Homeowner accounts of white fluffy woolly masses on woody ornamentals, oak trees and Muhly grass have been on the rise. The good news is they are native insects that need a nursery for their young and will cause little harm to the host plant. The bad news is scientists know very little about the complete live cycle and role in the environment of these insects.
Within the cottony mass there are citrus flatid planthoppers, woolly oak aphids, or Muhly mealybugs. The adults have laid eggs or birthed their young on the leaves. The young nymphs have excreted large amounts of the woolly wax to protect them from predators and weather while they grow larger. Food from the plants is needed to grow, so these piercing-sucking insects are removing sugars from the host plant. But, typically it is not enough to significantly change the plant’s appearance, so most people are not alarmed until they notice “all the white stuff”.
Adult citrus flatid planthopper, Metcalfa pruinosa
(Say). Credits: Photograph by: Lyle J. Buss, University of Florida
The only one that moves quickly are the citrus flatid planthoppers. When a person reaches for the flocked branch, something small moves and seems to jump at you. Most likely the jumping direction is away from you, but it still may be startling. They are planthoppers (Metcalfa pruinosa), an insect in the order Hemiptera. As the name implies, they occur on citrus but can also be found on many woody ornamentals and other fruit trees. The adult planthopper wing arrangement is tent-like, meaning that the forewings are held over the insect abdomen in a tent configuration.
Stegophylla brevirostris Quednau colony on oak. Photograph by Susan E. Halbert
Woolly oak aphids are conspicuous pests on oak (Quercus spp.), because they are covered with large amounts of flocculent wax. Two genera of woolly oak aphids occur in Florida. One species, Stegophylla brevirostris Quednau, is common, and the other, Diphyllaphis microtrema Quednau, is rare. Florida woolly oak aphids are recognized easily by the large quantities of woolly wax that they secrete. Beneath the wax, aphid bodies are pale. Young nymphs are typically pale green, and they tend to be more mobile than adults. The majority of reports of woolly oak aphids indicate a preference for live oak (Quercus virginiana Mill.) as the host. These aphids are live-bearing females. It is not known how these aphids disperse, but possibly they are picked up and carried by birds and larger flying insects because of the sticky wax that surrounds the bodies of the aphids.
Muhly grass infested with mealybug. Photo: Beth Bolles
Muhly grass (Muhlenbergia capillaris) is a generally pest free plant in its native habitat, however, the native mealybug, Stemmatomerinx acircula, has made an appearance on plants in various landscapes. Insects feed on the leaves and are grey with white wax that may have some filaments. You may also see long ovisacs on the leaves which contain eggs and crawlers. With close inspection, you will notice they have legs and can move about.
So “what do you do?’ If the plant doesn’t appear to be suffering, let nature take its course. “This to will pass.” If someone demands perfection, use insecticidal soap to reduce the population. The soft-bodied creatures will dry up before they can become adults. To read more about these odd creatures of nature go to: https://entnemdept.ufl.edu/creatures/
Many future problems can be avoided by paying attention to tree selection, planting and maintenance in Florida’s high wind climate. We may think of tropical storms causing tree damage but our typical summer thunderstorms can produce winds in excess of 50 miles per hour with downbursts reaching over 100 mph.
There is no way to protect trees from all storm damage. Trees are not adapted to worst-case storms, such as Hurricanes Michael or Ian, only to our average wind climate.
It’s wise to take time to select and correctly plant the right trees for North Florida.
Past hurricanes have taught us that large growing trees planted too close to curbs, sidewalks or buildings blow over easily because they don’t have adequate room to develop a sound root system. It’s best to either plant these trees farther away, plant trees that may stay small, or increase the size of space allocated for tree root growth.
Research and storms have taught us that tree roots need large soil spaces for strong, stable growth. The more rooting space trees have, the less likely they are to fail. Strong root growth is essential for tree stability and health. Large maturing trees need at least 30 feet by 30 feet (900 ft. sq.) of rooting space. Many construction practices such as paving over roots, raising and lowering soil grade, and soil compaction from equipment result in root injury for existing trees, making them less durable and less stable.
Magnolia Tree in the Landscape. Photo courtesy Stephen Greer
Studies have also shown that trees growing in groups better survive high winds compared to individual trees. A group was defined as five or more trees growing within ten feet of another tree, but not in a row.
A short list of large maturing, storm resistant trees to consider include live oak, sand live oak, bald cypress, pond cypress, black gum and magnolia.
Do some homework and take a look at tree species that have done well in your area. If you don’t want or need a large tree in your yard, there are many small and medium sized wind-resistant trees from which to choose, like Crape Myrtle and Vitex. Many palms are wind resistant too, particularly the cabbage palm.
Having success with trees in the landscape involves starting with healthy, well-developed trees. Plant the right tree in the right place. Follow good planting procedures, including not planting trees too deep and providing adequate root space to allow for strong, healthy root growth. Practice correct maintenance techniques, which includes learning how to prune to produce a structurally sound tree. Finally, consider if it is time to be proactive and have large over-mature, declining trees removed and replaced before the next storm.
Do any of the leaves change color down here in the fall? The most common answer is that there is none here in the land of evergreens. The prevalence of oaks (Quercus spp.) and pines (Pinus spp.) see to that. There is hope. Deciduous trees put on a show as the need for photosynthesis reduces. Chlorophyll production stops replaced with anthocyanins and carotenoids. As they take over, the beautiful display we all love begins. Several tree species thrive in the panhandle and have great autumn foliage. Once you know which, you’ll see a color pallet that would make DaVinci himself drool.
Tree for all seasons
Sweet gum (Liquidambar styraciflua) is a larger tree growing upwards of 75 feet tall with a 50 foot spread. The canopy has an early conical shape which evolves into an oval as the tree ages. This tree is excellent for local parks and to provide shade in your front yard. Red tinged flowers produced in spring combined with multi-shaded leaves provide interest throughout the year. However, autumn this tree comes into its own. As the days shorten and cool these leaves begin their journey to the ground by taking on shades of yellow, orange, red, or burgundy.
IFAS photograph Heather Kalaman
Panhandle Delight
A unique tree growing primarily in the Panhandle, the Florida maple (Acer floridanum) puts on an excellent autumn show. At that time of year, the leaves will change to a muted yellow or orange color. Reaching 60 feet high and 30 wide this oval canopied tree is ideal for shade or along streets. Fall is the only time you will see color changes from this tree, but in summer you’ll be treated to that classic maple leaf shape.
IFAS Photograph
An Oddity of a Tree
The bald cypress (Taxodium distichum) is a tree rife with oddity. Growing at times as high as 80 feet with a roughly 35 foot spread these trees excel in your lawn. Be wary as when grown in wet environments they develop “knees” thought to help aerate roots in standing water. Ball shaped cones are the primary reproductive organs of this tree. For the purposes of this article, we’ll focus on the color changing needles. When winter is nigh, they change from pale green to an eye catching yellow or rusty copper. One of the few deciduous conifers, the needles will fall off revealing peeled bark for winter interest.
IFAS Photograph Kathy Warner
To Sum it Up
These are but a few of the trees in north Florida known to change color in the autumn. The list is not overly exhaustive, but there are several in this category. For more information on landscape trees, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
There are numerous insects and insect relatives that can produce webbing, and webbing can be a sign that something unwanted is near. Arachnophobes might grow uneasy at the sight of a spiderweb, and gardeners might frown to see the tiny filaments that spider mites spin. Tree lovers might assume that webs on a tree are a sign that caterpillars such as the eastern tent caterpillar have taken up residence. But what about webs on a tree trunk?
Bark louse webbing. Photo courtesy of Evan Anderson.
If you come across a tree trunk coated in silk, chances are you’re looking at the work of a bark louse. Also known as psocids or tree cattle, these little insects eat all the stuff that sticks to a tree’s bark. Lichen, moss, algae, and dead bark can all end up as meals for a hungry bark louse. The good news is that while lichens don’t hurt trees, neither do bark lice!
Bark lice spin their webbing as protection from predators. They often produce large quantities of webbing, because there are often large quantities of bark lice present. The name ‘tree cattle’ comes from the fact that they form these large colonies, and move in a manner similar to cattle in groups. While swirling swarms of creepy-crawlies rarely make people feel at ease, don’t worry about these. Acting as a sort of clean-up crew, they will do their work, grow and mature, and move elsewhere by themselves.
There are often several generations of bark lice each year in Florida, so they may reoccur. No control is needed for these insects, though if leftover webbing is considered aesthetically unpleasing it can be removed by spraying with a sharp jet of water. For more information about bark lice, see our EDIS publication at https://edis.ifas.ufl.edu/publication/IN553.
Bark louse nymph. Photo courtesy of Evan Anderson.
Are you a homeowner in Florida? Do you have citrus on your property? Consider helping the University of Florida/IFAS Extension by taking a survey!
This survey is part of a research project carried out by the UF/IFAS to gather information on citrus pests in residential settings in Florida. This survey is designated for Florida residentswho have citrus on their property that are not intended for commercial use. The outcomes of this survey will serve to develop appropriate control methods against critical citrus pests for dooryard citrus. We kindly ask that you complete all questions on this survey which will take approximately 20 minutes.
There are many considerations to make when landscaping with small trees (under 20 feet) in the landscape that are not suitable for large trees. Some of the trees discussed can at times be considered large shrubs depending on definitions and opinions. For the purpose of this article, if it reaches 15 to 20 feet consider it a tree.
Choosing small trees for the right setting involves a number of reasons that could include the need for more privacy from other homes, use as a sound barrier from busy roads, hiding your utility area of the landscape or something unattractive nearby and making sure power lines are not obstructed. Other considerations might include soil types, drainage and holding capacity of the soils, irrigation needs, rate of plant growth and maturity height at 20 feet. Below are a few to consider for the Panhandle of Florida.
Little Gem Magnolia (Magnolia grandiflora ‘Little Gem’) and Teddy Bear Magnolia (M. grandiflora ‘Teddy Bear’) are strong hardy plants once established (within the first 6 months to a year). Both are evergreen with dark green foliage. The ‘Little Gem’ will grow to 20 feet tall by 15 to 18 feet wide. As it matures it tends to become more open and less dense which adds a nice character to show parts of the lower limbs. The ‘Teddy Bear’ will grow to 18 to 20 feet tall but at an even slower rate of maturity to 12 to 15 feet wide while maintaining its density of foliage from bottom to top. It may take a little work to locate the ‘Teddy Bear’ Magnolia.
Photo courtesy: Stephen Greer Teddy Bear Magnolia (Small compact grower)
Several hollies to consider would include the Cassine Holly ‘Tensaw’ (Ilex cassine ‘Tensaw’) and American Holly (Ilex opaca). Both are evergreen and produce red berries during the fall that are bird favorites. They have similar heights of 15 to 20 feet and widths of 10 to 12 feet. Pruning can assist in shaping and slowing these measurements, but keep in mind this will change the look of the tree and create a more formal plant presentation.
Photo courtesy: Stephen Greer Cassine Holly ‘Tensaw’
The Fringe Tree (Chionanthus virginica) has been a popular tree southeast U.S. for many years. It brings a bright spot to the landscape with white flower panicles that cover the tree in mid to late spring depending on location. For a full color effect, plant it with an evergreen hedge behind it. This oval deciduous tree will grow to 12 to 20 by 10 to 15 wide. The dark blue fruit appears in the fall and serves as good bird food source. This fruit is usually hidden behind the foliage. There might even be a nice yellow leaf change in the fall if temperatures and weather allow.
