Sicklepod

What is sicklepod?

Sicklepod identification gets easy once the plant sets fruit: its long, skinny pods bend downward like a farm sickle, which is where the name comes from. Before pods form, look for an upright, hairless plant in the pea family with leaflets arranged in pairs and an unpleasant smell when bruised. It is a warm-season annual that loves heat, shrugs off compacted or sandy soil, and is a serious weed of soybean and cotton fields, especially in the Southeast.

It matters for two reasons. A single plant can produce roughly 1,500 to 16,000 seeds, and their hard, waxy coats let many wait in the soil for later years. And it is poisonous to livestock in both fresh and dried form, so heavy stands in pastures, hayfields and feeding areas are a real hazard. Although it is a legume, it does not host nitrogen-fixing bacteria, so it gives nothing back to the soil.

Sicklepod identification: what to look for

Check the seed leaves on young plants, the leaflet tips on older plants, and the pods once they appear. Crushing a leaf is a good tiebreaker, because the rank odor is distinctive.

• Seedlings: Large, round, hairless seed leaves about 5/8 to 3/4 inch wide, with 3 to 5 pale veins spreading from the base like fingers. The first true leaves already carry 2 or 3 pairs of oval leaflets.
• Leaves: Alternate and pinnately compound, with 2 to 4 pairs of egg-shaped leaflets up to about 3 1/2 inches long. Tips are blunt and rounded, both surfaces are smooth, and the outermost pair is the largest. Look for a small orange-brown gland near the bottom pair.
• Stems: Green, mostly hairless and slightly angular, branching here and there. Older stems can harden and become woody at the base.
• Flowers: Bright yellow with five veined petals, about 1/2 to 1 inch across, held on short stalks in the upper leaf axils, usually one or two together.
• Pods and seeds: Four-angled, hairless pods 3 to 8 inches long but only about 1/4 inch wide, curving downward. They split when ripe and hold roughly two dozen glossy brown, irregular seeds.
• Smell and roots: Crushed foliage gives off a strong, unpleasant odor. Underground is a branching taproot that can reach about 3 feet.

Where it grows in the United States

USDA treats sicklepod as native to the lower 48 states. It is common across the Southeast, from the Gulf Coast north through Tennessee and Virginia, and appears sporadically as far north as Wisconsin and New York, west to Nebraska, and in southern California. It is worst where midsummer days and nights both stay hot, which is why farmers in the Deep South battle it hardest.

Within that range it favors open, disturbed ground: row-crop fields on sandy or coarse soils, gravel such as railroad beds, roadsides, waste places, and thin pastures. It tolerates compacted layers and a very wide soil pH range, and heavy stands often build up around hay rings and feed bunks, where livestock traffic leaves bare soil.

Sicklepod look-alikes

A few plants get mixed up with it:

• Coffee senna (Senna occidentalis): A close cousin with pointed leaflet tips (sicklepod's are rounded), more leaflet pairs (3 to 7) and larger leaflets. Its pods are flattened or cylindrical rather than four-angled and curve upward, not down. Coffee senna seedlings also show white hairs below the seed leaves, which sicklepod lacks.
• Partridge pea (Chamaecrista fasciculata): A native legume whose seed leaves are spade-shaped with a blunt point instead of round. Mature leaves carry 8 to 15 pairs of tiny leaflets, each under about 3/4 inch, and the pods are only slightly curved.

How to get rid of sicklepod

Pulling, digging and mowing: Pull or hoe sicklepod while it is young; hand pulling works best early, because once the taproot lengthens, pieces left in the ground can regrow. For larger plants, cut the stems with a sharp blade before any pods form. In pastures, mowing before flowering sharply reduces seed production, but mowing plants that already carry pods can scatter seed, so timing matters. Do not leave pod-bearing plants lying in the field.

Cultural control matters most, because the right conditions keep it from coming back.

• Keep pastures thick: soil-test and lime or fertilize as recommended, avoid overgrazing, and rotate paddocks so healthy grass shades out seedlings.
• In gardens and crop ground, plant early and in narrow rows so a dense canopy suppresses later flushes of seedlings.
• Till shallowly; deep plowing buries seed that comes back up and sprouts in later years.
• Use plastic (synthetic) mulch in vegetable beds, which works as an effective barrier.

Herbicides: Sicklepod responds best to herbicides while it is small and tender. UGA Extension names several active ingredients used against it, including picloram combined with 2,4-D, metribuzin, imazaquin and flumetsulam; soil-applied products go on at planting in crop fields, and post-emergence products are used on emerged plants. Any product you use must be labeled for your exact site (pasture, hayfield, crop or landscape) and for sicklepod, and you must follow the label, including grazing and haying restrictions, because the label is the law. Your county Extension office can suggest a current option. If you hire someone to spray, make sure they hold your state’s pesticide applicator license; the rules for each state are in our pesticide applicator license guide.

Keeping it from coming back

Sicklepod spreads almost entirely by seed, so the whole game is stopping pods. Pull or mow young plants before they flower, and never let a plant with pods stand into fall. Watch spots where new soil, hay or animals arrive, and pull newcomers right away.

The seed bank does wear down if you stay ahead of it: in Mississippi research about 40 percent of buried seed died each year, but hard-coated survivors kept sprouting for several seasons. Plan on at least three years of steady follow-up, and keep the soil covered with healthy grass, crops or mulch so fewer seeds find bare ground.

Questions we get about sicklepod

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