Purple loosestrife is an invasive, introduced plant that is usually associated with wetland, marshy, or riparian sites. It is found across the northern tier states and provinces in North America. Purple loosestrife affects the diversity of native wetland ecosystems. Infestations lead to severe wildlife habitat degradation, loss of species diversity, and displacement of wildlife-supporting native vegetation, such as cattails and bulrushes. The plant spreads effectively along waterways, and the thick, matted root system can rapidly clog irrigation ditches, resulting in decreased water flow and increased maintenance. Effective management of purple loosestrife along waterways and in riparian areas requires integrating management strategies to prevent further introductions, detecting and eradicating new infestations, and containing and controlling large-scale infestations. Management practices that aid in the control of purple loosestrife include herbicide, physical, and biological practices. Each infestation site should be individually evaluated to determine the appropriate control measure. Factors to be considered include the proximity and type of vegetation on the site, whether the water is flowing or still, and the utilization of the site and the water (domestic, irrigation, recreation, or scenic value).

Greenhouse and field studies were conducted to determine the interaction of clethodim sprayed in low volume with pyrithiobac or bromoxynil and to determine the influence of these mixtures on large crabgrass control. A low-volume, air-assisted spraying system was calibrated to deliver 26 L/ha and was compared to a conventional hydraulic fan spraying system calibrated to deliver 140 L/ha. Greenhouse data indicated that carrier volume had no effect on large crabgrass control with clethodim. The addition of pyrithiobac to clethodim in mixture was antagonistic compared to control with clethodim applied alone. The addition of bromoxynil to clethodim in mixture was synergistic. Field studies showed similar results.

Pluchea lanceolata (DC.) C. B. Clarke # PLULA is an aggressive, pernicious, rhizomatous evergreen weed in the Asteraceae. In other literature, P. lanceolata Oliv. & Hiern has also been mentioned (Anonymous 1992, pp. 731 and 1147). With heavy root branches and dense subterranean parts, P. lanceolata is a common weed of sandy and saline tracts of the dry plains of the northwestern parts of India (Dakshini and Sabina 1981; Inderjit 1993; Rice 1995). It also occurs in North Africa, Afghanistan, and Pakistan (Nasir and Ali 1972; Oliver 1885). In India, it occurs both in cultivated and uncultivated areas. It causes considerable damage to winter and summer season crops. The control measures through conventional methods such as deep plowing, burning of aboveground parts, and herbicides are found to be unsuccessful. This rapidly spreading perennial weed apparently cannot be used for forage because of its disagreeable bitter taste (Anonymous 1976). Allelopathy has been reported as a probable cause of P. lanceolata interference (Inderjit and Dakshini 1990, 1992b, 1994a, 1994b, 1996a, 1996b; Inderjit et al. 1996).

Field experiments were conducted for the control of perennial pepperweed with tillage and herbicides. Perennial pepperweed infests a wide range of soils and plant communities. These studies were conducted in native hay meadows, with wild-flooding irrigation and saline/alkaline soils. Such meadows are typical of livestock ranches throughout the Intermountain Area. Tillage with periodic disking over a 2-yr period resulted in no permanent reduction in perennial pepperweed cover. Applications of 2,4-D or glyphosate eliminated perennial pepperweed seed production and greatly reduced top growth but had no permanent influence on cover of the weed by the second season following application. Applications of chlorsulfuron in the spring at flowering, in late summer after hay harvesting, or in the autumn, were effective in suppressing perennial pepperweed for 2 yr or more following application.

The genus Conium is comprised of two or three temperate species of biennial herbs with highly divided leaves and compound umbels of small white flowers. All parts of C. macula tum have long been recognized as being highly poisonous; it was the plant used to kill Socrates in BC 399 (Gledhill 1985; Holm et al. 1997; Hyam and Pankhurst 1995). Conium is a member of the Umbelli ferae or Apiaceae, the carrot family, which accommodates 300 genera and between 2,500 and 3,000 species.

Field studies were conducted for 3 yr to determine weed and potato response to preemergence (PRE) and postemergence (POST) applications of rimsulfuron, metribuzin, and rimsulfuron plus metribuzin. Preemergence applications of rimsulfuron at 27 g ai/ha and POST applications at 18 g/ha controlled barnyardgrass, redroot pigweed, and wild buckwheat. Common lambsquarters was controlled by PRE or POST applications of metribuzin or a tank mixture of 18 g/ha rimsulfuron plus 140 g ai/ha of metribuzin. ‘Russet Burbank’ potato was relatively tolerant to all rimsulfuron, metribuzin, and rimsulfuron plus metribuzin applications, and potato yield was not reduced compared to the hand-weeded control.

Wetland nightshade (WNS) (Solanum tampicense Dunal) is a member of the family Solanaceae. In some texts, WNS has been referred to as Solanum houstonii Dunal, but this homonym of the 1807 S. houstonii Martyn is illegitimate according to the International Code for Botanical Nomenclature (Wunderlin et al. 1993). WNS is thought to have originated in southern Mexico, the West Indies, Guatemala, Belize (Gentry and Standley 1974), Cuba, and El Salvador (Standley 1924). It was first reported from mainland Florida in a marsh south of Punta Gorda, Charlotte County, in 1983 (Wunderlin et al. 1993). Since that time, it has been detected in Florida in Highlands (1985), DeSoto (1991), Lee (1995), and Glades (1996) counties. Recently, WNS was rediscovered on Garden Key in the Dry Tortugas (110 km west of Key West) where it was growing in a moist seep area within the partially ruined Small Magazine in Fort Jefferson. This species has been included in the plant list of the Dry Tortugas National Park since 1974 (Reimus and Robertson 1995).

The grasses or Poaceae (Gramineae) comprise some 9,000 species grouped into about 650 taxa. Although not the largest, the family is ecologically the most dominant and economically the most important in the world (Heywood 1993).