Oxalis

Creeping woodsorrel, scientifically known as Oxalis corniculata, is a weed species that can be found in various regions across the globe. Typically, it thrives below 2,500 feet in elevation and commonly appears in lawns, flower beds, gardens, nurseries, and greenhouses.

Originating from Southern America, Oxalis is a perennial ground cover. It grows in a prostrate manner, with its stems and roots forming where nodes come into contact with the soil. This plant can tolerate both full sun and shade, as long as it receives sufficient moisture.

The leaves of creeping woodsorrel consist of three heart-shaped leaflets attached to a long stem. They exhibit green to purple colors and tend to close and fold downward in bright light and during the night. When subjected to drought or intense heat, the leaves may turn reddish and wilt.

Creeping woodsorrel can flower throughout the year, although it typically blooms heavily and produces seeds in spring. Its flowers feature five small, yellow petals measuring about 1/8 to 1/3 inch in length. These flowers grow singly in small clusters of two to five on short, slender stalks.

In terms of environmental requirements, O. corniculata thrives in open, disturbed areas and does not perform well in shade, although it can still be found in shady locations. It exhibits adaptability to a wide range of environments, from tropical to cooler climates. It can grow in light, medium, or heavy soils with acidic, neutral, or basic pH levels. The extensive distribution of creeping woodsorrel suggests that it has diverse requirements.

This weed possesses various adaptations that enable it to thrive in different conditions. It is abundant in its native range and benefits from its association with humans, acting as a human commensal. Creeping woodsorrel grows rapidly, displays a broad native range, exhibits high genetic variability, possesses high reproductive potential, and shows high adaptability to different environments. It is a pioneering species in disturbed areas and has proven to be invasive outside its native range. Additionally, it reproduces asexually.

O. corniculata has a widespread distribution globally, occurring in numerous countries. It is considered a cosmopolitan weed in tropical and temperate zones. Some examples of its presence as a weed include tea plantations in Sri Lanka, Indonesia, and Taiwan; bean, maize, potato, rice, and vegetable crops in Japan; cereal crops in Ethiopia; rice cultivation in India and Indonesia; pastures in Australia; and coffee plantations in El Salvador, India, Kenya, Mexico, Tanzania, and Venezuela.

There are several disadvantages associated with oxalis weeds. They can reduce crop vigor and yields, serve as alternative hosts for diseases such as maize rusts and sorghum rusts, compete with crops for nutrients and light, require labor-intensive management, and negatively impact lawns by overshadowing the grass.

Regarding its spread and dispersal, creeping woodsorrel does not naturally spread far through stolons or rhizomes, but its seeds can be carried over long distances by human activities, either intentionally or accidentally. The plant’s stolons can root at nodes, allowing for clonal spread. Seeds can also disperse naturally when the capsules open, reaching considerable distances (up to 2 meters) from the parent plant. Rodents may contribute to further seed dispersal, and the presence of creeping woodsorrel on remote islands suggests that birds might carry its seeds.

Accidental introduction of O. corniculata to new countries or within countries is easily achieved due to its widespread occurrence. This can happen through contamination of agricultural machinery or seeds, or through the transfer of seeds on footwear, clothing, vehicle wheels, and other means. Furthermore, intentional introduction has occurred historically due to its recognized value as a condiment and for its medical or herbal properties, which has contributed to its global spread.

The following are examples of hosts or crops affected by creeping woodsorrel: cereal crops such as maize, fruit crops like pineapple, tea, cotton, and beans.

Greenlife Crop Protection Africa Limited solutions to Oxalis weed include:

Greenlife Crop Protection Africa Limited has developed a range of highly effective solutions for tackling the Oxalis weed through chemical applications. The recommended herbicides to suppress Oxalis weed are provided below:

  1. WEMBE 200 SL:
    • A non-selective post-emergence herbicide that effectively controls annual and perennial grasses as well as broad-leaved weeds like Oxalis.
    • It is particularly effective in clearing tough Oxalis weed during land preparation.
    • Recommended rate of use: 3.0 liters per hectare (300ml in 20L).
  2. CATAPULT 480 SL:
    • A non-selective post-emergence herbicide that controls annual and perennial grasses, including broad-leaved weeds like Oxalis.
    • It is suitable for use during land preparation to eliminate all types of weeds.
    • Recommended rate of use: 2.0 liters per hectare (250ml in 20L).
  3. BENTAGRAN TOP 240 EC:
    • A selective early post-emergence herbicide designed for controlling annual grasses and broad-leaved weeds, including Oxalis, in common beans and French beans.
    • It should be applied when the weeds are actively growing.
    • Recommended rate of use: 0.5 liters per hectare (50ml in 20L).
  4. HOTLINE 450 SC:
    • A non-selective pre-emergence herbicide effective against annual grasses and broad-leaved weeds, including Oxalis, in French beans, carrots, baby corn, coriander, and onions.
    • It should be applied when the soil is well moistened.
    • Recommended rate of use: 1.0 liter per hectare (50ml in 20L).
  5. COMMANDER 240 EC:
    • For the onion family, it is a selective early post-emergence or post-transplant herbicide to be used 2-10 days after transplanting onions.
    • For the brassica family, it is a selective pre-emergence or pre-transplant herbicide to be applied 2 days before transplanting cabbages and broccoli.
    • It controls annual grasses and broad-leaved weeds, including Oxalis.
    • Recommended rate of use: 1.0 liter per hectare (50ml in 20L).

 

 

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