FISHER, SUSAN W. 1989. The evolution of insecticide resistance. American Nurseryman 169(6):107-111.
Contrary to popular belief, resistance is not a new phenomenon. The evolution of resistance precisely parallels the use of pesticides. Following World War II, the modern age of insectides was inaugurated. Insecticide applications intensified, and the number of compounds available for use as insecticides increased dramatically. The evolution of resistance kept pace. Not only are more insects today exhibiting resistance to one or more insecticides, but they are displaying many degrees of resistance. Because it is not possible to measure resistance in an absolute sense, resistant individuals must be compared to normal, susceptible individuals. A resistance factor of 10 times is thought to make control efforts useless.
HECHT-POINAR, E.I., L.R. COSTELLO and J.R. PARMETER, JR. 1989. Twig blight of oaks In California. California Agriculture 43(1):15-16.
A recently recognized disease called "twig blight" has become a serious problem on oaks in California. Coast live oak appears to be the principal host. At least two fungi have been implicated in twig blight infections: Cryptocline cinerescens and Discula quercina. Twig blight of landscape oak trees was reduced to an acceptable level by pruning plus treatment with a fungicide.
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