Submitted to: Nursery and Landscape Association Journal
Publication Type: Popular Publication
Publication Acceptance Date: 1/15/2005
Publication Date: 2/5/2005
Citation: Hoitink, H.A., Taylor, N.J., Locke, J.C. 2005. Control of phytophthora and other major diseases of ericaccous plants. Nursery and Landscape Association Journal. Interpretive Summary:
Technical Abstract: Phytophthora diseases affect many nursery crops. Disease prevention during propagation including sanitation is important. Puddling and flooding should be avoided at all cost to reduce sporulation and spread of the pathogen. All cleaned surfaces should be washed with sanitizing agents such as Physan 20 or Greenshield. Propagating knives and other tools should be dipped into the sanitizing solution from time to time when harvesting cuttings. Always use fibrous peat in propagation media. Cuttings should be taken from plant parts free of soil. The most widely used Phytophthora-suppressive container media are those amended with tree barks and composted rice hulls. This effect is due to the improved aeration and drainage properties as compared to peat-sand container media. Percent air-filled pore space after saturation and drainage must be 25% or higher. Percolation rate must be greater than 0.5 inch per minute. Fungicide treatments often have short-term effects. Best procedure for chemical control is to alternate fungicides with different modes of action. Chipco, Aliette, Reliant and Subdue MAXX are examples of fungicides that are very effective when applied as drench treatments for control of Phytophthora root rots. Resistance of the host to these diseases is not a realistic control option at this time.