Читать книгу Herbicides and Plant Physiology - Andrew H. Cobb - Страница 14

On a global basis only about 250 species are sufficiently troublesome to be termed weeds, representing approximately 0.1% of the world’s flora. Of these, 70% are found in 12 families, 40% alone being members of the Gramineae and Compositae. Interestingly, 12 crops from five families provide 75% of the world’s food and the same five families provide many of the worst weeds (Table 1.1). This implies that our major crops and weeds share certain characteristics and perhaps common origins.

Table 1.1 Important plant families which contain both the major crops and the worst weeds of the world.

Source: Radosevich, S.R. and Holt, J.S. (1984) Weed Ecology: Implications for Vegetation Management. New York: Wiley. Reproduced with permission of John Wiley & Sons.

Number of species classified as the world’s worst weeds (%)	Family	Examples of major crops	Examples of major weeds	Common name
44	Gramineae	Barley, maize, millett, oats, rice, sorghum, sugar cane and wheat	Elytrigia repens (L.)	Couch
Alopecurus myosuroides (L.)	Black‐grass
Avena fatua (L.)	Wild oat
Sorghum halepense (L.) Pers.	Johnson grass
Echinochloa crusgalli (L.)	Barnyard grass
4	Solanaceae	White potato	Solanum nigrum (L.)	Black nightshade
Datura stramonium (L.)	Jimsonweed
Hyoscyamus niger (L.)	Henbane
5	Convolvulaceae	Sweet potato	Convolvulus arvensis (L.)	Field bindweed
Cuscuta pentagona (Engelm)	Field dodder
Ipomoea purpurea (L.) Roth	Tall morning glory
5	Euphorbiaceae	Cassava	Euphorbia maculata (L.)	Spotted spurge
Euphorbia helioscopia (L.)	Sun spurge
Mercurialis annua (L.)	Annual mercury
6	Leguminosae	Soybean	Cassia obtusifolia (L.)	Sicklepod
Melilotus alba (Desc)	White sweetclover
Trifolium repens (L.)	White clover