Survey: Has Cocklebur invaded your fields?

You have almost certainly come across the ‘cocklebur’—small, oval fruits with hook-like spines at the tip. Once mature, they cling to clothing and animals; a single walk through the fields can leave your trouser legs covered in them. Although the native cocklebur has a long history of growth in China, an exotic variety, the Italian cocklebur, has appeared in recent decades. While they are close relatives of the native species, they may pose a significant threat to agriculture.

The Italian cocklebur, along with China’s native cocklebur species, belongs to the genus *Xanthium* of the Asteraceae family. An annual herb native to Southern Europe, it is now widely distributed across many parts of Europe, the Americas, Asia, and Oceania. Since its first discovery in Beijing in September 1991, the Italian cocklebur’s range in China has expanded rapidly. It has now spread to areas including Liaoning, Hebei, Beijing, Shandong, Shaanxi, and Xinjiang. In Beijing, the species has been recorded in Badachu, Shidu, Guanting, Baihuashan, Beishuhe, Wali, and Miyun, becoming the dominant species in certain local areas.

Due to its low environmental requirements and its ability to withstand saline-alkali soils and frequent waterlogging over long periods, it often forms extensive patches in some regions. Farmers and scientists are growing concerned: the Italian cocklebur now poses a serious threat to agricultural production and biodiversity conservation in infested areas.

Research indicates that once the Italian cocklebur invades fields of maize, cotton, or soybeans, it competes with the crops for survival space, causing significant damage—a coverage of just 8% can reduce crop yields by 60%. It also competes with solanaceous crops for sunlight during their critical flowering period, resulting in yield losses.

Additionally, aqueous extracts from the stems and leaves of the Italian cocklebur significantly inhibit the seed germination of maize, European oilseed rape, sunflowers, and liquorice, as well as wild plants such as shepherd’s purse, primrose, dandelions, and violets.

As for animals, the Italian cocklebur’s fruits are larger than those of native varieties, with denser, hooked spines that cling easily to wool and are difficult to remove, significantly reducing wool production.

Due to the rapid spread of the Italian cocklebur in northern China and its tendency to establish monoculture dominance, causing severe damage to agriculture and livestock, it was listed as a Category 3 quarantine pest for import in 1997.

Currently, Teacher Yue Xiaoxiao from the Beijing Xuanwu Youth Science and Technology Museum, along with a group of primary and secondary school students passionate about biology and agriculture, is conducting research into the invasive hazards of the Italian cocklebur. Through questionnaires, interviews, and field visits, they hope to understand the distribution of the Italian cocklebur across farms and villages in and around Beijing (and potentially beyond), including details such as growth locations, health, distribution area, and the impact on agriculture, in order to assess the extent of the threat and propose appropriate management measures.

If you live or work on a farm or in a village in or around Beijing and have observed the impact of the Italian cocklebur on agriculture and the local ecology, we welcome you to join this study. Farmers from other regions are also encouraged to complete the questionnaire and become citizen scientists. Teacher Yue and the students are also looking for typical farms and villages to conduct field research.

If your farm is also troubled by other invasive species, please feel free to leave a comment below.

How to Participate

Survey Period 

July to September 2023

(The Italian cocklebur is most easily identified during this period)

Geographic Scope

Farms or villages in and around Beijing

(Participants from other regions are also welcome to complete the questionnaire)

How to Get Involved

Complete the questionnaire (photos may be uploaded)

http://lxi.me/3aq01

Once we receive your response,

we will contact you via WeChat or telephone

Project Initiator

Project Assistance

Text: Yue Xiaoxiao

Edited by: Wan Lin