White mold (WM), caused by Sclerotinia sclerotiorum, causes yield loss and grain contamination in soybean ( Glycine max [L.] Merr.) in Pennsylvania each year. S. sclerotiorum infects soybean flowers when conducive conditions are present, such as cool, moist weather and a dense soybean canopy. WM signs include black sclerotia in the stem and pods and white mycelia on the stem. Other symptoms include leaf wilting, water-soaked lesions, and plant death. This fungicide efficacy trial tests single application and two-pass treatments for preventing white mold in soybean ‘P30A93’ at an on-farm location in Lebanon, PA. Results from this trial will provide growers with recommendations for management strategies to reduce yield loss due to WM.

The golden palm ( Dypsis lutescens) is widely cultivated as an ornamental plant in tropical and subtropical regions. In June 2022, golden palms in residential areas of Yautepec, Morelos, Mexico, exhibited leaf anthracnose symptoms. Fungal isolates obtained from symptomatic tissue consistently displayed morphological features of a species belonging to the Colletotrichum gloeosporioides species complex. Cultural, morphological, and molecular analyses, including Bayesian phylogenetic analysis, identified the pathogen as C. grevilleae. Pathogenicity tests confirmed C. grevilleae as the causal agent of the disease. This study represents the first global report of C. grevilleae causing leaf blight in D. lutescens and its first occurrence on the American continent. Considering the economic significance of D. lutescens, further research is essential to understand the epidemiology of this emerging disease and to develop sustainable management strategies.

Potato pink rot, caused by Phytophthora erythroseptica, is a significant soilborne disease affecting potato production. Symptoms include tuber rot with a characteristic salmon-pink discoloration when exposed to air. To evaluate the efficacy of chemicals for controlling pink rot in potatoes, a field trial was conducted in 2024 at the Aroostook Research Farm in Presque Isle, ME, using the susceptible cultivar ‘Kennebec’. This study evaluates the performance of four fungicides applied as seed and soil treatments under field conditions, providing valuable insights for improving disease management strategies for potato growers.

Sugar beet is highly susceptible to the beet curly top virus (BCTV), which significantly reduces sugar yield and is prevalent in semi-arid growing regions. Typical BCTV symptoms are leaf vein swelling, thickening, and curling, leading to chlorosis and plant death. Insecticide seed treatments with neonicotinoids have been the primary management option, but neonicotinoids face regulatory restrictions due to environmental concerns. Thus, insecticides and biochemicals that are relatively safer to use were evaluated for efficacy against BCTV during the 2024 growing season. New treatments identified in this work can potentially be used by the growers to improve sugar beet BCTV management.

Pepper ( Capsicum annuum L.) is an important vegetable crop in the United States. Thrips-transmitted tomato spotted wilt virus (TSWV), a causal agent of tomato spotted wilt (TSW) disease, causes severe yield losses across the globe. TSWV management is centered around planting resistant pepper cultivars containing a single dominant gene, Tsw. However, due to a long-term overreliance on Tsw-resistant cultivars, resistance-breaking (RB) strains of TSWV disrupting Tsw resistance have been reported globally. To comprehensively understand the extent of protection offered by Tsw-resistant pepper cultivars against RB isolates, we studied the TSW incidence and severity and TSWV accumulation in resistant and susceptible pepper cultivars through multiyear field trials (2021 to 2023) in Bushland, TX. For the 2022 and 2023 growing seasons, the presence of RB isolates in field-infected plants was confirmed using controlled mechanical inoculation experiments. During all three seasons, resistant cultivars (2021: 6.77%, 2022: 17.33%, and 2023: 11.29%) had significantly lower TSW incidence compared with the susceptible cultivars (2021: 23.85%, 2022: 25.03%, and 2023: 20.63%). Furthermore, susceptible cultivars accumulated significantly higher amounts of TSWV than resistant cultivars. Additionally, the median severity of TSW symptoms in resistant cultivars was always lower than in susceptible cultivars. The results from this study show that TSWV-resistant pepper cultivars are still the best option against TSWV RB isolates under field conditions. However, they fail to offer complete protection against these isolates. The long-term success of single gene-mediated resistance warrants better harmonization of resistant cultivars with diverse sources of resistance and with existing integrated pest management strategies proven effective against TSWV and thrips.

Past research has demonstrated that soilborne pathogens can survive on buried strawberry crowns through fumigation. Devising methods to improve treatment of these tissues could help with disease control. The objectives of this work were to (i) investigate the extent to which fragmenting pathogen-infested crowns could improve fumigant disinfestation efficacy, (ii) evaluate the efficacy of fumigation with chloropicrin alone (Tri-Clor) versus a mixture of chloropicrin and 1,3-dichloropropene (Pic-Clor 60), and (iii) characterize the soil concentration and efficacy of fumigants at multiple depths. Fragmenting crowns did not result in improved disinfestation efficacy by any treatment. Neither fumigant achieved adequate Fusarium wilt disease control in the first trial, despite both treatments having high crown disinfestation efficacy. In the second trial, Pic-Clor 60 was significantly more effective than Tri-Clor at disinfesting Fusarium oxysporum f. sp. fragariae ( Fof) from strawberry crowns and suppressing Fusarium wilt disease. Broadcast-applied Pic-Clor 60 was significantly more effective than Tri-Clor at controlling Macrophomina phaseolina on crowns and soil across both trials. However, drip-applied Pic-Clor 60 EC was not significantly better than Tri-Clor EC at disinfesting crowns and soil or suppressing subsequent crown rot disease caused by M. phaseolina. Fumigant gas concentrations tended to be highest at the depth of injection (25 cm) and lowest at the 50-cm depth. Overall, these results indicate that there is a consistent advantage to using broadcast Pic-Clor 60 when M. phaseolina is present, but the advantages were not consistent for Fof or when drip applications were made.

Seedling damping-off and root and crown rot, caused by Rhizoctonia solani, are the most common root diseases of sugar beet in Minnesota and eastern North Dakota. Early season infection leads to poor stands, while mid-to-late season infection results in root rot with dark brown to black lesions that are accompanied by chlorotic and wilting foliage. In this study, we evaluated the efficacy of seed treatments, in-furrow fungicides, and biocontrol agents for managing Rhizoctonia diseases. The trial was conducted in 2024 in Crookston, MN, on a moderately susceptible sugar beet variety ( Beta vulgaris ‘Crystal 793RR’). Results from this trial will assist sugar beet growers in making informed decisions about managing this disease.

Early and late leaf spot and southern blight, caused by the fungal pathogens Passalora arachidicola, Nothopassalora personata, and Athelia rolfsii, respectively, are among the important diseases in peanut production regions of the United States. Leaf spot symptoms include lesions on leaves, petioles, and stems, often with a yellow halo in the case of early leaf spot, while southern blight symptoms include wilting and plant death. This report evaluates disease susceptibility within the Mississippi State Official Peanut Variety Trial located in Stoneville, MS, during 2023. Results from these trials will assist U.S. peanut producers in selecting management options for these diseases.

Black shank, caused by the oomycete pathogen Phytophthora nicotianae, is among the most devastating diseases of flue-cured tobacco in tobacco-producing regions throughout the world. Symptoms include yellowing, wilting, blackening and discing of the pith, and plant death. This report evaluates the efficacy of conventional fungicide programs for the management of black shank. The trial was conducted in 2024 in Johnston County, NC, on flue-cured variety ‘NC 196’. Results from these trials will help advise tobacco growers in developing integrated management programs for this disease.

Silver scurf, caused by Helminthosporium solani, is a surface blemish disease of potato ( Solanum tuberosum L.) that reduces tuber quality and market value. We obtained 75 H. solani monoconidial isolates from northwestern Washington-grown potato tubers and confirmed they were free of Sarocladium strictum using restriction enzyme digestion. These isolates were then evaluated using mycelial growth inhibition assays for their sensitivity to azoxystrobin (FRAC 11), difenoconazole (FRAC 3), and fludioxonil (FRAC 12), which are used commonly to manage silver scurf of potato. The mean absolute EC 50 values for azoxystrobin and difenoconazole were 0.72 and 0.26 µg/ml, respectively, with one isolate exhibiting an EC 50 value >10 µg/ml to azoxystrobin. In contrast, 89% of H. solani isolates tested were able to grow on an agar medium amended with 100 μg/ml of fludioxonil. The in vitro insensitivity of H. solani isolates to fludioxonil emphasizes the need for monitoring the field efficacy of fungicides with fludioxonil for management of silver scurf of potato.