Sugarcane In Florida Research Articles

Identification of Grass Weed Seedlings Commonly Found in Florida Sugarcane: A Quick Reference Guide

This article describes proper identification of grass weed seedlings associated with sugarcane in Florida to assist growers with selecting effective control measures. Written by Calvin Odero, Matthew VanWeelden, and Christian Kammerer, and published by the UF/IFAS Agronomy Department, May 2023.

Diagnosing Herbicide Injury Symptoms in Sugarcane and Rotational Crops in Southern Florida

This article describes how to diagnose injury symptoms from herbicides commonly used in sugarcane and rotational crops in southern Florida based on their mode of action. This information is intended to help growers to pinpoint sources of injury from off-target movement, carryover, or improper use of herbicides. Written by Calvin Odero, Matthew VanWeelden, and Christian Kammerer, and published by the UF/IFAS Agronomy Department, May 2023.

Evaluation of a neonicotinoid alternative to phorate for the management of soil insects in Florida sugarcane

Wireworms (Coleoptera: Elateridae) are the main soil insect pests of sugarcane (Saccharum spp. hybrids) in Florida. Melanotus communis (Gyllenhal) is the most abundant wireworm in Florida sugarcane fields, reducing stalk populations by feeding on buds of sugarcane seed pieces and on young sugarcane plants. At-planting use of the organophosphate insecticide phorate is the main wireworm management tactic in Florida; however, phorate is a hazardous and relatively expensive insecticide. Thiamethoxam is a neonicotinoid insecticide that has potential to become registered for use on sugarcane in the United States. Previous studies suggested that thiamethoxam decreases wireworm injury to sugarcane seed pieces but does not increase wireworm mortality. The present study conducted between 2018 and 2022 aimed to comprehensively evaluate thiamethoxam for wireworm control under laboratory, outdoor, and field conditions. In two laboratory bioassays, M. communis mortality associated with thiamethoxam (3–20%) was not different than mortality for the non-treated check (0–7%), whereas mortality associated with phorate attained 93–100%. In three large container experiments conducted outdoors with controlled M. communis infestations, thiamethoxam and phorate generally protected young sugarcane plant populations at comparable levels. Insecticide efficacy was mainly associated with the protection of seed-piece buds. However, the number of recovered live wireworms was 2.7–8.0 times greater in thiamethoxam treatments than in phorate treatments. In three field experiments, young sugarcane plant populations in thiamethoxam- and phorate-treated plots were not different than those in non-treated plots. However, the at-planting application of thiamethoxam decreased the number of sugarcane thrips, Fulmekiola serrata (Kobus), by 67–89% in two experiments with thrips infestations 12 weeks after planting. Although the evaluation of insecticide efficacy under natural wireworm infestations was inconclusive, this study confirmed that thiamethoxam should be considered as an alternative to phorate if registered. However, the long-term effects of low wireworm mortality associated with thiamethoxam use should be studied.

Draft Genome Sequence Resource for the Orange Rust Pathogen of Sugarcane Puccinia kuehnii.

Puccinia kuehnii is an obligate biotrophic fungal pathogen that causes orange rust of sugarcane, which is prevalent in many countries around the globe. In the United States, orange rust was first detected in sugarcane in Florida in 2007 and poses a persistent and economically damaging threat to the sugarcane industry in this region. Here, we generated the first genome assemblies for two isolates of P. kuehnii (1040 and 2143) collected in Florida in 2017 from two sugarcane cultivars, CL85-1040 and CP89-2143, respectively. These two rust genome resources will be of immense value for future genomic studies, particularly further exploration of the predicted secretomes that may help define key pathogenicity determinants for this economically important pathogen.

Eight Species of Poaceae Are Hosting Different Genetic and Pathogenic Strains of Sugarcane Mosaic Virus in the Everglades Agricultural Area.

Sugarcane mosaic virus (SCMV) was detected by reverse transcription polymerase chain reaction in eight different species of the Poaceae family in the Everglades Agricultural Area (EAA) of south Florida: broadleaf signalgrass (Urochloa platyphylla), Columbus grass (Sorghum almum), goosegrass (Eleusine indica), maize (Zea mays), sorghum (Sorghum bicolor), St. Augustine grass (Stenotaphrum secundatum), southern crabgrass (Digitaria ciliaris), and sugarcane (Saccharum interspecific hybrids). Based on their coat protein (CP) gene sequence, 62 isolates of SCMV from Florida and 29 worldwide isolates representing the known genetic diversity of this virus were distributed into eight major phylogenetic groups. SCMV isolates infecting Columbus grass, maize, and sorghum in Florida formed a unique group, whereas virus isolates infecting sugarcane in the United States (Florida and Louisiana) clustered with isolates from other countries. Based on the entire genome coding region, SCMV isolates infecting sugarcane in Florida were closest to virus isolates infecting sorghum species or St. Augustine grass. Virus isolates from Columbus grass, St. Augustine grass, and sugarcane showed different virulence patterns after mechanical inoculation of Columbus grass, St. Augustine grass, and sugarcane plants, thus proving that these isolates were different pathogenic strains. Sugarcane was symptomless and tested negative for SCMV by tissue blot immunoassay after inoculation with crude sap from SCMV-infected Columbus grass, indicating that Columbus grass was not a reservoir for SCMV infecting sugarcane in the EAA. Close CP sequence identity between isolates of SCMV from Columbus grass, maize, and sorghum suggested that the same virus strain was naturally spreading between these three plants in south Florida.

Biology and Control of Sedges Associated with Sugarcane and Rice in Florida

This article describes the biology and control options for sedges associated with sugarcane and rice in Florida to assist growers in making correct identification and appropriate management decisions to help control these species. Written by A. R. Calderon and D. C. Odero, and published by the UF/IFAS Agronomy Department, June 2021.

Predictive Modeling of Brown Rust of Sugarcane Based on Temperature and Relative Humidity in Florida.

Logistic regression models were developed from 5 years (2014 to 2018) of disease severity and weather data in an attempt to predict brown rust of sugarcane at the Everglades Research and Education Center in Belle Glade, Florida. Disease severity (percentage area of the top visible dewlap leaf covered by rust) was visually assessed in the field every 2 weeks for two varieties susceptible to brown rust. A total of 250 variables were derived from weather data for 10- to 40-day periods before each brown rust assessment day. A subset of these variables were then evaluated as potential predictors of severity of brown rust based on their individual correlation or their biological meaningfulness. Analyses of correlation and stepwise logistic regression allowed us to identify afternoon humid thermal ratio (AHTR), temperature-based duration variables, and their interaction terms as the most significant variables associated with brown rust epidemics of sugarcane in Florida. The nine best predictive models were identified based on model accuracy, sensitivity, specificity, and estimates of the prediction error. The prediction accuracy of these models ranged from 73 to 85%. Single-variable model BR2 (based on AHTR) classified 89% of the epidemic and 81% of the nonepidemic status of the disease. More than 83% of the epidemics and 81% of the nonepidemic status of sugarcane brown rust was correctly classified via multiple-variable models. These models can be used as components of a rust disease warning system to assist in the management of brown rust epidemics of sugarcane in south Florida.

Occurrence of two races of Puccinia kuehnii causing orange rust of sugarcane in Florida

AbstractOrange rust of sugarcane caused by Puccinia kuehnii was first reported in Florida in 2007. Since then, several sugarcane cultivars that were resistant during the initial epidemics became susceptible within a few years. These shifts in resistance were attributed to the evolution of the pathogen and appearance of new races. To study the variation in virulence of P. kuehnii, healthy leaf pieces of sugarcane cultivars susceptible to orange rust were brush inoculated with isolates of P. kuehnii collected from susceptible cultivars in the field. After inoculation, leaf pieces were placed in an incubator and disease severity based on the number of rust uredinia was determined 2 weeks postinoculation. Isolates of P. kuehnii collected from sugarcane cultivar CP 89‐2143, which only showed severe symptoms of orange rust starting in 2011–2012, produced 300%–500% more uredinia on CP 89‐2143 than the isolates collected from cultivar CL 85‐1040 that has been susceptible since 2007. Sugarcane cultivar CL 85‐1040 exhibited high and equivalent numbers of uredinia regardless of the inoculated isolate of the pathogen. These data support the occurrence of pathogenic specialization within P. kuehnii and the existence of at least two races of this pathogen in Florida. Analysis of amplified fragment‐length polymorphism among isolates of P. kuehnii from cultivars CP 89‐2143 and CL 85‐1040 differing in resistance to orange rust revealed genetic variation among rust uredinia. However, this variation was not associated with a specific sugarcane cultivar, suggesting that pathogenic variation was not linked to major, but rather to small genetic changes within the genome of P. kuehnii.

Molecular detection of sugarcane striate virus and sugarcane white streak virus and their prevalence in the Miami World Collection of sugarcane and related grasses

AbstractViruses in the genus Mastrevirus (family Geminiviridae), including those infecting sugarcane, have natural geographical ranges almost exclusively restricted to Africa and the Indian Ocean islands off the African coast. Only sugarcane white streak virus (SWSV) in Barbados and sugarcane striate virus (SStrV) in Florida and Guadeloupe are known to infect a few sugarcane varieties in the Western Hemisphere. In this study, PCR assays were developed to detect these two viruses in sugarcane. Five hundred and seventy‐one DNA samples from Saccharum species and interspecific hybrids from the Miami World Collection of sugarcane and related grasses were tested for the presence of SStrV and SWSV by PCR. No variety was found infected by SWSV but SStrV was detected in 19 varieties. PCR data were confirmed by sequencing amplified fragments (248 bp). These fragments shared 93%–100% nucleotide identity with SStrV sequences from the GenBank database. SStrV isolates were distributed in six phylogenetic groups, including the four strains of the virus. Most varieties infected by SStrV originated from Asia, thus confirming a previous hypothesis stating that this virus originated from this continent. Absence of SStrV in commercial sugarcane in Florida also suggested that this virus has not been spread in this location, while infected plants have been present for several decades.

Weather-Based Predictive Modeling of Orange Rust of Sugarcane in Florida

Epidemics of sugarcane orange rust (caused by Puccinia kuehnii) in Florida are largely influenced by prevailing weather conditions. In this study, we attempted to model the relationship between weather conditions and rust epidemics as a first step toward development of a decision aid for disease management. For this purpose, rust severity data were collected from 2014 through 2016 at the Everglades Research and Education Center, Belle Glade, Florida, by recording percentage of rust-affected area of the top visible dewlap leaf every 2 weeks from three orange rust susceptible cultivars. Hourly weather data for 10- to 40-day periods prior to each orange rust assessment were evaluated as potential predictors of rust severity under field conditions. Correlation and stepwise regression analyses resulted in the identification of nighttime (8 PM to 8 AM) accumulation of hours with average temperature 20 to 22°C as a key predictor explaining orange rust severity. The five best regression models for a 30-day period prior to disease assessment explained 65.3 to 76.2% of variation of orange rust severity. Prediction accuracy of these models was tested using a case control approach with disease observations collected in 2017 and 2018. Based on receiver operator characteristic curve analysis of these two seasons of test data, a single-variable model with the nighttime temperature predictor mentioned above gave the highest prediction accuracy of disease severity. These models have potential for use in quantitative risk assessment of sugarcane rust epidemics.

Miscellaneous Insect Pests of Florida Sugarcane

This 8-page fact sheet is a minor revision. The insects and mites discussed in this publication are occasional pests of sugarcane in Florida or are arthropods of concern although their pest status has not been determined. They have received less research interest and less is known about them, because they have not been as important as other sugarcane pests such as the corn wireworm (Melanotus communis) or the sugarcane borer (Diatraea saccharalis). However, these arthropods have the potential to become a problem if conditions favor an outbreak. Written by Gregg S. Nuessly, Ron H. Cherry, Hardev S. Sandhu, and Julien M. Beuzelin, and published by the Entomology and Nematology Department, July 2019. ENY-667/SC014: Miscellaneous Insect Pests of Florida Sugarcane (ufl.edu)

The Dynamics of Sugarcane and Sugar Yields in Florida: 1950–2018

The Dynamics of Sugarcane and Sugar Yields in Florida: 1950–2018

The Dynamics of Sugarcane and Sugar Yields in Florida: 1950–2018

Florida is the largest producer of sugarcane (Saccharum spp.) in the United States. Since 1911, the University of Florida continues to develop new sugarcane cultivars that are better adapted to the Florida environment. We use piecewise regression to determine the growth in both Florida sugarcane and sugar yields, and how new sugarcane cultivars have positively affected yields. We use breakpoints for periods between 1950 and 2018: Scenario 1 (1950–2018), Scenario 2 (1950–1980 and 1981–2018), Scenario 3 (1950–1980, 1981–2000, and 2001–2018), and Scenario 4 (1950–1968, 1969–2000, and 2001–2018). In most scenarios, new sugarcane cultivars have significantly increased sugarcane and sugar yield, as well as sugar content. For 1950 to 2018, sugarcane yield increased by 21.3 Mg ha−1 (30%, P < 0.01) and sugar yield increased by 5.1 Mg ha−1 (78%, P < 0.01). Sugar content also increased significantly (P < 0.01). Before 1980, sugarcane yield significantly decreased (P < 0.05), whereas sugar yield showed neither a significant increase nor decrease. For 1980 to 2018, both sugarcane and sugar yields significantly increased (P < 0.01). Sugar yield decreased from 0.16 Mg ha−1 yr−1 for 1950 to 1980 to 0.10 Mg ha−1 yr−1 for 1981 to 2000. Sugarcane yield had the same rate of increase for 1980 to 2000 (0.66 Mg ha−1 yr−1) and for 2001 to 2018 (0.69 Mg ha−1 yr−1). There was neither a significant increase nor decrease in sugarcane and sugar yields before 1968. For 1969 to 2000, the increase in sugarcane yield (0.29 Mg ha−1 yr−1) was less than the increase in sugar yield (0.09 Mg ha−1 yr−1).

Sugarcane Yellow Leaf Disease

Sugarcane Yellow Leaf disease was first recognized as Yellow Leaf Syndrome during the 1980s in Hawaii. Later it was reportedly associated with yield losses of 25% or more in the cultivar SP 71-6163 in Brazil. Subsequently the virus sugarcane Yellow Leaf Virus (SCYLV) was discovered to be associated with the disease. Yellow leaf has been found in numerous countries of the world. However, somewhat confusedly, another disease, “leaf yellows”, has been found in other areas. Although it has similar symptoms, it is caused by a phytoplasm rather than a virus. To date, this phytoplasm pathogen has not been identified on sugarcane in Florida. This document is SS-AGR-256, one of a series of the Agronomy Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. This publication is also a part of the Florida Sugarcane Handbook, an electronic publication of the Agronomy Department. Original publication date: September 2005.

Sugarcane Production in Southwest Florida: Mineral Soils and Amendments

This document integrates information that was presented at the Sand Land Workshop, held at the Dallas B. Townsend Hendry County Extension Center, LaBelle, Florida, 2003, dealing with the production of sugarcane on the mineral soils of southwest Florida. This document reviews challenges facing sugarcane growers dealing with soils, water management, and nutrients. Effective strategies, which are evolving to efficiently produce sugarcane in southwest Florida on mineral soils, are reviewed in this publication. This document is SL 230, a fact sheet of the Soil and Water Science Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date October 2005.

Comparison of Progress of Brown Rust and Orange Rust and Conditions Conducive for Severe Epidemic Development During the Sugarcane Crop Season in Florida.

Brown rust (caused by Puccinia melanocephala) and orange rust (caused by P. kuehnii) are two major diseases of sugarcane in Florida. To better understand the epidemiology of these two rusts, disease severity and weather variables were monitored for two seasons in cultivars CL90-4725 (susceptible to brown rust and resistant to orange rust) and CL85-1040 (susceptible to orange rust and resistant to brown rust). Brown rust was most severe during mid-May to mid-July, whereas orange rust severity peaked during two periods: mid-May to early August and then November to December. Overall, disease severity was higher for orange rust than for brown rust. Maximum disease severity was correlated with the number of hours at night with an average temperature of 20 to 22.2°C for brown rust one season and orange rust both seasons. Slightly higher correlation was obtained when relative humidity above 90% was included in the number of hours at night with an average temperature of 20 to 22.2°C for brown rust but not orange rust, suggesting that leaf wetness is not a limiting factor for either disease in Florida. Epidemics of brown rust began at lower night temperatures (16.7 to 22.2°C) in one season, but epidemics of orange rust lasted longer under higher temperatures. The correlation of rust severity on recently emerged leaves with conducive temperatures recorded in 10-, 20-, or 30-day windows starting 7 days before disease assessment suggested that earlier inoculum production is needed to create severe epidemics that result in yield loss.

Sensitivity of two sugarcane rust fungi to fungicides in urediniospore germination and detached leaf bioassays

Management of brown (Puccinia melanocephala) and orange (Puccinia kuehnii) rust of sugarcane in Florida primarily relies on fungicide applications. Using two different in vitro bioassays, we evaluated the efficacy of five fungicides registered for control of these diseases. Inhibition of P. kuehnii and P. melanocephala urediniospore germination varied from 96 to 100% at 0.01–10 μg per ml of pyraclostrobin and fluxapyroxad + pyraclostrobin. However, only 48% of the P. kuehnii spores were inhibited at 10 μg per ml of fluxapyroxad. Capacity to inhibit sugarcane infection and rust uredinia formation was tested with a detached leaf bioassay where fungicides were applied at different times with respect to inoculation with P. kuehnii or P. melanocephala. When fungicides were sprayed immediately after inoculation of leaf fragments, uredinia formation of P. melanocephala and P. kuehnii was suppressed at 99–100% regardless of the fungicide, except for metconazole (36–50% reduction). Uredinia formation of P. kuehnii was also nil when all fungicides (except metconazole) were sprayed 1 or 2 days prior to inoculation. However, maximum reduction in uredinia formation was 82% and 48% when leaves were sprayed with fungicides one or two days after inoculation, respectively. Therefore, these fungicides are more efficient in preventive than curative management of sugarcane orange rust.

Critical Timing of Fall Panicum (Panicum dichotomiflorum) Removal in Sugarcane

Fall panicum is the most troublesome annual grass weed in sugarcane in Florida. The critical timing of fall panicum removal in sugarcane or the maximum amount of early season interference that sugarcane can tolerate before it suffers irrecoverable yield loss is not known. Field studies were conducted from 2012 to 2015 in Belle Glade, FL to determine the critical timing of fall panicum removal and season-long interference in sugarcane. The effect of season-long fall panicum interference and critical timing of removal based on 5 and 10% acceptable yield loss (AYL) levels were determined by fitting a log-logistic equation to percentage millable stalk, cane, and sugar yield loss data. Millable stalks, cane, and sucrose yield decreased as the duration of fall panicum interference increased. Season-long interference of fall panicum resulted in 34 to 60%, 34 to 62%, and 44 to 60% millable stalk, cane, and sucrose yield loss, respectively. The critical timing of fall panicum removal based on 5 and 10% AYL for millable stalks was 5 to 9 wk after sugarcane emergence (WAE). At 5 and 10% AYL, the critical timing of fall panicum removal ranged from 5 to 9 WAE and 6 to 8 WAE for cane and sucrose yield loss, respectively. These results show that fall panicum is competitive with sugarcane early in the season, demonstrating the need for timely early-season control to reduce negative effect on yield.

Genotyping Sugarcane for the Brown Rust Resistance Locus Bru1 Using Unlabeled Probe Melting

Brown rust, caused by the fungus Puccinia melanocephala, is a major disease of sugarcane (Saccharum spp. hybrid) in Florida, Louisiana, and other sugarcane growing regions. The Bru1 locus has been used as a durable and effective source of resistance, and markers are available to select for the trait. The markers currently being used by the USDA Sugarcane Field Station in Canal Point, FL for Bru1 genotyping have two disadvantages. One marker (here Bru1B) is dominant, which means that a Bru1-negative individual cannot be distinguished from a failed PCR reaction. The second marker (here Bru1A) is codominant, but genotyping requires enzyme restriction and gel electrophoresis, adding time and cost to the analysis. A closed-tube, codominant assay for Bru1 would significantly decrease the time and cost currently required for Bru1 genotyping. By sequencing the Bru1A PCR product from Bru1-positive and Bru1-negative individuals, we indentified two SNPs (here Bru1A1 and Bru1A2) that alter the relevant restriction enzyme recognition sequence. An unlabeled probe assay was designed to target each of the SNPs. Unlabeled probe assays are DNA melting assays that rely on the dissociation of an oligonucleotide probe from its target DNA strand. The dissociation is detected by the decrease in fluorescence of double-stranded DNA binding dyes and is sensitive enough to detect single base pair changes. A comparison between the traditional genotyping method and unlabeled probe melting using 344 genotypes showed a 94.7 % success rate, with 100 % concordance between Bru1A and unlabeled probe genotyping. We also confirmed prior unpublished results that discovered a rare recombination between Bru1A and Bru1B. We have demonstrated that unlabeled probe melting can be used to detect the Bru1 locus, eliminates the risk of false negatives, and is faster and less expensive than the current method.

Effects of Harvest Method on Microclimate in Florida Sugarcane

The production systems for sugarcane include either green cane or burnt cane harvesting operations. Sugarcane in Florida is typically harvested with burnt cane mechanical harvesting, but there is a growing interest to better understand the effects of green cane harvest residue “trash blankets” on microclimate conditions for sugarcane growing on both organic and mineral soils of Florida, so the authors conducted a three-year study to determine the effects of each harvest method on microclimate within the surface soil profile and at a 10 cm height from the soil surface. Results are presented in this 3-page fact sheet written by Hardev Sandhu, Maninder Singh, Robert Gilbert, Kelly Morgan, Ronald Rice, Leslie Baucum, James Shine Jr., and Mike Irey, and published by the UF Department of Agronomy, April 2015. (UF/IFAS Photo: Josh Wickham.) SS-AGR-385/SC100: Effects of Harvest Method on Microclimate in Florida Sugarcane (ufl.edu)