Environmental Entomology (1989) 18, 208-212

David H. Oi, John P. Sanderson, Roger R. Youngman and Martin M. Barnes (1989)
Developmental times of the pacific spider mite (Acari: Tetranychidae) on water-stressed almond trees
Environmental Entomology 18 (2), 208-212
Abstract: Greenhouse and field studies were conducted to assess the effects of water stress on almond leaf temperatures and Pacific spider mite, Tetranychus pacificus McGregor, developmental times. Egg-to-egg developmental times on water-stressed almond trees were 11 % faster than developmental times on nonstressed trees. Leaf surface temperatures on the stressed trees averaged 2.1°C higher than those on the nonstressed trees. Accumulated degree-hours for egg-to-egg development were not significantly different among the mites from the stress and nonstress treatments. Thus, the faster developmental times for the mites on the stressed trees were the result of the higher leaf surface temperatures. Mean daily leaf canopy temperatures from 4-yr-old, water-stressed almond trees were 2.0°C higher than control trees under field conditions. Leaf canopy temperature differences were significantly correlated with differences in predawn leaf water potentials between the water-stressed and control trees. Mature almond trees under an irrigation regime of 55% evapotranspiration (ET) had significantly higher afternoon leaf canopy temperatures than trees under regimes of 85 and 100% ET. Increased leaf, surface temperatures in water-stressed almond trees have the potential for accelerating increases in spider mite populations.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): David H. Oi

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tetranychus pacificus	Almond (Prunus dulcis)