The wheat season is well underway and some growers are concerned about viral diseases showing up in their crops. The K-State Plant Disease Diagnostic Lab is available to help with these diagnoses. Here are some helpful reminders as you prepare samples for the 2019 season.
K-State Plant Disease Diagnostic Lab
1712 Claflin Road
4032 Throckmorton Plant Science Center
Manhattan, KS 66506
1. Use a sealed plastic bag to keep your sample fresh
When collecting your sample, place the plant materials in a plastic bag. Gallon-sized, zip style bags will work for smaller plants. For larger plant samples, a trash can liner or large plastic bag will work well. Be sure for both bags that the top is sealed or tied into a knot to retain moisture. Be sure to send the entire diseased plant (Figure 1) along with healthy plant around the same area to compare. Apart from the freshness of your sample, plastic bags make it easy track and keep different samples separate (healthy vs diseased or separate field locations). Be sure to label your bags appropriately.
Figure 1. A good sample of wheat symptomatic of a viral infection. Photo from K-State Plant Disease Diagnostic Laboratory.
2. Use a second bag to keep the soil separate from the rest of the plant
If you choose not to shake off the soil from the roots, please place a plastic bag around the roots and soil separately and seal with a rubber band, string, or the seal of the bag. This will prevent wet or dry soil from covering the leaves and causing damage. The plant with the bag covering the roots should then be place in the primary bag mentioned in tip #1 (Figure 2).
Figure 2. (Left photo) A poor quality sample with only one bag for the entire sample. The plant leaves have deteriorated from exposure to the wet soil. (Right photo) A good quality sample with two bags. One for the roots of the plant and one for the entire sample. Photo from K-State Plant Disease Diagnostic Laboratory.
3. Refrigerate the sample until shipping
After plants have been take from the field and bagged accordingly, be sure to refrigerate the sample to preserve freshness. Living plants left at warm temperatures in plastic bags will decompose greatly diminishing the quality of the sample. Plants should be keep at around 40 degrees F or the temperature of a regular refrigerator. Please do not freeze the sample.
4. Use packing materials to reduce sample damage during shipping
Many samples sustain damage during shipping if not properly packed. Use extra packing peanuts, newspaper, or pieces of cardboard to prevent movement of the plant sample. When the plants are jostled around during shipping, it is common for them to become mixed with soil. Plants in contact with moist soil rapidly deteriorate making diagnosis nearly impossible.
5. Use express or overnight services for shipping
Time in transit is the enemy of quality diagnostic samples. It is best to use an express carrier or overnight shipping service. Be sure to send the sample early in the week (Monday through Wednesday). Samples sent on Friday may not arrive until mid-week and deteriorate in transit. Shipping samples via standard mail is not a good option for plant samples (Figure 3). In many cases, these samples may be in transit for 7 to 10 days. This long time in shipping often renders samples unusable.
Figure 3. (Left photo) This good quality sample was express shipped. (Right photo) This poor quality sample spent 6 days in the mail. The quality was too low to test and a new sample was requested. Photo from K-State Plant Disease Diagnostic Laboratory.
Christian Webb, K-State Plant Disease Diagnostic Lab
Judy O’Mara, Director, K-State Plant Disease Diagnostic Lab
Erick De Wolf, Extension Plant Pathologist