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Title: Effect of sanitary measures on the survival of Phytophthora ramorum in soil

Author: Aveskamp, M.M.; Van Baal, P.J.M.; De Gruyter, J.

Date: 2006

Source: In: Frankel, Susan J.; Shea, Patrick J.; and Haverty, Michael I., tech. coords. Proceedings of the sudden oak death second science symposium: the state of our knowledge. Gen. Tech. Rep. PSW-GTR-196. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: 279-284

Station ID: GTR-PSW-196

Description: In May 2003, a Phytophthora ramorum infested garden in the surroundings of Nijmegen, the Netherlands, was cleared of infected Rhododendron shrubs by cutting the plants back at 30 cm. In an experiment the remaining parts of the Rhododendron plants were treated with thiophanate–methyl, glyphosate or untreated. In the same experiment, the effect of additional phytosanitary measures, removal of plant debris and humus or plant debris only, was tested. The re-growth and occurrence of new infections were monitored. Soil samples were taken monthly at 20 cm depth or at soil surface and tested for the presence of P. ramorum using a rhododendron-leaf baiting test, followed by a TaqMan® ITS-PCR. Two months after cutting back, development of new shoots was observed in all objects. A number of the new shoots were infected from the initial growth onwards by P. ramorum. These infections proved that the remaining parts of the stems were already infected. The different treatments had no influence on the percentage of infected shoots. The detection of P. ramorum in soil samples showed that the pathogen seems to be present more abundantly at 20 cm depth than at the soil surface. In the samples taken from the soil surface, P. ramorum was mainly found in samples from plots where both humus and plant debris were present. The recovery of P. ramorum in the samples taken from 20 cm depth was independent of the soil coverage. The results indicate that P. ramorum is capable of surviving in sandy soil for at least one year. Furthermore, in this experiment, cutting back Rhododendron shrubs at 30 cm was not sufficient for eradication.

Key Words: Phytophthora ramorum. Rhododendron, sanitary measures, survival, soil

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Aveskamp, M.M.; Van Baal, P.J.M.; De Gruyter, J.  2006.  Effect of sanitary measures on the survival of Phytophthora ramorum in soil  In: Frankel, Susan J.; Shea, Patrick J.; and Haverty, Michael I., tech. coords. Proceedings of the sudden oak death second science symposium: the state of our knowledge. Gen. Tech. Rep. PSW-GTR-196. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: 279-284.

US Forest Service - Research & Development
Last Modified:  May 13, 2008


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