"Nursery transplants are a potential source of Phytophthora spp. introduction to the field; therefore, disease management practices that suppress Phytophthora spp., such as raised nursery beds, fumigation, and fungicides, should be used in transplant production. All isolates of P. cinnamomi recovered from Fraser fir were sensitive to metalaxyl. Although this fungicide remains a useful management tool, growers should use this fungicide only at labeled rates and recommended frequencies to ensure that the fungus remains sensitive to the compound."3 3 Benson, D.M., and Grand, L.F. 2000. Incidence of Phytophthora root rot of Fraser fir in North Carolina and sensitivity of Phytophthora cinnamomi to metalaxyl. Plant Dis. 84:661-664.
Example #7:
Benson and Grand (2000) recommend the use of management practices, beyond the use of metalaxyl, that aid in the suppression of Phytophthora in Fraser fir. In their work all Phytophthora cinnamomi isolates tested were, at a minimum, inhibited approximately 90% by metalaxyl. Though this work shows that currently resistance to metalaxyl has not developed in Fraser fir transplant production, the possibility of resistance occurring remains, so utilization of raised nursery beds and nursery bed fumigation should be considered to reduce selection pressure by multiple metalaxyl applications (Benson and Grand, 2000). |