Evaluation of Floral Cuts on Eriophyid Mite Retention on Knock Out and Multiflora Rose Cuttings

Abstract

Current eriophyid mite quantification techniques require transportation of the Rosa spp. cuttings to the laboratory. It is thought that the change in xylem hydraulic conductance within the cut cane could trigger the mites to abandon their host, owing to the changes to the microenvironments that these mites are inhabiting. An experiment was conducted to determine the necessity of floral cuts (reducing stem embolisms by an additional cut underwater) for the retention of eriophyid mites during transit. Four groups of plants (rose rosette virus (RRV)-free Knock Out roses, RRV-infected Knock Out roses, RRV-free multiflora roses, and RRV-infected multiflora roses) were evaluated at different time intervals (0.5, 2, 4, 8, 24, 48, 72, and 96 h postharvest) to assess mite populations on each plant (number of mites per gram of tissue). Cut type (floral or dry cut) and rose species were found not to have a significant effect on the number of mites per gram of tissue found, indicating that floral cuts are not needed for accurately estimating eriophyid mite populations. Rose cuttings infected with RRV were found to have an average of 46 times more mites per gram in comparison with RRV-free cuttings.

Evaluation of Rosa Species Accessions for Resistance to Eriophyid Mites1

“…Some plant replicates only had RRD symptomatic tissue left to sample whereas other plants of the same species were asymptomatic. RRD symptomatic tissue has been reported to support a 14-fold increase of eriophyid mites on RRD symptomatic foliage of R. multiflora (Amrine 1996) and 43-fold increase on RRD symptomatic foliage of Knock Out roses (Solo et al 2019). It is not known if increases in mite populations would be similar for all Rosa species.…”