Cereal leaf beetle in 33.3% of fields in southern Alberta. Locally, adults spread to the exterior of fields during their overwinter. Larvae tend to stay on the outside of crop fields, but are also found in the center. Local populations are never homogenously distributed, hotspots and empty places occur in each field. "O. melanopus" consumes nearly all cereal crops, but has a strong affinity for oats, barley, and rye, and its favorite host is wheat. Alternatives are corn, sorghum, and sudangrass for adults, and wild oats, quackgrass, timothy, canary grass, reed canary grass, annual and perennial ryegrass, foxtail, orchard grass, wild rye, smooth
Cover crop recycle soil nitrogen already present. The catch crops take up surplus nitrogen remaining from fertilization of the previous crop, preventing it from being lost through leaching (Morgan et al. 1942), or gaseous denitrification or volatilization (Thorup-Kristensen et al. 2003). Catch crops are typically fast-growing annual cereal species adapted to scavenge available nitrogen efficiently from the soil (Ditsch and Alley 1991). The nitrogen tied up in catch crop biomass is released back into the soil once the catch crop is incorporated as a green manure or otherwise begins to decompose. An example of green manure use comes from Nigeria, where the