This document discusses methods for isolating the plant pathogenic oomycete Phytophthora from different plant substrates. It describes using the "swipe" method which involves washing infected plant leaves or fruit from the field in fresh water, placing them in a humid chamber with the underside facing up, incubating for one day at 18 degrees Celsius, and then swiping the leaf underside to transfer the pathogen to culture media for isolation and identification. Major crops in Western North Carolina that are affected by Phytophthora include vegetables, Christmas trees, burley tobacco, and ornamentals.

1. Methods for Isolating
Phytophthora
from Different Substrates
Kelly Ivors
Dept. of Plant Pathology
North Carolina State University
Fletcher, NC

2. Asst. Professor Extension Specialist
MOUNTAIN HORT. CROPS RESEARCH EXT. CENTER
(WESTERN) Fletcher, NC
vegetables, Christmas trees, burley tobacco, ornamentals

3. Major crops in Western NC
Phytophthora spp.
P. nicotianae
P. capsici
P. infestans,

4. Isolating from foliage, stems and fruit
using the ‘swipe’ method

5. Close up of underside of infected leaf
(P. infestans)