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Spotted lanternfly is now in U.S.

Jeffrey Hahn, Extension Entomologist

A new invasive insect species from Asia, the spotted lanternfly, Lycorma delicatula, was discovered last month in Pennsylvania. Despite its name, this insect is not a true fly but is actually a type of planthopper which is related to aphids, leafhoppers, cicadas and similar insects.

Lawrence Barringer, Pennsylvania Dept of Agriculture

Photo 1: Spotted Lanternfly. Note spots on most of the wing and the lacey pattern on the wing tips.

A spotted lanternfly is a large insect, measuring about one and a half inches long. It is very distinctly colored and patterned. About 2/3 of the forewing is a light gray with small oval, black spots. The wing tips have a series of tiny rectangular black spots that give it a lacey appearance. The hind wings, when exposed, are brightly colored orange-red, black and white.

There are some native insects that could be confused with a spotted lanternfly, especially tiger moths and underwing moths which also can have red hind wings. However, moths are much better fliers compared to a spotted lanternfly. Moths also do not jump while a spotted lanternfly (and other planthoppers) are good jumpers.

The spotted lanternfly is known to attack about 65 different plant hosts in Korea, especially tree of heaven and grapes. It is also known to attack plants in the same genera as apple, willow, oak, lilac, rose, maple, poplar, and pine. Spotted lanternflies (like other planthoppers) damages plants by using its needle-like mouthparts to feed on plant sap.

It is unclear what the potential for damage would be if this insect becomes established in Minnesota. While there are many plants on which they are known to feed that are present in this state, a key to their ability to infest an area seems to hinge on the presence of tree of heaven which is not a native to Minnesota. In fact only one specimen is presently known to occur in the state. The question then is whether this insect could thrive on other plants. Time will tell.

If you find an insect that you believe is a spotted lanternfly, report it to the Minnesota Department of Agriculture on their Arrest the Pest line by calling 1-888-545-6684 (voicemail) or e-mailing them at Arrest.the.Pest@state.mn.us.

Click here for more information on spotted lanternflies.

Mode of action of Neonicotinoids

Karl Foord, Extension Educator - Horticulture




science.education .nih.gov


Photo 1: Paired nerves





www.animalhealth .bayer.com


Photo 2: Neural synapse


Insecticides

Insecticides can be characterized by the way in which they disrupt important biochemical functions. Many insecticides target the nervous system of insects by imparing the control of neural transmission. This can be done by disabling the system, and shutting it down. However, the majority of neural insecticides put the system in a continual state of ON giving the organism no opportunity to stop neural transmission. This results in uncontrolled and uninterrupted nerve firing. The insect that is exposed to such chemicals exhibits tremors, hyperactivity and convulsions. Sublethal doses of these chemicals can impair proper functioning behaviors such as flight orientation, and feeding while greater doses lead to a quicker death.

Normal neural transmission

A normal neural transmission proceeds down the nerve axon which splits into branches and eventually into smaller branches called dendrites. The dendrites of one nerve cell pair with the dendrites of other cells. The space between these two dendrites is call a synapse (Exhibit 1).

The electrical signal of the nerve is translated into a chemical message made up of so called neurotransmitter molecules. These molecules diffuse across the synapse and attach to receptor molecules on the dentrites of the paired nerve (Exhibit 2). The chemical message is translated back into an electrical message that then travels down this nerve cell's axon, and the neurotransmitter molecules are disassociated from the receptor molecules by an enzyme.

Neonicotinoid disruption of neural impulse

Neonicotinoid molecules enter the neural synapse and irreversibly attach to the receptors on the receiving neuron (Exhibit 2). The neurotransmitter enzyme cannot remove the imidacloprid molecule and the receptor is thus continuously active. The organism has lost control of neural transmission and either loses function or dies.

Pine Wilt

USDA Forest Service

Photo 1: Scots pine killed by pine wilt

Dan Miller, MN Landscape Arboretum

Two mature Scots pines (Pinus sylvestris) at the Minnesota Landscape Arboretum started showing tan-colored needles at the end of the summer this year and by late September both trees were dead. When one of the trees was being removed, Assistant Gardener Mike Walters noticed a blue stain in the sapwood of the tree and from his previous experience with a tree care company in southeastern Iowa; he suspected the tree had been killed by nematodes. Cross-sections of the blue-stained wood were soaked in water and nematodes, microscopic roundworms, could be observed with a dissecting microscope. A sample was then sent to the University of Minnesota Plant Disease Clinic and they confirmed the presence of the pine wood nematode (Bursaphelenchus xylophillus). This nematode is the primary cause of pine wilt disease.

Dan Miller, MN Landscape Arboretum

Photo 2: Cross section of a Scots pine infected with blue stain fungus

Pine wilt disease is an interesting and complex disease. Two insects, the nematodes, and a fungus are all involved. The nematodes are transmitted by the pine sawyer beetle (Monochamus spp.). The adult pine sawyers feed on the young shoots of pine trees and even though they don't cause much damage to the tree, the feeding wounds create entry points for the hitch-hiking nematodes. When the nematodes enter the tree they feed on the cells surrounding the resin ducts causing resin to leak and plug the water transport system of the tree. As the tree is weakened and becomes stressed, bark beetles are attracted. When the bark beetles bore into dying pines, blue-stain fungi living in the beetles also enters the tree. This fungus provides another food source for the nematodes so their numbers multiply even faster.




Natasha Wright


Photo 3: White spotted pine sawyer; the beetle that transmits the pine wood nematode



Pine wilt disease was first reported in Minnesota by Dr. Robert Blanchette (University of Minnesota Professor of Plant Pathology) in the early 1980s but the nematode is believed to be native to North America. Pine wilt disease occurs most commonly in stressed nonnative trees. In the Midwest, 90 percent of the trees killed by pine wilt are Scots pine. The disease occasionally appears in Austrian (Pinus nigra), mugo (Pinus mugo), and Japanese red (Pinus densiflora) as well. Native pine species are usually not susceptible. In most cases, only trees greater than 10 years old are attacked. Once the tree is attacked, it dies within a few weeks.

Y. Mamiya

Photo 4: Pine wood nematode inside the resin canal of a pine tree

At this point management options are limited. Insecticides and nematicides have not proven to be practical or effective. The best strategy is sanitation. Dead trees should be removed in the fall or early spring before the adult pine sawyers emerge and should be burned, buried, or chipped. Scots pines are not recommended for new plantings.


Mary H. Meyer, extension horticulturist and professor, University of Minnesota

Mary Meyer

Table 1: BEST Crabapples for Minnesota

References and Further Reading:

Beckerman, J., J. Chatfield, and E. Draper. 2009. A 33-year Evaluation of Resistance and Pathogenicity in the Apple Scab-crabapples Pathosystem. HortSci. 44(3):599-608.

Chatfield, J. A. E. A. Draper, and B. Cubberley. 2010. Why Plant Evaluations Matter. American Nurseryman 210(9):10-15.

Draper, E. K., J. A. Chatfield, and K. D. Cochran. 2005. Marvelous Malus--Ten Crabapples Worthy to Know, Show, and Grow. Brooklyn Botanic Garden. Accessed October 6, 2014.

Green, T. L. 1995. Results of the national crabapple evaluation program. Accessed online October 3, 2014.

Green, T.L. 1996. Crabapples--When you're choosing one of those apple cousins, make flowers your last consideration. Amer. Horticult. 75:18-23.

Guthery, D.E. and E.R. Hasselkus. 1992. Jewels of the landscape. Amer. Nurseryman 175(1):28-41.
Iles, J. 2009. Crabapples..... With No Apologies. Arnoldia. Accessed online October 10, 2014.

Koetter, R. and M. Grabowski. 2014. Managing apple scab on ornamental trees and shrubs. Accessed online October 10, 2014.

Romer, J., J. Iles, and C. Haynes. 2003. Selection Preferences for Crabapple Cultivars and Species. HortTechnology 13:522-526.

Schmidt, J. Frank and Sons. 2014. Crabapple Information Chart. Accessed online October 8, 2014.


Mary H. Meyer, extension horticulturist and professor, University of Minnesota

Mary Meyer

Photo 1: Adirondack close-up

Mary Meyer

Photo 2: Adirondack - whole tree

Mary Meyer

Photo 3: Beverly close-up

Mary Meyerd

Photo 4: Beverly - Whole tree

Mary Meyer

Photo 5: Bob White close-up

Mary Meyer

Photo 6: Bob White - whole tree

Mary Meyer

Photo 7: Donald Wyman - whole tree

Mary Meyer

Photo 8: Firebird close-up

Mary Meyer

Photo 9: Firebird - whole tree

Mary Meyer

Photo 10: Louisa close-up

Mary Meyer

Photo 11: Louisa - whole tree

Mary Meyer

Photo 12: Pink Spires close-up

Mary Meyer

Photo 13: Pink Spires - whole tree

Which one would I plant in my yard? Anyone from this list, but something in the name 'Professor Sprenger' does resonate with me! It is a lovely tree that greets visitors on the Snyder Terrace at the Arboretum. Others you can see easily at the Arboretum are: 'Donald Wyman' planted in mass in the first parking lot bay across from the Oswald Visitor Center; 'Adirondack' marks the entrance to the espalier in the Cloister Herb Garden; 'PrairiFire' makes the double allée at the Sensory Garden, 'Pink Spires' flanks the entry to the new Green Play Yard at the Andrus Learning Center, and two 'Prairie Maid' trees fill an island in the staff parking lot.

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