In 2018, the MU PDC received a total of 426 samples which includes physical samples, walk-in samples (samples not charged) and digital images submitted by email for plant disease diagnosis, insect, weed and plant identification. Disease diagnosis accounted for 81% of the total sample processed and the month of June marked the peak of submission with 95 samples (Figure 1). Samples submitted to the clinic were categorized into different crop types such as field crops, turf, ornamentals, vegetables and fruits. Ornamentals were the largest sample category with 138, followed by field crops (79) and turf (74) (Figure 2).
Soybeans were submitted most often into the Clinic in 2018 with 50 samples, followed by corn (22), wheat (3), bean (2) and forage crops (2). The 2018 drought condition in Missouri delayed planting and disease emergence early in the season. Predominantly, physiological disorders, chemical damage and nutrient deficiencies were observed on corn and soybean early in the season. The hot and dry condition increased the incidence of late season diseases in soybean. Anthracnose stem blight, charcoal rot, pod and stem blight and soybean sudden death syndrome were the prevalent diseases observed. Diseases diagnosed on corn include gray leaf spot detected in one sample from Polk County, northern corn leaf blight from one sample in Lafayette County, and southern corn rust from Jasper County. Corn stalk rot caused by various fungi was also observed (Table 1).
# of samples
|Anthracnose stem blight||Colletotrichum spp.||9|
|Alternaria leaf blight||Alternaria spp.||1|
|Charcoal rot||Macrophomina phaseolina||5|
|Fusarium wilt/root rot||Fusarium spp.||3|
|Pod and stem blight||Diaporthe spp.||6|
|Soybean stem borer||Dectes texanus||2|
|Phytophthora root rot||Phytophthora sojae||1|
|Soybean brown stem rot||Cadophora gregata||1|
|Soybean sudden death syndrome||Fusarium virguliforme||5|
|Soybean frogeye leaf spot||Cercospora sojina||5|
|Soybean vein necrosis||Soybean Vein Necrosis Virus||1|
|Green stem syndrome||Unknown||1|
|Physiological disorder||Abiotic disorder||7|
|Corn gray leaf spot||Cercospora zeae-maydis||1|
|Fusarium root rot||Fusarium spp.||1|
|Northern corn leaf blight||Exserohilum turcicum||1|
|Southern corn rust||Puccinia polysora||1|
|Stalk rot||Various fungi||2|
|Physiological disorder||Abiotic disorder||5|
|No pathogen found||Identification Analysis||5|
|Chemical injury||Abiotic disorder||2|
|Nutrient imbalance||Abiotic disorder||3|
|Environmental stress||Abiotic disorder||3|
|Herbicide injury||Abiotic disorder||2|
|Forage, Alfalfa & Hay|
|Fusarium wilt||Fusarium spp.||1|
|Common thrips||Family: Thripidae||1|
The PDC is open year round for sample submission. A general diagnosis is $15, additional services are $10 each if special testing such as an ELISA/immunostrip, culture plating or molecular diagnosis is required. Please visit our PDC website http:// plantclinic.missouri.edu/ or call (573-882-3019) for more information.
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REVISED: February 21, 2017