SCHOENEWEISS, D.F. 1988. Low-temperature stress and cankers. Am. Nurseryman 168(9):69-75.
Every year, injury due to low temperatures occurs to some extent. Species planted north of their natural hardiness zones are most frequently damaged. A plant’s ability to withstand low winter temperatures begins to develop as the days of late fall shorten and dormancy sets in. Much, if not most, winter injury follows rapid, radical temperature drops to below-freezing levels following extended mild fall weather. To survive low midwinter temperatures, most hardy woody plants need to be exposed to temperatures at or below freezing for some time before they become fully acclimated. In many cases, the sensitivity of plant part to low temperatures limits the plant’s geographic or economic use.
BROWN, C.L. 1988. How the environment affects pesticides. Am Nurseryman 168(9):77-79.
Poor results with pesticides are sometimes caused by environmental factors. Sunlight, alkaline water and soil microorganisms destroy certain pesticides. Runoff, vapor drift and leaching may move pesticides away from target sites. Absorption is the binding of chemicals to soil particles. Absorption of a pesticide varies with the properties of the chemical. Volatilization occurs when solid or liquid changes into a gas. Some pesticides, when applied to soil, plants or water may convert into a gas and drift away. Runoff is the movement of chemicals in water over a sloping surface. It can carry pesticides mixed in water or bound to eroding soil. Leaching is the movement of chemicals in water through soil. Too much leaching can move a pesticide beyond a target site, reducing control of the pest and increasing the potential of injuring plants and animals. Degradation processes usually destroy pesticides. One of the most common chemical degradation processes in hydrolysis. Understanding the environmental processes that influence pesticide movement and degradation can enhance both the effectiveness and the safety of pesticides.
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