by Daniel J. Leonard | Aug 6, 2020
I know this is going to come as a shock to some readers, but not all bugs are bad. In fact, while there are over 1 million species of insects worldwide, less than 1% are problem pests! This problem 1%, composed of common garden pests, including aphids, stinkbugs, nuisance caterpillars, and scales, get all the attention and for good reason; they can be extremely destructive to home and commercial crops. However, the good guys, beneficial predatory insects, are out there too, providing valuable pest control day and night and should be considered in part of a quality garden pest management strategy.
Beneficials come in many shapes and sizes. Some are commonly known predators, such as spiders, Lady Beetles and Praying Mantids, while others are lesser known pest nemeses, like Paper Wasps, Pirate Bugs, and Lacewings. Regardless, gardeners should do their homework and be able to identify beneficials when they see them and allow them to do their jobs. The presence, or not, of a handful of Lady Beetles or Lacewings on the attack can be the difference between needing to treat with insecticides for an aphid outbreak or just letting nature take its course. Studies have shown that just one individual Lady Beetle in the larval stage can consume as many as 500 aphids; adult Lady Beetles are even hungrier aphid eaters! Paper Wasps, you know the ones who make the large “papery” nests around eaves of house and other structures, play an important beneficial role, frequently preying on caterpillars. If their nests aren’t near highly trafficked areas around your home and you don’t have family members allergic to wasp stings, your garden will thank you for leaving a few paper wasp colonies as caterpillar insurance!
Lacewing eggs on a Jade plant in close proximity to the author’s vegetable garden.
In many instances, beneficial insects can keep pest insect infestations at bay, allowing gardeners to spot treat outbreaks when they get out of hand or even prevent the problem from needing chemical intervention altogether.
As helpful as they are, beneficial insects in the garden won’t totally negate the need for chemical treatment entirely. From time to time, garden pest populations outpace the beneficials’ abilities to kill them and intervention from humans is needed. In these times, it is advisable to use a couple of best practices to limit exposure to beneficial insects. First, try to use selective insecticides that only target specific pests and are nontoxic to other bugs, like the product Bt for caterpillar pests (sold under many brands like Dipel, Garden Safe Bt Worm and Caterpillar Killer, Thuricide, etc). However, if a nonselective, general insecticide, like the Pyrethroids (many common homeowner insecticide brands) and carbamates (Sevin and others), is needed, timing these broad spectrum sprays for early in the morning and late in the evening when many beneficials are not very active can help reduce friendly fire casualties. Care should also be taken to only spot treat infested plants and not the entire garden, this helps reduce beneficial exposure to these broadly toxic pesticides.
Every gardener should have a plan for pest control and beneficials can play an important role in this overall strategy. Gardeners can help ensure that nature pulls its weight in controlling problem pests by taking a little time to scout for beneficial insect populations, keeping a close eye on developing pest outbreaks, using selective insecticides when you can, and only spraying broad spectrum products as spot treatments when necessary and timing those applications for very early or late in the day. If you have a question about whether or not a garden insect is a good guy or a pest or want more information on garden pest control strategies, contact your local UF/IFAS County Extension Office! Happy Gardening!
The following resources were used in the development of this article:
https://gardeningsolutions.ifas.ufl.edu/care/florida-friendly-landscapes/beneficial-insects.html
https://sfyl.ifas.ufl.edu/sarasota/gardening-and-landscaping/horticulture-commercial/integrated-pest-management/beneficial-insects/
http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/other/beneficial-insects.aspx
by Matt Lollar | Jul 30, 2020
On a daily basis, it is not unusual for our Extension Office to get calls, emails, and walk-ins with questions about insect identification. Sometimes we even get questions about imaginary insects! The overwhelming opinion by our clientele is that the insects in question are harmful to their landscapes and gardens. This is not always the case since there are more than 100,000 species of insects found in the United States, but less than 1% are harmful.
Recently I received a call about an abundance of bugs in a client’s newly installed sod. He was concerned that the insects were taking over his yard. Luckily, he was able to submit some good quality photos so the University of Florida/IFAS Extension Service could help him identify the insects.
An adult ground beetle (Mochtherus tetraspilotus). Photo Credit: Michael C. Thomas, Florida Department of Agriculture & Consumer Services
The photos were sent to a University of Florida Entomologist for identification verification. It turns out the insects were ground beetles (family Carabidae). Adult ground beetles are slender and range between 1/4″ and 3/8″ in length. Their head and thorax are much narrower than their abdomens. Ground beetles are beneficial insects that feed on moth eggs and larvae. They are known predators of soybean loopers, cabbage loopers, and velvetbean caterpillars. It is suspected that the beetles found by the client came from the sod farm and were living in the thatch layer of the sod. They were possibly feeding on sod webworms or other moth larvae.
Accurate identification is the first step of integrated pest management (IPM). In this case, the insect found wasn’t a pest at all. If you need help identifying an insect, feel free to contact your local Extension Agent. For more information on beneficial insects, visit these publications found at edis.ifas.ufl.edu.
by Larry Williams | Jul 23, 2020
A number of years ago a gentleman told me about an orb weaver spider that was living by his front door. He said that it had been there for about two months and that it was interesting to watch the construction of the intricate “bug catching” web. However, he explained that he had a number of people coming to visit and he wanted to know about relocating the spider to his backyard.
Golden silk orb-weaver spider. Photo credit: UF/IFAS
These types of spiders typically construct their webs in an area and stay in that location based on the environment. Many of the orb weaver spiders rely on flying insects and usually construct their webs several feet or more above the ground. This is a good height to capture many flying insects. As a result, there needs to be items within a reasonable distance to attach and place the web. If a spider is randomly relocated, there may be nothing in reasonable distance to support a web. There needs to be at least a couple of tall shrubs or tree trunks for the spider to construct a web in-between the plants several feet above ground level. It needs to be in an area with limited people movement to prevent disturbance by people walking into it. It needs to be in a location with enough flying insect activity to satisfy the spider. If it’s not the right location, the spider may move back to another location, perhaps the front door area.
Webs built by these types of spiders can be quite large and may be suspended several feet or more above the ground. Some people become annoyed and/or frightened as they accidentally come in contact with these webs, brushing the webs from their face and arms. I’m sure the spider becomes annoyed, too, having to rebuild its web.
Despite their size, orb weaver spiders pose little threat to people. They’re considered beneficial because they feed on a wide range of flying insects. They usually construct webs in relatively sunny, open areas with little wind.
Even though these spiders are beneficial, many people don’t like spiders. If you choose to control spiders in and around your home, keep in mind it’s unwise and impractical, if not impossible, to control all spiders.
By the way, the gentleman concerned about the spider decided to leave the spider at the front door area. He posted a sign next to the web in hopes that his guests would steer clear of the web. He offered his garage entrance to those frightened by the spider.
For more information on orb weaver spiders, visit the below UF/IFAS Extension website.
https://edis.ifas.ufl.edu/topic_orb_weavers
by Larry Williams | Jul 9, 2020
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.
Additional info on eye gnats is available online at https://edis.ifas.ufl.edu/in884 or from the UF/IFAS Extension Office in your County.
by Mark Tancig | Jul 9, 2020
North Florida vegetable gardeners have made it to summer and now the plants and gardeners are starting to give in to the heat and humidity. The squash has likely succumbed to squash vine borers, many of the tomato varieties are having trouble setting fruit, stink bugs are all over, and gardeners easily wilt by noon. This is a good time to use our oppressive heat to your advantage in the vegetable garden by solarizing the soil.
We have reached the peak of heat. Use it to your advantage in the garden. Source: National Weather Service.
Soil solarization is a method of pest control that creates a greenhouse to heat up the soil in an effort to drive away pests. Pests that can be reduced with soil solarization include weeds, various soil-borne fungal pathogens, and nematodes. Weed seeds can actually be killed by the increased temperatures, sometimes as high as 140 degrees Fahrenheit, while fungi and nematodes are merely driven deeper into the soil layer as they try to escape the heat. Although they are not killed, this can help vegetable gardeners as it may take these organisms 3-4 months to repopulate in high enough numbers to cause damage. Soil solarization can be considered another tool in your integrated pest management (IPM) toolbox, along with other cultural, physical, and chemical means of pest control.
A raised bed being solarized over the summer. Source: Evelyn Gonzalez, UF/IFAS Master Gardener Volunteer.
To properly execute soil solarization, the site should be in full sun and the existing vegetation removed, either by hand or with a tiller or other implement. Tilling can help loosen the soil surface and allow heat to penetrate deeper in the soil horizon. Before being covered with plastic, the area should receive rainfall or be irrigated, as the water will help conduct heat to greater depths. The next step is to cover the area with plastic. Note that this can also be done over raised beds! Clear plastic is best for maximum solar radiation penetration. Black plastic will heat up mostly on the surface and opaque plastic sheeting may not let enough light in to get temperatures high enough. The plastic should be slightly larger than the area covered, as the edges will need to be buried to create an air-tight seal. It’s recommended to leave the plastic in place for at least six to eight weeks, just in time to begin fall gardening preparations.
It’s important to monitor the site while it’s “cooking” to look for any holes that might appear. Small holes can be repaired with duct tape, while large holes or rips in the plastic may require starting over. Overlapping strips of plastic is not recommended since too much heat will be lost.
You may be wondering what happens to all of the good soil microbes. Well, unfortunately, they are also either killed or suppressed. Fortunately, researchers have found that they are able to repopulate quicker than the pest organisms, especially in soils with a good amount of organic matter.
Much more information on soil solarization can be found in these two documents:
Introduction to Soil Solarization – https://edis.ifas.ufl.edu/pdffiles/IN/IN85600.pdf
Solarization for Pest Management in Florida – http://edis.ifas.ufl.edu/pdffiles/IN/IN82400.pdf
Also, please contact your local county extension office for more gardening tips.
by Mary Salinas | Jun 23, 2020
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?
- Plant what bees and butterflies love!
- 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.
Happy gardening during National Pollinator Week!
For more information:
Pollinator Partnership: Pollinator Week Activities
US Fish & Wildlife Pollinator Site
Native Insect Pollinators of the Southeastern United States brochure
Purdue University: Protecting Pollinators in Home Lawns and Landscapes
Minimizing Honey Bee Exposure to Pesticides
Beneficials come in many shapes and sizes. Some are commonly known predators, such as spiders, Lady Beetles and Praying Mantids, while others are lesser known pest nemeses, like Paper Wasps, Pirate Bugs, and Lacewings. Regardless, gardeners should do their homework and be able to identify beneficials when they see them and allow them to do their jobs. The presence, or not, of a handful of Lady Beetles or Lacewings on the attack can be the difference between needing to treat with insecticides for an aphid outbreak or just letting nature take its course. Studies have shown that just one individual Lady Beetle in the larval stage can consume as many as 500 aphids; adult Lady Beetles are even hungrier aphid eaters! Paper Wasps, you know the ones who make the large “papery” nests around eaves of house and other structures, play an important beneficial role, frequently preying on caterpillars. If their nests aren’t near highly trafficked areas around your home and you don’t have family members allergic to wasp stings, your garden will thank you for leaving a few paper wasp colonies as caterpillar insurance!
