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Highlights from the Plant Pest Lab
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No regulatory pathogens of concern or invasive insects detected.
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Research survey on client satisfaction sent on March 22, 2021. Results will inform pricing for expanded diagnostic services.
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New partnership with Tennessee Department of Agriculture and Department of Entomology and Plant Pathology to create molecular diagnostic testing capacity.
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New protocol for internships in the plant pest lab for undergraduate and graduate students.
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Tennessee Extension Master Gardeners are welcome to volunteer in the plant pet lab. Email
e[log in to unmask]
for more details.
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 Interesting
Sample
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Cherry laurel,
Prunus laurocerasus, received in Tennessee from another state
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Virus-like symptoms on cherry laurel
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May viruses on cherry (Prunus) species
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Sent for molecular testing for potential regulated virus of concern
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Still a mystery
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Private labs offer molecular testing for
Prunus, and cost is high for single samples
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With establishment of molecular laboratory, the Soil, Plant and Pest Center aims to provide molecular tests for certain serious and common plant pathogens, and to meet research
objectives
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Pest Management Questions
Q: Based on diagnosis from the lab, what preventative fungicides are available and what brands do you recommend?
A: The answer differs based on the client; a homeowner will not be able to use certain treatments or products that require things like a pesticide license for safe use. As a rule, we do
not recommend specific brands but rather labeled active ingredients. For clients with pesticide licenses/large scale operations, I recommend the most effective active ingredients based on available resistance information, and
direct them to this helpful database where they can select a specific product. Here growers and green industry professionals can filter their search by pest type, host, and select for organic products only, if necessary.
Q: Are there any control options for no-see-ums?
A: No-see-ums are a common name for tiny biting midges (1 to 3 mm long) in the family Ceratopogonidae. Unfortunately, because they are so tiny and are able to develop in a wide range of
environments, there are not many options to manage them. These insects can fly through window screens that are size 16 or higher, so finding a smaller mesh size for window screens is one option. No-see-ums are also weak fliers, so using fans can prevent them
from entering an area. For more information on biting midges,
visit this website.
Q: Can you tell me if there is a pathogen in my soil?
A: For a few soil-borne pathogens, there are some methods of baiting pathogens as a method of detection. Currently, there is no one, cost-effective way to screen a soil sample to rule
out the presence of soil-borne pathogens. Many soil-borne pathogens are what we call soil-survivors, meaning they survive in small numbers in the soil until a susceptible and stressed host plant is introduced to the soil for them to infect. Sometimes these
pathogens only become problematic if a susceptible plant is introduced to the area. When answering this question, knowing what the client would like to plant is important in determining whether a soil test for a pathogen is warranted.
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Grass ID
Grass identification is challenging, but there are a couple of key structures and features that
really help with distance diagnostics. View more images and helpful grass management information in
this Extension Publication (PDF).
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Seed head: Reproductive
structure of grassy plant. These are not always present, and sometimes the grass has to grow fairly tall until it goes to seed.
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Leaf blade: Notice
the leaf blade. Is it covered in fine hairs, or is it smooth and glossy? Are the tips of the blades pointed, or rounded? Are there any colorations like stripes on the leaf blade?
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Collar: A
couple of structures around the leaf collar are important to distinguish grass species, including the
ligule and
auricle
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Stem:
Notice the stem. Is it covered in fine hairs, or is it smooth and glossy? When you cut the stem, what is the shape? Is it circular in diameter or
is it more triangular in shape?
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Insects to Watch for in Summer Months
Out En Masse in Eastern TN - Cicada brood X
It's the year of a Cicada brood that emerges every seventeen years! This species has more orange-ish coloration on the wing veins than other species of cicadas. The first of this brood has begun to emerge and numbers will increase significantly throughout East Tennessee
as we head into warmer months. These insects will not harm people, but they can cause damage to plants when they lay their eggs. See a map of
periodical cicada broods (PDF).
Left: Nymphal exoskeletons of cicada. Right: Adult periodical cicada.
Cicada eggs laid in Pecan tree. Photograph by David Qualls.
Cicada oviposition damage on a limb. Photograph by Steven Huff.
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Invasive Alert — Spotted Lanternfly
The spotted lanternfly, Lycorma delicatula, is an invasive planthopper that is not yet in Tennessee. So far, only one dead adult has been detected in the state. This insect is a voracious feeder
on many different host plants. It preferentially feeds on many economically important plants including grapevines, maple trees, black walnut, birch, and willow.
 
Left: Adult spotted lanternfly. Photograph by Richard
Gardner, Bugwood.org.
Right: Nymphal instar of spotted lanternfly. Photograph by Richard
Gardner, Bugwood.org.
Spotted lanternfly egg mass laid on the trunk of a tree. Photograph by Richard
Gardner, Bugwood.org.
The spotted lanternfly likes to lay it's eggs on just about anything, from tree bark to train cars, so take a look at the egg masses and be on the lookout for eggs as well as immature and mature bugs. Please contact the plant pest lab with images if you suspect
you have found a spotted lanternfly at any life stage at e[log in to unmask].
Learn more
about this pest.
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Plant Pathogen of Sassafras—Laurel Wilt and Its Beetle Vector, the Redbay Ambrosia Beetle
We have an estimated 142.4 million sassafras trees in Tennessee forests. An important sassafras
plant pathogen and its beetle vector have been detected in our state. Be on the lookout for signs and symptoms of this pathogen and beetle pest.
The pathogen: Laurel wilt, caused by fungal pathogen Rafaellea lauricola, is a serious disease of plants in the laurel
family (Laureaceae). In the forest setting, it has killed millions of redbay trees and sassafras trees. In terms of agriculturally important plants, it is also a serious pathogen of avocado trees.
Host Tree Foliage:
Sassafras albidum. Image by Norfolk Botanical Garden. Permissions here.
Symptoms of laurel wilt,
Rafaellea lauricola, on mature sassafras trees. Photograph by Alan Windham.
Symptoms of laurel wilt,
Rafaellea lauricola,
on sassafras with bark peeled back. Photograph by Alan Windham.
The vector: Laurel
wilt is spread from tree to tree by the redbay ambrosia beetle, Xyleborus glabratus. This wood-boring beetle attacks healthy trees and carries spores of laurel wilt in its mouth. These beetles
are very tiny, around 2 mm long.
Adult redbay ambrosia beetle, Xyleborus glabratus. Photograph by Rachel
Osborn, Southeast Asian Ambrosia Beetle ID, USDA APHIS PPQ, Bugwood.org.
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Featured Weed
Hairy Bittercress (Cardamine
hirsuta L.)
This winter annual weed is popping up all over the place on the Ellington Agriculture Campus.
Notes: This is a common weed in turfgrass. It is always best to consult with a turf professional or specialist before selecting a chemical control option. Certain species of turfgrass
are more sensitive to herbicides than others, and correct selection, timing, and application of herbicides is important for effective weed management.
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Flowers: White
in color, four petals, dense clusters at the end of stems, present in spring
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Leaves: Round
and wedged shaped, dissected, lower petioles hairy
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Fruit: Flattened
capsule, green then brown in color with maturation
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Aphid: This
little insect pest crawled off of this weed, reminding us that weeds can harbor insect pests and pathogens in a growing area
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Growth habit:
Basal leaves form a rosette, found most often in wet, disturbed areas
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UTIA Weed Diagnostics Resources
UTIA Weed Diagnostics Center
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The Weed Diagnostics
Center is located in Knoxville, and primarily identifies weeds for commercial clients. Please refer commercial clients to this resource, especially if you are encountering herbicide resistance problems.
The Mobile Weed Manual
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Be on the lookout mid-April 2021 for the launch
of the UTIA Mobile Weed Manual! The app will be available for mobile phones, and provides information on available herbicides for weeds in a variety of growing settings.
Turfgrass Weeds
Plant Pest Lab
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Currently establishing policy for homeowner weed identification costs. Presently, cost for one weed ID is $15. Clients will be referred to the UTIA Weed Diagnostics Center if
seeking guidance on commercial scale weed problems and herbicide resistance.
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Positive identification is not guaranteed if the condition of submitted weed is insufficient. Weed specialists may be consulted during identification process.
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Recommendations will always suggest seeking the assistance of a weed management professional to avoid herbicide damage to nearby plants.
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Soil, Plant and Pest Center
Sample Submission Links and Tips
Payment
We accept the following forms of payment:
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Online payment with a credit or debit card may be made here
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Payment by check may be made in-person or sent in the mail (do
not send cash in the mail)
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Payment by credit or debit card may be made in-person or by phone
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Payment by cash may
only be made in-person
Plant, Insect, and Soil Samples†
Plant Pest Lab Samples: plant pathogen, insect pest, tall fescue endophyte, golf course plug, homeowner weed identification
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Submission sheet here
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Information on sample submission
here
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Tip: include a handful of roots in a separate baggie from woody shrubs and trees to rule out root rot pathogens
Distance Diagnostics Samples: plant disease, insect pests, plant identification, weed identification
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Link for Extension agents
here
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Link for Tennessee Department of Agriculture agents
here
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Tip: This free service for plant pest identification is only for Extension agents and plant health regulatory specialists. You can send images to your local Extension agent to
upload for identification. Find your agent
here
Soil Fertility Samples: information on sampling and sending in your soil for testing can be found
here. See below for the submission sheet that is right for your needs.
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Lawn and Garden: Soil submission sheet
here
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Horticulture Resources: See
here
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Row and Field Crops: Soil submission sheet
here
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Row Crop Resources: See
here
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Potting mix/Raised Beds: Soil submission sheet
here
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Soil Nitrate for Pre-Sidedress Corn: Soil submission sheet
here
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Soil Researcher: Soil submission sheet
here
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**Biopond Screening (Metro Nashville): soil submission sheet
here
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Tip: If sending multiple samples, make sure your sampling notes correspond to the
sample name you give us so you can easily match results to specific sampled areas.
Plant Tissue Nutrient Analysis Samples: proper sampling is critical to accurate plant tissue nutrient analysis. Instructions
on sampling can be found
here
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Submission sheet
here
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Tip: If you suspect herbicide damage, we can rule out plant pathogens and insects as causes of plant damage, but we cannot provide chemical confirmation. Visit Tennessee Department
of Agriculture for herbicide damage claims.
Forage Samples: Forage analysis definitions can be found
here
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Submission sheet
here
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Tip: forage production, quality, and weed management information can be found
here
**This
is a provisional method formulated by our soil scientist to fulfill requirement of Metro Nashville construction requirements.
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†The University of Tennessee collects and summarizes sample data for research and extension education purposes. By submitting a sample you, or your agent, agree
to this action.
Programs in agriculture and natural resources, 4-H youth development, family and consumer sciences, and resource development. University of Tennessee Institute of
Agriculture, U.S. Department of Agriculture and county governments cooperating. UT Extension provides equal opportunities in programs and employment.
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Contact Us
Soil, Plant and Pest Center
5201 Marchant Drive
Nashville, TN 37211
Soil Lab: 615-832-5850
Plant Pest Lab: 615-834-5162
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