We hope you were able to join us for Gardening in the Panhandle LIVE! Butterfly Gardening on July 9th to learn about attracting butterflies to your Florida gardens. As promised, we have compiled a list of butterfly resources that we talked about during the webinar and a few extra that we didn’t have time to cover.
If you were not able to join us live, you can still watch the videos on Facebook or YouTube
Click on the topic of interest for links to resources:
Don’t forget to tune in for our next Gardening in the Panhandle LIVE! on July 23rd for Prepping for the Fall Garden. Register for that webinar on Zoom or Follow our Facebook Event for updates.
If you’ve been outside this spring, you’ve probably been bothered by gnats. These tiny flies relentlessly congregate near the face getting into the eyes, nose, mouth and ears.
Eye gnats come right up to the faces of people and animals because they feed on fluids secreted by the eyes, nose and ears. Even though eye gnats are considered mostly a nuisance, they have been connected to transmission of several diseases, including pink eye.
Close up of eye gnat. Photo credit: Lyle Buss, UF Entomologist
Eye gnats are true flies. At about one-sixteenth of an inch in length, they are among the smallest fly species in Florida. They are known as eye gnats, eye flies, frit flies and grass flies. The name grass flies is somewhat descriptive as open grass areas such as pastures, hay fields, roadsides and lawns provide breeding sites for these gnats. They also breed in areas of freshly disturbed soil with adequate organic matter such as livestock farms.
Even though these gnats can be found in much of North and South America, they prefer areas with warm, wet weather and sandy soils. Sounds like Florida.
The lack of cold weather in late winter and early spring is the more likely reason for why these gnats are such a problem in our area this year. Without having the typical last killing frost around mid-March and with early warm weather and rains, the gnats got off to an early start.
Short of constantly swatting them away from your face or just not going outdoors, what can be done about these irritating little flies?
By the way, I grew up in an area of Georgia where gnats are common. I’ll let you in on a secret… Folks who live in Georgia are known to be overly friendly because they are always waving at people who are just passing through. More than likely, these “friendly” folks are busy swatting at gnats, not waving at others who happen to be driving by. Swatting is a quick swinging action with hand as if waving.
Because of their life cycle, extremely high reproductive numbers in the soil and because insecticides breakdown quickly, area-wide chemical control efforts don’t work well in combating this insect.
The use of the following where gnats are common can be helpful.
Correct use of insect repellents, particularly those containing DEET
Screens on windows to prevent entry of gnats into homes
Face-hugging sunglasses or other protective eyewear
Face masks – another use for your COVID-19 face mask
We may have to put up with these annoying gnats until cold weather arrives and be thankful that they don’t bite.
For the 13th year we celebrate National Pollinator Week June 22-28 to bring awareness to the importance of our pollinators and the challenges they face. This is an opportunity to learn about ways to protect pollinators in our own landscapes. Every one of us can make a difference.
When we hear the word ‘pollinator’ most of us immediately think of honeybees. They are very important but there are so many other creatures that are important pollinators:
Native bees – Florida alone has over 300 species of bees
Hummingbirds – their long beaks can reach into long, tubular blooms
Bats – they pollinate over 500 plants including banana, mango, and agave (used to make tequila)
Beetles – considered to be a messy and minor pollinator; they pollinate the native paw paw
Butterflies – a minor pollinator as most have long legs that keep them perched above the pollen
Flies – pollinators of a variety of native plants
According to the USDA, 75% of flowering plants and about 35% of food crops around the globe rely on these animals for pollination. Without pollination, these plants would not reproduce or provide us food.
So, what can the average person do to make a difference?
Avoid using any insecticide unless it is absolutely necessary. Predators like assassin bugs, dragonflies and birds help to keep pests in check. Our songbirds rely on protein-rich insects (especially caterpillars) to feed their growing babies.
Don’t treat areas where pollinators are visiting the flowers, whether in the lawn or the landscape beds.
If you need to apply an insecticide to the lawn, mow first to remove the blooms from any weeds. Always follow the label instructions carefully.
Avoid using a systemic insecticide on plants that bloom and attract pollinators. The insecticide can remain in plants for a long time.
The bay laurel tree in the Escambia County Demonstration Garden had some dead branches on the outer canopy. Further investigation led us to the culprit, the black twig borer. Learn more In the Garden with UF IFAS Extension Escambia County.
Wheel bugs have large beaks and a distinctive semicircular crest on their backs resembling a cogwheel. Photo by Gerald J. Lenhard, Louisiana State University, Bugwood.org.
As a gardener, the summer is the season you might feel it takes knightly status to grow fruits and vegetables. You put on your metaphorical armor, hold up your shield, and draw your sword to battle the stink bugs, squash vine borers, armyworms, green peach aphids, and more.
In these instances, it may feel like nothing in nature is on your side. But alas, there are a few insects out there that carry their own defenses. One of them is the ferocious assassin bug. These insects are predacious, loaded with powerful curved beaks called proboscises that pierce their unsuspecting prey. Once pierced, the assassin bug injects a toxin that liquefies the muscles and tissues of the prey. It then sucks out the liquefied tissue, killing its host.
Although milkweed assassin bugs vary in appearance worldwide, those found in the United States are distinctly orange and black. Photo by Gerald J. Lenhard, Louisiana State University, Bugwood.org.
Assassin bugs feed on a wide range of insects, including many types of caterpillars, stinkbugs, aphids, flies, beetles, and even mosquitoes.
While assassin bugs are our garden allies, be mindful, as their injection does pack quite the punch! Fortunately, although a “bite” from an assassin bug is painful, they do not generally require medical attention. But do seek medical attention if it causes any type of allergic reaction such as swelling, itching, hives, or difficulty breathing.
There are nearly 3,000 known assassin bug species, including many in Florida. Common species you may come across in your Florida garden are the wheel bug (Arilus cristatus) and the milkweed assassin bug (Zelus longipes). Give them their space but know that they are on your side.
Fig. 1 An adult redbay ambrosia beetle compared to the size of a single penny. Credit: UF/IFAS File Photo.
While most bark beetles are important in forest ecology by recycling fallen dead trees and eliminating sick and damaged trees, some of them may impact healthy trees. A group of bark beetles that has become a major concern to forest managers, nurseries, and homeowners is the ambrosia beetle. Ambrosia beetles are extremely small, 1-2 mm in length, and live and reproduce inside the wood of various species of trees (Fig. 1). Ambrosia beetles differ from other bark beetles in that they do not feed directly on wood, but on a symbiotic fungus that digests wood tissue for them. Every year, non-native species of ambrosia beetles enter the United States through international cargo and we have now nearly forty non-native species of ambrosia beetles confirmed in the United States. Among them, the redbay ambrosia beetle (Xyleborus glabratus), originally from Southeast Asia, is the vector of the fungal pathogen causing laurel wilt, a disease that devastated the Lauracaea population in the southeastern USA, killing millions of redbay, swamp bay, sassafaras and silk bay.
Fig. 2: A mature dooryard avocado tree with large sections of dead and missing leaves, caused by laurel wilt disease. Summer 2009 Impact Magazine image. Credit: UF/IFAS File Photo.
When these beetles attack a laurel tree, the symbiotic fungus is vectored to the tree’s sapwood after the beetle has tunneled deep into the tree’s xylem, actively colonizing the tree’s vascular system. This colonization leads to an occlusion of the xylem, causing wilting of individual branches and in a matter of weeks progresses throughout the entire canopy, eventually leading to tree death (Fig. 2). The laurel wilt disease has spread rapidly after the vector was first detected in Georgia in 2002. The redbay ambrosia beetle was first detected in Florida in 2004, in Duval County, attacking redbay and swamp bay trees. At this point, it is estimated that more than one-third of redbay in the U.S.A., 300 million trees, have succumbed to the disease.
Starting in 2017, we examined the efficacy of verbenone against redbay ambrosia beetle in live laurel trees in a natural forest setting. Verbenone is an anti-aggregation pheromone that has been used since the 1980’s to protect lodgepole pine. Verbenone also has the potential to be used over large areas and is currently being used to protect ponderosa pine plantations from the Mountain Pine Beetle in the western US.
We have found verbenone to be an environmentally friendly and safe tool to prophylactically protect laurel trees against redbay ambrosia beetle. Our protocol consists of the application of four 17 g dollops of a slow-release wax based repellent (SPLAT Verb®, ISCA technology of Riverside, CA) to the trunk of redbay trees at 1 – 1.5 m above ground level (Fig. 3). The wax needs to be reapplied every 4 months during fall and winter and every 3 months during spring and fall when temperature is higher. When compared to the control trees without repellents, we found that trunk applications of verbenone reduced landing of the redbay ambrosia beetle on live redbay trees and increased survivorship of laurel trees compared to untreated trees (Fig. 4). Verbenone should be considered as part of a holistic management system against redbay ambrosia beetle that also includes removal and chipping of contaminated trees.
If you have Redbay or other bay species on your property and are concerned about Laurel Wilt Disease or Redbay Ambrosia Beetle damage, contact your local UF/IFAS Extension Agents for help!
This article is courtesy of Dr. Xavier Martini and Mr. Derek Conover of the UF/IFAS North Florida Research and Education Center (NFREC) in Quincy.
Fig. 3: Application of SPLAT Verb on a redbay tree during a field trial
Figure 4: (A): Cumulative capture of redbay ambrosia beetles Xyleborus glabratus following a single application of verbenone vs untreated control (UC). (B) Survivorship of redbay and swamp bay trees treated with verbenone on four different studies conducted in 2017 and 2018.
