florida from late summer to early fall on azaleas and other plants including blueberries. If left undetected, the caterpillars can defoliate (eat up the leaves) of much of a plant. In general, caterpillars seldom kill the plants they feed on, but the stress caused by defoliation can reduce flowering or fruiting the following spring, if it becomes a serious problem. Larry shows you how easy it is to find and remove this pest from your azalea bushes. While the caterpillar appears hairy, it is harmless to humans and can be handled without concern.
Perennial milkweed, Asclepias perennis, with oleander aphids; notice the brown aphid mummies that have been parasitized. Photo credit: Mary Salinas UF/IFAS Extension.
Milkweeds are appreciated for their beauty, but often we cultivate it for the benefit of the monarch butterflies who lay their eggs only on this plant genus. Avid butterfly gardeners want the monarch caterpillars to eat up the milkweed and become beautiful butterflies. Often instead, thousands of aphids show up and compete for space on the plants. These bright yellow aphids are known as oleander aphids.
Just how do aphids build up their populations so quickly? It seems that one day you have a small number on a few plants and then a few days later, thousands are all over your milkweed. Oleander aphids have a few advantages for quickly building their populations:
All oleander aphids are female and do not need to mate to produce their young
Aphids give birth to live young who immediately start feeding on the plant
Aphids start reproducing when they are 4 to 10 days old and keep reproducing during their one-month life span
When populations get heavy or the plant starts to decline, winged individuals are produced to migrate to new areas and plants.
Parasitic wasp and aphid mummies. Photo credit: University of California.
What can or should you do to control this pest?
One option is to do nothing and let the natural enemies come in and do their job. One of the best is a very tiny wasp that you will likely never see. This parasitoid lays its eggs only inside aphids. The wasp larva feeds on the inside of the aphid and turns it into a round brown ‘mummy’ and then emerges when mature by making a round hole in the top of the aphid. Look closely with a hand lens at some of those brown aphids on your milkweed and you can see this amazing process. Another common predator I see in my own garden is the larvae of the hover fly or syrphid fly. You will have to look hard to see it, but it is usually there. Assassin bugs and lady beetles also commonly feed on aphids. The larvae of lady beetles look nothing like the adults but also are voracious predators of aphids – check out what they look like.
Lady beetle larva feeding on aphid on tobacco. Photo credit: Lenny Wells University of Georgia Bugwood.org.
If you think your situation requires some sort of intervention to control the aphids, first check carefully for monarch eggs and caterpillars, keeping in mind that some may be very small. Remove them, shoo away any beneficial insects, and spray the plant completely with an insecticidal soap product. Recipes that call for dish detergents may harm the waxy coating on the leaves and should be avoided. The solution must contact the insect to kill it. Always follow the label instructions. Soap will also kill the natural enemies if they are contacted. One exception is the developing wasp in the aphid mummies – fortunately, they are protected inside as the soap does not penetrate. Oils derived from plants or petroleum can serve the same purpose as the insecticidal soap.
Syrphid fly larva and oleander aphids. Photo credit: Lyle Buss, University of Florida.
You also can squish the aphids with your fingers and then rinse them off the plant. If you only rinse them off, the little pests can often just crawl back onto the plant.
There are systemic insecticides, like neonicotinoids, that are taken up by plant roots and kill aphids when they start feeding on the plants. However, those products also kill monarch caterpillars munching on the plant and harm adult butterflies, bees, and other pollinators feeding on the nectar. So those products are not an option. Always read the product label as many pesticides are prohibited by law from being applied to blooming plants as pollinators can be harmed.
In the end, consider tolerating some aphids and avoid insecticide use in landscape.
Remember last year’s vacation trip? You picked the perfect location, checked into the hotel and made sure to check every mattress corner for bedbugs. Bugs can hide in the strangest places. Now with COVID-19 those people insisting on still taking a vacation are flocking to Northwest Florida. While some are still utilizing hotels, the majority are pulling into the RV park or campground. They are bringing anything and everything anyone could possibly need for the week, from firewood to camp chairs. That way no one will have to go to the store. Somewhere on the vehicle or within all the stuff there may be some hitchhikers, insect stowaways. The problem is that these bugs may be staying even after the human beings head back north. Florida is notorious for invasive species. With 22 international airports and 15 international ports in the state, hundreds of foreign insects are intercepted each month. But, not all the problem creepy crawlers are coming from the south. Many have been introduced to northern states and work their way here.
One to keep an eye open for is spotted lanternfly (Lycorma delicatula). The Asian native was first detected in Pennsylvania in 2014. Since then it has spread to the east and south. While the insect can walk, jump, or fly short distances, the quickest way for the spotted lanternfly to relocate is to lay eggs on natural and man-made surfaces. Some of those egg masses may fall off and get left at the park. Next spring after the eggs hatch the nymphs will begin feeding on the sap of numerous plants, often changing species as they mature. Host plants include grape, maple, poplar, willow and many fruit tree species.
Nymphs in the early stages of development appear black with white spots and turn to bright red before becoming adults. At maturity spotted lanternflies are about 1 ½ inches wide with large colorful, spotted wings.
Photo from USDA APHIS
At rest their forewings are folded up giving the lanternfly a dull light brown appearance. But when it takes flight its beauty is revealed. The bright red hind wings and the yellow abdomen are very eye-catching. Remember, in nature bright colors are often a warning. Though spotted lanternflies are attractive, they pose a valid threat to native and food-producing plants. The adults feed by sucking sap from branches and leaves. What goes in must come out. Sugar in, sugar out. Spotted lanternflies excrete a sticky, sugar-rich fluid referred to as honeydew. Black sooty mold often develops on honeydew covered surfaces.
Spotted lanternflies are most active at night, steadily migrating up and down the trunk of trees. During the day they tend to gather together at the base of the plants under a canopy of leaves. So, you may need your lantern (or head lamp) to locate them. If you find an insect that you suspect is a spotted lanternfly, please contact your local Extension office of the Florida Department of Agriculture and Consumer Services Division of Plant Industries.
A common question for gardeners at the end of the season is if one should till the soil or use no till practices. Opinions vary regarding this question, even among Extension Agents. However old crops harbor insects, both good and bad. This phenomenon was noticed on some recently cut back tomato plants. The intention was to cut the leftover spring garden tomatoes back to encourage fall production. Instead, a host plant for mealybugs was provided.
Mealybugs on a tomato plant. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County
Mealybugs are soft-bodied insects that possess a covering of flocculent, white, waxy filaments. They are about 1/8 inch in length and usually pinkish or yellowish in color. Mealybugs have piercing-sucking mouthparts which they use to siphon fluids from the leaves, stems, and sometimes roots of many ornamental and vegetable plants. Mealybug damage produces discolored, wilted, and deformed leaves.
One very common example of an insect pest likely to claim residence in your garden’s crop residue, are squash bugs. They like to overwinter on squash, cucumber, and other cucurbit crop residue. If you choose to not till your garden and leave a portion of last seasons crop in your garden, then you should consider applying an insecticide to your spent crop at the end of the season. A product containing a pyrethrin or pyrethroid as an active ingredient would be a good broad spectrum insecticide to control any pest that may reside on plant residue. More information on pyrethrins and pyrehtroids can be found at the EPA webpage: Pyrethrins and Pyrethroids. If you choose to apply an insecticide, it is important that you follow the information on the label regarding pollinator protection. Another option is to plant a trap crop on the edge of your garden to help attract pest insects away from your desired crops. More information on trap crops can be found in the EDIS Publication: Intercropping, Pest Management and Crop Diversity.
An adult squash bug on a zucchini leaf. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County
So the answer to the till or no till question is…it depends. It is really up to the gardener. Yes, the residue from crops will add nutrients and organic matter to your soil, but it could also increase pest pressure in your garden. If you don’t plan to remove crop residue and don’t plan to till, then keep an eye out for what could be hiding in your garden.
