Digitaria ciliaris, also known as Southern crabgrass or tropical finger grass, is an invasive weed that has been a major problem in most areas.
It is a fast-growing weed that is common in disturbed areas, roadsides, pastures, and agricultural fields.
Southern crabgrass is an annual weed and grows in open areas that have full sun or partial shade.
Scientific Classification
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Tracheophyta
- Subphylum: Angiospermae
- Class: Monocotyledonae
- Order: Cyperales
- Family: Poaceae
- Genus: Digitaria
- Species: Digitaria ciliaris
- Common Names: Fingergrass, Henry’s crabgrass, Southern crabgrass
Nativity and Distribution
Digitaria ciliaris is native to subtropics and tropic areas of Africa and Asia. The plant is also found in the following areas:
- North, Central, and South America
- Australia
Physical Appearance
- Leaves: Simple and alternate leaves that grow from the base of the plant.
- Fruits: Dry fruit that is fused with the seed wall.
- Stems: Erect stems branched near the top. Small flowers form at the tip of each branch.
- Flowers: Orange, red, or yellow, and they grow in clusters.
- Roots: Shallow fibrous root system.
Digitaria ciliaris leaves are 25cm long and 1cm wide. The sheaths and lower parts of the leaves are hairy on both surfaces.
The plant’s stems are erect but can also grow along the ground. The stems can grow up to 10 to 100 cm in height.
The inflorescence, which is usually much taller than the leaves, has 2-9 racemes. Each raceme is arranged in a finger-like pattern and consists of spikelets.
The Southern crabgrass spikelets are arranged in pairs, consisting of one sessile and a short pedicel measuring 2.5 to 3.5 mm long and tapering to a sharp point.
The lower glume is very short, approximately 0.33 mm long, while the upper glume is at least half that length and usually about three-quarters the length of the spikelet, possessing three nerves.
Life Cycle/Reproduction/Dispersal
- Life Cycle: Annual.
- Seeds: They are light brown. 4 to 5mm long and less than 1mm wide.
- Climate: Thrives in tropical to sub-tropical climates.
- Dispersal: Human activities such as mowing.
Digitaria ciliaris mainly relies on seed dispersal for reproduction. Seeds may fall to the ground due to gravity or be dispersed over large distances by human activities such as agricultural practices.
Once dispersed, some seeds have high dormancy levels and may not germinate immediately after dispersal. However, once the seeds germinate, a new plant emerges, and the life cycle is complete.
Additionally, the plant can reproduce vegetatively when parts of the plant, such as stolons, stems, and nodes, fall off to produce new growth.
Impact on Environment
Digitaria ciliaris is considered an environmental threat because it tends to outcompete native plants for essential nutrients. Its rapid growth rate allows it to quickly overtake and damage crops.
Southern crabgrass blocks sunlight from reaching plants beneath it, negatively impacting other plants’ health quality.
Additionally, the plant has allelopathic effects, which may suppress the growth of surrounding plants.
Southern crabgrass also transports harmful bacteria like E. coli and Salmonella, increasing the risk of vector-borne diseases, such as malaria.
Uses
According to the National Library of Medicine, Digitaria ciliaris flower absolute has been found to promote skin wound healing and can thus be used in pharmaceutical products. Other uses of the plant include:
- It can be used as livestock feed for cattle, deer, sheep, goats, and bison due to its high protein content.
- Can survive both heat and drought, thus producing a lot of grain.
- It can be used to suffocate other weeds.
Control
The following control methods are effective for Southern crabgrass:
1. Hand pulling
Hand pulling is a highly effective method for managing Digitaria ciliaris, particularly in its early growth phases.
However, the plant can root at its nodes; thus, some fragments may remain after manual removal, necessitating repeated weeding for thorough control.
2. Crop rotation
Implementing crop rotation can disrupt the life cycle of Southern crabgrass, decreasing its occurrence.
Additionally, planting competitive crops, such as specific cover crops, can further suppress its growth.
3. Chemical Control
Natural organic herbicides like vinegar or ammonia-based products can be used to control Southern crabgrass.
Additionally, chemical herbicides that are effective include aminopyralid and glyphosate, which are non-selective and will kill any plants they come into contact with.
However, if the growth of Digitaria ciliaris persists after using the herbicides, you can use Dicamba, which is used for controlling herbicide resistant weeds.
Lead Editor for Insight Weeds.