Waxy lady beetles come to the rescue of pest-plagued crapemyrtles, Hyperaspis spp.

 

This white waxy creature is no pest. It is the larva of a Hyperaspis lady beetle, destroyer of dastardly crapemyrtle bark scale.

 

In a previous episode we met the invasive crapemyrtle bark scale, a dastardly sucking insect new to the DMV that wreaks havoc on our widely planted crapemyrtles. Populations of this eruptive pest reach fantastic densities on the bark of these flowering trees. As thousands of probing mouthparts remove plant sap, branches of crapemyrtle wither and die. Prodigious volumes of sweet sticky honeydew excreted by the bark scale rain down on leaves and bark of infested plants and coat underlying vegetation and objects. Carbohydrate rich honeydew serves as a medium for the growth of black sooty mold fungus which reduces the photosynthetic capacity of fouled plants. Even more problematic are the yellow jackets, paper wasps, and other stinging insects that are attracted to the honeydew.  

Adult Hyperaspis beetles will continue the carnage of crapemyrtle bark scales.

Ah, but there are heroes in this story and one such natural enemy of scales insects in general and crapemyrtle bark scale in particular are small black and red-spotted lady beetles known as Hyperaspis.  Several species of Hyperaspis are native to North America and many specialize at making meals of scale insects and their eggs, which are deposited in waxy egg sacs like those of the crapemyrtle bark scale. Larvae of Hyperaspis look much more like a mealybug than the fierce predators that they are. Cases of mistaken identity surround this predator insect and many of these fine beneficial insects are misidentified and mistakenly killed. The larva of Hyperaspis produces wax from glands lining its sides. This wax is more than a way to be styling. Studies of related species of waxy lady beetles reveal that the wax reduces the effectiveness of ants and other predators that might like to make a meal of a lady beetle larva. In this way, the wax serves much like the cloak of trash carrying lacewing larvae we met in a previous episode. One fairly easy way to distinguish the larva of this beneficial ladybug from pesky mealybugs is to give it a little poke in the behind. Mealybugs tend to stay in one place and move slowly. Ladybug larvae usually amble away quickly when disturbed.

Honeydew, sooty mold, and white waxy egg sacs full of pink eggs are hallmarks of dastardly crapemyrtle bark scales. But native heroes are on the scene, the larvae of lady beetles called Hyperaspis, wearing cloaks of white wax. See these two parked near egg sacs of the scale. What are they up to? Through the lens of the microscope, watch as one chews a hole in the egg sac, thrusts its head inside and gobbles up eggs, and then when finished, leaves to find another meal. After completing larval development and pupating, adults will return to the scale hunting ground to continue their carnage of crapemyrtle bark scales. You go Hyperaspis!

Hordes of waxy larvae may eat several thousand immature scale insects during the course of development and the adult beetles consume many harmful scales too. Later in summer, Hyperaspis larvae complete development and become adults. Although the larvae of Hyperaspis are somewhat hard to recognize as good guys, adult beetles are easily recognized. The ones we met in this episode are gorgeous shiny black beetles with four red spots adorning their wing covers. Some species of Hyperaspis have fewer spots or bear combinations of yellowish spots or stripes on their back. By early December, adults have departed scale-infested trees to spend the winter in protected locations beneath bark or in leaf litter on the ground. Next spring, they will return to scale-infested trees and lay eggs that will hatch into stealthy, wax-cloaked larvae. Keep an eye out for these small masters of disguise and when you see them, do not spray them with insecticides. They are working for you!   

Acknowledgements

The fascinating article “Hyperaspis Lady Beetles” by James Baker was consulted to prepare this episode. Thanks to Dr. Shrewsbury for help wrangling lady beetles.

From the mail bag - “Oh they’re back and they’re bad”: Spotted lanternfly nymphs, Lycorma delicatula

 

Spotted lanternfly nymphs are back, and they’re bad!

 

Last week I received a whimsical video from two avid young bug hunters who spotted spotted lanternfly nymphs in a park in Washington County, Maryland. Dressed in domino-colored exoskeletons of black and white, nymphs of spotted lanternflies are unmistakable. As these budding naturalists noted, they’re back and they’re bad. This season of lanternfly evil began about three weeks ago when lanternfly nymphs hatched from overwintering eggs deposited by their mothers last autumn.

Tiny, wraithlike spotted lanternfly nymphs pop the lid on their egg case and hatch head-first from eggs deposited last autumn.

Recently, I was asked when lanternflies would go away. Like other invasive species we’ve met, such as gypsy moths, brown marmorated stink bugs, emerald ash borers, and euonymus leaf-notchers just to name a few, the answer is this: they are not going away. At this time in Maryland, spotted lanternflies are established members of our ecosystems in all but four of our southernmost counties according to the Maryland Department of Agriculture. They have also established breeding populations in more than a dozen states and spread some 600 miles distant from their point of introduction in Berks County, Pennsylvania. The good news is that, in many locations, spotted lanternfly populations have declined dramatically. In parts of Pennsylvania, naturally occurring fungi put a beatdown on lanternfly populations. A recent study by scientists revealed that a vast number of established predators are helping to quell the lanternfly invasion. Arthropods led the reported carnage with more than 200 attacks by spiders, 196 attacks by mantids, 177 attacks by wasps, 55 attacks by sucking predators like assassin bugs, and another 21 attacks by other arthropods. Twenty some families of birds accounted for more than 500 attacks, with ground dwellers like chickens and pheasants leading the way. Death delivered by members of the cardinal, mocking bird, wren, and several other bird clans contributed to the total. Mammals, amphibians, fish and non-feathered reptiles also got into the act accounting for 106 additional observations.

Two budding naturalists have it right. Spotted lanternflies are back and they’re bad. Don’t be surprised to see dozens of spotted lanternfly nymphs feeding on small branches of trees and shrubs and stems of herbaceous plants. White spotted nymphs are scrambling up tree trunks. Leaves of maples and scores of other plants can be festooned with legions of lanternfly nymphs. Will predators and disease quell their mischief? Only time will tell.

Ravaging hordes of spotted lanternfly nymphs may be controlled by natural enemies, by simple mechanical means such as knocking them into soapy water, or by the use of OMRI approved pesticides.

Circling back to the lanternfly nymphs at the top of this episode, what should you do if you find these rascals on your plants?  Well, you could just let them serve as a feast for the many predators and pathogens that will make a meal of them. Of course, if you are a viticulturalist, eliminating as many as possible is the order of the day and there are many highly efficacious insecticides to help do the job. But for homeowners, if you don’t want to wait for Mother Nature to intercede, you can knock them off your plants into a container of soapy water. They are not good swimmers. Or you can use one of several products such as insecticidal soaps, horticultural oils, or natural pyrethrins (not synthetic pyrethroids) listed for use on organic vegetables by the Organic Materials Review Institute (OMRI). Look for the OMRI symbol on the label of the insecticide. Excellent studies conducted by scientists at Penn State found these active ingredients provided excellent or good control of spotted lanternfly nymphs. Always read the label and follow instructions to the letter if you decide to go the insecticide route. Good luck dealing with these noisome pests from afar.

To learn more about the biology and management of spotted lanternfly, please click on this link: https://extension.psu.edu/spotted-lanternfly-management-guide

Acknowledgements

Penn State’s most excellent spotted lanternfly website was used to prepare this episode. Bug of the Week thanks Eloise and Abbigail for providing video footage and inspiration for this episode.

Vanishing viburnums: vandalism by the Viburnum leaf beetle, Pyrrhalta viburni

 

Larvae of viburnum leaf beetles can lay waste to beautiful viburnums.

 

Yikes! Shredded leaves are the hallmark of feeding by viburnum leaf beetle larvae.

Last week I encountered a planting of viburnums vandalized by yet another invasive species of insect. One of my favorite flowering shrubs, viburnum, had been stripped of 99.9 % of their leaves. My first thought was that some devastating weather event like drought or flood or some hideous disease had laid waste to these usually lovely shrubs. On closer inspection of the few leaves that remained, the culprit of this devastation was found - larvae of the viburnum leaf beetle. The saga of this invader from Europe begins in 1947 when it was first discovered in Canada. It took almost five decades to move south across the US border, when it was detected in New York in 1996. It has now spread to more than 20 states ranging from Maine to Florida and as far west as Washington state.

As adult beetles and their offspring feed on viburnum leaves, they create a type of injury called skeletonization, dining on tender leaf tissue between tough leave veins. So complete is their feasting that only a lacy memory of a leaf remains when they are done. These ghostly leaves soon wither, die, and drop, leaving naked stems behind. This season of misery began when eggs deposited last summer and autumn by female beetles hatched from tiny egg-niches lining small branches. In Maryland, eggs hatch near the time when Japanese camellia is in full bloom in early spring. Each female beetle can lay as many as 500 eggs. Little wonder why viburnum leaves vanish with so many hungry mouths at work.  After completing three stages of larval development, larvae move to the soil and pupate. By June, adults emerge from the soil, clamber up stems, and begin to skeletonize nutritious viburnum leaves. In summer and autumn females chew small pits along branches and deposit five to eight eggs in each pit. This tiny nursery is then sealed with a cap of mother’s poop, chewed bark, and mucous. I have to wonder if young beetles undergo intense sessions of therapy to understand why their mother pooped on them. Well, this poopy mucous cap is thought to protect developing eggs from predators and help prevent moisture loss.

Oh no, what happened to these viburnums? They look beat. Environmental stress? Hideous disease? Let’s take a closer look at the few green leaves left standing. This is the larva of the nefarious viburnum leaf beetle, invader from Europe that vandalizes viburnums. Thousands of hungry larval mouths completely stripped these shrubs.  Later this year adults emerge, mate, feast, and lay eggs, levying more misery on viburnums.

In June adult viburnum leaf beetles will emerge from the soil and move to leaves to mate, feed, and lay eggs.

What can be done to thwart these rascals? Clever research conducted by Cornell University revealed significant variation in susceptibility of different species of viburnums to attack by viburnum leaf beetle. Sadly, some of my favorite viburnums are on the “most susceptible” list, including our abundant native arrowwood viburnum, Viburnum dentatum. Two other species on the “most susceptible” list are   Viburnum trilobum (previously known as Viburnum opulus var. trilobum), European cranberry bush viburnum, and Viburnum sargentii, Sargent viburnum. The University of Maryland lists these viburnums as resistant to viburnum leaf beetle: ‘Dawn’ viburnum, V. x bodnantense, Koreanspice viburnum, V. carlesii, David viburnum, V. davidii, Judd viburnum, V. x juddii, doublefile viburnum, V. plicatum, doublefile viburnum, V. plicatum f. tomentosum, leatherleaf viburnum, V. rhytidophyllum, tea viburnum, V. setigerum, and Siebold viburnum, V. sieboldii. 

Viburnum branches bear the scars of egg nests made by viburnum leaf beetles.

If redesigning your landscape by planting resistant viburnums is not feasible, here are a couple additional things to consider. Sometime between the last killing frost of a season and the following spring, prune out branches bearing egg masses of viburnum leaf beetles and destroy them. Several species of predators attack and eat viburnum leaf beetles, including lacewing larvae, lady beetle larvae, and assassin bug larvae and adults. Including a rich diversity of flowering herbaceous and woody plants in your landscape will help support these beneficial insects that depend on floral resources and alternate prey to become resident in your landscape. If all else fails and as a last resort, you can annihilate infestations of beetles for at least a short period of time by applying insecticides labeled for beetle control. Because viburnums are so heavily visited by pollinators, systemic insecticides that may show up in nectar or pollen are not the best choice. Several products listed for use on organic vegetables listed by the Organic Materials Review Institute (OMRI) may be a better choice. Always read the label and follow instructions to the letter if you decide to go the insecticide route. Good luck saving your lovely viburnums.

Acknowledgements

Bug of the Week thanks Dr. Paula Shrewsbury for contributing images and comments to the episode. Bug of the Week is supported by the Department of Entomology at the University of Maryland and grants from USDA – NIFA. To learn more about viburnum leaf beetle and its management, please visit the following websites that were consulted for this episode:

https://extension.umd.edu/resource/viburnum-leaf-beetle/

https://www.youtube.com/watch?v=_BPp-9MljSc

https://entnemdept.ufl.edu/creatures/orn/beetles/viburnum_leaf_beetle.htm#:~:text=The%20viburnum%20leaf%20beetle%20overwinters,%2F5%20inch)%20at%20maturity.

https://www.canr.msu.edu/news/keep_your_eyes_open_for_the_viburnum_leaf_beetles

When ants move in: Odorous house ants, Tapinoma sessile

 

Odorous house ants regularly tend aphids and gather sugar-rich honeydew produced by the aphids.

 

A drop of syrup on a countertop can attract a large crowd of ants.

Last week with the return of summer weather here in the DMV, it wasn’t just periodical cicadas that amped up activity. When Mother Nature turns up the heat, other cold-blooded insects resume their quest for food and shelter. My personal home invasion began on a warm day last week when legions of foraging worker ants laid down a trail from my patio door, along the baseboard, and up the wall to a drop of syrup on the kitchen counter. Odorous house ants have become a perennial guest at Bug of the Week. These small brown ants invade homes throughout our region each spring. This ant earns its name by virtue of the distinctive smell it makes when crushed between your fingers or on a counter. The odor is reminiscent of slightly fermented coconuts. 

How and why does this invasion recur each year? After spending the chilly months of winter and early spring in a state of relative inactivity outdoors, with the return of warm weather, worker ants conduct an unending search for sugars, proteins, and fats to feed hundreds of hungry mouths in their burgeoning colony. In the wild, plants like my peony and other insects like the aphids on my peony provide these foods. When ants locate a rich source of food, such as the sugary honeydew produced by a colony of aphids or scale insects, they establish a trail marked by chemicals called pheromones. The trail leads other workers from the nest to the bounty. 

With the return of summer-like weather, odorous house ants can be found outdoors foraging at floral nectaries like those on a peony. Honeydew produced by phloem feeding insects like aphids is an irresistible source of food for ants. When sweets drip on countertops, scouts recruit other workers and a full-blown home invasion can ensue.  Baits laced with insecticides can foil ant invasions as one by one, workers collect the toxic treat, return to the colony, and poison their nestmates.

Outdoors, odorous house ants nest beneath stones or fallen logs. I usually have several colonies in my yard in a woodpile or under stones in a wall. However, odorous house ants are very opportunistic and will occasionally enter homes to set up shop. I have discovered colonies of these rascals in my wall voids and in electrical appliances, including a surge protector beneath my desk. Their quest for food brings them into homes and a few grains of sugar on the counter, a pet dish on the floor, or a leaky bottle of pancake syrup in the pantry, will often initiate a full-scale invasion by searching workers. If you find ants and their telltale trails on counters or along baseboards, try to locate the source of food and then follow the trail back to the point of entry into your home. To foil these raiders, first eliminate as many sources of food as possible. Clean the counters, mop up drips, and get pet food off the floor after your pets have eaten. Be sure that no syrup or sweets are spilled or leaking in your cupboards. Ant trails on the counter or floor can be disrupted by spraying them with household cleansers. 

This highly attractive poison bait will bring a swift end to home-invading odorous house ants.

You can buy ant traps or purchase tubes of liquid or gelatin ant baits. Place ant traps or baits at locations indicated on the label. I usually place one near the point of entry to my home and several others around my counters and near their raiding columns. The traps and baits contain a lure that attracts ants searching for sweets or fatty foods. The lure contains poison. Workers ingest the toxin and are killed, or in some cases they carry the toxic treat back to the colony and feed the deadly meal to the queens and their nest mates and, voilà, the royals are assassinated and the colony along with them. A few well-placed bait stations in my kitchen put an end to the ant trails in a matter of days. To be effective, the bait must attract the ants you want to control. If you purchase a bait or ant trap, and the ants eschew your invitation, well, get yourself another type of trap or bait.

Whenever you use a product containing an insecticide, be sure to follow precisely the instructions on the label. Never apply pesticides directly to surfaces used for food preparation or consumption like countertops or tables. Many species of ants can become visitors or residents in our homes. Large black ants in the home, especially ones with wings, may be carpenter ants and a sign of more serious problems than just a little sugary larceny. If you have concerns or questions regarding the identity or management of any six-legged vandals, contact the local university extension office in your county or state for advice.