Insect Updates - Page 12 of 32 - Insects in the City

Tougher head lice in schools this year

Posted on August 20, 2015 by p-porter

The head louse is a very small insect (2-4 mm-long) and well-adapted to spending its life among the hairs on human scalps.

Sending your children off to the first day of school comes with plenty of concerns. Will they enjoy their new teachers? Will they make good friends? But one concern often overlooked in the rush of the new school year is head lice.

Now the last thing anyone should stress over when it comes to schools is head lice. But with a new school year, reports of head lice always go up. And according to a new paper delivered at the American Chemical Society and reported this week in Smithsonian.com, this year’s head lice are running with a tougher crowd.

In the paper Texas is among 25 states shown to have head louse populations that are resistant to the most commonly used head louse shampoo treatments, including pyrethrins and the pyrethroid insecticide permethrin. In fact, most states (104 out of 109 samples) tested so far have lice that are resistant to these over-the-counter (OTC) louse treatment options.

Researcher Kyong Sup Yoon, at Southern Illinois University-Edwardsville, is lead author of the study. He points out that “Just one louse that manages to survive a pyrethroid treatment can live for up to a month and lay five eggs a day. Multiply that by an elementary school, a community, and soon you’ve got plenty of resistant lice.”

Not to panic.

There are almost as many home remedies for head lice as there are worried moms; but even resistant lice can be successfully treated with OTC products with careful attention to head inspection and combing after treatment. Using two methods (insecticide plus mechanical control in this instance) is almost always better than one method when it comes to controlling pests.

In addition, new treatment options are now available through your doctor. These products include ivermectin (Sklice®), spinosad (Natroba™), and benzyl alcohol (Ulesfia®). These products will likely be more expensive, you you might want to try the OTC route + combing first. But it’s always good to have options.

I remember the battle I had with my daughter and head lice several years back. It took three treatments and repeated sessions with the comb to exterminate the cunning creatures. At least we didn’t have to resort to the barber shears.

So send those little people off to school with a smile. Chances are they will have a great year. But in case they come home some night with unwanted friends, be prepared. For more information about head lice, see our free publication on human lice. If you are a doctor or nurse looking for treatment options for head lice, check out this recent paper from the American Academy of Pediatrics on head lice guidance for the clinician.

Mosquito threat highest Now

Posted on August 13, 2015 by p-porter

In 2012 Dallas was the national epicenter of a West Nile epidemic. A mild winter and very hot summer combined to make conditions that resulted in approximately 400 reported cases and 19 deaths in Dallas county alone. While 2015 has not approached the mosquito numbers or disease transmission potential of 2012, this year’s data suggests that risk for getting a WNV infection from a mosquito is peaking higher than any time since then.

Average mosquito trap catches (bars) and the Vector Index (VI) of disease risk (lines) for West Nile Virus in Dallas County in 2012 and 2015. The VI for Aug 2015 is the highest seen since

Traditionally the potential for WNV transmission peaks in August and this year looks like no exception. Data published this week by the Dallas County Health and Human Services shows a key measure of disease risk (the Vector Index) to be higher this month than at any time since 2012. The vector index peaked on Aug 1 at 0.31. In comparison in 2013 and 2014 the VI reached only 0.19 and 0.14, respectively. A VI of 0.5 is considered high enough to justify intensified vector control methods like aerial spraying.

Though numbers of WNV are still considered low for our area (only 3 reported cases this summer), there have already been 3 cases of Chikungunya (out of 9 cases reported in the state), a disease that wasn’t even on our health officials’ radar in 2012. So far these appear to have been cases picked up from out of country travel, but anyone infected with this disease can spread it back to mosquitoes locally. This has resulted in a number of locally acquired cases in Florida and could easily happen here.

All this to say that all of us should be taking special care to protect ourselves from mosquito bites this time of year. Don’t assume that because it’s not been raining, you don’t have to look for sources of standing water. As irrigation and septic systems continue to flow, and creeks begin to dry up, there are plenty of mosquito breeding sites around. And don’t assume that because you can go out during the day and not see mosquitoes, you don’t need repellent when out at night. The Culex mosquitoes that are our primary disease carrying mosquito come out primarily after dark.

On the other hand, anyone travelling to the Caribbean or Central America should also be diligent to wear repellent day and night to protect against Chikungunya, which is carried by day-active Aedes mosquitoes.

As the lazy days of summer pass slowly, consider this reminder. Don’t get lazy about protecting you and your family from mosquito-borne disease risk.

Spiders Gone Wild in Rowlett

Posted on July 31, 2015 by p-porter

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.

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.

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

Posted on June 16, 2015 by p-porter

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

Posted on May 29, 2015 by p-porter

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

Posted on May 28, 2015 by p-porter

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

Posted on May 22, 2015 by p-porter

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.

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

Posted on May 19, 2015 by p-porter

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. 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

Posted on May 14, 2015 by p-porter

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. 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. 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

Posted on May 13, 2015 by p-porter

Last 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.