Spiders Gone Wild in Rowlett

giant spider webs in Rowlett TX
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Spider gossamer covers roadside trees in Rowlett’s Lakeside Park.

Rowlett, Texas is a relatively quiet suburb of big neighbor, Dallas.  Driving along the city’s CA Roan Drive, a quiet stretch of road running through Lakeside Park South, you can feel a long way from the big city.  But cyclists and drivers along that route this week may have noticed the trees looking a little shiny, and maybe just a little creepy.

Along a football field length stretch of the drive, the spiders are taking over.  Glistening webs are draping the trees like shrouds at Lakeside Park, a stone’s throw away from the shores of Lake Ray Hubbard.  Someone stepping off the road for a closer look will see thousands of lanky spiders darting among the webs that extend up to 40 feet into the trees.

Another view.

There is a surreal quality to the extensive webbing covering the trees next to Lake Ray Hubbard.

It turns out that while rare, large webs like this do occur from time to time. In 2007 local news stations reported a similar giant spider web at Lake Tawakoni State Park, about 35 miles east of Rowlett. At the time the web was more than creepy–it was a revelation to many arachnologists (spider experts).

If you’ve ever watched them you may have noticed that, like their comic book friend Spiderman, spiders tend to work alone.  So it was surprising, even to many arachnologists, to find spiders in a communal setting, apparently building a nest together.  The spiders turned out to be Tetragnathus guatamalensis, a spider previously reported to build communal nests when conditions are right.

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While the exact species has not been confirmed, the communal spiders are some kind of long-jawed spider. These spiders are unusual in that they are not aggressive to other spiders of the same species. They also are not known to bite or be harmful to humans.

The right conditions appear to include a glut of small insects like midges that emerge at night from lakes.  Without lots of food, these communal webs just don’t seem to form.  Dr. Roy Vogtsberger, of Midwestern State Univerisity in Wichita Falls, TX, has been studying the Tawakoni site since it stirred up worldwide interest in 2007.  He reports that the communal web has never returned.  It appears that these spider “art exhibits” are relatively rare.

“What is really interesting about these spider aggregations is the lack of aggression among spiders of the same species on the same web. They can be extremely close proximity [and still tolerate each other],” said Vogtsberger.

If you get the chance to take a drive along CA Roan Drive in Rowlett, take a few moments to admire the spider handiwork.  But please don’t touch the art.

 

Your chance to hear REAL cicadas

Periodical cicadas are recognized by red eyes

Texans are no strangers to cicadas.  One writer in 1933 proclaimed east Texas “a veritable cicada paradise,” before going on to list all the different species he had encountered here. Indeed, you would have to be hard of hearing, or very unobservant, not to notice the buzzing sounds of annual cicadas coming from nearly every summertime tree between June and August.

Periodical cicadas are recognized by red eyes (faded in this image), black bodies and orange wing veins.  Specimens collected by Tim Brys. Photo by Valerie Wielard.

Periodical cicadas are recognized by red eyes (faded in this dried specimen), black bodies and orange wing veins. Specimens collected by Tim Brys. Photo by Valerie Wielard.

Even if the annual singing of cicadas is not your cup of tea, you have to marvel at the once every seventeen year emergence of the periodical cicadas.  Sometimes deafening, the periodic cicadas are exceptionally abundant in their areas of emergence.  Mostly Texans hear about these impressive displays of cicada firepower on national news, or remember them from youth (for those of us naturalized from other parts of the U.S.).  But this year, possibly the only Lone Star periodical cicada brood is emerging along the Red River in north Texas.

“It was almost uncomfortable to listen to,” said Tim Brys of the Dallas Zoo, who recently heard and collected some of the red-eyed periodical cicadas in Fannin County.

This periodic emergence is thought to serve as a protection from predators for the tasty cicada.  By emerging en masse only once every 13 years, predators like birds can only hope to harvest a small percentage of the loud, clunky and relatively slow insects.

If you’ve always wanted to see a periodic cicada emergence, this could be your year.  Texas counties where the cicadas have been found in the past include Montague to Red River counties along the Red River, and further south Wise, Denton, Hunt and Kaufman counties.  There is no guarantee that if you live in these counties, you will hear or see these red-eyed relics of the ice age.  By some accounts, numbers of periodic cicadas are in decline, likely due to development and destruction of native tree groves that have fed these insects for thousands of years. Brys collected his Texas cicadas after hearing them along a hike to a remote area on the north Sulfur River.

You can recognize periodical cicadas by their red eyes, black bodies and orange veins on the wings. The last time the 17-year periodical cicadas were heard in Texas was 1998. A resource page on this year’s Brood IV cicadas has been set up by entomologist Mike Quinn.  Relatively little is known about our Texas cicadas, so if you think you have seen periodical cicadas in your area, you can even report them here, and by all means collect some if you can (they may be dead on the ground after completing mating and egg laying).  And if you want to hear the periodical cicada call before you explore, click here.  For a link to sites where spotters have seen periodical cicada this year, click here.

Mosquito news release out today

Mosquito on leaf
Even if you don't allow standing water in your own yard, mosquitoes will fly from nearby breeding sites and rest in shade until evening arrives.

Even if you don’t allow standing water in your own yard, mosquitoes will fly from nearby breeding sites and rest in shade until evening arrives.

Probably most of you don’t need to be told mosquitoes are bad right now and it has to do with rain.  But Texas A&M AgriLife Extension just posted a news release on the subject that might shine some light on why, and what you can do.  Check it out at http://today.agrilife.org/2015/05/28/texans-expect-mosquito-explosion/ 

Webinar on emerald ash borer available

Green ash
Green ash is an important forest and shade tree in many parts of Texas.

Green ash is an important forest and shade tree in the eastern third of Texas.

If you live anywhere in east Texas and have an ash tree you love, you may want to check out this new webinar on emerald ash borer.

The webinar reviews some history and background on the new invasive pest that is likely to enter Texas very soon. I was invited to present on this topic by Dr. Mengmeng Gu as part of her Spring Quick-Bite webinar series this week.  So fair warning that you will be listening to me for 43 minutes.

The webinar goes over some basic biology and how to identify the EAB.  I also discuss control strategies and what pesticides are being used to manage this pest.  Although the prognosis for Texas ash is uncertain, we do have the advantage of 10 years of research managing this beetle in the midwestern states.  In addition, new biological control agents show some promise for slowing the natural advance of this pest.

So check it out.  You owe it to someone you love.

Time for repellents

bottle of Repel spray with lemon eucalyptus
The natural repellent, lemon oil of Eucalyptus, is a good alternative to DEET for those who prefer organic. The important thing is to find a repellent you will use, and use it.

The natural repellent, lemon oil of Eucalyptus, is a good alternative to DEET for those who prefer organic. The important thing is to find a repellent you will use, and use it.

Yesterday the Texas Department of State Health Services announced the first 2015 case of West Nile virus in Texas.  Coincidentally, Dallas County Health and Human Services issued a health advisory reported the first positive mosquito pool of the year was collected Wednesday.

And to add insult to injury, this week my wife and I both got our first chigger bites of the year.

All of this is a good reminder that summer is around the corner, and that insect repellent is our best defense against the less savory insect and mite characters lurking out there.

The best way I’ve found to be consistent with my use of repellent is to keep a spray bottle just outside my doorway.  That way I am reminded, even if I’m only out for a short while, to spray exposed skin.  Similarly, keeping a repellent in your car is a very good idea.

There are very good formulations of DEET out these days, many with low odor, and in several different forms: wipes, creams, pump sprays and aerosols.  DEET has some of the best persistence; however there are good alternatives to DEET if you aren’t going to be outside very long.  The U.S. Environmental Protection agency provides a repellent calculator to help you dial in your needs and find the repellent you like best and will use consistently.

West Nile virus is something everyone should take seriously.  Check out these videos for tips on reducing mosquito numbers around your home.  And if you haven’t taken part in the Mosquito Safari, this is a great time to take the tour.

 

 

A roly poly invasion

Pillbugs feeding on vinca
Pillbugs are semi-aquatic organisms that breath via gills. No wonder they seem to love this rainy weather.

Pillbugs are semi-aquatic organisms that breath via gills. No wonder they seem to love this rainy weather.

Is it just me, or are we in the midst of a roly poly invasion?  Now, I tend to not “see” some of the same pests other people see, because they just don’t bother me.  I’ll look right past a spider in the house, because it’s just doing its thing.  Similarly, I don’t tend to notice roly polies, also called pillbugs, because I’m so used to them living in the heaping piles of mulch around my home.

The past month, however, working on my lawn and landscape, even I have noticed the pillbugs. They are everywhere… BY THE MILLIONS. While I know to expect pillbugs in my garden mulch, I don’t believe I have ever seen so many pillbugs in the grass of my lawn.

So what’s going on here?  Pillbugs are isopods, a type of Crustacean, and only a few evolutionary steps away from the water.  In fact, pillbugs and sowbugs breath, like their aquatic cousins, through gills, and do especially well in wet environments. They are also one of the few arthropods that have the ability to eat and digest cellulose.  It appears that with our unusually wet Texas spring, pillbugs have everything they need.

Pillbugs feeding on vinca. When numerous, pillbugs can do significant damage to young garden plants.

Pillbugs feeding on vinca. When numerous, pillbugs can do significant damage to young garden plants.  Photo by D.W. Reed.

I wouldn’t mind pillbugs so much if they confined themselves to feeding on mulch (even if I curse them a little every spring when I have to re-mulch our landscape beds).  But when numerous as they are right now, pillbugs are not shy about feeding on roots and tender stems of garden flowers and vegetables.  In the past week I’ve watched my proud double row of green onions fall like dominoes, chewed at the base by hungry pillbugs.

I suppose some of this is our own fault.  With the increased use of garden mulch and wood chips in recent years, we’ve provided lots of food for pillbugs.  In yards hard hit by drought and disease and winter cold, there is plenty of food in the form of thatch and new growth to keep pillbugs happy.

While there’s little we can do to stop the rain, there may be a few steps we can take to discourage pill bugs.  Avoid putting too much mulch in your garden.  A four-inch layer is generally sufficient for insulation and water retention, anything over that will serve to attract and feed more pillbugs.  Keep mulch away from the foundation of your home by 6 to 12 inches.  If you are planning to mulch, keep your initial layers thin (enough to hold the soil) until we see some drier weather.  You can always add more later, and your garden does not need the mulch as much when it’s wet anyway.

If planting new flowers or vegetables, consider treating the planting bed first with a liquid insecticide like permethrin, labeled for garden use.  Newly emerged plants may need a protective spray every week or so.  When treating vegetables, just make sure to allow enough time between last application and harvest, according to label instructions.

For more information about pillbugs, see https://citybugs.tamu.edu/factsheets/landscape/veggie/ent-1006/ 

 

May beetles on pecans

unknown species scarab beetle adult
unknown species scarab beetle adult

An early April-emerging species of scarab beetle. These early emerging beetles often fool people into thinking they are being invaded by the grass-destroying June beetle.

Nearly everyone who’s grown up in a rural or semi-rural area of Texas knows about “Junebugs”, or more correctly, June beetles. These are the heavy bodied, spindly legged beetles that flock to lights at night.  Even in my suburban home, miles from pastures or farm fields, we get June beetles and their relatives coming in waves throughout the spring, clumsily bumping against window screens, drawn by the light.

It seems that “June beetle” is not a very accurate descriptor of the dozens of species of spring emerging scarab beetles that we see every year.  Some species emerge long before June, as early as March. And unlike the June beetle, which can be a pest of turfgrass during late summer and fall, these early beetles do not seem to cause much damage to lawn or garden or farm… with a few exceptions.

Pecan orchard in Wharton, TX. Note the younger trees have been almost completely stripped by May beetles.

Pecan orchard in Wharton, TX. Note the younger trees have been almost completely stripped by May beetles. Photo by Bill Ree.

Some of these early species, especially those that emerge during May when trees are leafing out, do cause significant damage to tree foliage. Over 15 species of Phyllophaga (the June beetle genus) have been recorded feeding on pecan alone. According to Bill Ree, Texas A&M AgriLife Extension pecan program specialist, these early emerging beetles can strip the new vegetation from pecan trees.

The tricky thing about diagnosing the cause of damage by May beetles is that they are active only at night.  During the day you won’t see any sign of the beetles.  To tell if defoliation is caused by May beetles, Ree recommends looking for these things:

Presumed beetle damage to pecan.  Note the notched petiole indicated by the arrow. This is a sign of beetle damage.

Presumed beetle damage to pecan. Note the notched petiole indicated by the arrow. This is a sign of beetle damage. Photo by Bill Ree.

  • there is damage but the culprit is nowhere to be found
  • damage may be severe, but small patches of foliage may remain in the canopy
  • damage is more severe on young trees although larger trees can have some of the same symptoms
  • damage goes above any grazing height for deer or livestock, and
  • there may be feeding damage on the new stem or petiole where it looks like the adult beetle took a few bites (as indicated by the arrow in the picture)

Whether to treat trees is not an easy question to answer.  This sort of damage is unpredictable, and according to Ree it’s not a good idea to treat trees with “hard” (broad spectrum) insecticides early in the season, because of possible negative effects on beneficial insects that control later season pests, like pecan nut casebearer.  And, he points out that in most cases, the trees should re-leaf and recover quickly. Nevertheless, if treatment is judged to be needed, beetles can be killed with standard broad-spectrum insecticides labeled for use on pecan, such as chlorpyrifos or one of the pyrethroid insecticides.

For landowners with just a few pecan trees, and no access to commercial spray equipment, treatment should hardly ever be justified.  Defoliated trees may need a little extra fertilizer and zinc, according to standard recommendations for pecan production.  For more information about pecan growing for homeowners, see http://agrilifelearn.tamu.edu/Guide-to-Pests-of-Peaches-Plums-and-Pecans-p/e-145.htm

Wild about insect photography

seven-spot lady beetle adult

IMG_5341_smLast week renowned insect photographer Alex Wild gave a webinar (web delivered speech) on insect photography for Entomological Society of America members.  Anyone interested in insect or macrophotography stands to get a lot out of this hour-long video.

If you’re thinking I don’t have a good enough camera to get into insect photography, the talk focuses on five principles that will help anyone with any digital camera, including a cell phone.  The principles include:

  • Keep it simple
  • Consider the light
  • The Center’s not the Center
  • Tell a Story with your lens position
  • Patience is a virtue

And lastly, something I really appreciate, he talks about dealing with uncooperative subjects.  I’ve often envied my horticulture and weed specialist colleagues whose subjects don’t run when the camera emerges. Alex shares a few tips that will help you tame those frisky insects prior to taking the shot. All in all, a worthwhile way to spend an hour.

Bug with a punch

fourlined plant bug
As pretty as they are, fourlined plant bugs like to stay out of sight.  Look for damage first, then the bugs.

As pretty as they are, fourlined plant bugs like to stay out of sight. Look for damage first, then the bugs.

I ran a story about this insect 5 years ago, and thought it might be time for a refresher course. The fourlined plant bug,  Poecilocapsus lineatus, is a small, attractively colored insect that is active right now. Don’t be fooled by its pretty face.  This insect has been recorded as a pest from about 250 different plant species, both herbaceous and woody plants. Herbs, mints, and composite flowers seem to be especially favored.

What makes the fourlined plant bug unique is the rather severe damage (see image) that can be caused by relatively few individuals. Its damage is one of the most severe for a leaf-feeding bug of this size, according to USDA scientists who recently reported on the feeding behavior of these insects. They found that the four-lined plant bug’s saliva, produced by unusually large salivary glands, making up 15-20% of the insect’s body weight.  In addition the saliva itself packs a special punch. Special enzymes attack the glue that holds plant cells together, causing pits in the leaves where the cells literally collapse after feeding.

The damage on some plants look like round pits or craters.  On other plants feeding spots are delineated by leaf veins. The pitted areas eventually turn black or translucent, and may eventually drop out of the leaf, leaving holes that sometimes looks more like a caterpillar than a sap-feeding insect.

Fourlined plant bug damage on Shasta daisy appears like round pits.

Fourlined plant bug damage on Shasta daisy appears like round pits.

Most of the damage seems to be caused by the nymph stage. By the time adults appear much of the damage has been done.

Treatments for fourlined plant bugs include insecticidal soaps, oils or other insecticides labeled for the plant attacked. Soaps and oils will be most effective on the wingless nymphs, and may not harm the adults. Sevin, malathion, and some of the newer pyrethroids, such as cyfluthrin and permethrin, should work well against both nymphs and adults.

If a close inspection of the plant reveals no insects, don’t treat.  Also restrict your treatments to just those plants in the garden that show damage.  There is little need to treat other plants and you’ll minimize your impact on beneficial insects.  And don’t treat plants in bloom that are attracting bees.  If you need to treat flowering plants, do it late in the day, just after sunset when bees are no longer foraging.

Kern’s flower scarab

Color variation in Kern's flower scarab
Color variation in Kern's flower scarab.

Color variation in Kern’s flower scarab.

I’ve received several reports this week from worried gardeners concerning an attractive (yes, bugs can be pretty!) beetle feeding in flowers.  The Kern’s flower scarab, Euphoria kernii, is a medium-sized (8-11 mm-long) beetle reported to feed on pollen of a number of different species of flowers ranging from roses to irises to certain grasses.  Coloration and markings of this beetle is also variable, ranging from all black to nearly all yellow with black markings.

There are several species of Euphoria found in Texas, but the one that seems to be common now in the Dallas area is E. kernii.  All Euphoria are found in fields, meadows and thickets and are abundant in early spring (April-May). An interesting thing about these beetles is that after feeding on flowers their larval habitat is reported to be in the nests of pack rats or mounds of soil associated with other ground dwelling rodents like pocket gophers.

A decision about whether to treat these interesting beetles is up to the individual gardener.  Sevin (carbaryl) and any of the common garden pyrethroid insecticides are effective against a wide range of chewing insects, and should work well against these beetles.  But for my part I’m hoping you’ll put up with a little damage and simply admire the beetles for their colors and their interesting place in nature.