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It’s in your nature: Alien invaders — introduced species

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    Fence rows, once hosting blackberries, green briars, witch hazel, dogwood and wild grapes now are often smothered by knotweed. Rabbits, cardinals, catbirds and mourning doves will be seriously affected by plants offering no food and little winter cover.

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    Japanese knotweed leaves and flowers. The photo was taken on Aug. 17, and most are currently still in bloom.

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    Female gypsy moths cover a section of an oak tree trunk as they begin laying their eggs. Each female deposits hundreds of eggs and the emerging caterpillars next spring remind us of the financial and aesthetic losses caused by introduced species.

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    The tree of heaven, itself a damaging introduced species, is the favored host plant of the spotted lanternfly for food and breeding.

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    The spotted lanternfly, a serious introduced pest, is about 1 inch in length, spotted on the front half of the body, and displays bright red under wings in flight. BARRY REED/SPECIAL TO THE TIMES NEWS

Published August 24. 2018 08:43PM

 

Before our European ancestors arrived on our East Coast, we had no Norway rats or house mice. These are introduced species, stowaways on the ships arriving to our new developing ports. These rodents spread across America along with the settlers and their goods. Luckily for us, rodent poisons and a number of predators were able, except for larger cities, to keep them in check. Ports still use deterrents to keep out more.

Today, with rapid travel from coast to coast and from continent to continent, introduced species can readily move along and colonize suitable new areas. Some of our introduced pests were intentionally introduced, such as the starling and even the gypsy moth. Today, we fight a constant battle to keep unwanted (introduced species) from creating havoc.

Locally we have battled the Japanese beetle, gypsy moth, brown marmorated stink bug, Japanese knotweed, and now a new threat, the spotted lanternfly.

I don’t think any of our readers saw the beautiful hardwood forests of Pennsylvania when American chestnuts dominated the forests. Chestnut blight, an introduced fungus arrived in the northeast by accident, and today, no mature chestnuts can be found.

Why are these alien animals and plants such a problem? Gypsy moths, for example, were native to Europe. They were kept in check by birds that adapted with them and were able to ingest their caterpillars. Parasitic flies and wasps were found there too and did their job. When introduced to America they had no natural controls.

Imagine taking cottontail rabbits to a state in the U.S. where no snakes, foxes, hawks, owls or weasels lived, and how exponentially the rabbit population would explode. This is how “aliens” become so harmful/devastating.

One of our newest threats is an insect called the spotted lanternfly. First introduced in Berks County in 2014, it has now spread into Lehigh, Northampton, Bucks, Chester and Montgomery counties. I have heard of no reports of them in the Times News area (yet). They are especially damaging to grapes, fruit trees, hops and hardwood trees. My son and grandsons, beginning in July of 2017 were killing dozens a day on their ornamental trees. That is in southwestern Lehigh County.

Farmers, vineyard and orchard owners have a reason to be worried. Pesticides do kill them, but that is an additional cost and applying more pesticide kills many beneficial insects, too. The counties listed above are quarantined and efforts to halt their spread may help. The lanternfly is not a strong flyer (long distance) but can hop away and take a short flight burst. Most are spread by firewood deliveries, RVs being moved from affected areas, or even hitchhiking in delivery vans.

The damage occurs when their sapsucking mouthparts produces a honey dew substance, which encourages a leaf scourge called sooty ash, effectively stopping the leaves’ photosynthesis. The lanternflies display a bright red underwing when they fly. Hopefully my photo will help you identify them. If you find any in our area, contact badbug@pa.gov.

Its favored host tree, tree of heaven, has been in our country over 150 years. (Brought here intentionally from its native China.) It does not tolerate shade well so it grows extensively along roadsides, railroad beds, and mechanically cleared or abandoned lots. They reproduce by underground shoots spreading an incredible distance so “chain sawing them down” simply encourages shoots to sprout up everywhere near the stump. If that isn’t bad enough, they can produce over 250,000 seeds per plant which spread great distances by the wind. They have compound leaves (like walnut or sumac) that can reach 30 inches in length. They are blooming or just finished blooming as you read this column. To see them, drive Route 248 south from Weissport to Palmerton. They dominate most of the nonforested roadside.

Japanese knotweed has been established here for over 125 years. They were introduced to serve as an ornamental around homes. Almost impossible to kill, it has spread to recently cleared areas, roadsides, railroad beds and culm banks. It particularly likes moist areas, and unfortunately our native and beneficial streamside plants are disappearing. It spreads rapidly by underground stems (rhizomes) or by seeds. The roots can spread underground over 6 feet and soon knotweed completely engulfs an area. It can grow 8 to 10 feet tall each summer, creating almost impenetrable, junglelike growths. One area along Pohopoco Creek is impossible to walk through. (You would need a machete to cut your way through it)

Unfortunately, herbicides can be effective if applied repeatedly (following specific guidelines) but any vegetation nearby is killed as well. Identified by its heart-shaped leaves and bamboolike stems, look for them along almost every road side. The largest concentration and best place to see the scope of their dominance is along Route 209 between Lehighton and Packerton (In the “Packerton Dip.”) Knotweed covers acres and acres of the old Packerton Yard area.

I remember a long ago commercial quoting: “It’s not nice to fool Mother Nature!” We indeed have made a “mess of things “with our introductions. Be aware of quarantines and why we try hard not to bring unwanted and then uncontrollable species to new habitats.

This Week’s Nature Trivia: As most know, bald eagles preferred food is fish. However since late July until this past week, a few eagles have been observed feeding on carrion or “roadkills.” Why might that be occurring?

Last Week’s Trivia answer: Assateague Island has a protected and monitored section of beach where endangered piping plovers are able to breed successfully.

This week’s nature hint: By the time this column is published the barn swallows will be well on their way to South America, the warblers and flycatchers are now moving south through our forests so this is the second best time of the year to get out there and bird. Enjoy!

Contact Barry Reed at breed71@gmail.com.

 

 

 

 

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