Reference

Development of laboratory resistance to metalaxyl in Phytophthora citricola

Development of laboratory resistance to metalaxyl in Phytophthora citricola. Joseph, M. C.; Coffey, M. D. (Dep. Plant Pathol., Univ. California, Riverside, CA 92521, USA). Phytopathology, 74(12), 1411-14 (English) 1984. CODEN: PHYTAJ. ISSN: 0031-949X. DOCUMENT TYPE: Journal CA Section: 5 (Agrochemical Bioregulators) Isolates of P. citricola resistant to metalaxyl [57837-19-1] were obtained by treating zoospores with UV radiation or MNNG [70-25-7]. Both methods produced similar nos. of resistant mutant isolates from a total of ~8.9 ′ 107 zoospores. In vitro resistance was exhibited by 22 isolates that had growth rates indistinguishable from the parent isolate, and 5 of these isolates were also resistant in vivo. The stability of metalaxyl resistance was tested by using single-zoospore isolates of the resistant strains cultured for >20 generations in the absence of the fungicide. Three single-spore isolates were extremely stable, both in vitro and in vivo. In vivo resistance to metalaxyl was assocd. with cross-resistance to 4 acylanilide fungicides: benalaxyl [71626-11-4], RE 26745 [67932-71-2], cyprofuram [69581-33-5], and oxadixyl [77732-09-3]. However, these resistant isolates remained sensitive to the chem. unrelated fungicide fosetyl-Al [39148-24-8]. The competitive fitness in vivo of one resistant mutant isolate was high as only that isolate was recovered from stem lesions that developed on seedlings of Persea indica previously inoculated with zoospores in the ratio of 1:1 of the parent and mutant isolates.

Fungicides and their use

Fungicides and their use. Devoise-Lambert, Andre; Gisi, Ulrich (Sandoz-Patent-G.m.b.H., Fed. Rep. Ger.). Ger. Offen. DE 3301281 A1 28 Jul 1983, 29 pp. 58810-48-3 and 57966-95-7 which are cas registry numbers are also used here. (German). (Germany). CODEN: GWXXBX. CLASS: IC: A01N037-18; A01N047-34; A01N057-12; A01N043-00. APPLICATION: DE 83-3301281 17 Jan 1983. PRIORITY: GB 82-2125 26 Jan 1982; GB 82-31012 29 Oct 1982. DOCUMENT TYPE: Patent CA Section: 5 (Agrochemical Bioregulators) Mixts. of 150-300 g cymoxanil [57966-95-7] or 1-2 kg phosethyl-Al [39148-24-8]/ha with 150-300 g/ha of furalaxyl [57646-30-7], metalaxyl [57837-19-1], Galben [71626-11-4], Milfuram [58810-48-3], I; R3 = H [77732-09-3], I; R3 = 3-Cl [77731-22-7], I; R3 = 3-Br [77731-23-8], II; Y = cyclopropyl, R1 = 3-Cl, R2 = H [69581-33-5], and II; Y = CH2OMe, R1 = 2-Me, R2 = 6-Me [67932-71-2] are synergistic fungicides. Thus, the synergistic factor in the control of Phytophthora infestans on greenhouse tomatoes was 16 for a 1:3 I (R3 = H)-cymoxanil mixt. .