Carefully follow the instructions below to select, package, and mail the plant disease specimen. The accuracy of diagnosis depends upon the quality of the information provided, the plant material selected, and the condition of the specimen when it arrives at the Clinic.

Submission Forms

Collecting a Sample for the Penn State Plant Disease Clinic

Checklist: Did you…

  • fill out the specimen information form thoroughly and for each sample?
  • select a large enough specimen with symptoms?
  • read the appropriate submission instructions (below) for the type of specimen being submitted?
  • package the contents correctly, using dry paper towels if needed, enclosing any roots, and placing them in a plastic bag?
  • protect the sample with newspaper, cardboard or other material to prevent crushing if necessary?

Specimen Information Form

  • Complete the specimen submission form as thoroughly as possible.
  • Fill out a separate form for each plant specimen submitted
  • The form should be separated from the plant material by plastic or another waterproof barrier

Commercial growers : Please note in the 'Additional Comments' area of the clinic specimen information form if you suspect that the sample being submitted could contain fungal toxins (such as found on moldy wheat or corn samples, or moldy paper containers used in greenhouses), or could harbor a USDA-APHIS designated select agent (such as Ralstonia solanacearum, race 3, biovar 2 or soybean rust).

Selecting and Packaging Plant Disease Material

Correct Packaging

  • Select plants showing symptoms of concern
  • When possible, send several plants showing a range of symptoms
  • Please do not send dead, dried samples
  • Do not add water or wet paper towels to the package

When possible, send entire plants including roots

  • Place root ball in plastic bag and fasten around stem
  • Place a dry paper towel around leaves
  • Enclose entire plant in a larger plastic bag

Vegetables and Fleshy Fruit Samples

  • Select firm specimens that show early and intermediate stages of disease
  • Wrap each specimen separately in dry, absorbent paper, such as toweling
  • Pack individually to avoid crushing

Leaf, Stem and Branch Samples

  • Send several affected parts
  • Cut stem/branch samples so that a piece of live, healthy tissue is attached to the diseased portion
  • Wrap the specimen(s) in a plastic bag with a few small ventilation holes
  • Protect tender leaf/stem samples by placing between cardboard/heavy paper

Root Samples

  • Collect a handful of roots (about 1-2 cups) from multiple locations around the plant.
  • If only one side of the plant is affected, collect roots from the side of the plant showing symptoms.
  • Select a mix of large roots and fine feeder roots showing root rot symptoms (necrosis, sloughing).
  • Sample live and dead roots. If roots are completely dead, keep in mind that we may no longer be able to detect root rot pathogens, even if they were responsible for plant death.

Dutch Elm Disease, Verticillium Wilt, and Oak Wilt Specimens

  • Select specimens from branches having wilted, yellowing or dying leaves
  • Cut and send several branch sections that are ½ to 1 inch in diameter and about 6 inches long
  • Wrap in aluminum foil to prevent drying; do not allow samples to be exposed to high temperatures; Please do not send dead wood.

Bacterial Leaf Scorch Samples

  • Collect foliar cuttings (stems and leaves) showing marginal necrosis/chlorosis of the leaves.
  • Select material from symptomatic areas of the canopy (you may need arborist to collect out of reach samples).


  • Please do not send completely dead turfgrass
  • Collect two or three squares (each 3x3 inches square), with at least one inch of attached soil and roots, from the edges of affected areas
  • Include both dying and apparently healthy plants
  • Wrap each sample in one thickness of slightly dampened newspaper or paper toweling, then in dry newspaper. Aluminum foil can also be used to wrap turf samples
  • Turfgrass diseases can be very difficult to diagnose accurately, so include as much information about the problem as possible
  • Photographs of the lawn are also very helpful. Please include the photographs with the sample or email them to

Nematode Soil Samples

Note: The Plant Disease Clinic does not perform nematode assays for commercial samples (orchards, vineyards, etc.). Contact the clinic for more information on where to send samples (814-865-2204).

  • Collect at least one pint of soil from the root zone of the affected plant
  • Any living roots should also be submitted
  • Place the soil and roots in a plastic bag, seal, and properly label
  • After the soil sample is collected, it should be kept cool and sent as quickly as possible
  • Samples should not be allowed to dry, freeze, or be exposed to high temperatures
  • Do not store nematode samples in sunlight or in a parked vehicle because temperatures above 100°F can kill nematodes


  • The Plant Disease Clinic does NOT identify mushrooms for edibility, but we will evaluate mushroom samples associated with plant problems.
  • Package mushroom samples in brown paper and a crush-proof box.
  • Include photos of the mushroom with your sample, including images of the underside of the mushroom.

Mailing Specimens

  • Use strong containers such as corrugated cardboard boxes or mailing tubes that will not crush in transit when mailing large samples.
  • Fill empty spaces in the mailing cartons with crushed or shredded paper to strengthen the carton and protect the specimens.
  • Mail promptly! Avoid weekend and holiday layovers by mailing the specimens early in the week.
  • Walk-in and hand-delivered samples are accepted from 9:00 am to 4:00 pm on weekdays in 220 Buckhout Lab
  • Mail to:
    Plant Disease Clinic
    The Pennsylvania State University
    220 Buckhout Lab
    University Park, PA 16802