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Moisture loss from bare-root plants during postharvest handling and storage can have a significant impact on plant survival and growth during establishment. Three film-forming antitranspirants and hot wax were applied to bare-root roses (Rosa) packaged after harvesting from the field and before 13 weeks of –2C storage to determine effects on vegetative growth and flowering. Subsequently, during 15 days under simulated display conditions (22 to 32C), plants treated with hot wax resumed growth at the fastest rate compared to control or antitranspirant treatments. Hot-wax-treated plants remained at an advanced phenological stage compared to the other plants for 2 weeks following transplanting in the field. For the remaining 10 weeks of the experiment, vegetative growth and flowering development were similar for all treatments. More than 60% of the plants treated with hot wax developed moderate to severe cane damage and plant dieback. Less than 20% of the antitranspirant-treated plants were damaged. A laboratory experiment confirmed that hot wax treatment was most effective; it reduced weight loss from stem sections by 85% relative to the control. The other antitranspirants reduced weight loss by 27%.

Two field evaluations were conducted concurrently, one with acaricides registered for use on field-grown rose plants at the time of the test and another with experimental materials. Avid was included in the latter for comparison. Treatment design and procedure for both experiments was a RCB with 6 replications. Each plot was a single row of roses 25 ft in length with a 5 ft buffer between plots in the row. Treatments were applied with a CO2 backpack sprayer at 30 psi with a TJ 8002 flat fan nozzle. Water was used at the rate equivalent to 100 gpa. Sampling consisted of twenty leaves per plot taken at weekly intervals, transported to the lab, brushed onto glass plates, and counted in concentric fashion using a template. Data are the mean of replicates, and represent the spider mites counted on one-sixth of the plate. Registered acaricides were applied in the first experiment 14 May under clear skies with temperature 25°C and wind velocity less than 5 mph. Experimental acaricides were applied in the second experiment 15 May under identical weather conditions.

No abstract

Acaricides were compared for efficacy in reducing numbers of mites and mite eggs on field roses. Plots were sampled on 1 Jun, 3 days prior to treatment; pretreatment counts did not significantly differ. Treatments were applied with a CO2 backpack sprayer at 100 psi with hollow cone nozzles. The Avid treatment at 400 gpa was applied with a Solo knapsack sprayer at 32 psi. Treatment design was a RCB with 8 replications. Each plot was 20 ft of row of two adjacent rows (42 inch row spacing) with a 5 ft buffer between plots in the row. Plots were bordered by untreated rows of roses. Twenty leaves per plot were taken at weekly intervals, transported to the lab, brushed onto glass plates, and counted in concentric fashion using a template. Data are the mean of replicates, and represent the mites counted on one-sixth of the plate. Data were (x + 1) transformed to establish homogeneity of variance. Means shown were obtained by back-transforming the data. No phytotoxicity was observed.