Star grass, scientifically known as Cynodon aethiopicus, is an invasive weed that thrives in warm climates. It spreads through its extensive network of creeping rhizomes and stolons. This weed belongs to the poaceae family, which includes grasses.

Characteristics of Star Grass

Rhizomes and Stolons: Star grass possesses slender, tough, and scaly rhizomes and stolons. These structures produce roots at the nodes. Most of the rhizomes are found within the upper 6cm of the soil, although some can extend deeper. While the rhizomes can endure drought and dehydration to a significant extent, prolonged exposure to sunlight is detrimental to their survival.

Stems: The stems of star grass are woody, relatively thin, and mostly upright. They are not heavily branched.

Leaves: The leaf blades of star grass are flat and flexible, measuring approximately 10cm in length. They feature long hairs, particularly around the edges.

Inflorescence: Star grass produces inflorescences that resemble umbels, typically consisting of 4-8 spike-like branches, each measuring 1.5-3 inches in length.

Habitat and Growth Conditions

Star grass thrives in regions with temperatures ranging from 18 to 27°C. It requires full sunlight to achieve optimal growth.

A rainfall range of 800-1200mm per year favors the growth of star grass. While it exhibits some drought tolerance, it cannot withstand waterlogging for prolonged periods.

This weed can adapt to a wide range of soil types, from sandy to heavy clay. However, it thrives best in well-drained soils with a lighter texture. Star grass can tolerate soil pH ranging from 4.5 to 8.0, but it shows superior growth in neutral to slightly alkaline conditions, with a pH range of 6.5-8.5.

Distribution

Star grass is indigenous to East Africa, specifically Kenya, Uganda, Ethiopia, and Tanzania. It primarily grows at altitudes of 800-2000 meters above sea level, primarily along the Rift Valley. Over time, it has become naturalized and widely distributed in tropical and subtropical regions.

Propagation and Spread

Star grass can propagate through both seeds and vegetative means. Soil movements disperse the rhizomes and stolons, while seeds can be carried away by water, agricultural machinery, and human activities. Seeds germinate under favorable conditions and can remain dormant for up to 4 years, although they usually sprout within 2 years.

Impact on Crops

Star grass poses a significant threat to various crops, including maize, baby corn, and sugarcane. Its presence in cropped areas leads to several disadvantages:

1. Yield Reduction: Star grass competes with crops for nutrients and sunlight, resulting in reduced crop yields.
2. Increased Production Costs: Farmers incur additional expenses in dealing with the weed, thereby increasing the overall cost of production.
3. Lowered Produce Quality: The quality of the harvested produce diminishes when star grass is present.
4. Host for Pests and Diseases: Star grass serves as an alternative host for pests and diseases, which can further harm the crops.
5. Water Flow Obstruction: In irrigation channels, star grass impedes the smooth flow of water, causing disruptions.
6. Soil Fertility Decline: The presence of star grass leads to reduced soil fertility, affecting the overall health of the land.

Control Methods

Controlling star grass requires employing mechanical, cultural, and chemical means.

Mechanical Control: In small areas, persistent manual removal of rhizomes can help eliminate star grass.

Cultural Control: Implementing cultural practices such as shading by other plants and using mulches can suppress the growth of star grass.

Chemical Control: Chemical herbicides can be used to effectively manage star grass. At Greenlife, we offer the following solutions:

1. WEMBE 200 SL: A non-selective post-emergence herbicide that clears annual and perennial grasses, including star grass, as well as broad-leaved weeds. It is recommended for use during land preparation to eliminate all weeds. The suggested rate of use is 3.0 liters per hectare (300ml in 20L).

2. CATAPULT 480 SL: This non-selective post-emergence herbicide is used during land preparation to control annual and perennial grasses, including star grass, and broad-leaved weeds. Apply CATAPULT 480 SL to clear all weeds. The recommended rate of use is 2.0 liters per hectare (200ml in 20L).

3. HURRICANE 200 SL: A non-selective post-emergence herbicide suitable for controlling annual grasses and broad-leaved weeds on crops like maize, sweet corn, baby corn, and sugarcane. It should be applied between rows when crops are above waist high. The recommended rate of use is 1.5 liters per hectare (150ml in 20L).

Conclusion

Star grass is a problematic weed that can cause significant harm to crops. Understanding its characteristics, preferred habitat, and methods of control can help farmers effectively manage and mitigate its impact on agricultural productivity. Through mechanical, cultural, and chemical means, it is possible to combat the growth and spread of star grass, protecting the crops and ensuring higher yields.

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