Taking an environmentally sensitive approach to pest management


Pierce Taylor
University of Missouri
Plant Science & Technology

Peng Tian
University of Missouri
(573) 882-3019

MU Plant Diagnostic Clinic Field Crops Annual Report

Pierce Taylor
University of Missouri

Peng Tian
University of Missouri
(573) 882-3019

January 20, 2023

minute read

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).

bar graph

Figure 1 Number of digital samples processed at by Month

pie chart

Figure 2. Number of physical samples by service type

multi-colored bar graph

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

Crop category # of sample %
Ornamentals 119 34.79
Agronomic/Field crops 110 32.16
Turf 15 4.38
Fruits 45 13.15
Vegetables 31 9.06
Insect/Weed ID 30 6.43

Summary of Field Crops Diagnosis

Sugarcane samples submitted by a St. Louis based research group accounted for the most number logged into the clinic in 2022 with 55, followed by soybean (18), corn (16), and wheat (13). Due to short-period freeze and prolonged rainfall in the spring of 2022, the planting of both soybean and corn was delayed, which reduced the emergence of early-season diseases. As the majority of Missouri experienced severe drought for several months in 2022, very few fungal or bacterial diseases, especially foliar and root/crown rot diseases were detected due to lack of favorable living condition. Predominantly, physiological disorders, chemical damage and nutrient deficiencies were observed on corn and soybean early in the season and drought-related diseases such as soybean Charcoal rot and Sudden Death Syndrome were confirmed by the clinic through the growing season. The hot and dry condition increased the incidence of late season diseases in crops especially insect damage caused by spider mites. The Corn Tar Spot disease continued to spread through Northwest and Northeast counties of the state. Thanks to the dry weather, the dissemination and corresponding yield loss was severely limited. However, we anticipate the prevalence of this disease will persist in 2023 and more counties will report the presence of this corn disease. Another relatively new diseases such as Corn Bacterial Leaf Streak, Goss's Wilt and Target Spot of Soybean were not detected in Missouri in 2022. The clinic offered wheat virus screen service in the spring and fall and had detected the presence of all four viruses from samples collected from several counties in Missouri. We will continue to offer this service in the spring for all wheat growers in 2023.

Table 2 A list of diseases and abiotic issues diagnosed among field crop samples in 2022

CORN (Zea mays)
Northern Corn Leaf Blight Exserohilum turcicum
Tar Spot Phyllachora maydis
Abiotic Disorders Chemical/Drought Damage
Gray Leaf Spot Cercospora zeae-maydis
Anthracnose Leaf Blight Colletotrichum graminicola
Diplodia Ear and Stalk Rot Stenocarpella maydis
Physoderma Brown Spot Physoderma maydis
WHEAT (Triticum sp/spp.)
Pythium root and/or crown rot Pythium sp./spp.
Septoria Leaf spot Zymoseptoria tritici
Sooty Mold; Black Dot Epicoccum sp./spp.
Barley Yellow Dwarf Virus (BYDV-PAV) Luteovirus Barley Yellow Dwarf Virus PAV
Wheat Streak Mosaic Virus (WSMV) Tritimovirus Wheat Streak Mosaic Virus
Soil-borne Wheat Mosaic Virus (SBWMV) Furovirus Soil-borne Wheat Mosaic Virus
Cereal Yellow Dwarf Virus (CYDV-RPV) Polerovirus Cereal Yellow Dwarf Virus RPV
SOYBEAN (Glycine max)
Charcoal Rot Macrophomina phaseolina
Damping Off Fusarium sp./spp.
Environmental stress; Problem Abiotic disorder
Herbicide Injury Abiotic disorder
Purple Seed-stain; Leaf blight Cercospora kikuchii
Pythium Damping Off Pythium sp./spp.
Root Rot Phytophthora sp./spp.
Septoria Leaf Spot Septoria sp./spp.
Soybean Bacterial Pustule Xanthomonas axonopodis pv. Glycines
Soybean Cyst Nematode Heterodera glycines
Sudden Death Syndrome Fusarium virguliforme
Pod and Stem Blight Diaporthe phaseolorum var. sojae
Twospotted Spider Mite Tetranychus urticae
SUGARCANE (Saccharum spp.)
Fusarium Root Rot Fusarium sp./spp.
Fusarium Leave Blight Fusarium sp./spp.

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.


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

Office 28 Mumford Hall
Columbia, MO 65211
Phone 573-882-3019
Email plantclinic@missouri.edu

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REVISED: January 20, 2023