The twelve pests of Christmas (trees)

The Invasives Blog

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

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Is parthenium weed allergy problem worse than that of annual ragweed?

A small clump of field-growing parthenium weed plants approximately 80 days old
Photo Credit: S. Adkins

By Asad Shabbir

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.

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