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United States Department of Agriculture

Agricultural Research Service

Research Project: Development and Application of An Epidemiological Framework for Management of Phytophthora Ramorum on Rhododendron in Nursery Settings

Location: Horticultural Crops Research

2012 Annual Report


1a.Objectives (from AD-416):
1. Parameter estimation of transmission rates and dispersal kernels for foliar Phytophthora spp. on Rhododendron in nursery settings. 2. Development and validation of spatially-explicit epidemiological model for invasion within nurseries to screen potential management scenarios. 3. Evaluation of different management scenarios for control of P. ramorum in nursery settings.


1b.Approach (from AD-416):
Work will include controlled, replicated experiments for both Phytophthora species. We propose to use a combination of small-scale ‘challenge experiments’ with which to estimate transmission probabilities, percolation thresholds and incubation periods that are then used to parameterize models from which to predict efficient methods for control. The challenge experiments will be complemented by population experiments to test and modify the model predictions for invasion and disease control.


3.Progress Report:

A weather station was setup in Corvallis, Oregon, to monitor microclimatic conditions during infection. A similar weather station is currently being purchased for installation at the California research site in San Rafael. A large batch of Rhododendron plants has been purchased to conduct inoculation studies. Phytophthora isolates for inoculation have been characterized and the first inoculations have been conducted. Work at the National Ornamentals Research Site at Dominican University, California will be initiated in Fall or Winter of 2012. A generic epidemiological model has been developed using a lattice and SIR modeling approaches. This research was conducted in support of objective 2C of the parent project.


Last Modified: 4/19/2014
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