Browne G T, Viveros M A
USDA-ARS, Department of Plant Pathology, University of California, Davis 95616.
UC Cooperative Extension, 1031 S. Mt. Vernon, Bakersfield, CA 93307.
Plant Dis. 2005 Mar;89(3):241-249. doi: 10.1094/PD-89-0241.
Orchard experiments were conducted to evaluate chemical treatments for management of perennial cankers caused by Phytophthora cactorum and P. citricola on almond (Prunus dulcis) in the San Joaquin Valley of California. Single preventive foliar sprays with phosphonate were tested by wounding and inoculating tree trunks and branches with either pathogen at time intervals from 15 days to 5 months after spraying. One to 3 months after inoculation, resulting cankers were measured. Preventive foliar sprays with phosphonate in the fall or spring suppressed development of cankers for up to 5 months after treatment; mean canker lengths on the trees sprayed with phosphonate before inoculation were 22 to 98% smaller than those on trees that received no phosphonate. In subsequent tests, preventive chemigation with phosphonate in spring or summer also inhibited canker expansion. A curative topical treatment with either fosetyl-Al or mefenoxam on cankers caused by P. cactorum or P. citricola reduced canker expansion by 36 to 88%. Neither preventive nor therapeutic treatments eradicated the pathogens from the diseased tissues, but disease ratings made 1 year after the treatments indicated extended disease suppression. Phosphonate and mefenoxam treatments can effectively manage almond scion cankers caused by P. cactorum or P. citricola.
在加利福尼亚州圣华金谷的果园中开展了试验，以评估化学处理方法对由恶疫霉和柑橘褐腐疫霉引起的杏仁（扁桃）多年生溃疡病的防治效果。在喷洒膦酸盐后15天至5个月的不同时间间隔，通过对树干和树枝进行创伤接种这两种病原菌，测试了单次预防性叶面喷施膦酸盐的效果。接种后1至3个月，测量产生的溃疡病斑。秋季或春季进行预防性叶面喷施膦酸盐可在处理后长达5个月抑制溃疡病发展；接种前喷施膦酸盐的树上溃疡病斑的平均长度比未喷施膦酸盐的树小22%至98%。在后续试验中，春季或夏季进行膦酸盐预防性滴灌施肥也抑制了溃疡病扩展。用乙膦铝或甲霜灵对恶疫霉或柑橘褐腐疫霉引起的溃疡病进行局部治疗，可使溃疡病扩展减少36%至88%。预防性和治疗性处理均未从患病组织中根除病原菌，但处理1年后的病情评级表明病害抑制期延长。膦酸盐和甲霜灵处理可有效防治由恶疫霉或柑橘褐腐疫霉引起的杏仁接穗溃疡病。
