Parthenium weed and annual ragweed are closely related members of the Asteraceae, known for their high allergenicity. The detrimental effects on human health of the more temperate annual ragweed are very well known. However, those of the more tropical parthenium weed are less well known and in fact much more severe, affecting many tens of millions of people each year.
For many, December means celebrating Christmas and a central part of that is a Christmas tree. Evergreen trees have been used in celebration for centuries. The ancient Egyptians, Chinese, and Hebrews used evergreen trees, wreaths, and garlands to symbolize eternal life. Pagans worshiped trees, and Romans used evergreen wreaths during the festival of Saturnalia.
The trees commonly used as Christmas decorations come from the genus Picea which is made up of around 35 species of coniferous evergreen trees in the family Picaceae. Popular Christmas tree species include Balsam Fir, Douglas Fir, and Norway Spruce.
The modern-day Christmas tree is thought to have started in 16th century Germany when Christians brought decorated trees into their homes. The Christmas traditions we know today were shaped by the Victorians, when the first Christmas tree was brought from Germany to the British royal household by Prince Albert in the 1840s. These days, around 7 million real trees are sold each year in the UK, and as many as 30 million in the USA.
Last week CABI launched the full version of its invasive species Horizon Scanning Tool, a free and open access online resource available via the Invasive Species Compendium that helps users make decisions about invasive species and identify possible risks in countries, provinces and states.
Latest book in the CABI Invasive Series: Parthenium Weed
Parthenium weed (Parthenium hysterophorus) is considered one of the worst weeds in the world. It has invaded and is widespread in about 48 countries in Africa, Asia and the South Pacific, and has the potential to spread to new countries in Africa, Asia and parts of Europe. In the countries it has invaded, it has devastating effects on the livelihoods of millions of people causing significant economic, health and environmental loss. In order to effectively manage parthenium weed and mitigate the impacts it has, one needs a good understanding of the biology and ecology of the weed as well as effective management strategies already utilised. As the editors of CABI’s new book on Parthenium so candidly put, ‘know your enemy’ is the first step in effective management.
Invasive alien weed species have been a global environmental and human health issue for decades. In 1969, CABI organised the first International Symposium on Biological Control of Weeds (ISBCW) in Delémont, Switzerland. Weed biocontrol research was then in its early stages and 20 scientists attended.
CABI scientists are stepping up the fight against one of the UK’s most invasive non-native aquatic weeds.
Approval has been given for the release of a novel biological control agent – the mite, Aculuscrassulae – to assess its ability in the real-world environment to suppress Australian swamp stonecrop (Crassula helmsii), also known as New Zealand pigmyweed. This follows carefully controlled laboratory testing to ensure the safe, controlled release of the mite in the UK.
Giant hogweed (Heracleum mantegazzianum) is a monocarpic perennial herb, native to the Caucasus region. Since the late 1800s, giant hogweed has spread extensively across Europe and in eastern and western parts of North America following its likely initial introduction to the continent as an ornamental curiosity as early as 1917. Hogweed is an extremely successful invader in part due to its prolific seed production and growth rate. These attributes coupled with its large size allow giant hogweed to significantly alter natural environments and plant community structures. In addition, the plant is hazardous to humans and leaves riparian banks susceptible to erosion as it dies off in autumn.