azoxystrobin (Heritage; Syngenta Crop Protection, Greensboro, NC), kresoxim-methyl (Cygnus; BASF Corp., Research Triangle Park, NC), and trifloxystrobin (Compass; OHP, Inc., Mainland, PA) are considered METIs with activity on complex III in the mitochondria of
Raymond A. Cloyd, Cindy L. Galle, Stephen R. Keith and Kenneth E. Kemp
Stephanie L. Schupbach-Ningen, Janet C. Cole, James T. Cole and Kenneth E. Conway
The effectiveness of chlorothalonil, mancozeb, and trifloxystrobin applied alone or in rotations of two or three fungicides to control anthracnose symptoms caused by Colletotrichum gloeosporioides was evaluated on three cultivars of field- and container-grown wintercreeper euonymus (Euonymus fortunei) during the 2001 growing season. Studies were conducted at Stillwater, Okla.; Fayetteville, Ark.; and Park Hill, Okla. Rooted cuttings of wintercreeper euonymus `Emerald Gaiety', `Emerald 'n Gold', and `Emerald Surprise' were transplanted from 1-gal plastic containers into field soil at the Oklahoma State University Nursery Research Station and at the University of Arkansas Horticulture Farm on 10 May 2001. In a parallel study, recently transplanted rooted cuttings of the same cultivars in 1-gal pots containing substrate consisting of pine bark and sand were placed in a shadehouse under 30% shade at Stillwater and Fayetteville and 73% shade at Park Hill on 11 May 2001. `Emerald Gaiety' had fewer disease symptoms than `Emerald 'n Gold' or `Emerald Surprise' in the field and in containers at Stillwater and Fayetteville. At Fayetteville, mancozeb applied alone or in rotation with chlorothalonil or trifloxystrobin provided better anthracnose control than treatments without mancozeb, but no fungicide eliminated anthracnose symptoms. Application of fungicides in rotations that include mancozeb and use of resistant cultivars can help decrease anthracnose symptoms.
D.A. Rosenberger, J.R. Schupp, S.A. Hoying, L. Cheng and C.B. Watkins
Control of bitter pit in `Honeycrisp' apples (Malus ×domestica) from trees treated during the growing season with foliar sprays of trifloxystrobin fungicide and calcium was evaluated in four replicated trials over 2 years. All trials were in commercial orchards of `Honeycrisp' trees that were 3 to 6 years old. The effectiveness of combining boron with foliar applications of calcium chloride (CaCl2) was evaluated in two trials, and effectiveness of harpin protein, used either alone or in alternating sprays with CaCl2 was assessed in one trial. Trifloxystrobin applied twice during the 30 days before harvest reduced bitter pit incidence at harvest in one of the four trials, but the reduction was transitory, no longer being evident when fruit were re-evaluated after 63 days of cold storage. Harpin protein did not affect disorder incidence. Calcium sprays failed to control bitter pit in treatments where the total elemental calcium applied was less than 2.7 lb/acre (3.03 kg·ha–1) per year for tree canopies that were sprayed to drip using 100 gal/acre (935.4 L·ha–1) of spray solution. In the two trials where some treatments involved application of at least 2.9 lb/acre (3.25 kg·ha–1) of elemental calcium per season, the incidence of fruit with bitter pit at harvest was reduced by 76% to 90%. Effectiveness of calcium sprays for bitter pit control was not enhanced by superimposing trifloxystrobin, boron, or harpin protein treatments. Flesh firmness at harvest was lower in calcium-treated than in non-treated fruit, and fruit maturity was more advanced on trees receiving boron sprays than on trees receiving no boron. In one trial, where the first calcium application was made approximately 2 weeks after petal fall and 4 days prior to a fruit thinning spray, crop load of trees that received calcium sprays, measured as number of fruit per cm2 trunk cross-sectional area, was 38% greater than on trees that received no calcium sprays. CaCl2 provided better control of bitter pit in `Honeycrisp' than any of the other materials tested.
Oleg Daugovish, Hai Su and W. Douglas Gubler
plantings. The combination of captan with the premixtures of boscalid + pyraclostrobin or of cyprodinil + fludioxonil did not significantly reduce disease incidence compared with the single product treatment ( Fig. 1C ). Trifloxystrobin (Flint®; Bayer
M. Babadoost, P.S. McManus, S.N. Helland and M.L. Gleason
The effectiveness of a disease-warning system and efficacy of reduced-risk fungicides for management of sooty blotch (Peltaster fructicola, Leptodontium elatius, Geastrumia polystigmatis) and flyspeck (Schizothyrium pomi) (SBFS) of apple (Malus × domestica) were evaluated in Illinois, Iowa, and Wisconsin in 2001 and 2002. Warning system-timed applications of the second-cover fungicide spray occurred when 175 h of leaf wetness had accumulated; wetness data were derived either from a sensor placed beneath the canopy of apple trees (on-site) or according to remotely sensed estimates. In replicated experiments, using sensor measurements as inputs to the warning system saved one to three (mean 1.8) and zero to four (mean 2.3) fungicide sprays per season in 2001 and 2002, respectively. Because remotely estimated wetness hours accumulated more rapidly than did on-site measurements, the warning system using remotely sensed wetness data saved only zero to one (mean 0.3) and zero to two (mean 0.7) sprays per season in 2001 and 2002, respectively. SBFS incidence in the integrated pest management (IPM) plots did not differ significantly from that of conventional calendar-based fungicide sprays plots in 11 of 12 site-years. When on-site wetness measurements were used in demonstration trials at 14 cooperating commercial orchards in 2001 and 2002, the SBFS warning system saved one to six (mean 2.6) and two to seven (mean 3.1) sprays per season, respectively. Incidence of SBFS in IPM plots did not differ significantly from trees managed with cooperating growers' conventional fungicide schedules in 16 of 28 siteyears. The on-site warning system was more consistently successful in Illinois and Iowa than it was in Wisconsin in both replicated experiments and in cooperating commercial orchards. The reduced-risk fungicides kresoximmethyl and trifloxystrobin provided control of SBFS equal to conventional fungicides (benomyl or thiophanatemethyl) in all trials. Potassium bicarbonate controlled SBFS less effectively than either conventional fungicides on a calendar-based or disease-warning schedule, or treatments incorporating reduced-risk fungicides.
Cheryl R. Boyer, Janet C. Cole and Mark E. Payton
–methyl ( LaMondia, 2001a , b ; Ningen, 2003 ), copper hydroxide ( Cole et al., 2005 ; LaMondia, 2001a , b ), azoxystrobin ( Cole et al., 2005 ; LaMondia 2001a ), myclobutanil ( Cole et al., 2005 ), trifloxystrobin ( Cole et al., 2005 ; Schupbach–Ningen et al
chlorothalonil, mancozeb, and trifloxystrobin applied alone or in rotations of two or three fungicides to control anthracnose symptoms was tested using three varieties of winter-creeper euonymus ( Schupbach-Ningen et al. , p. 211 ). `Emerald Gaiety' had fewer
. Rosenberger et al. (p. 342) evaluated bitter pit control achieved with various formulations of calcium chloride and with several other products reputed to affect bitter pit development and/or stress responses in plants. Trifloxystrobin fungicide, harpin
Leo G. Albrigo and Ed W. Stover
Falls, WI)], a strobilurin fungicide pyraclostrobin [88 g/acre a.i. (Headline™; BASF, Research Triangle Park, NC)], and four tests included other strobilurins, trifloxystrobin [48 g/acre a.i. (Gem™; Bayer CropScience, Research Triangle Park, NC
G. Schnabel and C.H. Crisosto
Applications of the quinone outside inhibitor (QoI) fungicides azoxystrobin, kresoxim-methyl, trifloxystrobin, picoxystrobin, or pyraclostrobin can increase yield and quality of cereal crops, likely due to improved disease control ( Ammermann et al