Effect of fumigants on inoculum of spp. in strawberry crowns and soil.

Florida's strawberry industry has been facing an emerging threat after several outbreaks of an aggressive sp. affecting fruit, leaf, and crown caused severe yield losses. Our studies found sp.

sp. nov., a novel bacterial species causing leaf spots on strawberry (×).

In Florida, angular leaf spot, caused by , was the only known bacterial disease in strawberry, which is sporadic and affects the foliage and calyx. However, from the 2019-2020 to 2023-2024 Florida strawberry seasons, unusual bacterial-like symptoms were observed in commercial farms, with reports of up to 30 % disease incidence. Typical lesions were water-soaked and angular in early stages that later became necrotic with a circular-ellipsoidal purple halo, and consistently yielded colonies resembling on culture media.

Utilizing High-Resolution Imaging and Artificial Intelligence for Accurate Leaf Wetness Detection for the Strawberry Advisory System (SAS).

In strawberry cultivation, precise disease management is crucial for maximizing yields and reducing unnecessary fungicide use. Traditional methods for measuring leaf wetness duration (LWD), a critical factor in assessing the risk of fungal diseases such as botrytis fruit rot and anthracnose, have been reliant on sensors with known limitations in accuracy and reliability and difficulties with calibrating. To overcome these limitations, this study introduced an innovative algorithm for leaf wetness detection systems employing high-resolution imaging and deep learning technologies, including convolutional neural networks (CNNs).

sp. nov. Causing Anthracnose Leaf Spot of × (Araceae) in Florida, U.S.A.

Caladium ( × ) is an ornamental plant popular for its variable and colorful foliage. In 2020, plants showing leaf spots and blight, typical of anthracnose, were found in a field trial at the University of Florida's Gulf Coast Research and Education Center in Wimauma, Florida, U.S.

Exploring the genetic basis of resistance to Neopestalotiopsis species in strawberry.

Aggressive strains of Neopestalotiopsis sp. have recently emerged as devastating pathogens of strawberry (Fragaria × ananassa Duchesne ex Rozier), infecting nearly all plant parts and causing severe outbreaks of leaf spot and fruit rot in Florida and globally. The development of host resistance is imperative due to the absence of fungicides that effectively inhibit Neopestalotiopsis sp.

A Semi-Selective Medium to Evaluate Over-Summering Survival of sp. in Florida Strawberry Fields.

Devastating disease outbreaks with leaf spot symptoms and fruit rot caused by a fungus identified as a cryptic species of have generated concern in the Florida strawberry industry. Some species are saprobes in soil and plant debris, but the ability of the new sp. to survive in strawberry debris was unknown.

Blueberry floral probiotics: nectar microbes inhibit the growth of Colletotrichum pathogens.

Aims: To identify whether microorganisms isolated from blueberry flowers can inhibit the growth of Colletotrichum, an opportunistic plant pathogen that infects flowers and threatens yields, and to assess the impacts of floral microbes and Colletotrichum pathogens on artificial nectar sugars and honey bee consumption.

Methods And Results: The growth inhibition of Colletotrichum (Colletotrichum acutatum, Colletotrichum fioriniae, and Colletotrichum gloeosporioides) was screened using both artificial nectar co-culture and dual culture plate assays. All candidate nectar microbes were screened for antagonism against a single C.

New Genotypes of Found on Strawberry in Florida.

is the most common causal agent of Phytophthora crown rot and leather rot of strawberry, but is also responsible for the disease in Florida. Studies of populations have suggested that different groups of genotypes are associated with different hosts; however, it is not yet clear how many lineages exist globally and how they are related to different production systems. The aim of this study was to determine the genetic relationships of isolates from Florida strawberry with genotypes reported from other hosts, quantify the genetic variation on strawberry, and test for an association with nursery source.

Identification of sequence mutations in Phytophthora cactorum genome associated with mefenoxam resistance and development of a molecular assay for the mutant detection in strawberry (F. × ananassa).

Phytophthora crown rot (PhCR) caused by Phytophthora cactorum is one of the most damaging diseases of strawberry worldwide. Mefenoxam is one of the major fungicides currently used to manage PhCR. However, the emergence and spread of resistant isolates have made controlling the pathogen in the field problematic.

Old but Gold: Captan Is a Valuable Tool for Managing Anthracnose and Botrytis Fruit Rots and Improving Strawberry Yields Based on a Meta-Analysis.

Botrytis fruit rot (BFR) and anthracnose fruit rot (AFR) are diseases of concern to strawberry growers. Both diseases are managed mainly by fungicide applications from the nursery (plant production) to the end of the growing season (fruit production). In Florida, captan is the main broad-spectrum fungicide used to control BFR and AFR.

Effective Management of Powdery Mildew in Cantaloupe Plants Using Nighttime Applications of UV Light.

Ultraviolet light at wavelengths from 254 to 283 nm/has been reported to effectively suppress powdery mildews in several crops, including some cucurbits. Its use to suppress powdery mildew () specifically in cantaloupe has not been previously reported. We evaluated the foregoing technology in cantaloupe fields for suppression of powdery mildew and possible effects on plant growth and yield.

Construction of a genome-wide genetic linkage map and identification of quantitative trait loci for powdery mildew resistance in daisy.

Powdery mildew (PM) is a common fungal disease in many important crops. The PM caused by has been the most challenging problem in commercial () production globally, often leading to severe losses of crop yield and quality. A small number of PM-resistant breeding lines and cultivars have been reported in , but the underlying genetics for PM resistance in is largely unknown.

Efficacy of Single- and Multi-Site Fungicides Against spp. of Strawberry.

Recently, the Florida strawberry industry faced unprecedented outbreaks of an emerging disease caused by the fungus spp. Currently, there are no fungicides labeled to control this disease in the United States and the efficacy of single- and multisite fungicides is unknown. Therefore, this study aimed to determine the in vitro sensitivity of spp.

Phosphite Is More Effective Against Phytophthora Crown Rot and Leather Rot Caused by than .

Phytophthora crown rot (PhCR) and leather rot (LR) caused by spp. are major threats to strawberry production worldwide. In the United States, these diseases are mainly caused by ; however, has also been recently reported causing PhCR.

Development of a Molecular Tool for Identification of a New sp. Associated with Disease Outbreaks on Strawberry.

A new sp. was recently reported causing outbreaks of leaf spot and fruit rot on strawberry in Florida, Georgia, and South Carolina. In contrast to other pathogens, the new species appears more aggressive and destructive on strawberry.

Imaging and Deep Learning Based Approach to Leaf Wetness Detection in Strawberry.

The Strawberry Advisory System (SAS) is a tool developed to help Florida strawberry growers determine the risk of common fungal diseases and the need for fungicide applications. Leaf wetness duration (LWD) is one of the important parameters in SAS disease risk modeling. By accurately measuring the LWD, disease risk can be better assessed, leading to less fungicide use and more economic benefits to the farmers.

Resistance of Strawberry Cultivars and the Effects of Plant Ontogenesis on and Causing Crown Rot.

Phytophthora crown rot (PhCR) is an important disease of strawberry worldwide. is the most common causal agent, however, was also recently reported causing PhCR in the U.S.

Causing Leaf Spots on Commercial Blackberry ( sp.) in Florida.

Blackberry ( L. subgenus Watson) is a deciduous berry crop that is the fourth most economically important berry crop, and its production is expanding in the southeastern United States. However, since most commercially available cultivars were bred under temperate conditions, they are not always well adapted and could be threatened by new pathogen populations inhabiting subtropical areas.

A reassessment of the fungicidal efficacy of 1,3-dichloropropene, chloropicrin, and metam potassium against Macrophomina phaseolina in strawberry.

Background: The effectiveness of metam potassium, 1,3-dichloropropene, chloropicrin, and different ratios of 1,3-dichloropropene and chloropicrin on the reduction of natural and artificial inoculum of Macrophomina phaseolina were investigated in laboratory and field experiments. Additionally, a multivariate meta-analysis with data from six field trials conducted in Florida from 2012 to 2018 was performed.

Results: In small-plot field experiments using drip stakes, the highest rate (468 L ha ) of metam potassium was most effective in controlling M.

Sensitivity of Species Complex from Strawberry to Fungicide Alternatives to Quinone-Outside Inhibitors.

is a species complex that causes anthracnose fruit rot and root necrosis on strawberry. The major and minor species within the complex that affect strawberry production are and , respectively. The disease can significantly reduce yield under conducive weather, and its management has greatly relied on quinone-outside inhibitor fungicides (QoI).

UV-Transmitting Plastics Reduce Powdery Mildew in Strawberry Tunnel Production.

Strawberry powdery mildew, caused by , can be particularly destructive in glasshouse and plastic tunnel production systems, which generally are constructed of materials that block ultraviolet (UV) solar radiation (about 280 to 400 nm). We compared epidemic progress in replicated plots in open fields and under tunnels constructed of polyethylene, which blocks nearly all solar UV-B, and two formulations of ethylene tetrafluoroethylene (ETFE), one of which contained a UV blocker and another that transmitted nearly 90% of solar UV-B. Disease severity under all plastics was higher than in open-field plots, indicating a generally more favorable environment in containment structures.

First Report of Leaf Rust on Blackberry ( spp.) Caused by in Florida.

During the fall of 2020 and summer of 2021, symptoms of leaf rust were observed on blackberry plants of 'Kiowa', and breeding line 1734 (progeny of 'Natchez' and Arapaho') in a field trial at the University of Florida, Wimauma, FL. Symptoms consisted of small chlorotic spots (1 to 3 mm) on the upper side of the leaf, while the underside had yellow-orange pustules. Disease incidence was up to 100% on both 'Kiowa' and the breeding line 1734, and severity was up to 20% with most of the symptoms observed on older leaves.

Feeding Selectivity of and on Fungi Associated with Florida Strawberry.

and are foliar nematodes associated with commercial strawberry production in Florida, United States. The reproductive and feeding habits of these two nematode species were assessed on Florida isolates of the fungi , , , and , which are pathogenic to strawberry, and nonpathogenic isolates of and grown on potato dextrose agar in Petri dishes. Each culture was inoculated with six specimens of mixed life stages of or and incubated at 24°C under axenic and nonaxenic conditions 23 and 31 days after inoculation, respectively.

Detection and Characterization of Quinone Outside Inhibitor-Resistant and . Causing Leather Rot in Florida Strawberry.

and . cause leather rot (LR) of fruit and Phytophthora crown rot (PhCR) in strawberry. LR occurs sporadically but can cause up to 70% fruit loss when weather is conducive.