by Evan Anderson | May 20, 2021
A number of landowners in our region have been noticing a number of caterpillars coming down from the treetops. Sometimes appearing in vast numbers, the forest tent caterpillar has been found throughout Florida and the United States. Several years of heavy infestation occurred in Central Florida more than a decade ago, but populations are usually not high enough to cause significant damage to trees.
A forest tent caterpillar. – Photo courtesy of Shoal Sanctuary Nature Preserve.
The forest tent caterpillar is the larval stage of a somewhat nondescript brown moth. The moths lay their egg masses on twigs, and the eggs hatch in the spring. Caterpillars feed on a variety of tree species, but seem to prefer oak and gum trees. They spend anywhere from two to six weeks eating. When they are nearing maturity, they can become a problem for humans who do not appreciate the many droppings they produce, or their habit of descending from the trees to find places to spin their cocoons. They are sometimes attracted to lights or the walls of buildings, where they congregate in search of a place to pupate. They are not harmful to people, however.
A forest tent caterpillar egg mass. – Photo courtesy of Jeffrey Lotz, Division of Plant Industry
Particularly cold winters may help decrease populations of these caterpillars. Inclement weather or high temperatures may do the same in the summer, and natural predators often help to control populations when present as well. Controlling forest tent caterpillars is most often unnecessary even when there are large numbers of them. It may help to avoid parking cars under large infestations or to turn off outdoor lighting that might attract them at night. If they wander indoors, check screens and window seals to be sure there are no gaps for them to enter.
If these or other caterpillars become such a nuisance that control measures must be considered, consider using a product such as Bacillus thuringiensis, or Bt, which specifically affects caterpillars and not other beneficial insects. Keep affected trees healthy with proper fertilization and watering, and even a defoliated tree will probably recover from any damage these insects cause. For more information, see our EDIS publication on the Forest Tent Caterpillar or contact your local Extension office.
-Evan Anderson, Walton County Horticulture Agent.
by Matt Lollar | Apr 1, 2021
If you’ve been raking leaves recently, you’ve probably noticed little green worms hanging from the trees. They seem to be in abundance this year and can be found crawling on driveways, just hanging around, and maybe even feeding on oak tree leaves.
These green worms that are all over the yard are oak leafrollers (Archips semiferanus) or oak leaftiers (Croesia semipurpurana). Some people may refer to them as inchworms, however a number of different caterpillars can go by that name. Leafrollers and leaftiers range in length from 1/4″ to 1″. The adult form of these insects is a 1/2″ long moth. The oak leafroller moth is mottled tan and brown and the oak leaftier moth is yellow with brown markings.
An oak leafroller caterpillar crawling on a leaf. Photo Credit: Blair Fannin, Texas A&M University
In May, the adults of both species lay their eggs in the twigs and leaf buds of a number of tree species. The eggs don’t hatch until March of the following year. When the caterpillars emerge, they feed on the newly forming leaves and flowers of oak, hackberry, pecan and walnut trees. If they are disturbed, they will stop feeding and hang from a strand of silk. Oak leafroller caterpillars pupate in tree branches, while oak leaftier caterpillars drop to the ground and pupate in leaf litter. Adult moths emerge in one to two weeks.
A leafroller moth with wings spread. Photo Credit: U.S. National Museum
The oak leafrollers and oak leaftiers don’t really do enough damage to be considered pests, but they are a bit of a nuisance. Thankfully, birds and parasitic wasps will eat and kill the majority of the population. For in-depth information on most of the interesting insects in your yard, please visit the UF/IFAS Featured Creatures Website.
by Molly Jameson | Mar 18, 2021
Butternut squash is more resistant to squash vine borers and it has a vining growth habit, perfect for growing on a trellis. Photo by Janis Piotrowski.
Last spring, I fought the good fight against a very pesky garden pest. As the pandemic ramped up, I started working remotely from home, which I figured would at least afford me the ability to scout my patch of summer squash a bit more diligently.
I was able to successfully remove a few tiny eggs that had been deposited individually on the base of the squash’s elongating bright green stems. And, since I planted early in the season, I was able to harvest a few beautiful looking – and very delicious tasting – summer squash for the dinner table. But alas, most of my hard work succumbed to my biggest garden foe: Melittia cucurbitae. Aka, the squash vine borer.
Squash vine borer larvae can most easily navigate the stems of summer squash varieties. Photo by Molly Jameson.
This year, I am trying a new approach. Instead of marching through my garden morning and night swatting wildly at borer moths – or repeatedly coating Baccillus thuringiensis biological insecticide spray over the squash stems every week – I am switching it up. This year, it is all about Cucurbita moschata. Aka, butternut squash.
How can this cucurbit avoid the mighty squash vine borer, you ask? Well typically, after hatching, squash vine borer larvae will quickly chew into the succulent stem of a summer squash variety. These large, hollow stems then act as an open highway for the borers, and they easily work their way up. The stems of butternut squash, on the other hand, are less palatable for the larvae. Their vining habit produces stems that are harder to navigate, thicker, and tougher than summer squash stems. Although not completely resistant, they are certainly not the borers’ preferred host plant.
And thankfully, butternut squash is quite delicious. It can be roasted to accompany just about anything, including spaghetti, lasagna, salads, chilis, and stews. It can also be blended into soups or purees to be paired with herbs and spices, such as turmeric, sage, garlic, and thyme. Or, it can be used as a filling in pies or frittatas, brushed with brown butter to sweeten up the plate as a delicious side dish, or be paired with goat cheese and crackers to be served as an appetizer.
Sometimes, simply omitting your toughest garden foe’s favorite host plant is the best path to both garden and dinner plate success.
by Daniel J. Leonard | Oct 14, 2020
Article by Jessica Griesheimer & Dr. Xavier Martini, UF/IFAS North Florida Research and Education Center, Quincy
Dioscorea bulbifera, commonly known as the air potato is an invasive species plaguing the southeastern United States. The air potato is a vine plant that grows upward by clinging to other native plants and trees. It propagates with underground tubers and aerial bulbils which fall to the ground and grow a new plant. The aerial bulbils can be spread by moving the plant, causing the bulbils to drop to the ground and tubers can be spread by moving soil where an air potato plant grew prior. The air potato is commonly confused with and mistaken as being Dioscorea alata, the winged yam which is also highly invasive. The plants look very similar at first glance but have subtle differences. Both plants exhibit a “heart”-shaped leaf connected to vines. The vines of the winged yam have easily felt ridges, while the air potato vines are smooth. They also differ in their aerial bulbil shapes, the winged yam has a long, cylinder-shaped bulbil while the air potato aerial bulbil has a rounded, “potato” shape (Fig. 1).
In its native range of Asia and Africa, the air potato has a local biocontrol agent, Lilioceris cheni commonly known as the Chinese air potato beetle (Fig. 2). As an adult, this beetle feeds on older leaves and deposits eggs on younger leaves for the larvae to later feed on. Once the larvae have grown and fed, they drop the ground where they pupate to later emerge as adults, continuing the cycle. The Chinese air potato beetle will not feed on the winged yam, as it is not its host plant.Current methods of air potato plant, bulbil, and tuber removal can be expensive and hard to maintain. The plant is typically sprayed with herbicide or is pulled from the ground, the aerial bulbils are picked from the plant before they drop, and the underground tubers are dug up. The herbicides can disrupt native vegetation, allowing for the air potato to spread further should it survive. If the underground tuber or aerial bulbils are not completely removed, the plant will grow back.
The Chinese air potato beetle is currently being evaluated as a potential integrated pest management (IPM) organism to help mitigate the invasive air potato. The beetle feeds and reproduces solely on the air potato plant, making it a great IPM organism choice. During 2019, we studied the Chinese air potato beetle and its ability to find the air potato plant. It was found the beetles may be using olfactory cues to find the host plant. Further research is conducted at the NFREC to increase natural aggregation of the beetles on air potato to improve biological control of the weed.
Chinese Air Potato Leaf Beetle.
If you have the air potato plant, or suspect you have the air potato plant, contact your local UF/IFAS Extension Agents for help!
by Matt Lollar | Aug 24, 2020
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.
