Location: Sugarcane Research
2022 Annual Report
Objectives
1. Develop systems-level precision agriculture strategies and tools based on climate, soil, water and nutrients to increase sugarcane yield, sustainability, and ratoon longevity. [NP 305, Component 1, Problem Statement 1A]
1.A. Develop variable-rate nutrient application systems to increase yields, ratoon longevity and sustainability.
1.B. Utilize UAV-based remote sensing systems to estimate yields prior to harvest.
2. Analyze the impacts of existing and emerging pathogens that affect sugarcane or its wild relatives to enhance genetic control and chemical control strategies. [NP 305, Component 1, Problem Statement 1A]
2.A. Identify germplasm of hybrid sugarcane and wild relatives of sugarcane for resistance to economically limiting diseases that breeders can use for parental clones.
2.B. Characterize races, strains, or other biotypes of endemic pathogens and monitor the Louisiana sugarcane industry for the emergence of new pathogens.
3. Optimize and integrate the chemical and cultural control of weeds including identifying key factors that promote proliferation in sugarcane production. [NP 305, Component 1, Problem Statement 1A]
3.A. Develop new herbicide programs that optimize application timing, placement, and herbicide use rates for management of problematic grass and broadleaf weed species in sugarcane.
3.B. Identify weedy characteristics that promote divine nightshade proliferation.
4. Integrate pest management systems into sugarcane production systems including genetic sources of host-plant resistance for greater sugarcane yield, sustainability, and ratoon longevity. [NP305, Component 1, Problem Statement 1A]
4.A. Determine the required level of sugarcane borer control after subsequent borer damage to ratoon crops.
4.B. Assess compatibility of billet seed treatments with biological control of the sugarcane borer.
Approach
To address the first objective, precision agriculture (PA) methods such as soil electrical conductivity (EC) mapping, variable-rate application and remote-sensing will be utilized to increase sugarcane yield, sustainability, and ratoon longevity. Soil EC mapping will be used to develop management zones to optimize nutrient application with variable-rate application procedures. Sugarcane yields in the successive ratoon crops of PA systems will be used as an index of the progress made in increasing ratoon longevity as compared to conventional management methods. Imagery acquired by unmanned aerial vehicles (UAV) will be utilized to predict cane and sucrose yields prior to harvest.
To address objective two, we will identify and develop parental germplasm with resistance to the economically limiting diseases affecting sugarcane in the United States. Highly domesticated and wild clones of sugarcane and near relatives will be evaluated for disease resistance following either natural infections or artificial inoculation. Genotypic and phenotypic expressions of variability within populations of pathogens will be used to identify the genetic variability among pathogen populations and determine the distribution of races, strains, or biotypes. The domestic sugarcane industry will be monitored for the introduction of exotic pathogens.
To address the third objective, three new 4-hydroxyphenylpyruvate dioxygenase (HPPD) herbicides will be evaluated for their efficacy in controlling problematic weeds postemergence in sugarcane. The HPPD herbicides will be applied separately and tank-mixed with various herbicides to evaluate the weed spectrum controlled. Analysis of both herbicide efficacy data and yield data, will allow us to determine effective herbicides and herbicide use rates that maximizes weed control while at the same time minimizes injury to the sugarcane crop. Research will also be conducted to understand the phenology of divine nightshade during a sugarcane cropping cycle to assist in developing the necessary management tactics to prevent weed proliferation.
To address the fourth objective, methods will be developed to assist in preventing and managing infestations of the primary economic pest of sugarcane in Louisiana, the sugarcane borer (Diatraea saccharalis (F.); Lepidoptera: Crambidae). We will determine the required level of sugarcane borer control after subsequent borer damage to ratoon crops by comparing yield, borer infestation levels, and natural enemy presence in the first and second year of growth after plants have accumulated different levels of borer damage. We will also assess the compatibility of billet seed treatments with biological control of the sugarcane borer by estimating the arthropod community activity density changes after treatment with insecticides (neonicotinoid) and fungicides (azoxystrobin and propiconazole) alone and in combination.
The end product of this research will be new crop, soil, disease, weed and insect management strategies that ensure efficiency and sustainability of sugarcane production while increasing ratoon longevity.
Progress Report
In fiscal year (FY) 2021, sites were located for all repeated variable-rate (VR) fertilizer studies on commercial sugarcane farms. A collaboration with ARS researchers from Houma, Louisiana, and commercial sugarcane farms was developed to collect soil electrical conductivity (EC) data from all studies using a non-contact, EC mapping system that will facilitate the collection of EC data under a wider range of environmental and soil conditions than traditional EC mapping systems. Raw EC data will then be used to develop VR management zones for all fields. VR soil samples were collected, and management zones were created for all fields mapped in 2020. Plant cane data was harvested in the fall of 2021 using a sugarcane harvester equipped with a commercial yield monitor. Data from first ratoon and plant cane trials will be harvested in November/December 2022 using a weigh wagon and sugarcane harvester equipped with a commercial yield monitor. Post-harvest soil samples will be collected from all studies in November/December 2022.
Four fields for the unmanned aerial vehicle (UAV) trials were initiated in July 2022 on commercial sugarcane farms. The fields selected were planted to major Louisiana varieties and were approximately 5 hectares in size. UAV imagery will be collected using a drone equipped with a multi-spectral sensor from each field monthly until harvest. Fields will be harvested in the fall of 2022 as described above.
In FY 2022, progress was made by ARS researchers from Houma, Louisiana, in identifying sugarcane germplasm resistant to economically important diseases. Varieties (61) for possible release into commercial production within the next five years were screened through artificial inoculation in the field for susceptibility to smut and leaf scald. New assignment varieties (36) were also screened for Ratoon Stunting Disease (RSD) by artificial inoculation with the causal bacterium. In other ARS breeding trials and nurseries, candidate varieties were observed for natural infection by pathogens that cause mosaic, brown and orange rust, sugarcane yellow leaf, smut, and leaf scald diseases. Pathology recommendations were made at variety advancement and variety release meetings. Disease ratings were used as criteria to release two new sugarcane varieties (L 15-306 and HoL 15-508) in 2022.
In FY 2022, populations of the viruses that cause mosaic in sugarcane were monitored for genetic diversity. Sorghum mosaic virus (SrMV) remained the predominant virus causing mosaic. No isolates were identified as Sugarcane mosaic virus (SCMV), another virus that causes mosaic symptoms in sugarcane, from samples collected among commercially released and experimental varieties. Sequence data suggest the SrMV population contains multiple genotypes. Climatic conditions were favorable for orange rust among variety trials at the ARS research farm in Houma, Louisiana; however, no epidemics have been observed in commercial fields. Highly susceptible clones were not advanced to the next stage of the variety development program.
Several rates of pyroxaysulfone were applied with and without an adjuvant to L 01-299 cane at first ratoon in early March. Each treatment had four replicates. Following treatment, weed control was assessed by monitoring weed counts and weed injury. Sugarcane was also monitored for injury as an indicator of tolerance to the herbicide. Stalk number and height for each treatment will be measured prior to harvest. In August, cultivar L 01-299 will be planted so that applications in plant cane can be examined this spring. The current study in first ratoon will be continued into second ratoon.
Analysis of the nightshade phenology data indicated that pairing a 4-Hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitor with an auxin mimic such as 2,4-D or dicamba, might be effective in controlling this weed. In late March, treatments including different rates of HPPD inhibitors and auxin mimics, as well as conventional weed control strategies such as metribuzin paired with pendimenthalin, were applied to a plant cane field of L01-299. Weed counts, weed injury, and sugarcane injury were monitored after treatment. Before harvest, stalk number and height will be determined. A new plant cane trial will be initiated in August of 2022 and treatments will be applied both in plant cane and in first ratoon.
In FY 2022, the field site to assess impacts of prior borer damage was planted in fall 2021 with initial plant emergence documented later in the fall as well as the following spring. Insecticide treatments in this field were applied to assigned plots in June 2022, and sentinel sugarcane borer egg masses to assess borer damage-induced differences in predation and parasitism rates were deployed for 24, 48, and 72 hours (h) in July 2022. In fall 2021, the plant cane trial was harvested, and cane and sugar yield data were obtained to assess differences in billet and whole stalk plantings with and without seed cane sugarcane borer damage. Preliminary data from the plant cane harvest were presented at winter/spring 2022 grower meetings.
In fall 2021, the billet seed treatment field was harvested to determine cane and sugar yields. The summer of 2021 was particularly wet, and the original field flooded for the entire month of July, removing any remaining seed treatment and red imported fire ant colonies nesting in the area. For this reason, another field for treated billets was located for 2022 sampling. Pitfall traps were deployed in this new field throughout the summer of 2022, and sentinel egg masses were deployed in July 2022 for 4, 24, and 48 h to assess predation rates in each plot. In fall 2021, and again in summer 2022, red imported fire ant colonies were captured and brought into the laboratory. Workers from these colonies were exposed to soil-applied insecticides matching the field trials, followed by an assessment of survival and behavior. The plant cane data from the field trial and the laboratory trial data were presented to sugarcane growers and agricultural consultants at winter/spring 2022 meetings.
Accomplishments
1. Nitrogen fertilizer and sugarcane variety change borer pressure. The nitrogen content of plant tissues is a key factor influencing the development and reproduction of insect pests but is also necessary for sugarcane growth and development. The impact of nitrogen fertilizer application on the primary economic insect pest in Louisiana sugarcane, the sugarcane borer, has not previously been studied. ARS researchers in Houma, Louisiana, in collaboration with scientists from Louisiana State University compared sugarcane borer infestations across four rates of nitrogen fertilization (0, 50, 100, and 200 lbs/acre) in four separate field trials planted with two varieties over a two-year period. Results indicated that excessive nitrogen fertilization can increase sugarcane susceptibility to sugarcane borer damage without any benefits to sugar yield. The benefits of reducing unnecessary nitrogen fertilizer application include input savings for growers as well as prevention of yield loss from insect pests. The incumbent and collaborators have been presented this information at numerous grower meetings and at the American Society of Sugarcane Technologists.
2. Treatment efficacy and resistant sugarcane varieties for Mexican rice borer management in south Texas. Over 40,000 acres of sugarcane are grown in the Lower Rio Grande Valley (LRGV) in south Texas, with few acres treated for the primary pest of concern, the Mexican rice borer, due to unsuccessful control measures in prior decades despite an estimated $575 loss per hectare from borer damage. To provide LRGV sugarcane growers with more management tools, ARS researchers in Houma, Louisiana, collaborated with growers in south Texas to evaluate commercial sugarcane varieties for resistance to the Mexican rice borer, as well as the effectiveness of foliar applications of a chlorantraniliprole-containing insecticide. Varieties were planted in two fields, across two years, then assessed for Mexican rice borer damage and final yield during the first and second years of crop production. Results of this study indicate that two varieties, CP 07-1824 and L 01-299, are more resistant to the borer in south Texas compared to other commonly planted varieties such as L 12-201. In addition, the insecticidal control of the Mexican rice borer was successful, with all internodes protected, and increased crop yields observed if applications are conducted both in the summer and the early fall prior to harvest. The incumbent has presented these results to LRGV stakeholders, resulting in an estimated 90% of LRGV sugarcane acres being treated for Mexican rice borer in 2022.
Review Publications
Rivera, D., Noval, J.A., Elliott, L., Penn, H. 2021. Tropical milkweed herbivore and predator dynamics in suburban South Texas. Subtropical Agriculture and Environments: Research Note. 72:16-20.
Salgado, L.D., Wilson, B.E., Villegas, J.M., Richard, R.T., Penn, H. 2021. Resistance to the sugarcane borer (Lepidoptera: Crambidae) in Louisiana sugarcane cultivars. Environmental Entomology. 51(1):196-203. https://doi.org/10.1093/ee/nvab118.
Elliott-Vidaurri, L.V., Rivera, D., Noval, A., Choudhury, R.A., Penn, H.J. 2022. Red harvester ant (Pogonomyrmex barbatus F. Smith; Hymenoptera: Formicidae) preference for cover crop seeds in South Texas. Agronomy. 12(5):1099. https://doi.org/10.3390/agronomy12051099.
Dasilva, D.P., Johnson, R.M., Crusciol, C.A. 2022. The effects of cobalt on sugarcane growth and development in plant cane and two ratoon crops. Sugar Tech. 2022:1-12. https://doi.org/10.1007/s12355-022-01108-4.
