1. Weed Management Systems in Florida Sugarcane Calvin Odero TREC Seminar Series

2. Everglades Research & Education Center Weed Science Research (35%) Extension (65%) Crops ‒ Sugarcane ‒ Vegetables ‒ Bioenergy crops ‒ Rice ‒ Commercial sod

3. Everglades Agricultural Area 700,000 acres of land –Major crop - sugarcane –Other crops – vegetables, rice & sod 416,000 acres of sugarcane –78% on muck (organic) soils (Histosols) –22% on mineral (sandy) soils (Spodosols & Entisols) Source: http://www.doi.gov/pmb/oepc/wetlands2/v2ch7.cfm

4. Muck soils Formed ~5,000 years –Decaying saw grass & marsh plants under flooded conditions High soil organic matter content –Up to 85% Soil depth –6 inches to over 4 feet

5. Muck soil subsidence Drainage of soils resulted in –Oxidation & mineralization of large quantities of organic N Microbial oxidation –50 to 75% of the subsidence Subsidence rates for EAA Histosols –0.13 to 1.71 inches/year In 1924 a 9ft post was driven into the bedrock at the EREC

6. Sugarcane taxonomy Giant grass (Poaceae) Tribe: Adropogoneae Saccharum officinarum L. Saccharum officinarum L. is –‘Noble cane’ with long, thick, heavy, juicy & sweet stalks Other species –S. barberi –S. robustum –S. sinese –S. spontaneum Commercial clones are typically 3-part hybrids

7. General agronomy Sugarcane is perennial that is harvested annually Planting season: mid-October to end-December The first year is referred to as plant cane and the successive years are ratoon or stubble crops Harvest season: mid-October to March/April –Plant cane (1 st year): 13-18 months –1 st ratoon ≈ 11 months –2 nd ratoon until final year ≈ 10 to 11 months –Final ratoon (early harvest plow-out) ≈ 8 to 10 months Typically replanted every 3 to 5 years Planting Following fallow period ‒ Temporary rotation with different crops following final ratoon Successive ‒ Replanting several weeks after final ratoon

9. Furrowing for planting 3 or 5 furrows made in one pass GPS guided Furrows typically 4-6 inches deep 5 ft

10. Fertilizing before planting Fertilizer is Broadcasted or Banded in the furrow Custom blended fertilizer Primary nutrients applied ‒ P, K, Mg ‒ Cu, Zn, Mn, B ‒ N (mostly on sand soils)

11. Seed cane

12. Seed cane loading Whole stalk seed cane is loaded on wagons using a “Grab Loader”

13. 2 to 6 crews depending on size of operation 30 to 120 A/day Hand planting sugarcane 8 or 9 people crews ‒ 4 droppers ‒ 4 choppers

14. Covering sugarcane after planting

15. Weed management in sugarcane Major cost associated with sugarcane production Successful weed control is essential Weeds can reduce sugarcane yields by competing –Moisture, nutrients & light Several weed species serve as alternate hosts –Disease & insect pests Weed control is most critical early in the season prior to sugarcane canopy closure over the row middles Weeds that mature and produce seed become –Source of seed bank replenishment –Source of re-infestation in subsequent years

16. Common weed species Grass & grass-like weeds Fall panicum * Guineagrass Goosegrass Bermudagrass * Almum sorghum Elephantgrass Yellow nutsedge * Purple nutsedge Broadleaf weeds Common lambsquarters * Amaranths * Common ragweed * Common purslane Alligatorweed Nightshades

17. Common lambsquaters Spiny amaranth American blacknightshade

18. Weedy and woody host plants of the sugarcane root weevil Odero et al. 2013. J Ento Sci 48:81-89 Odero et al. 2015. J Ento Sci 50:3-13 Coffee senna Spiny amaranth Common purslane Sugarcane

19. Fall panicum Bermudagrass

20. Weed control: crop rotation Crop rotation patterns will affect weed management –Leafy greens, sweet corn, snap bean, radishes, rice Fallow period has effectively been used to manage troublesome perennial weeds –Mechanical cultivation & herbicide application Flooding fallow fields also aids in weed control

21. Head lettuceSnap beansRiceSweet corn

22. Weed control: crop competition Crop competition for sunlight is important A good stand of sugarcane –Emerge rapidly & uniformly –Form a complete canopy –Shade the row middles early in the season Loss of sugarcane stools in ratoon crops –Rodent, insect, or harvest damage –Create open spaces in the cane canopy Maintaining maximum sugarcane populations throughout all production phases –Benefits weed control efforts

23. Fall panicum Bermudagrass

24. Weed control: cultivation Economical means of suppressing weed growth Sugarcane plants get the early advantage in the competition for light –Height differential must be established between cane plants and weeds Preemergence herbicides are most effective in establishing this height differential Only when the sugarcane plants are growing taller than competing weeds can mechanical cultivation be effective Cultivation when weeds are not present due to application of a herbicide or previous cultivations are not recommended Cultivation when weeds are not present can –Encourage germination of additional weed seeds –Remove the layer of herbicide present for soil-applied herbicides In ratoon crops, mechanical cultivators must –Cut through surface debris and thoroughly mix the soil –Row middles

26. Weed control: herbicides Useful and economical tools in sugarcane production Must be incorporated into an overall management plan to obtain their maximum benefit. Sugarcane must have the initial competitive advantage against weeds Application –Preemergence (PRE) –Postemergence (POST) –POST-directed Sprayer calibration is important before herbicide application

29. Weed control: herbicides Preemergence Atrazine Metribuzin Pendimethalin Postemergence 2,4-D Dicamba Ametryn Atrazine Metribuzin Asulam Halosulfuron Trifloxysulfuron Preplant/Preemergence/Fallow Glyphosate

30. Dissipation of oil-based pendimethalin Dissipation of water-based pendimethalin Odero & Shaner. 2014. Weed Technol 28:82-88 Preemergence herbicides

31. Dissipation of atrazine DT 50 4-10 days Dissipation of metribuzin DT 50 19-24 days Odero & Shaner. 2014. Weed Technol 28:578-586

32. Broadleaf weeds 2,4-D, dicamba, atrazine, metribuzin, mesotrione Grasses Asulam, trifloxysulfuron, ametryn*, metribuzin* Sedges Halosulfuron Postemergence herbicides

33. Lumax A commercial premix of –Atrazine (110 g/L) –Mesotrione (30 g/L), –S-metolachlor (300 g/L) PRE or early POST –Control of fall panicum & other weed species

34. S-metolachlor PRE Mesotrione POST Control Premix 1x POST Premix 1x PRE

35. Non-crop areas Fernandez et al. 2015. Weed Technol 29:233-242

36. Contact information Calvin Odero Phone: 561-993-1509 Email: dcodero@ufl.edu http://erec.ifas.ufl.edu/weeds/

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