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The effect of pesticides on development of Beauveria bassiana (Balsamo) was examined both in liquid culture and in the field. The commonly recommended lateblight fungicides and insecticides inhibited growth of B. bassiana . The experimental fungicide CGA48988 and the insecticide permethrin showed the least inhibition of the fungus. Field experiments with the Colorado potato beetle, Leptinotarsa decemlineata (Say), supported laboratory findings.

The adult cereal leaf beetle population was studied in an 1842-acre area in Kalamazoo County, Michigan from 1970-74. Adults were found to survive winter in highest densities at the edge of the woodlots. Other habitats include sparse woods, fence rows, dense woods, and croplands (in order of “preference”). Emergence from overwintering is temperature-dependent and, although cumulative emergence is quite regular on a degree- day scale, differences occur between years. Following emergence, the adult beetle population moves among wild grasses and grain fields as it decreases rapidly clue to mortality. The density within a field depends on the size of the regional population and the stage of development of the crop during this period of mobility. Generally early-planted winter grains and late-planted spring grains maintain lower populations than normal plantings of each. The cereal leaf beetle population in the study area declined between 1970 and 1974 and several factors were investigated as possible causes. This decline was apparently not caused by spring mortality rates, planting dates, or relative acreages of crops, however a shift of the majority of the population from oats to wheat was associated with the declining densities and may be a factor in population regulation.

Since the colorado potato beetle (CPB), Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), was first recognized as a pest of potatoes (Edgerton 1861) it has had a profound effect. on the potato crop and on all persons engaged in agricultural production and research. This insect resulted in the first large-scale use of insecticides on an agricultural crop, and this successful use quickly stimulated widespread applications to other crops. For over 80 yr the CPB was successfully controlled by insecticides, influencing generations of agriculturalists to depend upon this unilateral approach for managing this pest and others.

Generations of entomologists have learned and taught that the Colorado potato beetle, Leptinotarsa decemlineata (Say), originally lived on the eastern slopes of the Rocky Mountains and fed on buffalo bur (or sand bur), Solanum rostratum Dunal. As the story goes, when the settlers moved west and planted the potato, Solanum tuberosum, in the foothills of these mountains, the beetle adapted to this new host, subsequently moving east from one potato patch to another. This account, which has been presented in most textbooks on economic entomology (Sanderson 1921, Metcalf and Flint 1928, Davidson and Lyon 1979), had its origins with Walsh (1865). Riley (1869) accepted the account of Walsh (1865), and it has been accepted since.