Ambrosia artemisiifolia

This species is host to the following insect induced galls:

• Aceria ambrosiae Wilson, 1959 midge that forms bud-galls
• Asphondylia ambrosiae Gagné, 1975
• Aulacidea ambrosiaecola Ragweed stem gall wasp (see image)
• Epiblema strenuana (Walker, 1863) stem borer moth
• Neolasioptera ambrosiae Felt, 1909 small stem midge.
• Procecidochares gibba (Loew, 1873) gall fly
• Rhopalomyia ambrosiae Gagné, 1975 bud gall midge

Asphondylia ambrosiae gall

external link to gallformers

Ambrosia in chicken coop in Belgium

Common ragweed, Ambrosia artemisiifolia, is a widespread invasive species, and can become a noxious weed, that has naturalized in: Europe; temperate Asia and the Indian subcontinent; temperate northern and southern Africa and Macaronesia; Oceania in Australia, New Zealand, and Hawaii; and Southwestern North America in California and the Southwestern United States.[2][9][11][12][13][14][15][16] A scientific study investigated the genomic basis of invasiveness in Ambrosia artemisiifolia, introduced to Europe in the late 19th century, by resequencing 655 ragweed genomes, including 308 herbarium specimens collected up to 190 years ago.[17] In invasive European populations, the study found selection signatures in defense genes and lower prevalence of disease-inducing plant pathogens. Together with temporal changes in population structure associated with introgression from closely related Ambrosia species, escape from specific microbial enemies likely favored the remarkable success of common ragweed as an invasive species.

Common ragweed is a very competitive weed and can produce yield losses in soybeans as high as 30 percent. Control with night tillage reduces emergence by around 45 percent. Small grains in rotation will also suppress common ragweed if they are overseeded with clover. Otherwise, the ragweed will grow and mature and produce seeds in the small grain stubble.

Its wind-blown pollen is highly allergenic.

As of 2005 several herbicides were effective against common ragweed, although resistant populations were known to exist.[18] In 2007 several Ambrosia artemisiifolia populations were glyphosate resistant, exclusively in the USA.[19]

As of 2014 the ragweed leaf beetle, Ophraella communa, has been found south of the Alps in southern Switzerland and northern Italy. Many of the attacked plants were completely defoliated.[20] Zygogramma suturalis was introduced to Russia, and then China, for ragweed control, with very positive initial results.

SMARTER is a European interdisciplinary network of experts involved in the control of ragweed, health care professionals, aerobiologists, ecologists, economists, and atmospheric and agricultural modellers.[21]

Three sesquiterpene lactones isolated from the aerial parts of Ambrosia artemisiifolia were identified as psilostachyin A, psilostachyin B and psilostachyin C. All of them have some molluscicidal activity against the small tropical freshwater snail Oncomelania hupensis.[22]

Ambrosia artemisiifolia has been a traditional medicinal plant for Native American tribes, including the Cherokee, Lakota, Iroquois, Dakota, and Delaware.[23]

Ambrosia artemisiifolia is used in phytoremediation projects remediating soil pollution, for removing heavy metals such as lead from contaminated soil.[24]