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