Bentley, Walter J.

Viveros, Mario

Undetermined

ScholarsArchive@OSU

Nutsa. Biology1. Pacific Mite (Tetranicus pacificus) in Almonds (Prunus amygdahts)Walter Bentley, Mario ViverosDave Goldhammer and Peggy Schrader1031 S. Mt Vernon Avenue, Bakersfield, CA 93307The effect of waterstressofalmonds on subsequent pacific miteoutbreaks was studied in 1991 and 1992inMcFarland, California. Thetrial orchard is a two Nonpareil andoneCarmel variety arrangement. It is irrigated with minisprinklers. Eightwater stress treatmentswere applied to48tree plots (6trees x 8 trees) replicated sixtimes. Thetreatments were based onwater cutoffof 52,46,39,32,25,18,11and 4 days prior toharvest of theNonpareil variety in 1989-1990-1991. Active spidermites were counted from 10to20leaves, sampledfrom a single Nonpareil and a single Carmel tree at the center of each plot.In 1991, readings were taken onApril 5, May 28, June 6, July 32, and August 21. Significant differences inmite densities were foundbased on the stress applied in 1990to the Nonpareils for the Mayand June readings. Mite densities on the Carmels were lower andsignificantly different on only June6. These differences were basedon stressapplied in 1990.In 1992, readings weretakenon April23 and May 19. Significant differences in spider mitedensities were found orbothdates for theNonpareil variety andonly on May 19 for the Carmel variety. These differences werebased on stress applied in 1991.PACIFIC MITE DENSITY IN ALMONDS BASED ON DEFICIT IRRIGATIONMCFARLAND, CA 1991ACnvmES PER LEAFDAYS WITHOUTWATER5-APR 28-MAY 6-JUN 31-JULNONPARIEL CARMEL NONPARIEL CARMEL NONPARIEL CARMEL NONPARIEL CARMEL53 1.47a 31a 6.15b 1.93a 11.12a 8.67d 0 046 .72a .18a 330ab 2.82a 16.58a 5.67d 0 039 1.50a .20a 34Mb .47a 8.07a 4.52bc 0 032 35a .08a 143a .43a 10.45a 135ab 0 025 .02a .13a 1.90a 7.22a 5.65a .40a 0 018 .07a .07a 1.05a .93a 4.57a 33a 0 011 .07a .08a 1.37a .13a 538a .62a 0 04 .15a .07a .48a .03a 3.17a .23a 0 0PACIFIC MITE DENSITY IN ALMONDSBASED ON DEFICIT IRRIGATIONDAYS WITHOUTWATER4/23/92 5/19/92NONPARIEL CARMEL NONPARIEL CARMEL53 111b 1.4a 13.2a 35.7b46 6.9ab 0.2a 811b 10.1a39 12a 0.7a 18.3ab 16.0a32 33a 0.8a 10.0a 25.0a25 0.4a 03a 6.0a 6.1a18 13a 03a 4.1a 33a11 1.6a 0.0a 4..4a 6.1a4 0.7a 0.0a 63a 2.4a95

Biology : Pacific mite (Tetranicus pacificus) in almonds (Prunus amygdahts)

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Biology : Pacific mite (Tetranicus pacificus) in almonds (Prunus amygdahts)

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