2024 Schutter Diagnostic Lab Annual Report 

Table 1. Number of diagnoses by the Schutter Diagnostic Lab in 2024.

Diagnosis Type	Number of Diagnoses
Plant Disease	846
Insects and other Arthropods	679
Plant and Mushroom Identification	317
Herbicide Injury	69
Other Abiotic Disorders	398
Total	2,309

 

We received samples from all 49 counties in Montana and 5 additional states – Arizona, Colorado, Michigan, North Dakota, and Wyoming. Most samples, 62%, were submitted through MSU Extension services, and 38% were submitted from non-Extension clientele. Most samples from Extension were received from Gallatin, Hill, Sanders, and Ravalli Counties. Ninety percent of Extension samples were from non-commercial clientele while 10% were from commercial sources. For the non-Extension samples, 60% were from non-commercial clientele and 40% from commercial sources. Eighty percent of the sample diagnoses were associated with a weed, disease, or pest while 20% of the diagnoses were from abiotic causes (i.e., winter injury, nutrient imbalance, suspected herbicide injury, drought, or cultural problems).

In addition to diagnostic services, SDL diagnosticians provide outreach materials about pests of concern to clients in Montana. For example, the SDL maintains a Facebook page that has over 1,000 followers. In 2024, we published a total of 20 Facebook posts reaching over 63,000 people, with an average of 83 engaged users per post. Our posts usually focus on timely information about plant diseases, insects, and plant identification for our wide range of clientele.

We also send out Urban Alerts and AgAlerts that inform our clientele about pertinent issues statewide via text or email. The MSU Urban Alert system (865 subscribers) is intended for Extension field faculty, landscape professionals, arborists, and anyone concerned with ornamental plants and vegetables. In 2024 we posted 6 Urban Alerts. The MSU AgAlert system (2,179 subscribers) provides current and research-based information for Montana agricultural clients. There were 16 AgAlerts posted in 2024.

 Back to Top

2024 Plant Disease Summary

Diagnostic Staff:

Dr. Uta McKelvy, Assistant Professor Extension Plant Pathology

Dr. Eva Grimme, Plant Disease Diagnostician & Associate Extension Specialist III

Other Assistants/Specialists:

Erin Gunnink-Troth, Research Associate

Abiya Saeed, Extension Horticulture Specialist

Sarah Eilers, Montana Master Gardener Coordinator

Impacts and Outcomes

• Accurate and timely diagnosis of plant diseases is key to applying successful management strategies. The SDL team is focusing on integrated pest management strategies to address plant problems. Through collaboration of the SDL team with MSU Extension specialists, best management strategies are developed to effectively address plant health issues.
• Over two hundred submitted woody ornamental samples were suspected of disease but were diagnosed as winter injury or other abiotic disorders, making a pesticide application unnecessary.
• Suspected fire blight samples were diagnosed utilizing disease diagnostic kits, rapidly confirming the disease on 33% of the submitted samples. Clients were able to implement IPM strategies promptly.
• The SDL is testing in-vitro mint plants for Verticillium dahliae for the fifth year. The absence of Verticillium is essential for mint growers to ensure that only healthy plant materials are distributed to customers. In 2024, we tested in-vitro samples of nine lines. We will continue to support Montana’s mint producers by providing this testing service.

Sample Summary

In 2024, the SDL completed 846 plant disease diagnoses (agricultural and horticultural samples). Samples submitted through the Plant Diagnostics Information System (PDIS) by MSU Extension personnel (54.6%) consisted of 49.2% non-commercial and 5.4% commercial entities. Samples submitted by entities outside of MSU Extension accounted for 44.9 % with 22.4% coming from commercial sources and 20.5% from non-commercial sources.

A total of 188 agricultural samples were submitted for disease diagnosis in 2024. Small grain crops accounted for 60% of all crop samples 4 (113 samples processed; 42 winter wheat, 23 unspecified wheat, 11 barley, 8 spring wheat, further durum wheat, oats, corn, triticale, and kernza). Pulse crops (17%) constituted the second-largest group of crop samples (32 samples processed; 8 chickpea, 6 dry field pea, and 3 lentil samples), followed by potato (17 samples). Other crops submitted for disease diagnosis in 2024 included garlic (8%), potato (7%), alfalfa (4%) dry beans (3%) and forage grasses (2%).

Deciduous woody ornamentals accounted for 26% and evergreen woody ornamentals accounted for 21% of the horticulture diagnoses made by the SDL in 2024. Sample hosts of these categories included Colorado blue spruce, blue spruce, pine trees, fir, lilac, juniper, poplar, crabapple, oak, arborvitae, and maple trees.

Fruit and vegetable samples (apple, pear, cherry, raspberry, tomato, garlic, herbs) accounted for 19%, perennial & annual plants for 6%, and turf samples accounted for 2% of the horticulture diagnoses.

Trends from 2024: Agriculture

Agricultural crops accounted for 308 plant disease diagnoses in 2024. This is a decrease compared to 458 diagnoses processed in 2023. Of these, 236 diagnoses identified disease problems (77%) and 72 diagnoses identified abiotic disorders (33%). Samples were received from 37 of 56 Montana counties, with Gallatin, Hill, Choteau, Cascade, Pondera, and Teton counties contributing over 50% of agricultural crop samples.

Fifty-five percent of diagnoses that identified a disease problem in 2024 were associated with fungal and fungal-like pathogens. Root, crown, and seedling rots accounted for 28% of all crop disease diagnoses in 2024. Root rots associated with Fusarium sp. were very common (17%) affecting spring and winter wheat, chickpea, field peas, garlic, lentil, blue flax, bluebunch wheatgrass, and triticale; Rhizoctonia sp. (5%) caused root diseases in chickpea, garlic, spring and winter wheat; Cochliobolus sativus caused common root rot (2%) on spring and winter wheat and oats, while oomycete pathogens (Aphanomyces sp., Pythium sp.) caused root rot (3%) on dry peas, flax, garlic, soybean, and sugar beet. Phytophthora root rot was diagnosed on a blue flax sample.

Fungal foliar diseases accounted for 13% of all crop disease diagnoses in 2024 (29 diagnoses). This represents a decrease compared to 2023 when a total of 82 diagnoses described fungal foliar disease. Although the 2024 growing season started cool and wet, conditions quickly changed to hot and dry weather in mid-June which was not conducive for foliar disease development. Leaf spot diseases accounted for 8.1% of all crop diseases in 2024 and included net blotch (Drechlsera teres) in barley; tan spot (Pyrenophora tritici-repentis) in winter wheat; Ascochyta blight (Didymella rabiei) in chickpea, Septoria leaf spot (Septoria pisi)in field peas, and Stemphylium blight in lentil (Stemphylium botryosum); and spring black stem (Phoma medicaginis), Stemphylium leaf spot (Stemphylium sp.), and common leaf spot (Pseudopezizia medicaginis) in alfalfa. White mold, caused by Scleoritnia sclerotiorum, was diagnosed on six agricultural samples in 2024, including garlic, dry bean, and hemp. Other fungal foliar diseases observed in agricultural crop samples included stripe rust and powdery mildew on wheat and Fusarium foliar blight on garlic.

Several fungal wilt diseases were diagnosed in 2024, including Fusarium yellows on dry bean, Verticillium wilt on dry peas, and fusarium wilt on potatoes and sugar beet (one diagnoses each).

Post-harvest and storage disorders associated with fungal pathogens accounted for 9% of all crop disease diagnoses in 2024. This included mold issues in hay and silage associated with Alternaria sp., Aspergillus sp., Penicillium sp., Fusarium sp., and Rhizopus sp.; black point (Alternaria sp.) and sooty molds in oats, northern wheatgrass, and winter wheat; and skin blotch (Embellisia allii) and blue mold (Penicillium hirsutum) in garlic.

Seven percent of disease diagnoses were associated with bacterial pathogens in 2024. Pseudomonas sp. caused bacterial stem blight in alfalfa, bacterial brown spot on beans, bacterial leaf blight on dry peas and oats. Other bacterial diseases observed in 2024 included post-harvest and storage such as bacterial soft rot in potato (Erwinia sp./spp.) and garlic (unidentified bacteria) and common scab in potato (Streptomyces scabies).

Three percent of disease diagnoses identified pathogenic nematodes: the stem and bulb nematode (Ditylenchus dipsaci) was identified in one chickpea and field pea sample and 4 garlic bulb samples in 2024. The increasing number of stem and bulb nematode detections in seed garlic samples is a noteworthy trend.

Few diagnoses were attributed to viral disease in 2024; 1% of all disease diagnoses. Only two diagnoses identified symptoms of Wheat streak mosaic virus infection and confirmed the presence of the wheat curl mite vector (Aceria tosischella) in kernza and winter wheat.

The relatively cold start to the 2024 growing season is reflected in abiotic disorder diagnoses, where 20% of all abiotic diagnoses were attributed to frost, freeze or cold damage predominantly on spring and winter wheat, dry peas, and sugar beet. Low soil pH and nutrient imbalances were the second most common abiotic disorder (16%), followed by cultural/environmental problems (14%). The sudden switch to very hot and dry growing conditions at the end of June 2024 is reflected in several diagnoses of heat and drought stress (11%) mostly on oats, winter and spring wheat.  Physiological leaf spot was diagnosed on 9 winter wheat samples in 2024, reflecting a markable decrease compared to 2023.

Trends from 2024: Horticulture

Horticultural samples accounted for 554 diagnoses (samples submitted through the Plant Diagnostic Information System [PDIS]) and 56 plant disease diagnoses for electronically submitted samples (i.e., photos in emails).

Foliar fungal diseases were again predominant during 2024 due to the cool and moist conditions in spring. Evergreen samples, especially Colorado blue spruce and blue spruce, were submitted with signs of Rhizosphaera needle cast disease (11) and/or sudden needle drop (23). Pine trees were mainly affected by Dothistroma needle blight (15) and junipers by tip blight (16). In deciduous samples, apple scab was confirmed on apple (1) and crabapple (4) samples. Anthracnose disease was confirmed this season on green ash (1), lilac (1), maple (1), oak (1), and viburnum (1). Oak leaf blister disease was confirmed on one oak tree sample. Cytospora canker was diagnosed on spruce trees (5), chokecherry (3), fruit trees (12), poplar trees (2), weeping willow (1) and mountain ash (1). Powdery mildew infection was confirmed on currant (1), lilac (1), mockorange (1), penstemon (1), peony (1), and wild comfrey. Dutch elm disease was confirmed on one American elm tree sample. Marssonina leaf spot was confirmed on four poplar samples.

Eighteen plant samples, including apple, crabapple, pear, raspberry, and serviceberry were submitted to the SDL with suspected fire blight infection. Samples were tested with rapid disease diagnostic kits, confirming positive results on three apple tree samples, two crabapple samples, and one raspberry sample. 

Root rots caused by Rhizoctonia sp. and Pythium sp. were only minor diseases this season. Rhizoctonia root rot was confirmed on one turfgrass and one garden pea sample. Pythium root rot was confirmed on one sample each of ranunculus, garden pea, pepper, petunia, poinsettia, and turfgrass. Phytophthora crown rot was confirmed on one rhubarb sample.

Due to extreme changes in temperature, thin barked fruit trees (8), including cherry, plum, apricot, and crabapple, were stressed and expressed signs of gummosis (abiotic disorder).

Statewide, juniper shrubs and trees showed severe dieback. While tip blight (a fungal disease) was found on some samples, the majority of plants did not show any disease or insect-related issues. We suspect that the drought and harsh winter conditions and potential wildlife damage of the last years contributed to the plants’ decline.

 Back to Top

2024 Insect Diagnostics Summary

Diagnostic Staff

Chloe Rice, Extension Associate Specialist, Urban Arthropod Diagnostician

Marni Rolston, Research Associate, Arthropod Diagnostician

Other Assistants/Specialists

Dr. Michael Ivie, Systematic Entomologist, Montana State University 

Dr. Casey Delphia, Research Associate/Entomologist, Montana State University 

Dr. Frank Etzler, State Survey Coordinator, Montana Department of Agriculture

Abi Saeed, Horticulture Extension Specialist, Montana State University

Dr. Justin Runyon, Entomologist, USDA Forest Service

Impacts and Outcomes

• An aphid from a conifer tree was determined to be a new aphid record in Montana. We are currently working with a specialist to confirm the species identification.
• The common crypt ant (Hypoponera opacior) was identified from a commercial building in Broadwater County. This is the first report of this species in Montana. These ants are often predators of termites, so the building owner was told to inspect for these pests.
• Some arthropods were diagnosed as species which were less damaging/harmful than the species the clients had originally suspected. Examples included:
  • a suspected kissing bug (a vector of Chagas disease) identified instead as a masked hunter (not a vector of Chagas disease)
  • a suspected brown recluse spider (has necrotic venom) identified instead as a hobo spider (there is no conclusive evidence that hobo spider venom causes necrosis in humans)
  • damage to an aspen tree which the client was concerned was caused by emerald ash borer (a highly invasive beetle not yet detected in Montana) which we suspected was instead caused by poplar borer (a common beetle pest in Montana)
• Twenty-five percent of diagnoses were made via photos, saving clients the financial cost of sending physical samples by mail
• A tick found inside a home in northeastern Montana was identified as a bat tick (Carios sp.). These ticks usually spend their lives close to bats but occasionally enter living spaces when bats roost in lofts. Bat ticks are rarely recorded in Montana and comparatively little is known about their biology compared to other ticks.
• Spotted blister beetles (Epicauta maculata) were submitted from home gardens and alfalfa fields from multiple counties. Clients were informed that the blister beetle numbers were probably higher than normal because their larvae feed on grasshopper eggs, which have been abundant in recent years.
• Annual white grubs (Cyclocephala spp.) were identified from organic corn and potato fields in different parts of the state. Producers said it was helpful to learn that soils with high organic matter are attractive to these root-destroying grubs.

Arthropod Identification Activities and Trends

In 2024, 679 arthropod diagnoses were completed. Fifty-four percent of diagnoses were from samples submitted from Extension agents and the rest were from samples submitted directly from non-Extension sources such as home gardeners, growers, crop consultants, arborists, businesses, and others. Eleven percent of the diagnoses were for commercial clientele while 89% were for non-commercial clients. Samples were submitted from 44 counties in Montana. Samples were also submitted from North Dakota, Wyoming, and Iowa. 627 (92%) diagnoses were from urban (horticulture, structural, indoor) settings and 52 (8%) were from agriculture-related settings. In addition to 515 diagnoses made for samples submitted through the Plant Diagnostics Information System (PDIS), 164 diagnoses were made via emails or phone calls.

Agriculture-Related Arthropod Samples

Fifty-two arthropod samples collected from agricultural settings were submitted to the SDL in 2024. Common host crops included spring wheat/winter wheat (20%), garlic (12%), pasture/rangeland (12%), and alfalfa (10%). The remaining samples were from a wide range of agricultural crops, including camelina, field peas, potato, yellow mustard, safflower, triticale and corn. Samples were also received from commercial greenhouses, livestock, and stored grain bins.

The most common small grain pest in 2024 was the wheat curl mite (Table A2). Other insects diagnosed from wheat include the cereal leaf beetle, false chinch bugs and the Hessian fly. Insects submitted from alfalfa fields include the spotted blister beetle and alfalfa weevils. Most of the alfalfa blister beetle samples were sent in by producers concerned about toxicity to livestock that may ingest these beetles. Other crop arthropods submitted to the SDL include pea leaf weevil in field peas, bulb mites and onion maggots in garlic, army cutworm and wireworms in safflower, flea beetles in yellow mustard, seedcorn maggot in soybean, and root-damaging white grubs in potato and organic corn fields.

Arthropods collected from agricultural-related stored grains were also submitted to the SDL in 2024, although none of them were economically important. Clients shared samples/pictures of broad-nosed weevils in hog feed, oribatid mites in barley bins, and long-horned beetles in lentil containers shipped from out-of-state.

A few samples of non-damaging/beneficial arthropods were also submitted from agricultural lands, including parasitic wasp cocoons in camelina, and a carabid beetle in safflower. Clients are often concerned about these non-damaging insects and are relieved to hear they are beneficial and don’t need to be managed. Reports associated with the diagnoses of arthropod pests in agricultural landscapes usually include information about how to preserve these important beneficial arthropods.

Urban Arthropod Samples

 Back to Top

2024 Weeds Lab Diagnostic Summary

Diagnostic Staff

Noelle Orloff, Associate Extension Specialist III

Other Assistants/Specialists:

Dr. Cathy Cripps, Professor Emerita, Mycology, Montana State University

Dr. Jane Mangold, Extension Rangeland Invasive Plant Specialist, Montana State University

Dr. Tim Seipel, Extension Cropland Weed Specialist, Montana State University

Impacts and Outcomes

• Our plant ID services help clients such as Extension agents, county weed coordinators, and other professionals serve their clientele better. For example, one respondent of our annual SDL survey stated, “Noelle Orloff provides such a great benefit to myself and the landowners I represent. While I’m fairly familiar with noxious and common weedy/non-native plants, she helps me tremendously by identifying plants that are less common. It’s great to be able to designate between native and non-native plants with her expertise.”
• Early detection of agriculturally important pests is an important role of our lab. Two Amaranthus species, Palmer amaranth ( palmeri) and waterhemp (A. tuberculatus), are of increasing concern in Montana due to their projected economic impact on agriculture. Due to this concern, in 2024 we received eight Amaranthus samples for identification along with numerous questions.
  • Working with local Extension field faculty we confirmed Palmer amaranth in one new county in Montana and sent the samples for PCR testing for confirmation. This is the third known detection of Palmer amaranth in Montana, with the first being confirmed by the SDL in 2023.
  • In the remaining cases where field faculty, clients, and partners were concerned about Palmer amaranth and waterhemp, we identified other common weedy species instead. These identifications saved producers and land managers significant time and money by avoiding unnecessary and costly treatments.

Plant Identification Activities and Trends 

In 2024, the SDL processed 179 physical specimens for plant identification, and 109 electronic samples (i.e. photos in emails and our sample submission app). Most samples came from noncommercial sources accounting for 80% of sample submissions. Noncommercial samples may be from agency or regulatory personnel, or from residential or small acreage landowners who need information on how to control a plant in their management area or in gardens or small pastures. Samples from commercial clients such as farmers, ranchers, consultants, nurseries, and representatives from agribusinesses accounted for 20% of all submissions. About 57% of plant identification samples were from local Extension offices submitting samples on behalf of their clients. We identified plants from 47 Montana counties and reservations, and one additional state (Colorado).

Plant identification samples submitted represented 185 unique species. Thirty percent of samples were of exotic plants. The most commonly submitted exotic species were kochia (Kochia scoparia, 10), catchweed (Asperugo procumbens, 5), and bur buttercup (Ranunculus testiculatus, 5). We also identified one specimen of Palmer amaranth (Amaranthus palmeri); a species native to North America but not to Montana. Fifty-one percent of samples were Montana native plants. The most common native species submitted were horseweed (Conyza canadensis, 3), common yarrow (Achillea millefolium, 2), redroot pigweed (Amaranthus retroflexus, 2), California oatgrass (Danthonia californica, 2), Lewis flax (Linum lewisii, 2), and witchgrass (Panicum capillare, 2). Notably, we received eight samples in the Amaranthus genus in 2024, due largely to concern about Palmer amaranth and waterhemp (A. tuberculatus).

Seven confirmed specimens of state-listed noxious weeds and other state-regulated plants were submitted representing nine unique species (Table 1). The SDL provides a valuable resource where land managers can get accurate information about suspected problematic plants such as noxious weeds.