Common Ragweed

Type Description

It is native to North America. It is an annual, 15-20 cm (rarely 2 m) tall, often branched, shrub-like plant. The stem is erect, branched and long-pubescent. The leaves are 5-10 cm long, short-petiolate, mostly spirally arranged in opposite upper parts of the stem, the leaf blade finely pinnate to tripinnate, the uppermost ones rarely without lobes. Male and female flower bases are usually located in different parts of the plant. Plants can rarely have completely female flowers. The bracts on the flower plates are united. Female flower plates are 1-flowered, sessile, small and not showy. The male inflorescences (capitula) are located at the tips of the inflorescences, while the female inflorescences are in clusters of 2-3 or individually at the base of the inflorescences and in the leaf axils of the upper leaves. Male inflorescences have 5-25 flowers with a conspicuously distinct yellow color. Numerous male flower bases with thin and short stalks are found together to form long spike-like panicles (Bayfield and Baytop, 1998; Önen et al., 2015). Life form is herbaceous.

Habitat

It is an invader that has spread to almost all continents of the world and can adapt to very different climatic conditions, ecological zones and agricultural systems. The plant can invade agricultural ecosystems with very different characteristics, such as field and horticultural crops, meadow and pasture areas and vineyard areas. It is also frequently found along the banks of streams, canals and rivers, along roads and railroads, on field edges, and in vacant and debris fields. It can even develop on roadsides where salting is done against ice (Önen et al., 2015). The species was discovered in Trabzon in 1995, but it is still widespread in the Black Sea Region, with a fragmented distribution in Thrace (Figure 2 42). It is distributed in the Americas, Europe, Africa, Asia and Australia. Bulgaria, Armenia, Georgia and other Eastern Mediterranean countries and North Africa are considered to be at risk. European countries, Russia and Azerbaijan are other countries where its spread has been detected (EPPO, 2020).

Reproductive Information

Lifecycle

Nutrition Information

General Impact Information

It can cause major problems in agricultural and non-agricultural areas. The plant competes with cultivated plants and can cause significant yield losses. It causes significant yield and quality reductions in all field crops (such as soybean, sunflower, potato, maize, tobacco), especially cereals. The plant is not palatable to livestock, making it unpalatable, thus significantly limiting the use of infested grasslands and pastures. In addition, its pollen has a strong allergenic effect for humans. The pollen or the plant itself also causes skin inflammation (dermatitis). It is rapidly covering non-agricultural areas and natural ecosystems such as roadsides, railways, debris fields, water channels, stream banks, etc. and causing significant problems in these areas. It causes significant damage especially in agricultural areas by affecting soil fertility.

General Management Information

Due to climate change, it is predicted that the increasing density and prevalence of the plant will increase the problems it will cause in agricultural and natural ecosystems, and this increase may lead to greater problems in terms of human health; therefore, the importance of the invasive species may increase even more.

General Pathway Information

It is one of the world's major invasive species and its seeds can be spread over large areas and long distances by contaminated seed, bird and livestock feed, hay and straw. The seeds are spread over short distances by birds, rivers and strong winds, bales of hay or straw, excavation and construction equipment, agricultural machinery, roadside mud stuck to tires, etc. Although the entry route of the species into our country is not known for certain, the entry and spread routes may vary in different places and habitats (Zambak and Uludağ, 2019). The possible vectors in our country are considered to be natural causes such as animals, animal feeds and wind-river (USDA, 2012). Considering the terminology used internationally, it has been evaluated that it enters our country both unknowingly (human activities) and naturally (such as animals, rivers and wind).

Notes

As it is not palatable, it is not preferred as animal feed, thus significantly limiting the use of infested meadow and pasture areas. It also reduces the quality of feed when mixed with feed and negatively affects the quality of dairy products when consumed by cattle. The plant therefore does not have an accepted use.

References