Grove said when growers plant new orchards they should avoid poorly drained sites. The choice of rootstock is important, as some rootstocks are more susceptible than others. Malling 9 is resistant, M.7 and M.111 are moderately resistant, Mark may be susceptible, and M.26, M.104, and M.106 are susceptible. Grove noted that M.106 is also highly susceptible to fireblight. Grove cautioned growers against overwatering, which gives the zoospores more opportunity to swim up to the roots and infect the trees.
Chemical controls are available as a protective measure.
Grove said if the trees are on a susceptible rootstock, he would recommend applications both spring and fall. Whereas Ridomil kills the fungus in the soil, Aliette is supposed to boost the tree's resistance. Another option is to treat the irrigation water before it reaches the orchard. This technique has been used to control sprinkler rot. Asked if overfertilized trees are more susceptible, Grove said he believes the opposite is true.