. Agricultural plant pest control : a study manual for commercial and governmental pesticide applicators . Weeds; Pests. SOURCES OF WEED INFESTA TIONS ? Humans are the most effective agent in the dissemination of weeds. Most exotic weeds found in the United States are here because of the movement of people and their products. Weed seeds are moved in hay and seed products; by machinery and vehicles; and in common carriers, railroads and trucks hauling cargoes of grain, hay, livestock, and other farm commodities. Movement along travel corridors scatter seeds along rights-of-way and highways, whi
. Agricultural plant pest control : a study manual for commercial and governmental pesticide applicators . Weeds; Pests. SOURCES OF WEED INFESTA TIONS ? Humans are the most effective agent in the dissemination of weeds. Most exotic weeds found in the United States are here because of the movement of people and their products. Weed seeds are moved in hay and seed products; by machinery and vehicles; and in common carriers, railroads and trucks hauling cargoes of grain, hay, livestock, and other farm commodities. Movement along travel corridors scatter seeds along rights-of-way and highways, which become sources of infestation to adjoining fields. Wind spreads seeds over great distances. Many weed seeds have structural features which aid their distribution by wind (Figure 11-1). Some seeds have wings, like those of maple trees, or they may have long, silky hairs or parachutes attached to them. Tumbleweeds (such as Russian thistle) are especially adapted for seed dispersal when blown along the ground. Figure II-2 Water also effectively spreads seeds. Most weed seeds will float if they fall on the surface of streams, lakes or irrigation canals (Fig- ure II-2). Flood waters, running streams, and irrigation water all contribute to spreading weed seeds. Irrigation canals, when first filled, often carry heavy loads of weed seeds downstream where they may be washed ashore or deposited in silt along the way. curly dock seed has bladder-like floats. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Montana. Dept. of Agriculture; Hinck, Laura; Johnson, Kim; Mullin, Barbara H; Montana. Agricultural Sciences Division. Helena, Mont. : Montana Department of Agriculture
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Keywords: ., bhlco, bookcentury1900, bookcollectionamericana, booksubjectweeds
