On 2 October 2025, at a wholesale nursery in Albemarle County, VA, approximately 40 out of 100 Betula nigra plants in 11.4-liter containers were observed with light brown, zonate lesions and sclerotia on the leaves. Closer inspection revealed hypophyllous, pyramidal sporophores where the lesions formed, measuring 234 to 482 μm long and 75 to 111 μm wide (average 433 × 97 μm, n = 10). Necrotic leaf tissue from three plants was surfaced sterilized with 70% ethanol and cultured on potato dextrose agar medium. DNA was extracted from three isolates (GS25-AE41, GS25-AE42, and GS25-AE43), and they were Sanger sequenced. All three isolates had identical ITS sequences. A 510-bp fragment of the internal transcribed spacer region and a 1,146-bp fragment of the 28S ribosomal RNA from isolate GS25-AE41 were deposited into NCBI GenBank under accessions PX572933 and PX890849, respectively. Koch's postulates were fulfilled by placing agar plugs colonized with isolate GS25-AE41 mycelia facedown on 15 wounded B. nigra leaves. Grovesinia moricola was isolated from 12 out of 15 leaves, while the control leaves did not form lesions. The cultures from the inoculated leaves had a 100% ITS sequence homology to isolate GS25-AE41. G. moricola has been reported from Japan on Corylus (Betulaceae), but this is the first report of the fungus infecting a host in the genus Betula.

Botrytis blight, caused by Botrytis cinerea, is one of the most destructive diseases of poinsettia in greenhouse production. On bracts, leaves, and stems, Botrytis blight typically develops as rapidly expanding water-soaked lesions that become necrotic with characteristic gray sporulation. This PDMR reports on the evaluation of the efficacy of spray programs with conventional fungicides for the management of Botrytis blight. The trial was conducted in 2025 in Storrs, CT on greenhouse grown ‘Christmas Eve Red’ poinsettias. Results from this trial will aid in developing management programs for this disease.

Guava trees exhibiting symptoms of root-knot and foliar yellowing were observed in a backyard orchard in Juan José Ríos, Sinaloa, Mexico. Based on a combination of morphological characteristics, detection using species-specific primers, and phylogenetic analysis employing ITS and coxI sequences, the nematode was identified as Meloidogyne enterolobii. The pathogenicity of M. enterolobii was confirmed by inoculating guava seedlings, which consistently developed root galling symptoms and exhibited a reproduction factor of 21.2 at 110 days post-inoculation. This study constitutes the first report of M. enterolobii causing root-knot disease in guava in Mexico.

In the state of Arkansas, U.S.A., rice ( Oryza sativa) yield has been affected by a disease caused by the fungus Cercospora janseana. Previously considered to have low impact, its resurgence has led to noticeable yield losses. Moreover, symptoms have been observed on different plant structures. This report evaluates the use of host genetic resistance and the fungicide Tilt at different application timings to control Cercospora in rice. The experiment was conducted in the 2024 growing season in Colt, AR, using three cultivars recommended for the region. The use of the fungicide propiconazole at different timings during the boot stage in cultivars PVL03, CLL19, and RT7521FP allowed for inferences about the integration of host resistance and fungicide application. The results of this study provide important insights into the understanding and effective management of C. janseana in rice.

Purple spot, a fungal disease caused by Stemphylium vesicarium, renders spears unmarketable and on the fern, causes premature defoliation which can decrease next year’s yield and quality. Fungicides, including azoxystrobin, mancozeb, and chlorothalonil, are applied to the foliage according to the TOMCAST disease forecaster at 15 disease severity values (DSVs) in order to manage purple spot disease. The objective of our study was to identify fungicides that control purple spot disease on asparagus fern. The ability of fungicides to provide extended protection was of interest. Twelve fungicides, alternated with chlorothalonil, were applied to ‘Sequoia’ asparagus fern every 9-11 days and compared to an untreated control in 2022 and 2023. Relative area under the disease progress curve (rAUDPC) data indicated that all treatments within and beyond the interval period limited purple spot disease compared to the control except for fluopyram + pyrimethanil (2022), and pyrimethanil (2022). For industry standards, azoxystrobin had a lower disease severity than the control both within and beyond the treatment interval. Pydiflumetofen + fludioxonil, and fluxapyroxad + pyraclostrobin consistently had the lowest rAUDPC among unregistered fungicides within and beyond the treatment interval. The registration of new fungicides can protect the fern from purple spot and expand management options for growers.

Verticillium wilt of potatoes is an important soil-borne disease of potatoes, with reported yield losses exceeding 40%. It is caused by Verticillium species, most notably Verticillium dahliae. Symptoms include leaf chlorosis, limp and flaccid leaves, stunted growth, vascular discoloration towards the stem base, and discoloration of the vascular ring of the tuber. Infection may lead to premature plant decline 4-6 weeks before natural senescence, a condition known as potato early dying. While early dying can occur due to Verticillium alone, symptom severity may increase with co-infection by Pectobacterium spp. or plant-parasitic nematodes. Early dying can also be caused by Colletotrichum coccodes and nutritional deficiencies in the absence of Verticillium. The objective of this guide is to provide detailed information on methods related to disease diagnosis, including isolation, morphological and molecular identification, pathogen detection, isolate storage, and pathogenicity testing for verticillium wilt of potatoes.

Citrus black spot (CBS), caused by Phyllosticta citricarpa, is one of the most destructive citrus diseases worldwide, leading to fruit blemishes, premature drop, and trade restrictions. In Brazil, CBS control relies primarily on quinone outside inhibitor (QoI) and copper fungicides. During the 2024-2025 growing season, several commercial orchards in the São Paulo (SP) citrus belt exhibited increased CBS severity and reduced QoI effectiveness, suggesting shifts in pathogen sensitivity. Forty isolates of P. citricarpa were collected across the SP citrus belt and compared with historical wild-type isolates from 1998 and 2012. Sequencing of cytb gene fragments containing codons 129, 137, and 143 revealed a G137S substitution in isolates from multiple SP regions, while no mutations were found in wild-type isolates. Conidial germination assays with pyraclostrobin (1 µg/mL) showed rates from 12% to 96% among isolates with G137S mutation, compared with <15% in the 2012 sensitive isolate without G137S mutation, confirming reduced QoI sensitivity. The presence of an intron downstream of codon 143 prevents full resistance (G143A). These findings provide the first molecular evidence of emerging QoI resistance in P. citricarpa populations in Brazil and reinforce the need for fungicide rotation and integrated antiresistance management strategies.

Root-knot nematodes (RKN; Meloidogyne spp.) are the most prevalent and damaging nematode taxa on solanaceous and cucurbit vegetable crops in the southeastern United States (U.S.). An RKN-resistant pepper hybrid was evaluated for its effects on root galling, RKN population density, and yield in a pepper-cucumber double crop system, relative to a susceptible hybrid and compared with factorial treatments of 1,3-dichloropropene (1,3-D) fumigation in Kinston, NC. Effects of these treatments were also evaluated on the subsequently planted cucumber. These results guided the selection of seven different nematicide and pepper hybrid combinations, as management programs, for a three-year study in Elm City, NC. Treatment effects on yield, root damage, and population densities of free-living and plant-parasitic nematode species were examined. In Kinston, both 1,3-D fumigation and the RKN-resistant hybrid significantly reduced root galling and RKN densities. Use of the RKN-resistant pepper hybrid was the only factor to significantly improve pepper and second crop cucumber yields (P<0.05). In Elm City, higher pepper and cucumber yields were observed in RKN management programs that included the RKN resistant pepper hybrid combined with fluopyram application, regardless of fumigation application. No significant difference in densities of free-living or plant parasitic nematode species were observed across management programs, though RKN densities trended lower when using an RKN resistant hybrid. These results highlight the potential for increasing yields and improving RKN management in pepper-cucumber rotations by using RKN-resistant pepper hybrids, combined with fluopyram application. Reducing dependence on 1,3-D fumigation improves both the economic and environmental sustainability of vegetable production.

Charcoal rot, caused by Macrophomina phaseolina, is a major soilborne disease of strawberry in Florida causing major economic losses to growers. Typical symptoms affect the crown by causing a reddish-brown discoloration, leading to plant wilt and collapse. This trial evaluated the efficacy of biological and synthetic products, applied by drip or drench, for the management of charcoal rot. The transplants of ‘Florida Medallion’ were obtained from a California nursery. Over 16 weeks, marketable yield and disease incidence data were collected. Our results will assist Florida strawberry growers in improving disease management programs.

Mummy berry, caused by Monilinia vaccinii-corymbosi (Mvc), is a disease characterized by blighted young shoots and flower clusters, and mummification of fruits in blueberry (Vaccinium corymbosum), resulting in economic losses. To monitor the timing of primary inoculum (ascospore) release from apothecia, rotating-arm air samplers were deployed in a northern highbush blueberry field in Whatcom County of northwestern Washington during the 2022, 2023, and 2024 production seasons. Mvc was detected and quantified via a quantitative real-time PCR (qPCR) using species-specific primers. To complement these data, field observations on host and pathogen phenology were recorded from February to April in all three study years. While qPCR results aligned with visual observations of apothecia formation on mummified berries in the field, use of air samplers did not result in earlier detection of primary inoculum compared to visual observations during the study period. In parallel, 64 Mvc isolates were obtained from blueberry fields with mummy berry across five Washington counties during 2021 and 2022. These isolates were evaluated with mycelial growth inhibition assays for their sensitivity to fenbuconazole and metconazole fungicides, which are commonly used to manage mummy berry. All tested isolates exhibited EC50 values less than 0.08 µg/ml for both fungicides, indicating their in vitro efficacy.