The term "weed" denotes an unfavorable plant species. Weeds reduce crop yields by competing for space and nutrients; they may be harmful to animals and humans and may be costly and difficult to eradicate. They may also serve as hosts to insect pests and diseases of crop species. "Noxious weeds" have the most undesirable characteristics of all weeds. They are masters of survival. As well as producing great numbers of seeds from one plant, they may reproduce asexually by means of specialized stems and roots. They may complete several life cycles in one growing season, and some seeds may remain viable for many years. Some have allopathic properties that prevent the growth of other species.
State and commercial seed testing laboratories provide a valuable service in performing seed analyses. A Seed Purity analysis checks for the presence of weeds in crop species intended for seed production. Analysts must know the noxious weeds of their state and the states where seed will be shipped. This precaution will help prevent the introduction of unwanted species into that state.
Each state has its own seed law and regulations with a list of "Noxious weed" species. Seed labeling laws require that the name and rate of occurrence of each "Noxious weed" be listed. The law may prohibit the sale of seed with 'Noxious' weeds or will limit the number allowed. The best means of weed control is to plant weed free seed. The proper identification of the weed species is also necessary to determine the proper reductive measures in the field.
The species listed and pictured below have been designated as Noxious by the New York State Department of Agriculture and Markets and are listed in Article 9 of the Agriculture and Markets law Chapter 631 Relating to Inspection and Sale of Seeds with Rules and Regulations (Revised 2003).
1) Annual bluegrass Poa annua (in lawn seed)
3) Bindweed Convolvulus arvensis
4) Canada thistle Cirsium arvense
5) Corncockle Agrostemma githago
7) Horsenettle Solanum carolinense
8) Leafy spurge Euphorbia esula
9) Quackgrass Elytrigia repens
10) Russian knapweed Acroptilon repens
The Uniform Classification of Weed and Crop Seeds, Contribution No. 25 to the Handbook on Seed Testing of the Association of Official Seed Analysts (AOSA) is the standard reference used by seed laboratories to identify weed species through out North America. Botanical names are current to the 2004 edition. The AOSA Handbook 25 is complied with assistance from the AOSA Nomenclature Committee, the USDA Germplasm Resources Information Network and with the Canadian Food Inspection Agency and is updated as needed.
Click on the articles listed below to download the complete information:
Noxious Weed Seeds of New York (PDF) | Article 9: NYS Seed Law (PDF)