Assertion: fungus | /r/CapableOf | attack resistant cultivars
Facets:
value: formerly
type: TEMPORAL
Source sentences:
text: Notable examples include: Certain hybrid potato cultivars are resistant to late blight (Phytophthora infestans); Soybean cultivars resistant to downy mildew (Peronospora manshurica) have been developed; In the United States, apple cultivars are available from the Indiana and the New York agricultural experiment stations that show high resistance or immunity to apple scab (Venturia inaequalis); In the cereal crops (oats, wheat, rye, barley), powdery mildew (Erysiphe graminis) can be controlled only by the use of resistant cultivars developed by plant breeders; Tomatoes can be grown in Fusarium-infested soils only if Fusarium-resistant cultivars are planted; Plant breeders are continuously developing wheat cultivars resistant to stem rust (Puccinia graminis tritici), but the fungus rapidly mutates, attacking the formerly resistant cultivars, requiring new resistant cultivars to be developed.