by Sheila Dunning | Apr 23, 2018
With cool, foggy mornings you may have noticed the large number of spider webs hanging on low vegetation. Some of them have unusual shapes. One of the most notable is the bowl and doily spider. This spider (Frontinella pyramitela) is a species of sheet web weavers found throughout the United States, including Northwest Florida.
It is a small spider, about 3-4 mm (0.16 in) long, boldly marked with black and white stripes on the abdomen, a brown cephalothorax, and brownish legs. They weave a fairly complex shaped webs only a few inches across, usually well off the ground and stretched between twigs or other objects. Webs consist of an inverted dome-shaped web, or “bowl”, suspended above a horizontal sheet web, or “doily”, hence its common name. The webs are approximately circular when viewed from above, where there is a tangled scaffold “knock down” threads of silk invisible to flying insects. The webs are commonly seen in weedy fields and in shrubs.
Small flies, gnats and other small insects crash into the strands of barrier silk and fall down into the non-sticky webbing. The spider hangs from the underside of the “bowl”, and bites through the web, pulling the prey through in order to consume them while resting comfortably on the “doily”. Bowl and doily spiders serve a very important ecological role by controlling human-biting and plant damaging insects.
Among web-building spiders, bowl and doily spiders (Frontinella pyramitela) are unusual because both males and females often cohabitate. The males rarely build webs, however, and so depend upon females ‘ snares for food. These cohabiting males capture about 32% of the prey that hit the web despite the female’s efforts to capture the same prey.
Mating in this species occurs on the underside of the bowl of the female’s web and is preceded by a complex vibration- and chemical-mediated courtship during the late summer. Eggs are laid in silken sacs in the web or hiding in leaf litter on the ground. Both eggs and adults have been known to overwinter. Like all spiders, bowl and doily spiders develop through simple metamorphosis: spiderlings look like tiny adult spiders (but with lighter coloration), and shed their outer skin in order to grow. Most sheet web weavers live only one year.
by Beth Bolles | Apr 9, 2018
The change in North Florida temperatures from cooler to warmer is making many winter weeds more noticeable as they begin to flower and form seed. Not all of these plants should be considered for mowing or hand pulling. There are several wildflowers that grow in landscape beds and thinning areas of lawns and can be enjoyed before consistent heat returns.
Toadflax flowers are held above the foliage and are light purple. Photo by Beth Bolles, UF IFAS Extension Escambia County
One very delicate wildflower that is growing now is the Toadflax, Linaria canadensis. The leaves are very small and grow low on the ground. Thin flower stalks grow several inches and are topped with light purple flowers. Although toadflax pops up in beds and lawns don’t be so quick to pull it out. This wildflower is a host to the Buckeye butterfly, one of our earlier visitors to gardens. If you look closely you may even see the tiny black, spiny caterpillar eating toadflax leaves. Visit the UF publication on the Buckeye butterfly to learn more.
Adult buckeye butterflies are common in landscapes in early spring and late summer. Photo by Lo Sitton, UF IFAS Extension Escambia County
by Molly Jameson | Mar 26, 2018
Digger bees resemble honey bees, although they do not sting, and would only bite if mistreated. Photo by Molly Jameson.
Have you noticed many little dirt piles that resemble mini ant mounds around your yard? Well, fear not, for these mini mounds are made by digger bees who are excellent, yet ephemeral, early-spring pollinators.
These solitary ground-nesters are native to our area and only appear for four to six weeks to raise their offspring. Although they do not produce honey, they resemble honey bees in size and shape. They also do not sting and would only bite if they were handled roughly.
Female digger bees build their nests close together, creating clusters of many small mounds. Photo by Molly Jameson.
Otherwise known as miner bees, females create their underground cylinder-shaped nests in dry, well-drained soils, often right next to each other, creating patches of many mounds in a small area.
These bees will pollinate many early-spring blooming flowers – a bonus for gardeners – as they collect pollen to add to each cell that they excavate. They then lay their eggs on these pollen masses, cap the cells with clay, and complete their life cycles. The eggs hatch about five days later and emerge from the chamber created by their mothers.
While digger bee mounds may detract from an otherwise tidy lawn, they will do no harm, and can actually be beneficial, in that they improve air, water, and nutrient percolation. If you feel you must discourage their presence, simply run a sprinkler over the area as their season approaches. They prefer dry soil rather than wet soil and will look elsewhere to build their nests.
But better yet, take a seat on your front or back porch, pour yourself some lemonade, and take in the soothing hums of their wings as they do their work.
by Carrie Stevenson | Mar 26, 2018
Ah, the oft-ignored pine tree. They are so ubiquitous throughout the southeast, that many people consider them undesirable in a landscape. Having grown up near the “Pine Belt” of Mississippi, I figured I knew plenty about them, but this week I learned something new. While on a field tour with local foresters in the business of loblolly and longleaf pine farming, they introduced me to the pine tip moth. These insects can wreak havoc on valuable young pine trees.
Dead branch tip and needle damage caused by pine tip moths. Photo credit: Carrie Stevenson, UF IFAS Extension
Hollow space in pine tree branch created by pine tip moth. Photo credit: Carrie Stevenson, UF IFAS Extension
Female pine tip moths lay eggs on the growing end of a pine branch—particularly young, healthy loblolly and shortleaf (longleaf is rarely affected). When the eggs hatch 5-30 days later, the larvae start feeding. They tunnel into the shoot and bud of the pines, feeding on the tissue and burrowing a hollow cavity for several weeks. The larvae then pupate inside the space until becoming adult moths, exiting from the hole they created. The cycle restarts, with more adult moths, eggs and larvae.
Adult Nantucket pine tip moth Rhyacionia frustrana (Comstock). Photograph by James A. Richmond, USDA Forest Service, www.Forestryimages.org.
Two insect species are most common in our area; the subtropical pine tip moth (Rhyacionia subtropica) and Nantucket pine tip moth (Rhyacionia frustrana). The moths are reddish copper in color, small (1/2” wingspan and 1/4” body length) and active at night. Caterpillar larvae have black heads and start out with off-white bodies, but change in color to brown and orange as they age.
While this insect activity typically does not kill the tree, it does cause some die-off of terminal needles and branches. In extreme cases, it can cause tree death. Moths prefer younger trees and rarely affect pines taller than 15 feet.
If you see a cluster of dead needles at the ends of young pine branches of your property, you can easily snap off the dead tip. You will likely find the hollow space formed by the larvae, which in spring may still contain the insect. Treatment in a home landscape can managed by hand removal of infested shoots, but those in the commercial forestry business may need to install traps and consider insecticidal management.
Visit the UF School of Forest Resources and Conservation website for more information.
by Mary Salinas | Mar 21, 2018
European honey bee. Photo credit: UF/IFAS.
Bees, butterflies and other insects play important roles as pollinators in our environment. Over 50 major crops in the United States and at least 13 crops in Florida depend on honey bees. Many native plants in natural areas also depend on insect pollinators for reproduction. In Florida, over 300 bee species play a role in pollination!
Many factors affect the health of our pollinators. One of those factors we can easily control in our own landscapes is exposures to pesticides. How are bees and other pollinators exposed to pesticides? Here are some of the major routes:
- Drift of pesticides sprayed in breezy/windy conditions
- The erosion of contaminated topsoil blowing in the wind
- Direct feeding on pollen and nectar of treated plants
- Contact with pesticides that have blown onto plant surfaces
- Contact with water transpired by leaves of treated plants
- Pesticides that move down through the soil to affect ground dwelling bees and other insects
Did you know that bees become statically charged when they fly causing particles in the air to attract to them?
What are some ways that we can reduce the risk of exposure to pollinators in our landscapes?
- Use integrated pest management principles to reduce the incidence of pests and their impacts.
- Avoid treating areas containing flowering weeds/plants with insecticides. If you must treat your lawn with an insecticide, and it contains flowering weeds, mow the lawn and remove the flowers just before applying the insecticide.
- If you must apply a systemic insecticide to your lawn, leave a buffer strip of several feet between the lawn and the border of landscape beds with flowering plants. This will prevent the flowering plants from up taking the systemic product.
- Postpone any insecticide treatment until after all blooms have fallen from flowering ornamentals. Never apply an insecticide to blooms or flowering plants.
- Avoid the use of neonicotinoids as this class of insecticides can be more toxic to bees than other classes of insecticides. There are many effective alternatives.
Bee friendly to our pollinators!
For more information:
Minimizing Honey Bee Exposure to Pesticides
Creating and Maintaining Healthy Pollinator Habitat – Xerces Society
by Matt Lollar | Nov 20, 2017
Sometimes you don’t realize a tree is dying until it is dead. A few weeks ago, we got a call from a client who said he had insects killing his trees. Before having someone drive out to the property, our Master Gardener volunteer recommended that the client bring in some of the insects for us to take a look. It turned out the insects invading his pine tree were a type of longhorned beetle, but more specimens were required for identification. A site visit soon ensued.
There were a number of pine trees on the property, however only one was infested with the insects in question. Upon closer investigation, we noticed a number of different sized holes in the tree. The larger holes are nearly the size of a dime.
Arrowhead borer damage on a pine tree. Photo Credit: University of Florida/IFAS Extension.
It turns out the insects making the larger holes are a type of longhorned beetle known as an arrowhead borer (Xylotrechus sagittatus). The borers are brown to black in color with a reddish hue. They are moderately hairy and some specimens contain arrowhead markings pointing toward their heads. Adults feed on the bark of damaged or fire-killed pines. The adults are attracted to lights and may be mistaken for crickets because they run very fast. Eggs are laid in bark and larvae feed on sapwood, then tunnel deeper, often tunneling within a single annual ring. The borers pupate inside the tree and the newly emerged adults chew their way out.
Arrowhead Borer. Photo Credit: Tom Murray bugguide.net.
Given the fact that arrowhead borers are attracted to dead or dying trees, the killer of this particular tree is still in question. The smaller holes in the bark picture above were created by a much smaller beetle, but we were unable to get a specimen. We did see a couple of these beetles running around when we dug deeper into the bark. The small beetles that we saw closely resembled a type of Ips engraver beetle. Beetles in this genus have been known to kill trees, but most likely they weren’t the culprits either. Based on the overall appearance of the tree and the fact that other trees in the area were not infested with beetles, it is believed the tree was killed by other means. The tree was likely struck by lightening or suffered from poor genetics because it did not have a good form for a pine tree.
If you have a questionable looking tree on your property or if you have insects you would like identified, please feel free to stop by your local Extension Office and ask a Master Gardener!
Among web-building spiders, bowl and doily spiders (Frontinella pyramitela) are unusual because both males and females often cohabitate. The males rarely build webs, however, and so depend upon females ‘ snares for food. These cohabiting males capture about 32% of the prey that hit the web despite the female’s efforts to capture the same prey.
