The broadleaf weed Xanthium strumarium is argued to be one of the most competitive weeds in soybean crops and is distributed worldwide. Affected areas can lead to a direct decrease in combine efficiency due to the thickness of cocklebur stems. Cocklebur seeds and seedling are poisonous to livestock by causing toxicosis as the plant matures. Cocklebur is a summer annual broadleaf weed that is fairly easy to identify as result of the distinct burs produced.
The hypocotyls of cocklebur are purple in colour at the base and become green. Their overall shape is oblong and can range from 3-5 cm long. Initial leaves are opposite, but all remaining leaves will be alternating. Also, its prominent veins can help in early identification. At the growth stages of cotyledon and seedling, the cocklebur is highly poisonous due to the presence of toxic compounds.
The cocklebur plant can vary anywhere from 15-200 cm in height, depending on environmental conditions. The leaves are rough and can vary from 5-18 cm long. In a mature plant, the leaves will have stiff, long hairs that are very distinct, with a broadly triangular shape. Stems of a mature plant are very rigid, and green in colour with red-purple and black spots. Its key distinguishing feature in maturity is the production of a prickly cocklebur fruits.
Optimal growth conditions
The Cocklebur is associated with conventional tillage, and can often be found growing in agronomic and horticultural crops and pastures.