|TWOSPOTTED SPIDER MITES|
|Effects of Spider Mite (Acari:
Tetranychidae) Injury on Essential Oil Metabolism in Peppermintą
JACK D. DEANGELIS, ANNA B. MARIN, RALPH E. BERRY, AND G. W. KRANTZ
Department of Entomology, Oregon State University, Corvallis, Oregon 97331
© Copyright 1983 Entomological Society of America
Environ. Entomol. 12: 522 - 527 (1983)
Studies were conducted to examine the effects of injury by the twospotted spider mite, Tetranychus urticae Koch, on metabolism of essential oil components (monoterpenes) in peppermint, Mentha piperita L. Mite injury increased the relative amounts of menthol and neomenthol and decreased the amount of pulegone in oil extracted from single leaves, thereby effecting more rapid oil ''maturation.'' We believe this resulted from accelerated enzymatic reduction of pulegone to the menthol isomers brought about by increased availability of soluble carbohydrate to oil - producing epidermal gland cells. Osmotic adjustment, utilizing soluble carbohydrate, in response to mite - induced leaf water stress, is the probable mechanism operating to increase carbohydrate levels. Reduction of pulegone to menthol and neomenthol requires reducing power in the form of NADPH and thus is dependent on the energy status of the gland cells in which monoterpene metabolism occurs. Increased supply of carbohydrate from surrounding water - stressed mesophyll cells may provide the additional energy needed for the acceleration of pulegone reduction to menthol isomers in mite - injured peppermint leaves.