Foliar diseases of corn ( Zea mays ‘P0035AM’) can lead to significant yield losses in the United States. This report evaluates five fungicide treatments for the management of foliar disease on corn. The trial was conducted in 2025 in a research field in Vincennes, IN. Disease severity and yield were collected for each treatment. Results from this study will help inform corn growers in selecting fungicide programs to manage important foliar diseases.
Cranberry fruit rot is a major constraint to cranberry production and is managed using season-long fungicide programs. A series of replicated field experiments conducted over two study periods (1996–2000 and 2002–2007), together with supplemental commercial validation trials, examined how the timing of the first fungicide application relative to host phenology influences disease control. Each year, progressively delayed applications of chlorothalonil were initiated during bloom. Application timing was normalized across years using a phenological reference point corresponding to 60% out-of-bloom. Across both datasets, loss of disease control followed a significant nonlinear relationship with application timing. Disease control declined gradually when the first application was initiated prior to late bloom but decreased sharply when initiation was delayed into late bloom and early fruit set. In the more densely sampled 2002–2007 dataset, a second-order polynomial model explained 42% of the variation in disease control (R² = 0.42; P < 0.001; n = 55) and resolved a rapid collapse in efficacy associated with delayed application timing. Analysis of the 1996–2000 dataset independently confirmed the similar phenological response pattern (R² = 0.61; P = 0.0001; n = 24), despite coarser temporal resolution. Together, these results identify a reproducible phenological window during which infection of cranberry fruit greatly increases the probability of rot development. Collectively, the findings demonstrate that CFR expression is governed primarily by host developmental biology rather than by prolonged seasonal pathogen pressure or pathogen species composition, providing a biological foundation for reduced-input fungicide programs focused on precisely timing the first application.
Powdery mildew, caused by the fungus Golovinomyces ambrosiae, is among the most prevalent diseases of hemp ( Cannabis sativa) in the United States, and its management is crucial to support hemp grown for cannabinoids. Several fungicides have been registered for the control of hemp powdery mildew and are important tools to manage G. ambrosiae, but to date, there have been few studies of their effects on cannabinoid yields. Here, five disease control treatments were applied to susceptible hemp cultivars, and disease severity ratings (0 to 100%) were captured to calculate the area under the disease progress curve. Products with the active ingredients Bacillus amyloliquefaciens strain D747, potassium silicate, and a rotation between Bacillus mycoides isolate J and B. amyloliquefaciens strain D747 effectively reduced powdery mildew severity compared with the untreated control in the two consecutive field studies. An analysis of the cannabinoid composition of extracts from all the fungicide-treated plots, as well as uninoculated controls, revealed that neither biological fungicide treatments nor G. ambrosiae infection affected the profile of the cannabinoids Δ 9 -tetrahydrocannabinol, cannabidiol, cannabigerol, and cannabichromene. These results suggest that fungicides may provide an effective strategy to control G. ambrosiae without compromising end-use product quality.
Pythium root rot, caused by the pathogen Pythium ultimum, is a destructive disease of snapdragon in greenhouse production. Symptoms include stunting, chlorosis of lower leaves, and wilting. Eventually, plants wilt completely and plant death may occur. This report evaluates the efficacy of fungicide drenches with conventional fungicides for the management of Pythium root rot. The trial was conducted in 2026 on greenhouse-grown snapdragon ‘Rocket Red’ in Storrs, CT. Results from this trial will help in developing management programs for this disease.
Rhizomania, caused by beet necrotic yellow vein virus, is a leading disease of sugar beet and is vectored by a soil-borne protist, Polymyxa betae. Since 2017, rhizomania has become increasingly important on table beet in Michigan. On table beet, rhizomania is characterized by increased proliferation of petioles causing scarring along the main taproot, elongation and constriction of the main taproot giving a “wineglass” shape, and secondary rootlet proliferation which traps soil and gives the beetroots a “bearded” appearance. With limited chemical control options, genetic resistance remains the primary method to limit rhizomania. Cultivars with marketed intermediate resistance were compared to susceptible check cultivars in replicated field and greenhouse experiments. The susceptible-check cultivars, ‘Boro’ and ‘Red Ace’, had consistently high rhizomania disease index values in two of three field studies and two of three greenhouse studies. Among the best performing cultivars in the first field trial were ‘Grenade’, ‘Manzu’, and ‘Redval’. In the second trial, ‘Bazzu’, Grenade, Manzu, ‘Power Cruz’, and ‘Rhizu’ were among the best performing cultivars. In greenhouse trials 1 and 3, Grenade had lower rhizomania disease index values compared to the susceptible check cultivars. In one of three greenhouse trials, Manzu, Bazzu, and Palau had lower rhizomania disease index values compared to the susceptible checks. Our results indicate that table beet cultivars with marketed intermediate resistance to rhizomania can be used to limit the disease in order to produce more marketable beets in Michigan.
Bacterial gall of Loropetalum chinense, caused by Pseudomonas amygdali pv. loropetali (PAL), was reported to have become an invasive problem in nurseries due to a lack of proven control methods. We surveyed six nurseries to assess the frequency of loropetalum plants with and without galls and to assess PAL density on and in woody twigs in three vertical strata (base, mid-height, and new growth sections) of plants. Quantitative counts were determined using a quantitative real-time polymerase chain reaction method involving primers and probe specific for PAL. The whole-plant frequency of galled plants within a single cultivar block of loropetalum varied from 8 to 92%, with three nurseries having moderate levels of 27 to 39%. No consistent relationship was observed between gall frequency and PAL abundance across canopy strata. The pattern of the mean DNA copy number of PAL in twigs of the three vertical plant strata varied between nurseries, with the highest copy number occurring more frequently in the base stratum and least frequently in the new stratum. The presence of PAL in the phyllosphere of loropetalum plants indicates a risk for spreading the pathogen on vegetatively propagated stem cuttings.The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2026.
Glomerella leaf spot, caused by a Colletotrichum spp. complex, results in leaf and fruit spots on genetically susceptible apple trees, leading to defoliation and unmarketable fruit. Axios (ipflufenoquin), a new fungicide with a novel mode of action, was evaluated for its ability to control this disease in a 24-year-old Malus domestica ‘Golden Smoothee’ orchard in Blairsville, GA. The standard treatment involved fungicides effective against Colletotrichum spp. and adhered to resistance management practices. This standard protocol performed as expected, significantly reducing Glomerella leaf spot compared with untreated trees. While Axios demonstrated some efficacy, it did not match the level of control achieved by the conventional chemical fungicides used in the standard regimen.
Soybean cyst nematode (SCN, Heterodera glycines) is a damaging soilborne nematode pest that infects soybean roots. SCN has been extensively studied on soybeans, for which genetic resistance is the main management strategy. Dry beans ( Phaseolus vulgaris L.) are an alternative host for SCN and overlap with soybean production areas, leading to concerns about bean production. The objective of this study was to evaluate SCN reproduction on Ontario-adapted dry bean cultivars across navy, black, kidney, and cranberry market classes using three SCN populations (one HG 0- and two HG 2-, from Ontario and Illinois). Reproduction was measured as a female index (FI), calculated relative to the susceptible soybean cultivar Williams 82. All cultivars tested supported SCN development. Andean (large-seeded) cultivars, comprising kidney and cranberry beans, supported the highest reproduction, with many cultivars considered susceptible to SCN (FI > 60). Mesoamerican (small-seeded), comprising primarily black and navy bean cultivars, often had lower reproduction. Reproduction was lower on all cultivars when challenged with HG 2- populations compared with the HG 0- population. The SCN reproduction varied within the small-seeded cultivars, suggesting possible population-specific interactions. None of the cultivars tested were considered resistant (FI < 10). However, among navy beans, genetically similar cultivars Rexeter, OAC Rex, and ExRico23 had the lowest reproduction. This research highlights the range of SCN reproduction across Ontario-adapted dry beans when inoculated with different SCN pathotypes. Within Ontario dry bean production, SCN is a potential threat, and further research is needed on the development of SCN-resistant dry beans. [Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .
Anthracnose, caused by the fungal pathogen Colletotrichum cereale, is a devastating disease on annual bluegrass ( Poa annua) turf. Symptoms of anthracnose on annual bluegrass will present as elongated yellow leaf lesions, and these lesions can coalesce into a large area of declined turf. Oftentimes, small black acervuli appear in the centers of the lesions containing crescent-shaped conidia. As the disease progresses, the leaf tissue will turn brown and may develop abundant acervuli covering the leaves and crowns. This report evaluates the efficacy of synthetic fungicides on the management of annual bluegrass anthracnose. Results from this trial will help turfgrass managers develop effective management programs for anthracnose.
Colletotrichum orbiculare and related Colletotrichum species cause cucumber anthracnose, a destructive disease affecting cucumber production throughout the southeastern United States. Typical symptoms include tan to brown circular lesions 1 cm in diameter on leaf veins, petioles, and stems. As lesions mature, centers may crack or drop out. Black stromata with setae or salmon colored spore masses develop in lesion centers, enabling repeated infection cycles during the growing season. Fruit symptoms consist of circular, sunken lesions that sporulate under favorable conditions. This report evaluates anthracnose disease incidence and severity among pickling and slicing cucumber varieties in Goldsboro, North Carolina, during 2025.
Fusarium stem rot and decline (FRD), caused by two pathogens in the Fusarium solani complex (F. martii and F. noneumartii), is an emerging threat to processing tomato production in California. It causes a premature vine decline which exposes fruits to sunburn and mold damage. This report evaluates yield performance of 24 commercial cultivars in a naturally FRD-infested grower field trial near Knight’s Landing, CA in 2024. Results will allow growers to choose lower-risk cultivars to plant in FRD-infested fields, reducing yield losses and improving quality.
Alternaria blight and head rot (ABHR), primarily caused by Alternaria brassicicola, is a significant constraint in Virginia broccoli production, reducing yield and marketability. Although no ABHR-resistant cultivars are available, less susceptible cultivars can slow disease development and reduce epidemic severity. Fungicides can limit disease, but efficacy varies with environment and pathogen pressure. To evaluate integrated strategies combining cultivar selection with fungicide use, field trials were conducted in 2023 and 2024. Broccoli cultivars 'Burney', 'Emerald Crown', and 'Abrams' were evaluated in split-plot trials with conventional and biorational fungicide programs. Additional trials assessed cultivar susceptibility without fungicides. Across years, Burney consistently had lower foliar severity than Emerald Crown and Abrams, although head rot responses were more variable. Conventional fungicide programs reduced foliar disease and, during low disease pressure, kept head rot-related yield loss within commercially acceptable levels. No single fungicide program was consistently superior across cultivars. Biorational programs did not reduce foliar symptoms, but polyoxin D alternated with copper hydroxide consistently reduced head rot in Burney. Cultivar & times; fungicide interactions for head rot were significant, emphasizing the importance of cultivar selection. In unsprayed trials, Burney, 'Exp3622', and Abrams showed lower disease levels than other cultivars evaluated. Combining fungicides with partial cultivar resistance is essential for minimizing losses, and identifying ABHR-tolerant cultivars adapted to eastern United States conditions will further strengthen integrated management strategies for broccoli production in the region.
Alternaria leaf spot, caused by Alternaria brassicicola, is a major disease that affects all cultivated brassicas worldwide. The typical symptoms are characterized by expanding small black lesions into large lesions with a “target-spot” pattern of concentric rings. Stem and petiole infections manifest as dark, elongated lesions, while head infection results in black spots and rot across curds, significantly reducing harvest quality. This report evaluates the efficacy and crop safety of fungicides in controlling Alternaria leaf spot. The field trial was conducted in 2025 on Brassica oleracea var. italica ‘Castle Dome’. The results from this trial will help broccoli growers in the southwestern United States make informed decisions when developing spray programs.
Sclerotinia sclerotiorum, the causal agent of Sclerotinia stem rot, is a major fungal pathogen of soybeans, causing an estimated 31 million bushels (0.84 million metric tons) of yield loss in 2019 alone in the northern United States and Ontario, Canada. Fungicide applications are the primary management strategy, and their effectiveness depends on correct timing during the flowering period when apothecia are present on the soil surface. Accurate prediction of apothecial development can guide precise fungicide applications and reduce ineffective applications. In 2018, the University of Wisconsin–Madison developed three weather-based logistic regression models for irrigated conditions and three for non-irrigated conditions to predict the probability of S. sclerotiorum apothecial development, each incorporating different environmental variables. This current study aimed to validate the non-irrigated models and determine an appropriate action threshold for North Dakota. Models were evaluated using disease monitoring data collected from 52 non-irrigated commercial soybean fields across North Dakota over 3 years. To improve predictive accuracy, probabilities from non-irrigated models were averaged to create an ensemble model. The performance of individual and ensemble models was assessed. Results showed that the ensemble model achieved the highest accuracy (68%) among all the models in predicting end-of-season disease incidence (DI, %) across all fields using a 10% DI threshold and a 35% risk probability action threshold. The model also demonstrated balanced sensitivity (70%) and specificity (67%). These findings can improve disease risk predictions, reduce unnecessary fungicide applications, and guide soybean farmers in North Dakota on optimal fungicide application timing.
Sour rot of sweetpotato, a postharvest disease, is caused by the pathogenic fungus Geotrichum candidum. The disease occurs exclusively in wounds on sweetpotato roots and is characterized by dark brown lesions. In advanced stages, the lesions lead to tissue collapse, and white areas of pathogen sporulation become evident. This report evaluates the effectiveness of several fungicides for managing sour rot under postharvest conditions. The trial was conducted in 2025. The objective of this study was to generate initial information to support disease management by assessing the performance of different fungicides, representing the first assay conducted for this disease.
Grape powdery mildew, caused by Erysiphe necator, is one of the most common diseases affecting wine grape production globally. Symptoms include white, powdery growth over all green surfaces of the plant, which can inhibit photosynthesis, reduce fruit set, and degrade fruit quality. This report evaluates the efficacy of different fungicide regimes for their ability to control foliar and fruit powdery mildew on Vitis vinifera ‘Chardonnay’ in Prosser, WA, in 2025. Results from this trial can be used to better time different fungicides within a spray regime for improved disease control in wine grapes.
Phomopsis blight caused by the fungus Diaporthe vexans is commonly found on eggplant (Solanum melongena) leaves, stems, and fruits in the fall growing season in the southeastern United States. The objective of this study was to determine which of 10 fungicides currently registered on eggplant are effective against Phomopsis leaf blight. Field experiments were done in fall 2023, 2024, and 2025 with 10 fungicides applied preventatively before plants were inoculated with conidial suspensions of D. vexans. Chlorothalonil was used as the rotation partner with fungicides that required applications to be alternated with a different active ingredient. Plants treated with mefentrifluconazole (Cevya, Fungicide Resistance Action Committee [FRAC] Code 3), cyprodinil + difenoconazole (Inspire Super, FRAC 9+3), and difenoconazole + benzovindiflupyr (Aprovia Top, FRAC 3+7), all rotated with chlorothalonil (Bravo WeatherStik, FRAC 05), had significantly less foliar necrosis than the water control in 2023 and 2025; these three treatments did not differ significantly from each other. Pyraclostrobin + fluxapyroxad (Priaxor FRAC 11 + 7) also reduced foliar necrosis in 2023. Pyraclostrobin (Cabrio, FRAC 11) and boscalid (Endura, FRAC 7), both rotated with chlorothalonil, as well as chlorothalonil, chlorothalonil + zoxamide (Zing!, M05 + 22), copper oxychloride + copper hydroxide (Badge X2, FRAC M01), and chlorothalonil + cymoxanil (Cymbol Advance FRAC M05 + 27), were ineffective. The results of this study can be used to refine fungicide recommendations to manage Phomopsis blight on eggplant in the United States.
Reniform nematode ( Rotylenchulus reniformis) (RN) is a major constraint to cotton production in the southeastern United States, reducing plant vigor and yield. This study evaluated four cotton varieties (DP 2038 B3XF, DP 2131 B3TXF, DP 2143NR B3XF, and DP 2522NR B3TXF) with and without the in-furrow nematicide Velum at the Tennessee Valley Research and Extension Center in Belle Mina, AL, in 2025. Resistant cultivars DP 2143NR B3XF and DP 2522NR B3TXF supported lower egg densities and produced 20 to 30% greater seed cotton yields, resulting in an average gain of 265 lbs. of lint/acre valued at approximately $175/acre compared with susceptible varieties. Velum nematicide enhanced plant growth and increased yield by 13%, corresponding to an additional 144 lbs. of lint/acre valued at approximately $94/acre. These results demonstrate that combining resistant cultivar selection with nematicide use improves cotton productivity and economic returns in RN-infested fields.
Field trials conducted in 2025 at the Gulf Coast Research and Extension Center in South Alabama evaluated 16 cotton varieties under low to moderate southern root-knot nematode pressure. Varieties differed minimally in stand establishment, biomass, nematode density, and lint yield. Nematicide treatment significantly reduced nematode egg density and increased plant biomass. However, neither stand establishment nor lint yields were improved. While the varieties produced between 1,300 and 1,700 lbs./acre, lint yields were not significantly affected by either variety or nematicide treatment, reflecting the relatively low nematode pressure at the site. Results indicate that under low root-knot nematode pressure, varietal performance and nematicide application had limited impact on yield, emphasizing the importance of site-specific nematode management decisions.
