Sample Diagnosis

In 2023, MU Plant Diagnostic Clinic received a total of 901 physical samples and 253 sets of digital images submitted by email and online digital submission system. There was an increase of 135% in physical samples and 66% in digital samples, compared to the year 2022 (Figure 1 and figure 2). Among physical samples submission for services including plant disease diagnosis, insect, weed, and plant identification, disease diagnosis accounts for 55% of the total physical samples processed (Figure 3). 372 elderberry samples, accounting for 41% of the total physical samples, are for a research project funded by Missouri Department of Agriculture Specialty Crop Block Grant Program. Like previous years, the lab received the most submissions in the summer months (Figure 1, 2 and 4).

Figure 1 Number of physical samples processed by month in 2022 and 2023.

Figure 2 Number of digital samples processed by month in 2022 and 2023.

Figure 3. Number of physical samples by service type.

Figure 4. Number of physical samples analyzed by month.

Sample Submission

29 out-of-state samples were received from Iowa, Oklahoma, Wisconsin, Illinois, Kansas, and Arkansas. From Missouri, 872 in-state physical samples were received from 78 counties. 81% of the samples were submitted by commercial clients or extension agents. Submission received directly from educators and homeowners accounted for 19% of the total physical samples processed in 2022.

Sample Category

Samples submitted to the clinic were categorized into different crop types such as field crops, turf, ornamentals, vegetables, and fruits. Fruits are the largest sample category with 404 samples including 372 research samples, followed by field crops (265), ornamentals (124), vegetables (55), turfgrasses (4), and Other(20) (Figure 5).

Figure 5. Distribution of samples submitted for disease diagnosis by sample category.

Summary of Field Crops Diagnosis

Soybean (163) and corn (40) compose the two major field crop categories submitted to the clinic in 2023, followed by wheat (34) and industrial hemp (24) (Figure 6).

Figure 6 Summary of the types of field crop samples submitted to the clinic.

Due to the severe drought and fluctuation of temperature for several months in the beginning of 2023, very few fungal or bacterial diseases, especially foliar and root/crown rot diseases were detected due to lack of favorable living conditions. Predominantly, physiological disorders, chemical damage and nutrient deficiencies were observed on corn and soybean early in the season. Drought-related diseases such as soybean charcoal rot and sudden death syndrome were confirmed by the clinic towards the end of the growing season. A few less frequent diseases were confirmed in samples from Missouri and Illinois, such as downy mildew, target spot, soybean vein necrosis virus (SVNV) and red crown rot. Corn tar spot disease continued to spread through Northwest and Northeast counties of Missouri, and it was detected in several central counties for the first time in the history. Thanks to the dry weather, the dissemination and corresponding yield loss was limited. However, we anticipate the prevalence of this disease will persist in 2024 and more counties will report the presence of this corn disease. The clinic offered wheat virus screen service in the spring and fall and had detected the presence of all four common wheat viruses from samples collected in multiple counties across Missouri. We will continue to offer this service in the spring for all wheat growers in 2024.

Table 1 A list of diseases and abiotic issues diagnosed among field crop samples in 2023.

MU Plant Diagnostic Clinic is here to help you confirm if your plants are diseased. We encourage you to visit our website https://extension.missouri.edu/programs/plant-diagnostic-clinic and review submission guidelines before submitting your sample. If possible, you may take photos and send them to our email address: plantclinic@missouri.edu.

We just launched a new video, https://www.youtube.com/watch?v=9g312_U1iiI, about sample submission guidelines on YouTube to help you submit your sample step by step.

For sample submission and fee payment

Visit our new online submission system at https://extension.missouri.edu/products-and-services/plant-disease-sample. Fill out the submission form online using your computer or mobile device and make payment online securely with a credit card.

OR

Download the submission form at https://extension.missouri.edu/programs/plant-diagnostic-clinic/sample-submission. Fill it out and send to us together with your sample and payment. Check or money order. No cash please.

University of Missouri-Plant Diagnostic Clinic