U.N. Nanayakkara, M. Singh, Khalil I. Al-Mughrabi and R.D. Peters
Partner: Potatoes New Brunswick
Abstract: Pink rot caused by Phytophthora erythroseptica is found in most of potato-growing regions of the world.
The pathogen can survive for many years in soil as oospores which are disseminated from diseased potato tissues. Early detection
of the presence of the pathogen in soil is a valuable management tool that would enable growers to plan control strategies early.
However, soils are one of the most challenging environmental matrices to obtain microbial DNA that supports PCR. The developed
method combined traditional baiting technique with PCR methods to detect P. erythroseptica in infested soil samples. Two leaf stage
seedlings and cotyledon leaves of hairy nightshade (Solanum sarrachoides Sendt.) and bitter nightshade (Solanum dulcamara L.) were
successfully baited with P. erythroseptica using zoospore suspensions, artificially inoculated soils and naturally infested soils.
Phytophthora erythroseptica was detected in the bait tissue with PCR methods. PCR increased the precision of the bait test. However,
time was still required for the pathogen to infect and develop on the bait tissues. Although P. erythroseptica was detected in some
bait plants only after 2 days of incubation, 10 days of incubation produced consistent results across the replicates with hairy and
bitter nightshade cotyledon leaves and two leaf stage seedlings.