Broadleaf Weed Control in Sugarcane Curtis Rainbolt Sugarcane Extension Agent

Spiny pigweed Most common pigweed species –Stickerweed Large, upright growth habit, entire leaves Very evident spines located at nodes

Alligatorweed Common in many areas of the EAA –Prefers wet areas –Often spread by cultivation –Low growing Hollow stems when growing in wet spots Opposite leaves Small white blooms

Common lambsquarters Common some years –Usually during the cooler months (Dec, Jan) –Can be difficult to control Waxy leaf surface Alternate leaves Medium size lobes on leaves

Common purslane Very common –Probably not competitive –Prostrate growing –Succulent –Leaves small, smooth, opposite or alternate –Red stems –Controlled by most herbicides

Common ragweed Often found on ditch banks and field edges –Deeply dissected leaves –Many hairs on upper and lower surfaces –Long seedhead at top of plant –Yellow flowers

Ragweed parthenium Primarily ditchbanks –Less common than common ragweed –Leaves less deeply dissected Divisions don’t go all the way to the stem –White flowers Single, not multiples

Dayflower Common in open areas, field edges –Small, probably not competitive –Prostrate growth habit –Parallel veins on leaves Actually a monocot, not a dicot –Blue flowers

American black nightshade Occasional weed in EAA –Problematic in vegetables (tomato, pepper) Same family (Solanaceae) Resistant to paraquat in some areas –Alternate leaves Usually entire to somewhat lobed –Purple fruit –Competitive

2,4-D Amine Very versatile, useful product Controls most broadleaves Can use lower rates on smaller weeds At higher rates (2 lb ai) very good control of alligatorweed Coverage is the key to good alligatorweed control

Atrazine Backbone of sugarcane weed control –Used both PRE and POST PRE –Good soil activity (2-4 qt/A) –Controls most broadleaves –Suppress/control many grasses –Activity begins to fade 3-5 weeks after application –Broadleaf activity last longer than grass activity

Diuron (Karmex/Direx/Etc) Not used much –Sand soils (binds very strongly on muck) –Better control of broadleaves than grass –Not much experience Crop injury? Rate –1.6 lb/A PRE

Envoke Excellent control of alligatorweed Partial (slow acting) control of prostrate pigweeds Partial control of Dayflower Does not control American Black Nightshade or related species

Evik (Ametryn) Generally applied POST –Some is applied PRE Controls many small grasses and broadleaves –Weeds need to be less than 4 inches –Directed application Injury will be seen on treated foliage