Weed identification and common weeds associated with sugarcane Calvin Odero Everglades REC Belle Glade, FL

Weed classification Weeds come in all growth forms May be classified as –Grass –Grass-like (sedge) –Broadleaf Forbs Succulents Shrubs Monocots Dicots

Weed classification: life cycles  Annuals- reproduce by seed only  Biennial:  Life cycle completed in two years  Flowering and fruiting in second year  Examples: wild carrot, cudweed  Perrenials:  Simple- reproduce by seed only  Creeping- reproduce by seed and vegetative propagules

Grass identification: vegetative parts Leaf blade, blade margin Collar margin Midrib Ligule - structure which occurs in grasses at point where the leaf sheath and blade meet Auricle - projections where sheath and blade meet Sheath margins - split with overlapping margins or united

Auricle variations

Ligule variations

Sheath variations

Steps 1 to grass ID Overall characteristics –Relative length and width of first leaf –Seed characteristics

Step 2 to grass ID Stem Type –Round –Flat –Triangular

Step 3 to grass ID Ligule Type –Absent –Hairy –Membranous

Step 4 to grass ID Blade Type –Hairy or not (glabrous) –Midrib prominence and color –Margin characteristics –Presence of auricles

Step 5 to grass ID Sheath margins –Split with overlapping margins –United –Margin with hairs or not

Step 6 to grass ID Root systems –Perennial with creeping rhizomes –Annual

Monocots: grasses and sedges GrassesSedges (Grass-like) Stems Hollow or flattened Occasionally solid Nodes (jointed) Solid Triangular (3-sided) Without nodes Leaves Parallel veins 2 sides Parallel veins 3 sides Flowers Small Inconspicuous Small Inconspicuous Example Fall panicumYellow nutsedge

Yellow vs purple nutsedge Yellow (Cyperus esculentus) –Leaves gradually taper to a point –Flowers yellowish- brown –Tubers smooth, round shaped, at ends of rhizomes Purple (Cyperus rotundas) – Leaves abruptly tapers to a point – Flowers purple to brown – Tubers rough, irregular shaped, connected in chains

Purple vs yellow nutsedge

Fall panicum (Panicum dichotomiflorum) Most common grass in the area Relatively easy to identify –Stem can be hairy or smooth –Hairy when young –Ligule fringe of hairs –Round stem –Widely dispersed seedhead

Fall panicum (Panicum dichotomiflorum)

Goosegrass (Eleusine indica) Found in many fields Low growing –Very white, flattened stems –Looks like it has been stepped on –Probably not competitive

Crabgrass (Digitaria spp.) Very wide first leaf Initial clumping growth progressing to prostrate, tillering Visible membranous ligule Can be very hairy, or hairless, depending on species

Broadleaf panicum (Urochloa adspersa) Relatively prostrate growth –Wide leaves with wavy margins –Round stems –Usually dark green in color –Very similar to alexandergrass

Broadleaf panicum (Urochloa adspersa)

Crowfootgrass (Dactyloctenium aegyptium) Plants glabrous, blade margins hairy Seed head like a crow foot Bends and roots at the lower nodes

Bermudagrass (Cynodon dactylon) Easy to identify Small leaves Rhizomes and stolons Mat forming Ligule fringe of short hairs (hard to see) Produces seed and spreads vegetatively

Bermudagrass (Cynodon dactylon)

Sorghum (Sorghum almum) ‘Wild oat’ Closely related to johnsongrass –No rhizomes –Large, membranous ligule –Robust plant

Sorghum (Sorghum almum)

Torpedograss (Panicum repens L.) Perennial with robust, creeping, sharply pointed rhizomes Leaf blade stiff and erect Hairs on upper and lower leaf surface Seedheads with stiff, ascending branches Occurs in wet areas

Guineagrass (Panicum maximum) Some plants are extremely hairy, while others are hairless Small plants have narrow leaves Becomes very large Highly branched seedhead Round stem

Napiergrass (Pennisetum pupureum) Very robust plant –Forms dense clumps in fields –Long, wide leaves with finely toothed margin –Up to 12 feet tall –Seedhead has “bottle brush” appearance

Paragrass (Brachiaria mutica) Prostrate growing, medium size grass –Long stems covered with hairs Short hairs on leaf surface –Swollen nodes –Grows in very wet areas Often moves out of ditches –Pasture grass in Africa

Dicots: broadleaf plants Two cotyledons Primary root often becomes a strong tap root with smaller secondary roots Leaves are usually net veined and broad at the base with a petiole or stalk

Dicots: broadleaf plants ForbsShrubsSucculents Stems Solid Pithy Solid Growth rings Fleshy, thick Sharp spines Leaves Net-veined Small, fleshy Seldom present Flowers Small or large Colored Showy Small Showy Example Common lambsquarters LantanaCacti

Broadleaf identification: vegetative parts Cotyledons - seed leaves First true leaf Older leaves Midvein Leaf apex Margin Terminal bud

Steps 1 & 2 in broadleaf ID Overall appearance Shape of cotyledons

Steps 3 & 4 in broadleaf ID Leaf shape Leaf arrangement –opposite –alternate –whorled Root system

Spiny amaranth (Amaranthus spinosus) Most common ‒ Large, upright growth habit, entire leaves ‒ Very evident spines located at nodes

Livid amaranth (Amaranthus blitum) Can be prostrate or erect Notched leaf tips

Alligatorweed (Alternanthera philoxeroides) Common in wet areas of the EAA ‒ Often spread by cultivation ‒ Low growing Hollow stems when growing in wet spots Opposite leaves Small white blooms

Alligatorweed (Alternanthera philoxeroides)

Common lambsquarters (Chenopodium album) Common during the cooler months Can be difficult to control due to waxy leaf surface that leaves a white-gray color

Common purslane (Portulaca oleracea) Prostrate, succulent Leaves small, smooth, opposite or alternate Red stems Small, yellow flowers

Common ragweed (Ambrosia artemisiifolia) Deeply dissected leaves Many hairs on upper and lower surfaces Long seedhead at top of plant Yellow/white flowers in multiples

Ragweed parthenium (Parthenium hysterophorus) Less common than common ragweed ‒ Common along canals, ditch-banks, noncrop areas Leaves less deeply dissected ‒ Divisions don’t go all the way to the stem White flowers ‒ Single, not multiples

American black nightshade (Solanum americanum) Becoming more common in EAA ‒ Alternate leaves Usually entire to somewhat lobed ‒ Purple fruit

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

Sources of Weed ID Information Web Picture/Taxonomic Sites –Aquatic, Wetland and Invasive Plant Particulars and Photographs (U. of Florida) Excellent pictures and information –Weed Identification and Control in Southern Turfgrasses (U. of Georgia) Pictures, descriptions Southern Weed Science Society ID Guide

Sources of Weed ID Information Web Picture/Taxonomic Sites –Many, many more sites Many reputable sites –Many universities –Other public agencies Buyer beware –Some incorrect information on the web!

If you need help Actual plants are best –Store in plastic bag with damp paper towel 8 t0 10 hours –Press between two pieces of paper Change paper often while drying Will last indefinitely –Store on truck dashboard PLEASE DON’T! –Bring several plants Flowers and seeds if possible Different growth stages if possible

If you need help Pictures –Overall view (growth habit) –Specific characteristics Ligule (grasses) Hair characteristics Leaf shape Root system –Tubers, rhizomes, stolons Stem shape Seeds or flowers if available Other characteristics we looked at earlier

If you need help Additional information –What type of area Dry or wet Sandy or muck Cropped area, natural area, disturbed area History of area (previous crops, etc) –Actual location County, nearby town/city/landmark

Take Home Weed ID can be challenging –Many resources available Web is very helpful –When you need help: Provide as much information as possible –Quality plant sample –Identify important/unique characteristics –Site information (wet vs. dry, etc.)

Weed ID manuals

Contact Information Calvin Odero University of Florida-IFAS Everglades Research & Education Center 3200 E Palm Beach Road Belle Glade, FL