Spiders in the Landscape and Garden

Spiders in the Landscape and Garden

Unknowingly we interact with many small creatures in our everyday lives. Spiders are one of these groups that are beneficial to the function of human activity.  This group receives much publicity as being dangerous to people and our pets.  While there is always a possibility of being bitten and having venom injected by a few types of spiders, most all others are harmless to people.  The primary benefit of spiders is their propensity for catching insects outside and in the home that are identified as harmful to people.  Spiders come in all shapes and sizes with many hiding away, never to be seen by people.   

Spiders are often included in the same group as insects, but this is not true.  They belong in the group arachnids and are closely related to ticks, scorpions and mites.  Spiders have two body sections (cephlothorax and abdomen) and have eight legs while insects have three body sections (head, thorax and abdomen).  Scorpions usually remain outdoors and may be found indoors during hot dry periods.  They are nocturnal hunters of pests that include roaches.  None of the scorpions native to Florida are capable of providing a lethal sting, but it is painful when it occurs, leaving a sore and swollen at the sting area.  I was reminded of this after stepping on one in the late evening while moving around the kitchen with no lights on.  If the person that is stung has allergic reactions to bee stings, observe them and take precautionary health measures needed.

The spider is an important predator of harmful insects and can be found about any where in and around the home, in the garden, and many other places in the great outdoors.  An Extension Entomologist I knew from North Carolina State University always mentioned, when presenting to Master Gardener Volunteer classes, that at almost any time given time, we are within two to three feet of a spider, with most so small we never see them.  They are great at keeping the beneficial and harmful insect populations in balance in nature.

If you decide to spray to manage your spider population, keep in mind that by reducing the number of spiders in the landscape, you can create a reverse problem with harmful insect populations increasing dramatically.  If big webs are a bother, simply take a broom and knock them down.  They will rebuild by the next day, but you may not need to be in that area for a while.  Always be careful and wear gloves when working in the garden, especially areas that are dark and covered, such as irrigation valve boxes, wood stacks, and other similar places.  These are prime locations where the Black Widow or Recluse spiders may be set up, waiting to ambush roaches and other insects.  If you are bitten by either seek immediate medical care. 

Finally, spiders are fun to observe in nature! One of the most interesting spiders to watch is observable during fall in Florida – the Yellow Garden Spider.  They build large webs and often place a zig zap signature in the middle.  This large spider catches many insects in the garden and landscape.  With early morning sunlight and dew hanging on the web during the fall, it makes for a beautifully create piece of art.  Enjoy nature and all the creative processes that occur from a safe distance – spiders included!

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.

Friend or Foe – Horned Passalus beetle

Friend or Foe – Horned Passalus beetle

Have you ever been strolling through your garden and decide to rearrange or remove a log? You might be amazed or intimidated by the sight of a dark shiny creature with large mandibles (mouth parts).  But don’t be alarmed- it is the Horned Passalus, Odontotaenius disjunctus.  This beetle also is known by many other common names including the Betsy Beetle, Bess Bug, Patent Leather Beetle, Jerusalem Beetle, Horn Beetle, and Peg Beetle.  

This beetle is a widely distributed from mid-Florida to Massachusetts, Southern Texas to Minnesota, and Nebraska.  Beetles are easily recognized due to their large size, ranging between 30 and 40 mm (1.2 and 1.6 inches) in length. They are known to have pre-social activities, where both males and females perform the same duties of processing decaying wood and protecting larvae.

Friend or foe?

Horned Passalus Beetles are beneficial decomposers of decaying wood or logs, often found in large numbers to efficiently complete the task!  However, they are medically harmless and not considered a pest of urban structures. Horned passalus beetles are considered to be beneficial insects as these beetles help decompose deadwood by chewing the pulp and then expelling the frass.

Musically inclined or just a talkative beetle?

The phrase “crazy as a Betsy Bug” may refer to the sounds that these insects make — The adults are able to produce at least 17 different calls (Stridulation) as they communicate with other beetles or when disturbed/agitated, which are audible to humans.

Life cycle/ Developmental stage.

Using its large mandibles, the horned passalus cuts into fallen logs and creates tunnels where the eggs are deposited and hatched into white grubs (larvae) that have up to three instars. They appear to only have two pairs of legs, but a third pair is present and reduced. Only the first two pairs are used for movement. These grubs usually retain a distinctive C-shaped position when not active.

As pupae begin to form they become pearly white with a rainbow sheen. As the pupae age, they lose their rainbow sheen and can range in color from off white to earth-toned. Adult beetles aggregate and compete for sections of fallen wood.  

Nuptial flight or defense?

Newly mature adults will leave the parent log and participate in a nuptial flight, one of the only instances of their wing use. During observations of the nuptial flight, adults were found to be susceptible to light attractants such as light traps and street lights. At the end of the nuptial flight, adults will seek out a new log to start another aggregation.

For more information, please contact your local county extension office.
Supporting information for this article can be found in the UF/IFAS EDIS publications/websites below: horned passalus – Odontotaenius disjunctus (Illiger) (ufl.edu); EENY 487/IN879: Horned passalus, Odontotaenius disjunctus (Illiger) (Insecta: Coleoptera: Passalidae: Passalinae) (ufl.edu) and Odontotaenius disjunctus (tamu.edu)

What’s that Webbing on My Tree Trunk?

What’s that Webbing on My Tree Trunk?

There are numerous insects and insect relatives that can produce webbing, and webbing can be a sign that something unwanted is near. Arachnophobes might grow uneasy at the sight of a spiderweb, and gardeners might frown to see the tiny filaments that spider mites spin. Tree lovers might assume that webs on a tree are a sign that caterpillars such as the eastern tent caterpillar have taken up residence. But what about webs on a tree trunk?

Bark louse webbing. Photo courtesy of Evan Anderson.

If you come across a tree trunk coated in silk, chances are you’re looking at the work of a bark louse. Also known as psocids or tree cattle, these little insects eat all the stuff that sticks to a tree’s bark. Lichen, moss, algae, and dead bark can all end up as meals for a hungry bark louse. The good news is that while lichens don’t hurt trees, neither do bark lice!

Bark lice spin their webbing as protection from predators. They often produce large quantities of webbing, because there are often large quantities of bark lice present. The name ‘tree cattle’ comes from the fact that they form these large colonies, and move in a manner similar to cattle in groups. While swirling swarms of creepy-crawlies rarely make people feel at ease, don’t worry about these. Acting as a sort of clean-up crew, they will do their work, grow and mature, and move elsewhere by themselves.

There are often several generations of bark lice each year in Florida, so they may reoccur. No control is needed for these insects, though if leftover webbing is considered aesthetically unpleasing it can be removed by spraying with a sharp jet of water. For more information about bark lice, see our EDIS publication at https://edis.ifas.ufl.edu/publication/IN553.

Bark louse nymph. Photo courtesy of Evan Anderson.
Yellow Jacket Wasp – Aggression and Understanding

Yellow Jacket Wasp – Aggression and Understanding

It is late summer and many of us enjoy being outdoors in the landscape and taking early morning walks before the temperature rises for the day.  There are precautions to take while being outdoors and the activities as many insects are very active, including the yellow jacket.  Late summer and many of us being outdoor brings us increases the change of being stung by this insect.  The Yellow Jacket sting can be painful and potential dangerous to certain individuals with strong reactions to stings.

Yellowjackets are pollinators and eat caterpillar pests! Credit: Whitney Crenshaw, Colorado State University, Bugwood.org

In the State of Florida there are two species of this Yellow Jacket Wasp, the Eastern Yellow Jacket and the Southern Yellow Jacket.  It is difficult to distinguish between them and for this article I will refer to them as Yellow Jackets.  Yellow Jackets most often colonize in the ground and are often found in lawns that tend to stay dry, landscape beds and edge of woodlands.  Colonies of this flying insect can grow into hundreds or even larger numbers.  Often by observation in morning or evening light the entry and exit point of the nest can be see with some luck.  It looks like an extremely busy airport with lots of landings and departures.  The unfortunate way to find the nest can occur by mowing the lawn disturbing the nest with many yellow jackets emerging from the nest to protect it.  The colony quickly goes into defense mode with vibrations occurring nearby.  This has occurred with me on more than one occasion.  All modesty can be lost while run away from the nesting area with several yellow jackets stinging you move quickly move away.  Clothing has been known to be shed to hopefully remove the yellow jackets busily stinging either under or on the outside of clothing.    

yellowjacket nest
Southern yellowjacket, Vespula squamosa (Drury), nest dug from ground. Credit: Gerald J. Lenhard; http://www.insectimages.org/

During the early part of the spring and summer season yellow jackets are busy foraging for protein sources to feed to queen and young larvae.  During the consuming of the insects, with many of those harvested being harmful insects to plants.  The yellow jackets derive their sugar sources from the larvae secretions as they consume the proteins provided.  This is part of the reason we do not often see Yellow Jackets in late spring and early summer.  As the queen begins to reduce the amount of egg laying, hence the less numbers of larvae to feed and harvest the sugar for a wasp population at its peak creates a more aggressive need to find alternate sources of sugar.   This is part of the reason why yellow jackets show up in greater numbers at outdoor sporting events and other places to look for additional sugar sources.   Sugar water for hummingbirds is another backyard site for yellow jackets to work hard for the sugar.  Even the birds are careful about approaching the feeders. 

I do not advocate the destruction of yellow jacket nesting sites unless they are in proximity to human activity as this can set the situation of stings and potential health challenges for people.  If you identify a nest location do not approach and call a company that specializes in addressing these types of stinging insects.  Keep in mind that this insect provides a benefit in harvest of many harmful pests to plants yet do pose a potential threat.  Be observant as you garden situations that seemed fine last month may have changed quickly.