Plant Problem Sample Submision

The Plant and Insect Diagnostic staff can investigate plant problems, including diseases caused by pathogens, noninfectious disorders and insect damage in plants. Remember we do not test for herbicide residue in plants.

Proper samples and as much information as possible in the submission form is very important to reach an accurate diagnosis of the problem. Please print and complete a submission form to include it with your sample. 

Plant problem samples ($20 fee*) – disease, insect, disorders (suspected herbicide or other abiotic problems), please use form  PIDC 45 Sample Submission Form

Use the sections in the red boxes as indicated below.
 

* Fee applies for routine processing, standard morphological and microscopic diagnosis. Contact us before submitting an out-of-state sample for fees and restrictions. Additional fees may apply for molecular and serological-based diagnostic methods, use approval for additional testing fee box in the submission form (see additional testing options below).

Perform rapid serological testing (additional $15 immunostrip, result update within one business day)

Common greenhouse virus: CMV, INSV, TMV, & TSWV, Potyvirus, ZYMV - Zuchini Yellow Mosaic,Plum Pox Virus PPV, HVX - Hosta Virus X, Phytophthora, ArMV-Arabis Mosaic Virus, Erwinia amylovora, Ralstonia solanacearum. For limited time: CMM, Rhizoctonia, Pythium. Please contact us. 
 

Perform rapid serological testing (additional $25 ELISA, result update within 5 work days)

ApMV -Apple Mosaic Virus. For limited time: Bacterial leaf scorch. Please contact us. 

Perform DNA testing

Oak wilt May- October (additional $30, total cost $50)- especially recommended for oaks in the white oak trees (lobed leaves), and all oaks after mid September.

XVV (additional $10, total cost $30)

Other available, please contact us

DO not send Cash or payment with your sample, see submission form for details and visit our clinic services and fees page

 

General Tips for Sample Submission (including packaging and mailing)

Provide freshly collected specimens.

Provide plenty of plant material. When possible send the entire plant, including roots and top growth.

Be sure the specimen represents the problem. Include enough plant material to show all stages of the disease from healthy to sick.

Provide lots of information, such as a description of the soil, nearby plants, and a history of the problem.

Include quality photos when possible (follow guidelines “digital photography”). We welcome videos as well.  Send your digital files to pidc@iastate.edu and make sure to include in the subject:  submitter last name, crop and sample submission date (MM/DD/YY). Example: Smith-maple-05/20/15.

For entire plant samples: Bag the roots and seal at the soil line with a twist tie or a rubber band. Use another bag for the above ground plant parts, but do not cut the root ball off the above-ground plant parts. This will ensure the soil is contained, and it does not make contact with the foliage. See video Collecting Whole Plants For Plant Problem Diagnosis at https://youtu.be/WcY71SSVM0M

Wrap specimens in paper towels or clean newspapers. Do not add moisture. The additional moisture can result in rapid decay of the sample. Pack loosely in a plastic bag to reduce drying.

There is no need to add ice to the packages (except for oak wilt samples, see woody plants section). Ice will either melt and leak or freeze the plant material that is in contact with it, rendering the sample useless.

Mail in a sturdy container. Samples should be enclosed in boxes or another crush-proof packaging. Avoid sending crop/plant samples in flat envelopes because in most cases the sample will arrive too damaged to diagnose.

Keep in mind the transit time. We prefer samples to be sent overnight, but if regular mail is used, the sample will be in transit for up to 4 days, and the quality of the sample may be compromised, so please collect and send them on a Monday if using regular mail.

General Tips When Scouting and Sampling Agricultural Crops

While inspecting the issue, take pictures of the symptoms (close-up and general distribution in the field, greenhouse, high tunnel, garden, landscape, etc.).  Please make sure that the pictures are high quality and in focus. Use the macro option in your camera (tulip icon in most cameras and smart phone cameras) for close-ups. Attach the pictures to an email to pidc@iastate.edu and in the subject include submitter last name, crop/plant and sample submission date (MM/DD/YY). Example: Smith-pepper-5/20/17.

Collect several samples. Select plants from areas where symptoms are starting, developing and developed. Avoid plants with advanced symptoms. A completely wilted or dead plant is not a good subject to submit

When submitting a plant, roots and all, make sure the soil is contained, so it does not make contact with the foliage. Keep in mind we do not test for herbicide residue, nutrient levels in the foliage or soil, or these for pathogens (organisms that cause disease) in soil samples.

Specific Plant Submission Instructions

Field Crops

Seedlings: Send several whole plants, roots and all. Be sure to dig up the roots rather than pulling the plant from the ground. Watch our video “Sampling For Seedling Disease” 

Foliar diseases: Send 6-10 leaves showing disease symptoms with varying severity.

Root rots: Collect 2-3 whole plants. Be sure to dig the roots rather than pulling the plants from the ground. When packaging whole plants for delivery make sure to bag the roots to prevent soil from covering the plant foliage. Watch our video Collecting Whole Plants For Plant Problem Diagnosis 

It is also important to remember above ground symptoms can be caused by diseased roots. If you are unsure of what the problem might be, send in 2-3 whole plant samples. All samples should be wrapped in dry newspaper/paper towels. Never add water to a sample. Other details to include are cropping history, the pattern of symptoms in the field, chemical history, and cropping history.

 Send several whole plants, roots and all. Be sure to dig up the roots

 

 

Conifers

Needle drop/tip blight samples: collect 2-3 branches approximately 1.5-2 feet in length showing both symptomatic and healthy needles. Watch our video here Collecting Tip and Needle Blight Samples

Proper sampling of tip blight diseases in conifers. The sample on the left shows a mixture of healthy and symptomatic tissue. The picture in the top right shows a sample where the symptomatic tissue has already been shed and the photo on the bottom right shows only healthy tips in absence on symptomatic tissue.
 

Pine wilt: If you observe a pine tree (particularly an Austrian, Scots or other non-native pine) decline very rapidly a sample should be submitted to test for pine wilt. This requires a branch that is at least 2 inches in diameter and approximately 1.5-2 feet long.

If you are uncertain of what type of sample to collect, please email pictures of the tree/trees in question, and we can direct you on what type of sample to collect.

Proper sampling of pine tree for pine wilt. The pictures on the right and top left show banches that are at least an inch in diameter and showing blue staining. The picture in the bottom left shows an improper sample, where the branch is not thick enough to properly assess for the presence of pinewood nematode.

 

Woody Plants

Collect samples from branches that are showing symptoms but are not dead. Include branches and twig with leaves attached. In some cases, the root systems may be needed.

left, provide plenty of plant material, middle if a vascular disease is suspecte

Woody sample example. Left, provide plenty of plant material, middle if a vascular disease is suspected, we recommend to inspect the sapwood of branches and twigs and including multiple samples of the same plant (no extra charge). Right observe cankers

For Dutch elm disease, oak wilt*, and Verticillium wilt testing, branch specimens should consist of 4 to 6 pieces, measuring 6 to 8 inches long, and 1/2 to 1-inch thick, check for vascular discoloration when collecting sample and include branches with sapwood discoloration.

*For suspected oak wilt samples, check our video “Special type of sample needed when testing for oak wilt” at https://youtu.be/Fkgomb4pvsM, and use our oak wilt sampling check list here (https://hortnews.extension.iastate.edu/oak-wilt) that follow the forest service instructionsSend the samples overnight and include ice in the packets around the sample (see photo). Refrigeration is crucial, lack of refrigeration increases the chance of false negatives.  

Oak wilt packaging example. Top left Styrofoam cooler. Top right, note the icepack (red arrows) on each side of the branches in the bag. Note submission form filled and enclosed in a separate bag. Bottom pictures, please remember to include leaves samples. 

When submitting cankers, include the portion of the branch at the border between discolored and healthy bark.

For root rots and crown root confirmation, digging the root ball (see photo below) and send it along with some stems. The root ball and crown is the best tissue for us to recover (isolate) the pathogen.

For some diseases, eventhough the symptoms are observed in the leaves, the pathogen is located in the root and crown. You can contact us with photos at pidc@iastate.edu, and we can tell you if we recommend sending a sample of the plant root ball and crown.

Fruits

Collect samples with symptoms representative of what you are seeing in the field. Wrap specimens (twigs with leaves attached, branches and/or fruit) in enough clean, absorbent material (such as paper towels) to absorb all leaks. Do not add moisture. Please note in your submission form if you see cankers (sores in twigs, branches or trunk) or a gummy material oozing from them. Avoid sending detached leaves as they dry out very quickly.

Example of proper sample from tree fruits

 

Vegetable and annual ornamental crops

Before applying any disease‐controlling chemicals, collect samples from the affected area in the greenhouse or the field. The sample should include both healthy and infected plants.

For seedlings samples: send whole plug trays, leave the plugs in the tray, (see example below)

If potted, bag the pot and seal at the soil line with a twist tie or a rubber band bag. Use another bag for the aerial plant parts, but do not cut the root ball off the above-ground plant parts. See video Properly Collecting and Packaging a Sample for Diagnosis

In the field/ ground, dig around the roots instead of pulling the plants. Shake most of the soil off the roots. Bag the roots and seal at the soil line with a twist tie or a rubber band. Use another bag for the aerial plant parts, but do not cut the root ball off the above-ground plant parts. See videoCollecting Whole Plants For Plant Problem Diagnosis.” 

Example of proper sample, make sure to keep the root ball ant any soil contained in a plastic bag. 

 

Turfgrass

Before applying any disease-controlling chemicals, collect turf grass from the edge of the affected area. The sample should include both healthy and infected plants. Completely dead grass is of no use since secondary organisms quickly colonize it.

Take a sample of at least 6" diameter (a cup cutter works well). Include the underlying soil and root system. Two samples are preferred (no extra charge).

Wrap the sample in newspaper or paper towels. Please do not place it in a plastic bag and do not add water. Excess moisture can cause rapid deterioration of the sample and proliferation of secondary organisms.

Provide background information, such as when the symptom first appeared, turf grass variety, and pattern and distribution of the problem. Pictures of symptoms can be very helpful.

Pack your wrapped sample tightly in a box to prevent dislodging the soil. Ship the package early in the week via overnight delivery.

An example of proper samples from a lawn on the top, packaging on left bottom, and 1 of the two cores samples from a golf course.