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Chapter 10 of the Vegetable Production Handbook of Florida

Chapter 9 of the Vegetable Production Handbook of Florida

Chapter 6 of the Vegetable Production Handbook of Florida

Chapter 4 of the Vegetable Production Handbook of Florida

Chapter 1 of the Vegetable Production Handbook of Florida

The use of high tunnels, which allows growers to extend their season and improve yields, is increasing in the Southeastern U.S., yet growers face challenges related to weed and disease management, particularly in organic systems. On-station experiments were conducted during fall 2021 and spring 2022 in a split-plot design to assess the efficacy of anaerobic soil disinfestation (ASD) in high tunnels for the organic production of direct-seeded baby leaf lettuce. Soil treatments (ASD, Compost, and Control) and lettuce types (romaine and oakleaf cultivars) were included in whole plots and subplots, respectively. The ASD-treated soils received molasses and granular organic fertilizer as carbon and nitrogen sources. The Compost treatment involved the application of yard waste-based compost and the same organic fertilizer, while the Control soils received organic fertilizer only. The ASD treatment period lasted 8 days rather than the typical 21-day period evaluated in Florida. Crop yield, biometrics (leafy dry matter content, specific leaf area, specific leaf weight), and lettuce quality attributes (leaf color, soluble solids content, total titratable acidity, ferric reducing antioxidant power, ascorbic acid content, total phenolics) were assessed following harvest. In both trials, numerical differences in lettuce fresh weight yield between soil treatments were evident, though not statistically significant. Differences in leaf quality attributes were driven by lettuce cultivar rather than soil treatments. Bottom rot incidence caused by Rhizoctonia solani was reduced by 93% and 87% in the ASD-treated plots compared with the Compost- and Control-treated soils during the spring 2022 trial. The ASD-treated soils had a reduced population density of broadleaf weeds in both baby leaf lettuce production trials. The current study presents novel evidence of the potential of integrating ASD into HT organic production systems without reducing the yield and quality attributes of direct-seeded baby leafy greens compared with common grower practices.

Fusarium wilt, caused by Fusarium oxysporum f. sp. niveum (Fon), is a soilborne disease that significantly limits yield in watermelon (Citrullus lanatus) and occasionally causes the loss of an entire year's harvest. Reference-quality de novo genomic assemblies of pathogenic and nonpathogenic strains were generated using a combination of next-generation and third-generation sequencing technologies. Chromosomal-level genomes were produced with representatives from three Fon races, facilitating comparative genomic analysis and the identification of chromosomal structural variation. Syntenic analysis between isolates allowed for differentiation of the core and lineage-specific portions of their genomes. This research will support future efforts to refine the scientific understanding of the molecular and genetic factors underpinning the Fon host range, develop diagnostic assays for each of the four races, and decipher the evolutionary history of race 3. [Figure: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

This new 7-page article provides a concise overview of some influential high-tunnel tomato soilborne and foliar diseases and their cultural management techniques. Written by Zachary D. Eldred, Shufang Tian, Gary E. Vallad, Xin Zhao, Mathews Paret, and Nicholas S. Dufault and published by the UF/IFAS Plant Pathology Department. https://edis.ifas.ufl.edu/pp368

Chapter 9 of the Vegetable Production Handbook.

Chapter 4 of the Vegetable Production Handbook of Florida

Chapter 17 of the Vegetable Production Handbook for Florida.

Chapter 6 of the Vegetable Production Handbook.

Chapter 4 of the Vegetable Production Handbook.

This chapter covers production of cole crops and Asian crucifers, including broccoli, cabbage, cauliflower, Chinese broccoli, Chinese cabbage, Chinese mustard (bok choy), kohlrabi, lobok/daikon, collards, kale, mustard, and turnip.

Cucurbit downy mildew is a major disease that affects over 40 species of cucurbits, like watermelon, muskmelon, cucumber, squash, and pumpkin. The classic sign of the disease is the presence of dark sporangia, a structure that holds developing spores, on the underside of infected leaves. As the disease progresses, it may lead to large necrotic areas that cause defoliation and a reduction of yield and marketable fruit. This nine-page fact sheet describes the symptoms and signs, epidemiology and disease cycle, host range and pathotypes, and the ways to manage cucurbit downy mildew. Written by Mason J. Newark, Mathews L. Paret, Nicholas S. Dufault, Pamela D. Roberts, Shouan Zhang, Gary E. Vallad, Josh Freeman, and Gene McAvoy, and published by the Plant Pathology Department. http://edis.ifas.ufl.edu/pp325 Updated July 2019.

A quantitative PCR (qPCR)-assay was developed to detect airborne inoculum of Nothopassalora personata, causal agent of late leaf spot (LLS) on peanut, collected with a modified impaction spore trap. The qPCR assay was able to consistently detect as few as 10 spores with purified DNA and 25 spores based on crude DNA extraction from rods. In 2019, two spore traps were placed in two peanut fields with a history of LLS. Sampling units were replaced every 2 to 4 days and tested with the developed qPCR assay, while plots were monitored for symptom development. The system detected inoculum 35 to 56 days before visual symptoms developed in the field, with detection related to environmental parameters affecting pathogen life-cycle and disease development. This study develops the framework of the qPCR spore trap system and represents the initial steps towards validation of the performance of the system for use as a decision support tool to complement integrated management of LLS.

Temperature response curves under diurnal oscillating temperatures differ from those under constant conditions for all stages of the Phytophthora infestans infection cycle on potatoes. We developed a mechanistic model (BLIGHTSIM) with an hourly time step to simulate late blight under fluctuating environmental conditions and predict late blight epidemics in potato fields. BLIGHTSIM is a modified susceptible (S), latent (L), infectious (I) and removed (R) compartmental model with hourly temperature and relative humidity as driving variables. The model was calibrated with growth chamber data covering one infection cycle and validated with field data from Ecuador. The model provided a good fit to all data sets evaluated. There was a significant interaction between average temperature and amplitude in their effects on the area under the disease progress curve (AUDPC) as predicted from growth chamber data on a single infection cycle. BLIGHTSIM can be incorporated in a potato growth model to study effects of diurnal temperature range on late blight impact under climate change scenarios.

This 3-page document discusses the symptoms and management of powdery mildew, a problematic fungal disease, on watermelon in Florida. Written by Pamela D. Roberts, Mathews Paret, and Nicholas Dufault and published by the UF/IFAS Plant Pathology Department, January 2019. http://edis.ifas.ufl.edu/pp342

This 21-page fact sheet is chapter 6 of the 2018 Vegetable Production Handbook. Written by Lincoln Zotarelli, Peter J. Dittmar, Monica Ozores-Hampton, Nicholas S. Dufault, Bonnie Wells, Johan Desaeger, Joseph W. Noling, Eugene J. McAvoy, Qingren Wang, and Christian F. Miller, and published by the Horticultural Sciences Department, 2018. HS724/CV122: Chapter 6. Cole Crop Production (ufl.edu)

This 11-page fact sheet is the fourth chapter in the 2018 Vegetable Production Handbook. Peter J. Dittmar, Nicholas S. Dufault, Joseph W. Noling, Philip Stansly, Nathan Boyd, Matthews L. Paret, and Susan E. Webb, and published by the Horticultural Sciences Department, 2018. CV298/CV298: Chapter 4. Integrated Pest Management (ufl.edu)

Gummy stem blight (GSB) is a major disease of many cucurbits, including watermelon, cantaloupe, cucumber, pumpkin, squash, muskmelon, and other melons. The disease is also known as black rot due to its characteristic appearance on infected fruits. Learn the symptoms, causal agent and disease spread, and fungicides labeled for use in Florida. Updated August 2018

PP276 provides information on what crops white mold (Sclerotinia spp.) affects in Florida and available methods of control. Includes references. Updated August 2018.

This report includes a summary of the 2016 foliar fungicide programs for control of early and late leaf spot and white mold (southern stem rot) in peanut at Jay, Florida. It shows the effectiveness of 13 fungicide programs for disease control. All programs contained active ingredients for the control of white mold (Sclerotium rolfsii) except the Bravo treatment (program #2), which was considered a control. These data represent only one year at one location, and readers are cautioned that test results should be considered over several locations and years before final conclusions are considered valid. These data are meant to serve as a guide in the selection of effective fungicide programs for peanut.

This ten-page fact sheet includes a summary of various fungicide spray programs for fungal disease control of early leaf spot, late leaf spot, and white mold/stem rot of peanut in 2012-2016 on-farm trials in Hamilton County. Written by K.W. Wynn, N.S. Dufault, and R.L. Barocco and published by the Plant Pathology Department. http://edis.ifas.ufl.edu/pp334

Fusarium wilt of watermelon (Citrullus lanatus) caused by Fusarium oxysporum f. sp. niveum (Fon), has become an increasing concern of farmers in the southeastern USA, especially in Florida. Management of this disease, most often through the use of resistant cultivars and crop rotation, requires an accurate understanding of an area's pathogen population structure and phenotypic characteristics. This study improved the understanding of the state's pathogen population by completing multilocus sequence analysis (MLSA) of two housekeeping genes (BT and TEF) and two loci (ITS and IGS), aggressiveness and race-determining bioassays on 72 isolates collected between 2011 and 2015 from major watermelon production areas in North, Central, and South Florida. Multilocus sequence analysis (MLSA) failed to group race 3 isolates into a single large clade; moreover, clade membership was not apparently correlated with aggressiveness (which varied both within and between clades), and only slightly with sampling location. The failure of multilocus sequence analysis using four highly conserved housekeeping genes and loci to clearly group and delineate known Fon races provides justification for future whole genome sequencing efforts whose more robust genomic comparisons will provide higher resolution of intra-species genetic distinctions. Consequently, these results suggest that identification of Fon isolates by race determination alone may fail to detect economically important phenotypic characteristics such as aggressiveness leading to inaccurate risk assessment.