Bermuda grass (Cynodon dactylon) is a highly variable, sod forming perennial that spreads by stolons, rhizomes and seed. Stolons of Bermuda grass readily root at the nodes. Lateral buds develop at the nodes to produce erect or ascending stems that reach 5 to 40 cm (rarely over 90 cm) in height. In most Cynodon sp., leaves are borne on stems with long internodes alternating with one or more very short internodes. This characteristic gives the impression that the species has multiple-leaved nodes.
Leaf sheaths are compressed to round, loose, split, smooth, sparsely hairy, up to 15 cm long, and with a tuft of hairs 2 to 5 mm long. Auricles are absent. Collar is continuous, narrow, glabrous and hairy on margins. Leaf blades are 2 to 16 cm long, 1.5 to 5 mm wide, smooth to sparsely pubescent, folded or loosely rolled in the bud and sharply-pointed. The inflorescence consists of 3 to 7 spikes in a single whorl in a fingerlike arrangement and 3 to 10 cm long. Spikelets are 2 to 3 mm long, in 2 rows tightly appressed to one side of the rachis; glumes are to ° the length of spikelet; lemma is boot-shaped, acute with fringe of hairs on the keel and longer than the glume; seed is 1.5 mm long, oval, straw to red-colored and free within the lemma and palea.
Bermuda grass has a fibrous, perennial root system with vigorous, deep rhizomes. Roots are produced at the nodes after new leaves or tillers are produced during the growing season and after new shoots are produced in the spring. Mature roots are yellow to brown while new roots are white. Mature roots deteriorate throughout the growing season and new roots are produced continuously. Root production and dieback has been reported to be particularly high in the spring at the onset of shoot.
Distribution of Bermuda grass.
Bermuda grass is thought to have originated in Africa but now occurs worldwide in both tropical and subtropical regions including Asia, North, Central and South America, the Caribbean, and islands in the Pacific Ocean. It also spreads into temperate areas of Europe and North America but is limited by sensitivity to prolonged frost. Bermuda grass invades almost all kinds of crops and modified ecosystems, including urban areas and circulation paths (road and railroad tracks) in many regions
Ecological requirement of Bermuda grass
Cynodon dactylon is a warm grass which grows slowly in cold weather, in shade or in dry soils. Grows in a range of soils from sand to heavy clay to poor soil; thrives best in medium to heavy moist and well-drained soil. Grows in either acid or alkaline conditions and survives floods and drought (through regrowth from underground rhizomes). May be found in the tropics in areas with 600 to 1800 mm of annual rainfall.
May be found in arid regions thriving along rivers and in irrigated area. Found in lower altitudes throughout warm regions of the world and grows along roadsides and in exposed rocky or sandy sites up to 2270 meters in altitude. Widespread and common in Fiji especially near roadsides, riversides and hillsides to an altitude of 850 meters. Sometimes forms dense mats on the upper parts of beaches and near mangrove swamp. A common roadside, lawn grass and plantation weed in New Guinea found to an altitude of at least 1800 meters.
Harmful effects of Bermuda grass
- It competes for nutrients, water, soil, light and space with crops resulting to low production.
- It’s has allopathic effects on peach.
- Acts as host to very wide range of organisms and is often implicated as an important alternative host of crop pest and disease like bacterial leaf blight of rice /covered smut of sorghum.
- The pollen of Bermuda grass has been shown to produce allergy symptoms in asthmatics.
- Reduces native biodiversity.
- Its increase the cost of production because its capital intensive as well labor intensive through mechanical and chemical control.
Adaptation of Bermuda grass.
- Bermuda grass produces seed heads under stress condition such as drought.
- Bermuda grass produce numerous seeds which are small about 2000,000 seeds per pound.
- They grow under a wide soils from heavy clays to deep sand, provided fertility is not a limiting factor.
- Bermuda tolerates both acidic and alkaline soil conditions and is highly tolerant to saline conditions.
- Bermuda grass leaves and stems remain dormant until average dairy temperature rise above 50 for several day.
- The roots and rhizomes of Bermuda grass continues to grow several weeks after the leaves and stems stop growth.
- Bermuda grass develops into a semi dormant states during very dry condition, but has the capability of serving extreme drought.
- Rhizomes of Bermuda grass can loss 50% or more of their weight and still, recover when favorable moisture developed.
- It has deepest roots and rhizome penetration and better withstand prolonged drought period.
Weed management
Cynodon dactylon, in disturbed sites, is a competitive and invasive weed. The best management strategy is to remove all plant parts at first sighting. Invasion will be limited by tall plants. Spot herbicide and manual tilling may be adequate in controlling native fields with patchy weed distribution. A more drastic control plan is necessary in sites heavily infested with Bermuda grass. The appropriate manipulation is dependent on the location, humidity, temperature, soil type and precipitation at the specific site.
Burning, herbicide application, clipping and shading have all been effective in controlling Bermuda grass under various conditions. In order to prevent the sprouting and establishment of the remaining Bermuda grass rhizomes, native plants and shade material should be installed immediately after the eradication stage.
Management strategies depend on the extent of Bermuda grass and the height of the native vegetation.
Chemical control
Herbicide like glyphosate is very common for killing Bermuda. But remember, in order to get good results, herbicide should be applied (i.e. sprayed) on the grass leaves. This is because the leaves are the most effective part to absorb maximum quantity of herbicide and not the roots.
Another important point to remember is the time of herbicide application. In dormant state (like in January) Bermuda grass absorbs less herbicides. This is the time when they draw nutrients up from the roots and therefore the chemical applied on the leaves is unlikely to be down to the root system. So this is not the time to kill Bermuda by use of herbicides. Application of herbicides should be done from spring to fall, when the leaves are developed and green.
You should not clip and mow the lawn before getting rid of Bermuda grass. Instead, one or two weeks before the application of herbicide, water the lawn thoroughly so that the leaves of Bermuda grass get green and well spread out to absorb the chemical effectively.
Glyphosate is a broad-spectrum systemic herbicide. However, as mentioned earlier, it is not effective when Bermuda grass is in dormant state. Glyphosate can kill the deepest roots of Bermuda grass. After treatment, graying and browning of colors takes place within 7-10 days. Repeat the herbicide application and watering of lawn every ten days or so until new sprouts of Bermuda grass stop reappearing. Apply herbicide on the entire grass area.
Greenlife solutions for control of Bermuda grass.
Clampdown 480SL 200ml/20l
- Use of clean water to ensure effectiveness of the chemical.
