title: Detection of resistance to fungicides, mating types and fitness of Phytophthora infestans in Hebei, China.
abstract: In vitro, isolates resistant to metalaxyl (M) and oxadixyl (O) of Phytophthora infestans were 11.2% of 62 isolates from potato and tomato in Hebei Province, mean resistance factor was 15,022 fold and 24,733 fold, respectively, no isolates resistant either to cymoxanil (C) or to dimethomorph (D) were detected. On the other hand, in vivo, isolates resistant to M and O were 29.0% and 32.7%, respectively, among 217 isolates from potato plants in Weichang and Chongli, Hebei, only one isolate resistant to M and O was found among 88 isolates from tomato plants in Xushui, Hebei. Among 73 isolates from potato in Weichang and Chongli, 6 isolates with A2 mating type were 8.2%, 3 A2 isolates resistant to metalaxyl and oxadixyl. 3 A2 isolates were 6.8% of 44 isolates from tomato in Xushui. Cross resistance in Phytophthora infestans was confirmed between M and O, but no cross resistance between C or D and M or O. The field isolates resistant to M and O were outstandingly fitter than sensitive or intermediate ones, mainly due to stronger sporulation capacity of the field isolates.
authors.affiliation: Plant Protection Institute, Hebei Academy of Agricultural & Forestry Sciences, Baoding 071000, Hebei, China. wenqiaow@heinfo.net
authors.forename: Wen-Qiao
authors.initials: WQ
authors.lastname: Wang
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Ma
authors.forename: Xiu-Ying
authors.initials: XY
authors.lastname: Han
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Zhang
authors.forename: Shu-Long
authors.initials: SL
authors.lastname: Chen
mesh_terms: D000081:Acetamides / Q000378:metabolism / Q000494:pharmacology; D000409:Alanine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D002681:China; D046508:Culture Techniques; D025141:Drug Resistance, Fungal; D005659:Fungicides, Industrial / Q000378:metabolism* / Q000494:pharmacology; D018551:Solanum lycopersicum / Q000382:microbiology; D009025:Morpholines / Q000494:pharmacology; D010080:Oxazoles / Q000378:metabolism / Q000494:pharmacology; D010838:Phytophthora / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology; D011198:Solanum tuberosum / Q000382:microbiology; D013172:Spores, Fungal / Q000187:drug effects / Q000254:growth & development
chemical_list: D000081:Acetamides; D005659:Fungicides, Industrial; D009025:Morpholines; D010080:Oxazoles; C028175:metalaxyl; C076154:dimethomorph; C025644:2-cyano-N-((ethylamino)carbonyl)-2-(methoxyimino)acetamide; C062370:oxadixyl; D000409:Alanine