Getzin, L. W.

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EVALUATION OF SAMPLING TECHNIQUESFOR ESTIMATING PEA APHID POPULATIONS IN GREEN PEASL. W. GetzinWestern Washington Research and Extension Center Puyallup 98371Several procedures for sampling pea aphids on peas were comparedfor accuracy and efficiency. A method using the percentage of tipsinfested provided the most accurate and efficient means of estimatingaphid populations. The number of aphids per plant can be estimatedwith the linear regression equation, y = -0.99 + 0.24x, where y =aphids/plant and x = % infested tips. The r was 0.95 for the 1981 dataUsing a 100-tip sample size, the population was estimated within 40%of the actual populations in 27 of 28 cases. The tip method was moreaccurate than the sweep method, especially when aphid populations werein the low to moderate density range.STRAWBERRY SPIDER MITE CONTROL WITH PYRETHROID INSECTICIDESCraig CollinsAgricultural Consultant, Hillsboro, OR 97123Foliar Pyrethroid insecticide sprays were applied to Totum varietystrawberries on Sept. 13^981. S-3206 2.4 ec at 0.05, O.Uand 0.2 lbsai/A; compared to Pay-Off^2.5 ec at 0.1 lb ai/A and Vendex^4L at 1.25 lbai/A. Plots were one row by 12.5 ft. long replicated four times in arandomized block design experiment. A C02 powered sprayer was used toapply the materials in 121 gal. water per acre. Biofilm wetting agentwas used at 16 oz./lOO gal. water. Pre and Post treatment samples ofstrawberry spider mite (Tetranychus turkestani Ugarov and Nikolski)were taken by randomly picking three individual leaves per plot.Treatments Rate lbai/AS-3206 2.4ec 0.05S-3206 2.4ec 0.1S-3206*2.4ec 0.2Vendex^L 1.25Pay-Off^ 2.5ec 0.1Check*Average No. of mites per 3 leavesPre Count Post Count Post Count Post Count3 day 10 day 22 day15.0 28.7 53.54.2 27.7 42.53.0 3.2 3.520.0 12.2 29.528.5 45.7 65.0136.2 42.2 73.09/15/8187.0116.5110.5101.7136.7130.0

Evaluation of Sampling Techniques for Estimating Pea Aphid Populations in Green Peas

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Evaluation of Sampling Techniques for Estimating Pea Aphid Populations in Green Peas

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