by Ray Bodrey | Apr 8, 2020
Spring has arrived and so have the insects. Caterpillars are crawling around and one possesses a unique appetite.
Neodiprion spp. is the most common defoliating insect group affecting pine trees. In all, there are 35 species that are native to the U.S. and Canada. The redheaded pine sawfly, Neodiprion lecontei, is the primary species found in the Florida Panhandle.
Adult sawflies can be as large as 1/3 of an inch in length. The female can be two-thirds larger than the male and are mostly black with a reddish-brown head, with occasional white coloration on the sides of the abdomen.
Mature larvae of the redheaded pine sawfly. Credit: Patty Dunlap, Gulf County Master Gardener.
The ovipositor, the tube-like organ used for laying eggs, is saw-like, hence the common name. During the fall, females make slits in pine needles and deposit individual eggs, up to 120 eggs at a time. The eggs are shiny, translucent and white-hued. Mature larvae (caterpillars), as seen in the accompanying photo, are yellow-green, emerge in the spring and feast on pine needles. After weeks of feeding on needles, the mature larvae drop to the ground. The cocoon, a reddish-brown, thin walled cylinder, is spun in the upper layer of the soil horizon or in the leaf litter; this is called the pupae stage. The pupae overwinter, and adults emerge from the cocoon in the spring of the following year.
Mature larvae are attracted to young, open growing pine stands. Pine is the preferred host, but cedar and fir, where native, are secondary food sources. Neodiprion lecontei is an important defoliator of commercially grown pine, as the preferred feeding conditions for sawfly larvae are enhanced in monocultures of shortleaf, loblolly, and slash pine, all of which are commonly cultivated in the southern United States. Defoliation can kill or slow the growth of pine trees as well as predispose trees to other insects or disease.
Are there control methods? Yes, biological control is a major factor, as natural enemies are numerous. Disease, viruses and predators help regulate population control. For small scale control, physically removing eggs or larvae is key. Again, most infestations occur on younger tree plantings, so they’ll be in reach. Be sure to scout young pines for signs of infestation. Horticultural soaps and oils are effective chemical controls, if needed.
For more information, contact your local county extension office.
Supporting information for this article can be found in the UF/IFAS Extension EDIS publication, “Redheaded Pine Sawfly Neodiprion lecontei” by Sara DeBerry: https://edis.ifas.ufl.edu/pdffiles/IN/IN88200.pdf
UF/IFAS Extension is an Equal Opportunity Institution.
by Beth Bolles | Jan 13, 2020
The Southern magnolia (Magnolia grandiflora) has always been a favorite tree since it is associated with my childhood home in Tennessee. I always enjoyed the evergreen leaves and large white flowers. In my parent’s yard, the southern magnolia had branches to the ground that allowed the large leaves to stay hidden in a self- mulching area. I never recall the tree begin called messy because of this growth style.
A Southern Magnolia in a Tennessee winter. Photo by Beth Bolles, UF IFAS Extension Escambia County
Many landscapes today may not have room for a southern magnolia that can grow an average of 60 feet in height with an average spread of 25 feet. Because it’ qualities are still desirable, nursery professionals have developed southern magnolia cultivars that are very popular as landscape features due to different growth habits, leaf sizes, and hardiness to our area’s weather. Although the cultivars will be different from the old favorite southern magnolia in growth form and size, homeowners should still do their homework to make sure trees are located in spots for plants to reach proper height and width growth. Also, like I mentioned for my parent’s tree, many of the new cultivars look best if the lower limbs are not removed.
If you or your landscaper are considering a Southern magnolia cultivar, here are a few details about some you may find available.
‘Little Gem’ dwarf southern magnolia has been the go-to magnolia for new landscapes. The dark green leaves are smaller and the plant will be more compact than the traditional southern magnolia. It is often misplaced in landscapes because of these features. Trees still grow about 25 feet high with a spread of 15 feet.
‘Bracken’s Brown Beauty’ is a very attractive magnolia when given room to grow. Foliage is very attractive with shiny green above and brown on the undersides. This plant can grow 40 to 50 feet in height with a spread averaging 20 feet. Plan not to prune lower limbs to maintain a beautiful form.
Bracken’s Brown Beauty as an accent tree in a lawn area. Photo by Beth Bolles, UF IFAS Extension Escambia County
Bracken’s Brown Beauty flower. Photo by Beth Bolles, UF IFAS Extension Escambia County
‘Southern Charm’ magnolia, registered as Teddy Bear is also a compact plant. It grows upright to about 20 feet with a spread about 15. You still have the beautiful green and brown leaf color along with 6 inch wide flowers.
by Les Harrison | Oct 8, 2019
Mushrooms growing on the roots of trees is a bad sign. This indicates the roots are decaying and the tree will soon become (or already is) unsafe.
On the doorstep of autumn, the weather is making its seasonal change in north Florida. It has been a bit cooler in the mornings, but the afternoons still qualify as hot.
What the winds of October will blow in is still anyone’s guess, but last year it was Hurricane Michael. Unfortunately, the storm’s brunt came in causing severe damage to homes, businesses and marine enterprises in several counties.
October is typically the month when tropical cyclone activity lessens in the Atlantic, but accelerates in the Gulf of Mexico. While beastly events like Hurricane Michael are relatively rare, it only takes one such incident to necessitate recovery efforts and expenses for years, if not decades.
The prudent course of action is to prepare for the worst while hoping for the best. One area of preparation where residents can have a distinctly positive effect is readying their trees for the potential assault.
Damage from falling trees and limbs is a major cause of destruction during tropical storms and hurricanes. Removing potential problems before the storm can minimize harm to structures and injury to residents.
Trees in decline are especially hazardous. Their compromised health makes them subject to uprooting and breakage with far less force than would effect a healthy tree.
There are several key indicators for tree health. Any single factor or a combination can mark a tree as unsafe.
Mushrooms growing on or very close to trees is a sign the tree is dying. The fungus is not the cause of decline, but only an indicator of the eventual fate.
Spores of the mushrooms are scattered by wind and water. Landing randomly, most arrive on a site devoid of necessary resources and never sprout.
Those lucky spores which land on decaying wood will likely sprout and take nourishment from the rotting plant material. Their roots accelerate the decomposition of the wood by consuming the available material and exposing more of the tree to colonization by mushrooms.
Sites on trees and plants infected with mushrooms typically are break points when pressure or stress is applied. If the mushrooms are located at the base of the tree, it is likely to be detached from its roots and topple over in heavy winds.
Another indicator of tree health is its crown, or the uppermost branches and leaves. Healthy trees and plants have full, green, and growing crowns.
When the crown turns brown and the leaves drop off, it is a good indicator the tree’s days are numbered. The causes may be disease, lightning, or mechanical interruption of the root system.
Lastly, bifurcation or trunk forking is a sign of a structurally weak tree. This condition may display itself when the tree emerges from the ground or at an elevated place on the mature tree trunk.
When the wind direction stresses the tree with enough force at its angle of vulnerability, a collapse results. Unfortunately, there is no simple way to tell how much wind is required to produce the failure.
Any tree with these problems should be evaluated by a certified arborist and removed when necessary. It may result in an expense now, but can save on expenses, inconvenience and aggravation if a storm randomly removes the tree in the future.
The question must be asked: Is it worth the gamble to wait on the winds of October?
To learn more about the tree health in north Florida, read the UF/IFAS publication HOW TREES GROW IN AN URBAN ENVIRONMENT.
by Sheila Dunning | Aug 7, 2019
Damage caused by azalea lace bug, Stephanitis pyrioides (Scott), feeding. Photograph by James. L. Castner, University of Florida. Severely damaged leaves become heavily discolored and eventually dry or fall off. Symptoms may sometimes be confused with mite injury, but the presence of black varnish-like excrement, frequently with cast skins attached, suggest lace bug damage (Johnson and Lyon 1991).
You may be noticing the color disappearing from your azaleas right now. Do your azaleas look bleached out from a piercing-sucking insect. The culprit is probably azalea lace bug, Stephanitis pyrioides. This pest overwinters in eggs on the underside of infested leaves. Eggs hatch in late March and early April. The insect then passes through five nymphal instars before becoming an adult. It takes approximately one month for the insect to complete development from egg to adult and there are at least four generations per year. Valuable plants that are susceptible to lace bug damage should be inspected in the early spring for the presence of overwintering lace bug adults, eggs and newly-hatched nymphs. Inspect these plants every two weeks during the growing season for developing lace bug infestations.
Both adults and nymphs have piercing-sucking mouthparts and remove sap as they feed from the underside of the leaf. Lace bug damage to foliage detracts greatly from the plant’s beauty, reduces the plant’s ability to produce food, decreases plant vigor and causes the plant to be more susceptible to damage by other insects, diseases or unfavorable weather conditions. The azalea can become almost silver or bleached in appearance from the feeding lace bug damage.
However, lace bugs often go undetected until the infested plants show severe damage sometime into the summer. By then several generations of lace bugs have been weakening the plant. Inspecting early in the spring and simply washing them off the underside of the leaves can help to avoid damage later and the need for pesticides.
Adult lace bugs are flattened and rectangular in shape measuring 1/8 to 1/4 inch long. The area behind the head and the wing covers form a broadened, lace-like body covering. The wings are light amber to transparent in color. Lace bugs leave behind spiny black spots of frass (excrement).
Adult azalea lace bug, Stephanitis pyrioides (Scott), and excrement. Photograph by James. L. Castner, University of Florida.
Lace bug nymphs are flat and oval in shape with spines projecting from their bodies in all directions. A lace bug nymph goes through five growth stages (instars) before becoming an adult. At each stage the nymph sheds its skin (molts) and these old skins often remain attached to the lower surface of infested leaves.
Nymphs of the azalea lace bug, Stephanitis pyrioides (Scott), with several cast skins and excrement. Photograph by James. L. Castner, University of Florida.
Azalea lace bug eggs are football-shaped and are transparent to cream colored. Lace bug eggs are found on the lower leaf surface, usually alongside or inserted into a leaf vein. Adult females secrete a varnish-like substance over the eggs that hardens into a scab-like protective covering.
Other plant species, such as lantana and sycamore, may have similar symptoms. But, realize that lace bugs are host specific. They feed on their favorite plant and won’t go to another plant species. However, the life cycle is similar. Be sure to clean up all the damaged leaves. That’s where the eggs will remain for the winter. Start next spring egg-free.
For more information go to: http://entomology.ifas.ufl.edu/creatures/orn/shrubs/azalea_lace_bug.htm
by Logan Boatwright | May 27, 2019
Everyone likes their privacy. Usually, a large eight-foot privacy fence is built for that reason. That option tends to be expensive. What is a different approach for a similar result? A natural wall!
One advantage of having a natural wall is that a homeowner has options when choosing plants. When it comes to choosing plants for a natural wall, the first thing to decide is if a wall needs to be year round or seasonal. Size would be the next factor to determine.
Japanese Cedar (Cryptomeria japonica) has the capability of growing 40 to 60 feet in height and 15 to 20 feet in width. There are some smaller varieties to pick from, but where is the fun in having a small wall?
Another plant option that would require pruning, but make an excellent natural wall is Japanese Yew (Podocarpus macrophyllus). This specimen will grow 30 to 40 feet tall and 20 to 25 feet in width if left unpruned, however, it is a slow grower. Yaupon Holly (Ilex vomitoria) comes in several selections of various sizes so the height range is 3 to 20 feet. The width range is 5 to 15 feet.
The Emerald Green Arborvitae is a fast grower that would be ideal for the homeowner who does not want a tall wall. It keeps a tight pyramid shape that will reach heights up 12 to 14 feet and needs 4 to 6 feet of space. Green Giant Arborvitae or Thuja Giant (Thuja standishii x plicata ‘Gre) is an excellent tree to pick for a natural wall. It has the capability to reach 50 to 60 feet in height and spreads out 12 to 20 feet at maturity. This arborvitae is considered to be a fast grower since it can increase more than 24” per year.
The larger selections of Loropetalum are other shrubs that homeowners have used to establish their privacy wall. One can expect a height up to 15 feet if left unpruned and pinkish to purple strap-like flowers, which makes for a great wall height.
‘Yoshino’ Japanese cryptomeria
Photo by Karen Russ, ©HGIC, Clemson Extension
A yaupon holly cultivar (Ilex vomitoria ‘Roundleaf’). John Ruter, University of Georgia, Bugwood.org Creative commons license.
Thuja plicata: Giant Arborvitae. Credit: Ed Gilman, UF/IFAS
Podocarpus macrophyllus or Japanese Yew. Credit: UF/IFAS
These plants are some of the selections homeowners may choose to start their natural walls. Given time, these shrubs will develop into a dense screen for the interruption of unwanted light or noise. To learn more about the aforementioned plant material, contact your local UF / IFAS extension agent.
