Mole Crickets

Mole Crickets

A mole cricket has a face only a mother could love. They are so strange looking, in fact, that in the past week I’ve had two people ask me what they were. They have large, round, helmet-like heads, undersized eyes, and massive front claws used for digging. Unlike your garden-variety crickets, which really don’t cause any major damage to home landscapes, the mole cricket is quite the turfgrass menace. Instead of hopping about aboveground, they tunnel beneath the lawn and feast on the roots and leaves of grass, often destroying entire yards. They are also vegetable pests, going after tomatoes, cabbage, and peppers.

A young mole cricket. Its round head and large front claws distinguish it from other cricket species. Photo credit: Lucy Adams Stevenson
A) Horizontal and B) vertical view of a generalized tawny mole cricket burrow showing
1) horn, 2) 1st constriction, 3) bulb, 4) 2nd constriction, 5) turn-around,
6) surface tunnel, and 7) deep tunnel. Figure 1 from Nickerson et al. 1979. Ann. Entomol. Soc. Am. 72(3):438-440.

Mole crickets spend most of their time below ground and form burrows for hiding, laying eggs, and traversing through their territory. In mating season, males create a monotone song that averages 88 decibels—as loud as a motorcycle! The call comes from their burrows, which have funnel-like openings that expand at the surface, creating amplification comparable to a horn.

Beneficial larra wasp parasitizing a tawny mole cricket. Photo credit: UF IFAS

The tawny mole cricket (Neoscapteriscus vicinus) is the most common to our area and is an invasive species from South America. UF IFAS has had a specific research program related to mole cricket management since the late 1970’s. One successful outcome of this program has been the introduction of a biological control species, the larra wasp (Larra bicolor). The wasp manages mole cricket populations by stinging and temporarily paralyzing crickets. A female will then deposit an egg into the mole cricket’s body. The cricket recovers and goes about its daily routine until the egg hatches, at which point the larval wasp feeds on and eventually kills the mole cricket. Along with the wasp and release of flies and a nematode that also manage mole crickets, the biocontrol methods introduced between the 1980’s and 2004 have resulted in a 95% reduction in mole cricket populations in north Florida.

If you are seeing mole crickets, you can attract larra wasps to your property by planting shrubby false buttonweed or partridge pea plants, which the wasps feed on. If you have serious damage from mole crickets, check out this thorough Mole Cricket Integrated Pest Management Guide, or contact the horticulture agent at your local county extension office to get a site-specific recommendation for management.

Selecting Wind-Resistant Trees for Hurricane Season

Selecting Wind-Resistant Trees for Hurricane Season

The Pensacola area has had its fair share of rough weather lately. While the recent storms were not hurricanes, the rainfall totals rivaled many tropical storms, and the lighting and wind were disastrous. A tornado caused significant damage, including a tragic death, with more tumultuous weather in the forecast. Our rainy hurricane season has just begun, so it is worth talking about tree selection, management, and preparing for storms.

After the busy 1992, 1995, 1998, and 2004-05 hurricane seasons, several University of Florida researchers undertook an exhaustive on-the-ground project to look at tree damage statewide. Their goal was to determine which species survived high winds, and which trees were the most vulnerable during storms. Their findings were consistent, and have held up over the past few decades. A full description of the project can be found online, along with several publications that go over proper pruning and maintenance of trees, both before a storm and after recovery.

Live oaks have dense wood and are extremely wind-resistant species. Photo credit: Carrie Stevenson, UF IFAS Extension

For the “coastal plain” of north Florida, the most wind-resistant species are: live and sand live oaks (Quercus virginiana/Q. geminata), American holly (Ilex opaca), Sabal palm (Sabal palmetto), Southern magnolia (Magnolia grandiflora), bald cypress (Taxodium distichum), Florida scrub hickory (Carya floridana), dogwood (Cornus florida), sweet gum (Liquidambar styraciflua), and crape myrtle (Lagerstroemia indica). The live oaks and sweet gums do have a tendency to lose branches, so it is important to undertake proper pruning in the off season to trim up potential problem limbs.

This chart developed by UF researchers denotes the percentage of trees surviving Hurricane Ivan, by species.
Courtesy M. Duryea and E. Kampf

Live oaks, and sand live oaks (which live on coastal sand dunes) are slow-growing trees with extraordinarily dense wood. This protects them in hurricane-force winds. Part of the working theory on why bald cypress, holly, and magnolia do well in storms is their pyramidal shape, which seems to allow wind to whip circularly around the trees and avoid damage. Sabal palms are botanically considered part of the grass category and not trees, so their single, flexible trunk allows them to handle the onslaught of wind. Sweetgums are particularly hardy in tornadoes, due to their sturdy root system and shorter, “stout” branches. Smaller understory trees like crape myrtle and dogwood are likely dodging the strongest winds, but also have strong branch structures and dense wood. These two species, along with sand live oak, also lost an average of more than 80% of their leaves. This defoliation is an adaptation to heavy winds, with trees that lost leaves performing better overall than species that held onto their leaves but toppled at the trunk.

The least wind resistant species, according to the studies, included: sand pine (Pinus clausa), loblolly pine (Pinus taeda), and spruce pines (Pinus glabra)laurel and water oaks (Quercus laurifolia/Q. nigra), Southern red oak (Quercus falcata), Southern red cedar  (Juniperus silicicola), Carolina laurelcherry (Prunus caroliniana), black cherry (Prunus serotina), Loquat (Eriobotrya japonica), pecan (Carya illinoensis), sycamore (Platanus occidentalis), tulip poplar (Liriodendron tulipifera), Bradford pear (Pyrus calleryana), and red maple (Acer rubrum). A couple of pine species—slash and longleaf—performed in the medium range. In my experience post-hurricane, many of these trees that survived were stressed and ended up with pine bark beetle infestations. Water and laurel oak are common trees in Florida home landscapes, but typically have much shorter lifespans than live oaks. They are faster growing but have weaker wood, and are vulnerable to storms.

Significant damage to a home after a tornado struck Pensacola in 2016. Photo credit: Carrie Stevenson, UF IFAS Extension

Another list of tree survivability was developed for residents in tropical and subtropical regions of the state. If you have friends or family in south-central Florida, be sure to share this information with them.

Besides planting wind-resistant species, the research team shared other observations related to tree planting and arrangement, too. Single trees are more vulnerable than trees planted in clusters, as they protect each other from incoming winds. Older trees, and those with preexisting damage, are more likely to fall. Trees with plenty of space around their roots do better—if a tree is surrounded on two or more sides with buildings or other hard surfaces, they cannot spread adequately. Detailed information on identifying damaged or poorly structured trees, along with maintenance and pruning tips, can be found in the “Urban Forest Hurricane Recovery Program” series of articles written by the UF tree specialists involved in the studies. The publications include good diagrams and photos of specific examples.

Sandhill Milkweed – Attracting Butterflies in the Dunes

Sandhill Milkweed – Attracting Butterflies in the Dunes

Like finding buried treasure on a desert island, walking up on a mound of sandhill milkweed (Asclepias humistrata) may elicit cries of excitement from someone who understands what they’re seeing. And not unlike searching for pirate booty, there’s a bit of danger involved, too—milkweed is highly toxic.

The eye-catching pink coloration of the leaves, stems, and complex flowers make this variety of milkweed stand out among the dunes. Photo credit: Carrie Stevenson, UF IFAS Extension

Last month in the dunes of Perdido Key, our Master Naturalist class found robust clusters of eye-catching, pink-tinged leaves, blooms, and buds of sandhill milkweed. Also known as pinewoods milkweed, this variety thrives in dry, sandy soils. It is native to the southeast, found typically in the wilds of Alabama, Mississippi, Louisiana, Georgia, Florida, South Carolina, and North Carolina. Its genus name, “Asclepias” refers to the Greek god of healing—indigenous people have used the plant for medicinal purposes (dysentery treatment and wart removal, in particular) for centuries. The species name humistrata means “spreading,” which describes the growth habit of the plant. Milkweed is highly toxic, so we do not recommend trying any medicinal uses at home! The “milk” part of the common name refers to its sap, which is a thick, sticky, white substance containing that toxic chemical.

The seedpods of sandhill milkweed are large and full of seeds with wispy fibers that allow them to float through the air for dispersal. Photo credit: Gabriel Campbell, UF/IFAS

As the only food source for the monarch caterpillar, healthy milkweed plants are crucial for maintaining populations of the famous monarch butterfly.  The plant itself is rather complex and beautiful. Its five-petaled blooms grow in tight clusters, on stalks sticking several inches off the ground. The leaves are broad and a deep forest green, edged in the pale maroon/pink of the stems and flowers. The seedpods of milkweed are quite large (3-6” long), resembling pea pods and full of seeds. Each seed has a wispy white fiber attached, which helps it disperse in the wind like a dandelion. The fibers have been used for years as stuffing for pillows and mattresses, and were used for life jackets during World War 2.

Numerous monarch caterpillars feed on a sandhill milkweed plant. Photo credit: Carrie Stevenson, UF IFAS Extension

The first cluster of milkweed we found was host to multiple monarch caterpillars, recognizable by their greenish-yellow, white, and black stripes. By the time you see caterpillars, the milkweed is already working its magic, transferring its toxins to the insects but causing them no harm. Monarchs have evolved the capability to digest and metabolize this poison, which would induce heart attacks in nearly any vertebrate animal.  Adult monarchs use several nectar sources, including milkweed flowers, and females lay their eggs on the plant so that their young can begin eating once hatched.

In the animal kingdom, red and orange are signs of danger.  The bright orange coloration of an adult monarch butterfly serves as a warning to would-be predators to exhibit caution, as the toxins from their food sources stay within the butterfly’s body. The copycat viceroy, soldier, queen, and Gulf fritillary butterflies benefit from this trait by using mimicry in their own orange coloration to ward off predators.

Blueberry Bees

Blueberry Bees

It’s a bit early still for blueberries in north Florida, but they are definitely on the horizon. We have a handful of bushes at home and the office, and I’ve noticed the white blooms are gone and berries are forming as we speak. Many of us, myself included, look forward to the late-spring harvest of blueberries, taking our children out to u-pick operations and hunting down family recipes for blueberry-filled desserts.

Ripe Florida blueberries. Photo credit: Tyler Jones, IFAS Photography

Often, when people think of fruit growing in the wild, their minds naturally go to tropical rainforests, with visions of bananas, mangoes, and drooping fruit-laden trees. But blueberries are a home-grown local Panhandle fruit. A walk through any self-respecting northwest Florida wooded area is bound to have blueberry bushes growing wild.  Vaccinium species thrive in more acidic soil, (between 4-6 on pH scale), which we have in abundance here.  In northwest Florida, we have lots of pines and oaks dropping needles and leaves, seasoning our soil to a 6 or lower on the pH scale. Central and south Florida soils are alkaline due to all of the natural limestone, so while blueberries are grown on farms down south, they’re rarer in the wild.

Blueberries are pollinated by bees of many stripes, but most people are unaware of the specialized bee that literally lives for this season. During the last few weeks, this species has been furiously pollinating blueberry bushes during its short, single-purpose lifetime.

The blueberry bee uses “buzz pollination” on blueberry shrubs. Photo by Tyler Jones.

Southeastern blueberry bees (Habropoda labriosa) are active only in mid-March to April when blueberry plants are in flower. They are smaller than bumblebees, and yellow patches on their heads can differentiate males. Blueberry pollen is heavy and sticky, so it is not blown by the wind, and the flower anatomy is such that pollen from the male anther will not just fall onto the female stigma. Blueberry bees must instead attach themselves to the flower and rapidly vibrate their flight muscles, shaking the pollen out. Moving to the next flower, the bee’s vibrations will drop pollen from the first flower onto the next one. This phenomenon is called “sonicating” or ‘buzz pollination” and is the most effective method of creating a prolific blueberry crop.

The blueberry bee has a solitary and nearly single-focused lifestyle, yet one of great importance. Photo courtesy USGS

This native bee lives most of its life underground, emerging in the spring when blueberries are in bloom and living long enough to pollinate the plants. Blueberry bees do not form hives, but create solitary nests in open, sunny, high ground. Females will dig a tunnel with a brood chamber large enough for one larva, filling it with nectar and pollen. After laying an egg, the female seals the chamber and the next generation is ready. The species produces only one generation of adults per year.

By the time we are picking fresh blueberries in May and June, you probably won’t see any blueberry bees around. However, we should all consider these insects’ short-lived but vitally important role in Florida’s $70 million/year blueberry industry!

For more information, check out the beautifully illustrated USDA Forest Service publication, “Bee Basics—An Introduction to our Native Bees,” or North Carolina State University’s entomology website.

Magnolias

Magnolias

About a year ago, one of my regular blog readers asked if magnolia trees (Magnolia grandiflora) had any particularly redeeming qualities. The one in her yard was constantly dropping leaves and seedpods, and she was tired of it. Little did she know, she had stepped into the domain of an absolute devotee of the magnolia tree. I told her that as a child of the Magnolia State (Mississippi) with the new magnolia-centered state flag flying from my front porch, it was my sworn duty to defend this magnificent symbol of southernness. Well, maybe I wasn’t so dramatic, but I definitely took on the challenge.

Magnolia trees produce large cones/seedpods that are filled with wildlife food. Photo credit: Carrie Stevenson, UF IFAS Extension

First, I do empathize with the constant leaf dropping. We have a large, beautiful magnolia tree in our front yard, and it drops its thick leaves year-round. We just rake them into a natural mulch pile around the base of the tree, though. As for the seedpods—those I have learned to be wary of. A couple of summers ago as I walked to my mailbox, I didn’t see one on the curb, then promptly rolled my ankle on it and landed face-first onto the road. After massive swelling and bruising on my foot, I finally went to a doctor to discover I’d managed to tear a tendon. So, tread carefully around the dropping seedpods!

The sturdy branches of our magnolia tree have supported a swing for over a decade. Photo credit: Carrie Stevenson, UF IFAS Extension

But aside from that, it’s all positives. A Southern magnolia is as sturdy a tree as you could hope for—it is consistently ranked as one of the most wind-resistant trees in the landscape. Their thick, dense, upright trunks and the overall pyramidal shape allows the wind to whip around them, rarely causing damage. In fact, the only damage we’ve had to our tree was when a weaker tree fell on our magnolia and knocked some branches off. Eighteen years after Hurricane Ivan, it’s filled in and you’d never know it lost branches. Ours was planted 50 years ago to celebrate the birth of the previous homeowners’ son, and has been a source of shade and relaxation (we have a great swing hanging from it) ever since.

The broad, open shape of the fragrant magnolia bloom co-evolved with its beetle pollinator millions of years ago, before bees existed! Photo credit: UF IFAS

Like many other trees, magnolias have medicinal uses. The bark of a related magnolia species has been used in traditional Asian medicine to treat “anxiety, asthma, depression, gastrointestinal disorders, headache, and more” and our North American varieties were once used as an antimalarial drug. Modern research has shown seed extracts are effective in maintaining sleep and body temperature, as a sedative, and in reducing the intensity of epileptic seizures. As always, never attempt to use a plant-based home remedy without consulting a physician!

To me, nothing quite says springtime like a magnolia blossom. As buds, they are thick and velvety, completely covering the trees with pops of bright white. Once they bloom, these large (up to 8” wide) saucer-shaped blossoms give off a lovely fragrance, attracting pollinators. Interestingly, magnolias are such an ancient species that they evolved (in the Cretaceous period) before flying insects like bees and butterflies existed. Therefore, magnolias are pollinated by flies and flightless beetles, which crawl from one flower to the other, relying on their sense of smell to guide them. Because beetles are chewers, the flowers and leaves co-evolved to be thicker and tougher to offset and survive the bugs’ messy eating habits. Once the flowers have gone, the fuzzy grenade-shaped cones/seedpods grow on the trees. After the seedpods fall, they open to reveal brilliant red seeds. These have significant wildlife value, as songbirds, squirrels, deer, wild turkey, and quail eat the seeds. This time of year, many people use the waxy, deep green leaves for seasonal décor—magnolia wreaths are quite popular, especially in the south. Many people make their own, but companies often sell them for hundreds of dollars apiece!

Magnolia macrophylla ssp. macrophylla (Bigleaf Magnolia) Photo credit Danny Schissler

In our area, the Southern magnolia is only one of several beautiful native specimens of the Magnolia genus. In freshwater wetlands, the slightly more petite sweet bay (Magnolia virginiana) is easily recognizable by the backs of its leaves, fluttering a silvery gray in the wind. One of my very favorite trees is the bigleaf magnolia (Magnolia macrophylla) which boasts mind-boggling leaves that can be over 2 feet long! In his travels throughout the United States in the late 18th century, explorer and naturalist William Bartram described the leaves as “an expanded umbrella, superbly crested with a silver plume.”

The sweetbay magnolia is easily recognizable by the silvery gray color on the backs of its leaves. Photo credit: Dan Gill/LSU AgCenter

Magnolias may be so common as to seem unremarkable to many, but they are a hardy group of trees who have survived on the planet since dinosaurs roamed the earth. And that’s about as redeeming a quality as you can get. To learn about other magnolia varieties that work well in our area, check out this publication from UF IFAS Gardening Solutions.