Written by: Gloria R. Downing
Integrated Life Science Research Center | August 2016
Phytophthora infestans is a highly destructive fungus-like organism known to infect both tomato and potato plants. Although it is believed to have originated in Central America, this disease was responsible for the infamous Irish potato famine of the 1840’s and has been responsible for a number of epidemics on potatoes and tomatoes since it was first described in 1845 and 1847 respectively1
As stated by Mary Hausbeck of Michigan State University Extension in her article, “Late blight threatens Michigan tomatoes” blighting can be observed on all the above ground parts of the tomato plant. Additionally, the pathogen can also affect green and ripe tomato fruit. In potatoes, all parts of the plant are susceptible to infection, including the tubers2.
A number of in-house mycelial laboratory studies conducted by the Integrated Life Science Research Center® (ILSRC) on Phytophthora cinnamomi (Figure 1) and Phytophthora capsici (Figure 2) revealed moderate reduction of growth of the pathogens when grown in the presence of BioFlora’s GO Isolates®.
Although Phytophthora infestans has not been tested in the laboratory, the research conducted by the ILSRC
provides a good indication of the potential of GO Isolates on this genus.
Because P. infestans can survive on abandoned potatoes or tomatoes in cull piles on soil, GO Isolates can be an ideal soil conditioner. Improving the condition of soil is essential if one is to reduce the incidence of disease in any field. The microbial diversity in GO Isolates works to restore balance to the soil’s microbial ecology. Although the pathogen is question may remain the soil, its effects on the plant may decrease as the plant becomes stronger through improved soil structure and restored microbial communities.
Pre-plant land preparation with BioFlora® products, in particular GO Isolates, the implementation of crop rotation and good management practices, and proper fertilization program can be critical in managing soil-borne pathogens. Careful disease monitoring may be necessary in order to adjust application rates and timing throughout the season for optimal results.
Additionally, spoon-feeding (applying multiple times during the season instead of all at the beginning), product may be most beneficial. Pre- and post-fruit foliar applications with GO Isolates may also provide additional protection to potato and tomato plants.
Great Famine. (2016). In Encyclopædia Britannica. Retrieved from https://www.bri- tannica.com/event/Great-Famine-Irish-history
Hausbeck, M. (2016, July 7). Late blight threatens Michigan tomatoes. Michigan State University Extension Department of Plant, Soil and Microbial Sciences. Retrieved from http://msue.anr.msu.edu/news/late_blight_threatens_michigan_tomatoes