Weed science

[2] Weeds have existed since humans began settled agriculture have existed since the advent of settled agriculture around 10,000 years ago it has been suggested that the most common characteristic of the ancestors of our presently dominant crop plants is their willingness—their tendency to be successful, to thrive, in disturbed habitats, mostly those around human dwellings.

The size of a farmer's holding and yield per unit area are limited by several things and paramount among them is the rapidity with which a family can weed its crops.

In 1923, Clark and Fletcher suggested that the "annual losses due to the occurrence of pernicious weeds on farm land in Canada, although acknowledged in a general way, are far greater than is realized.

French scientists sprayed apple trees with dinitro dyes to control mosses, algae, and lichens.

From the early 1930s until about 1945, it was used extensively in grains, clover hay, grass seed crops, peas, cane berries, onions, and lawns.

Timmons, writing in 1970 reported that "available literature indicates that relatively few agricultural leaders and farmers became interested in weeds as a problem before 1200 A.D. or even before 1500 A.D."[5] The “critical attention” Clark and Fletcher thought was absent increased slowly, primarily because the general attitude seemed to be that “weeds were a curse which must be endured, and about which little could be done except by methods which were incidental to crop production, and by laborious supplemental hand methods."

Herbicides greatly expanded the opportunities and range of methods for vegetation management and weed control.

These methods while undeniably successful for their intended purpose also have created environmental, non-target species, and human health problems.

[6] Examples of some of these troublesome weed species in North America are Palmer amaranth (Amaranthus palmeri S. Watson), common lambsquarter (Chenopodium album L.), horseweed (Erigeron canadensis L.), morningglory (Ipomoea spp.

Another aspect of weed science research is concerned with generating knowledge about the active ingredients of herbicides.

Some herbicides degrade very quickly in sunlight and can be made inactive before entering the plant while others can persist for years in the soil after they are applied, causing problems for future crops.

Registering herbicides can cost hundreds of millions of dollars in order to demonstrate how the chemical moves and degrades within the environment it is applied.

Many other professional societies exist for weed science that support the current research challenges of a given country or region.