Sample Diagnosis

In 2022, MU Plant Diagnostic Clinic received a total of 492 samples which include 152 sets of digital images submitted by email and online digital diagnosis platform (Figure 1) and 340 physical samples for services of plant disease diagnosis, insect, weed and plant identification (Figure 2). There is an increase of 23% in physical sample number and 150% in digital sample number, comparing to year of 2021. Disease diagnosis accounted for 91% of the total physical samples processed (Figure 2). Similar with previous years, the lab received the most submissions in the summer months June, July and August (Figure 1 and Figure 3).

Figure 1 Number of digital samples processed at by Month

Figure 2. Number of physical samples by service type

Figure 3. Number of physical samples analyzed by months

Sample Submission

Seven out-of-state samples were received from Illinois, Kansas, and Arkansas. From Missouri, 333 in-state physical samples were received from 55 counties. 66% of the samples were submitted by commercial clients. Submission received directly from educators and homeowners accounted for 24% 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. Ornamental plants were the largest sample category with 119 samples, followed by field crops (110) and Fruits (45) and Vegetables (31) (Table 1).

Table 1 Distribution of samples submitted for disease diagnosis by sample category

Summary of Horticultural Plants Diagnosis

The majority of Missouri counties experienced severe drought for several months in 2022. Among the most of the horticultural plants, very few fungal or bacterial diseases, especially foliar and root/crown rot diseases were detected due to lack of favorable living condition. Drought stress related problems for wood ornamental plants were prevalent as the clinic observed the submissions of diseased samples of deciduous and evergreen trees from multiple counties. It was common to detect needle blight, needle cast, canker, dieback, leaf scorching diseases from those tree samples that were under severe environmental stress, but the stress itself could also cause needle yellowing and stem dieback. Although the symptoms may vary among different families of trees and they may take one or two following seasons to show up, once the symptoms show up, there is not too much you can do with the tree. Clients may consider keeping good irrigation for their trees even in the winter, performing a soil test early in the spring for recommendations of soil fertilization, and pruning dead branches when the trees are still dormant. Other ornamentals such as shrubs, annual and perennials didn't show up as many diseases as 2021 and the similar incidence also occurred to vegetables, fruit trees and turfgrass. Fungal diseases that are normally prevalent in the dry weather include Fusarium root rot and Rhizoctonia crown and root rot, which were detected from a few vegetables and turfgrass samples. It is always hard to predict the performance of the plants and prevalence of plant diseases right after a year with severe drought. Depending on the weather of this winter and spring of 2023, cold injury and excessive rainfall would worsen the situation of most of ornamentals and vegetables while continuous drought would result in more environmental stress on all plants.

Here is a comprehensive list of diseases and abiotic issues diagnosed among horticulture samples in 2022.

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://youtu.be/XEWVT9lUflo, 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/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