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Ragweed Planting Methods and Key Technical Points Explained

Growing Techniques By Emily Carter 0 views
Grass

Ragweed (scientific name: Ambrosia artemisiifolia L.): an annual herb, 20-150 cm tall; the stem is upright, with paniculate branching in the upper part, ridged, sparsely covered with dense rough hairs. The lower leaves are opposite, with short petioles, bipinnately divided, with narrow lobes, oblong to oblanceolate, entire. The upper surface is dark green, covered with fine short appressed hairs or nearly hairless; the underside is grayish green, covered with dense short rough hairs. The male capitula are hemispherical or ovate, 4-5 mm in diameter, with short peduncles, drooping, densely clustered in racemes at the branch tips. The involucre is broadly hemispherical or dish-shaped; the corolla is pale yellow, 2 mm long, with a short tube, bell-shaped above, with broad lobes. The achene is obovate, hairless, hidden within the hard involucre.


Morphological Characteristics of Ragweed

The stem is upright, the plant height is 20-150 cm, with branching and rough hairs. The leaves are opposite or alternate, 1-2 times pinnately divided, the lobes are strip-shaped with short rough hairs. The capitula are unisexual; male capitula are the majority, forming racemes at the branch tips, the involucre is dish-shaped, with wavy rounded teeth; female capitula are sessile, borne in the leaf axils below the male capitula, in clusters of 2-3 or solitary, each with a female flower lacking a perianth. The achene is enclosed in the involucre; the involucre is obovate, surrounded by 5-8 short beaks, with a conical beak at the tip. It spreads by seeds carried with crops, water flow, and vehicles.

Destruction of Ecology

After invading bare land, it can become the dominant species within one year. Because of its extremely strong vitality, it can cover and suppress native plants, causing destruction of the original ecosystem, reducing agricultural yields, consuming water and nutrients in the soil, and causing heavy agricultural losses; the spread of ragweed has eaten away large areas of land, caused farmland to be abandoned, and posed a relatively large threat to the ecological environment.
The potential harm of ragweed is quite serious, especially in extensive agricultural farming areas. Ragweed can mix with all dryland crops, especially intertilled crops such as corn, soybeans, sunflowers, hemp, and kenaf, as well as cereal crops, and can cause large-scale weed infestation in crops, even total crop failure. It can quickly form a single-species dominant community, leading to the decline and disappearance of the original plant community. According to experiments, in 1 sq m of corn field, as long as there are 30 to 50 ragweed seedlings, corn yields will be reduced by 30 to 40 percent; when the number of ragweed seedlings increases to 50 to 100, corn will yield almost nothing.

Pollen Allergy

The direct harm of ragweed to the human body is the pollen released after flowering. The pollen of this plant contains water-soluble proteins, which can be released quickly upon contact with people, causing allergic reactions. It is the main causative agent of autumn pollen allergy and can easily lead to hay fever, which is harmful to health. Mild cases cause coughing and asthma; severe cases can cause emphysema, and after infection it recurs year after year, worsening each year. Therefore, experts warn: never touch flowering giant ragweed. Giant ragweed is also very harmful to agriculture. Because ragweed has a powerful root system and a huge aboveground vegetative mass, it grows aggressively and competes with crops for water and fertilizer. It releases a variety of substances that have obvious inhibitory effects on cultivated crops and wild plants, and can quickly overwhelm local annual plants.
Ragweed pollen is the main pathogen causing a series of allergic symptoms in the human body - hay fever. When the density of ragweed pollen grains in the air reaches 40-50 grains per cubic meter, people can become infected with hay fever (autumn pollinosis). The clinical manifestations in patients are severe itching of the eyes, ears, and nose, paroxysmal sneezing, runny nose, headache, and fatigue; some have chest tightness, breathlessness, coughing, and difficulty breathing. Those untreated for years may also develop emphysema and cor pulmonale, suffering unbearably, and may even die. Ragweed plants and pollen can also cause some people to develop allergic dermatitis, with "wind blisters" all over the body. 

In the United States, 14.6 million people suffer from ragweed-related illness each year. Canada also has 800,000 people. In the Krasnodar region of the former Soviet Union, during the ragweed flowering season, about one-seventh of people were unable to work because of ragweed disease. Therefore, ragweed is designated as an international quarantine weed and a public nuisance weed. Relevant experts warn that because China has a large population base, only a little more than 10% of people suffer from pollen allergies, but if ragweed is not cleared as soon as possible at the beginning of its spread, the number of patients in the future will be no less than in Europe and America.


Control Measures for Ragweed

1. Agricultural control: the main measures are manual pulling and manual cutting. According to the different growth of ragweed caused by climate differences in different regions, determine the suitable period for eradication, that is, before ragweed flowers and sets seed. However, manual pulling is labor-intensive, difficult to fully clear, and if handled improperly can easily create the risk of human carrying and spread.

2. Chemical control: according to different areas, non-farmland and farmland, spray non-selective herbicides such as glyphosate, Roundup, Linta, or fomesafen aqueous solution to kill ragweed.

3. Biological control: introduce natural enemy insects of ragweed - the ragweed stem borer and Ophraella communa for biological control, with good results.

4. Plant replacement: use amorpha and Kentucky bluegrass for replacement control; use amorpha and Kentucky bluegrass for replacement control, eliminate wasteland, plant crops, and manage diligently. These all have relatively good control effects on ragweed.



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