Location: Sugarcane Research2011 Annual Report
1a. Objectives (from AD-416)
The broad objectives proposed in this Project Plan are to develop and improve sustainable management strategies for weeds and insects. The Project Plan will have the following four objectives. First, identify management practices that lessen the impact of weeds in sugarcane including tillage, residue management, herbicides, etc. This will be accomplished by determining the impact of cultivation frequency and sugarcane variety on bermudagrass and johnsongrass infestations. Also to evaluate the impact of planting rotational crops during the fallow season on weed control and sugarcane production. Second, evaluate herbicides for potential utility in sugarcane. Included in this objective will be evaluation of herbicide timing of spring applications and compatibility of new herbicides with existing herbicides and their fit in current weed control practices. Objective three will be to identify and exploit non-chemical tactics for controlling stemborers. Specifically this will involve identifying new sources of resistance and the potential of role of silica. The fourth objective will be to assess the quantitative relationship between sugarcane aphid densities and yield loss.
1b. Approach (from AD-416)
The approach to meeting the objectives of this project plan will be in the form of field evaluations and a green house evaluation. Cultivation requirements for weed control as a function of the rate of sugarcane emergence and the crops ability to shade the row will be compared. The hypothesis that planting short-season seeded crops during the fallow season will aid in reducing johnsongrass and bermudagrass infestations and will be economically advantageous over a non-crop fallow system, will be tested. New herbicides will be evaluated for their ability to reduce bermudagrass emergence following winter dormancy. New herbicide chemistries will likely offer increased options for weed control in sugarcane and when available will be evaluated for efficacy. Current forms of resistance to the sugarcane borer are associated with low sugar yields. Related species of sugarcane will be evaluated for forms of resistance that may not be associated with low sugar yields. Silica will be evaluated in the greenhouse and in field plots for its potential of increasing insect resistance. Finally, a series of evaluations will be conducted in commercial sugarcane fields determining if feeding by the sugarcane aphid is sufficient to cause economic yield losses.
3. Progress Report
This report documents progress for a new parent Project No. 6410-22000-015-00D which started October 2010 and continues research from expired Project No. 6410-22000-012-00D and bridging Project No. 6410-22000-014-00D. This project is centered on improving weed and insect management practices in sugarcane. We are evaluating crop and non-crop fallow systems for management of perennial grasses. Soybean and sweet sorghum fallow tests have been initiated and treatments were applied. We are continuing to evaluate the effects of herbicide application timing on bermudagrass control in sugarcane. Sugarcane was planted in the fall of 2010 and herbicide treatments were applied in the spring of 2011. We are evaluating the herbicides aminocyclopyrachlor, tembotrione, and thiencarbazone-methyl for control of annual and perennial weeds in sugarcane and in fallow fields and the tolerance of sugarcane to these herbicides. We will seek to identify and exploit non-chemical tactics for controlling stemborers, i.e., host plant resistance and cultural controls. A recently planted seedling population of sugarcane crossed with related species was evaluated for novel modes of stem borer host plant resistance. A greenhouse experiment is underway investigating the potential of silica for increasing the resistance of sugarcane to the sugarcane borer.
1. Resistance to the sugarcane insect (aphid) identified. Economically important virus diseases of sugarcane are transmitted by two aphid species in the United States, and bases of crop resistance have not been identified. Possible resistance mechanisms to include: tolerance, repellency, and host plant suitability for aphid reproduction were explored using five sugarcane varieties currently grown in Louisiana. Based on the results of this study, ARS scientists at the Sugarcane Research Unit, Houma, LA, ranked the varieties from most to least susceptible as L 97-128, LCP 85-384, HoCP 96-540, Ho 95-988, and HoCP 91-555 for the white sugarcane aphid, and L 97-128, LCP 85-384, HoCP 91-555 for the yellow sugarcane aphid. The study demonstrated that the ability to inhibit aphid population growth is the dominant basis of sugarcane’s resistance to both aphid species, and that the variety HoCP 91-555 might be useful as a parent for developing aphid resistant varieties.
2. Post-harvest leaf litter promotes beneficial insect development. The blanket of leaf litter generated during the mechanical harvest of green cane can reduce the yields of the subsequent ratoon sugarcane in Louisiana if not removed. Although research has shown that this litter must be removed, its impact on ants, earwigs, ground beetles, and spiders – all important predators of the sugarcane borer - has not been determined. After four years of sampling, ARS scientists at the Sugarcane Research Unit, Houma, LA, concluded that the litter enhances predator numbers when compared to the recommended practice of burning to completely remove the litter. Relocating the litter blanket by mechanically brushing from the row top to the row sides had an intermediate effect on both crop yield and predator number suggesting that this strategy could be a viable alternative to burning to minimize the impact on crop yield while encouraging increases in predator numbers thereby further reducing the need for insecticide application to control the sugarcane borer.
White, W.H., Hale, A.L., Veremis, J.C., Tew, T.L., Richard Jr, E.P. 2011. Registration of two sugarcane germplasm clones with antibiosis to the sugarcane borer (Lepidoptera: Crambidae). Journal of Plant Registrations. 5(2):248-253.