Do environmental conditions affect the activity of XPo?
As with all biological control agents, environmental conditions will affect performance. Infection and growth of the bacteria occurs best when air temperatures are between 65 and 80 degrees. At temperatures above 85 degrees growth of the Xanthomonas bacteria slows dramatically, infection rates are very low and few injury symptoms are seen on the Poa annua . However, since the expression of the infection (impact of the vascular plugging) occurs best when the Poa annua is under stress, injury and death of Poa annua will occur more rapidly when temperatures are above 80 degrees. The best environmental conditions for optimum performance of XPo is to have infection occur at temperatures between 65 and 80 degrees when Poa annua is actively growing, followed by a period of higher temperatures(above 80) under which the stress from the xylem plugging will kill the plants.
