Progress 04/01/99 to 03/31/05
Outputs
Apple disease management research during the 5-yr project period focused on evaluation of experimental compounds for fungicide resistance and broad-spectrum fungal disease management and testing new materials for managing fire blight. Fungicide testing on apples included 52 tests of 490 treatments. Alternating Scala (pyrimethanil) with the strobilurin, Flint, gave good scab and mildew control. Flint performed better than the sterol-inhibiting fungicide Nova as a mixing partner with mancozeb for scab control suggesting the onset of resistance to the sterol-inhibiting fungicides in the scab fungus in the Winchester area. Pristine, a mixture of pyraclostrobin and boscalid from two chemical classes, gave excellent control of scab, Brooks spot, flyspeck and fruit rots and good control of sooty blotch, and mildew. Two developments indicate potential for improved control of postharvest rot problems: Pristine, applied in the orchard in the late cover sprays, gave excellent
control of postharvest bitter rot, Botryosphaeria, Phomopsis and Monilinia rots and Penicillium blue mold. Fludioxonil (Scholar) applied as a postharvest dip treatment, gave unexpected control of latent bitter rot as well as control of blue mold. Eleven fire blight tests of 104 treatments on apple involved several management approaches including a plant growth regulator (PGR), antibiotics, coppers and several biocontrol agents. Over a 2-yr period, the PGR prohexadione-Ca (Apogee) gave 85 percent suppression of shoot blight strikes when applied at petal fall on king bloom in nine tests in commercial orchards. Hail injury, in the 3-wk period following bloom, was a factor in secondary infection in all of these tests. Gentamicin, Cuprofix and other copper formulations, Dithane + copper, and Famoxate gave significant suppression of blossom blight; several biocontrol agents, including Brotomax, BlightBan and Serenade were more variable and less effective in one or more tests. Seven
fungicide tests on peach and nectarine involving 78 treatments yielded brown rot, scab and leaf curl management data. Pristine and a mixture of Elite + Flint gave excellent brown rot control, comparable to Indar. Experimental V10116 gave excellent scab control, and USF2010 was also effective. Because the supply of active chemical classes of fungicides is limited and development of resistance to many of them is likely, a top priority of this revised project will be further testing of new reduced-risk chemistries and integration of these with economical cultural management practices to offset development of resistance among the 10-15 diseases that are an ongoing threat to quality apple production in Virginia and the mid-Atlantic region.
Impacts
Ongoing fungicide evaluations are essential to tree fruit disease management in view of the development of resistance to current materials and potential loss of older, useful materials through withdrawal of registration. For the first time, resistance to the sterol-inhibiting fungicides has been found in the apple scab fungus in the Winchester area. The heavy fire blight infection years in Virginia in 2001-02 and heavy wet weather fungal disease pressure in 2003-04 reiterate the erratic and unexpected demands on the fruit industry and emphasize the need for ongoing testing of new materials and novel approaches for economical, environmentally sensitive tree fruit disease management.
Publications
- Janisiewicz W., D. Peterson, K. Yoder and S. Miller. 2005. Experimental bin drenching system for testing biocontrol agents and chemicals for control of postharvest decay of apples. Plant Disease. 89:487-490. URL: http://www.apsnet.org/pd/SubscriberContent/2005/PD-89-0487.pdf.
- Byers, R. E., D. H. Carbaugh, L. D. Combs, and K. S. Yoder. 2005. Influence of Apogee, Ethephon, Adjuvants, Cations, and Water Source on Apple Tree Growth Suppression and Return Bloom. PGRSA. (In press).
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2005. Control of latent bitter rot and storage blue mold by Scholar on Fuji apples, 2003-04. F&N Tests 60:PF010.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2005. Effect of fungicide schedules and mixtures on postharvest rot development on Stayman, Idared, and Ginger Gold apples, 2003-04. F&N Tests 60:PF011.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2005. Late season disease and storage rot control on Red Delicious, Golden Delicious and Rome apples, 2003-04. F&N Tests 60:PF009.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2005. Broad spectrum disease management by organic production and home fruit fungicides on Ginger Gold apple, 2004. F&N Tests 60:PF014.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., S. W. Kilmer. and S. Cochran. 2005. Broad spectrum disease control on Redhaven peach and Redgold nectarine, 2004. F&N Tests 60:STF014.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2005. Fireblight control on Golden Delicious and Rome Beauty apple bloom, 2004. F&N Tests 60:PF017.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2005. Broad spectrum disease control by mixed fungicide schedules on Stayman, Idared, and Granny Smith apples, 2004. F&N Tests 60:PF015.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2005. Evaluation of mildew control by Bupirimate on Jonagold apple, 2004. F&N Tests 60:PF016.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2005. Evaluation of Difenoconazole for summer disease control on Red Delicious apple, 2004. F&N Tests 60:PF012.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2005. Season-long disease control by experimental fungicides on three apple cultivars, 2004. F&N Tests 60:PF013.
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Progress 10/01/03 to 09/30/04
Outputs
Apple disease management research in 2004 focused on evaluation of experimental compounds for broad-spectrum fungal disease control and testing new materials for managing fire blight. Fungicide testing on apples included 8 tests of 72 treatments. Alternating Scala (pyrimethanil) with Flint gave good scab and mildew control. The strobilurin Flint performed better than the sterol-inhibiting fungicide Nova as a mixing partner with mancozeb for scab control. This may be significant considering that in 2004 resistance to the sterol-inhibiting fungicides has been found in the scab fungus for the first time in the Winchester area. The experimental fungicide Pristine, a mixture of pyraclostrobin and boscalid from two chemical classes, gave excellent control of scab, Brooks spot, and flyspeck and good control of sooty blotch mildew and fruit rots. The experimental sterol-inhibiting fungicide, difenoconazole, was surprisingly effective for control of sooty blotch, Brooks spot
and fly speck. Tanos (a mixture of famoxadone and cymoxanil) was comparable to captan for control of Brooks spot, sooty blotch, flyspeck and rots. Two developments indicate potential for improved control of postharvest rot problems: Pristine, applied in the orchard in the late cover sprays, gave excellent control of postharvest bitter, Botryosphaeria, Phomopsis and Monilinia rots and Penicillium blue mold. Fludioxonil (Scholar) applied as a postharvest dip treatment, gave unexpected control of latent bitter rot as well as control of blue mold. Two fire blight tests of 18 treatments on apple involved three antibiotics, coppers and a biocontrol agent. Several gentamicin formulations and Cuprofix gave significant suppression of blossom blight; Brotomax, the biocontrol agent was more variable and less effective. A fungicide test on peach and nectarine involving 13 treatments yielded brown rot, scab and leaf curl management data. Pristine, V10116, USF2010 and a mixture of Elite + Flint
gave excellent brown rot control, comparable to Indar. V10116 gave excellent scab control and USF2010 was also effective.
Impacts
Ongoing fungicide evaluations are essential to tree fruit disease management in view of the development of resistance to current materials and potential loss of older, useful materials through withdrawal of registration. For the first time, resistance to the sterol-inhibiting fungicides has been found in the apple scab fungus in the Winchester area. The heavy fire blight infection years in Virginia in 2001-02 and heavy wet weather disease pressure in 2003-04 reiterate the erratic and unexpected demands on the fruit industry and emphasize the need for ongoing testing of new materials and novel approaches for economical, environmentally sensitive tree fruit disease management.
Publications
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2004. Effectiveness of delayed early season application of fungicides on three apple cultivars, 2003. F&N Tests 59:PF029.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2004. Evaluation of fungicide schedules and mixtures for broad spectrum disease management on Stayman, Idared, and Ginger Gold apples, 2003. F&N Tests 59:PF028.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2004. Evaluation of fire blight blossom treatments on Golden Delicious and Rome Beauty apples, 2003. F&N Tests 59:PF030.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2004. Evaluation of concentrate applications of experimental fungicides on Golden Delicious apple, 2003. F&N Tests 59:PF027.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2004. Evaluation of fungicides for road spectrum disease control on Loring peach and Redgold nectarine, 2003. F&N Tests 59:STF020.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2004. Effectiveness of Scholar as a post-harvest brown rot treatment on peach and nectarine, 2003. F&N Tests 59:STF021.
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Progress 10/01/02 to 09/30/03
Outputs
Apple disease management research in 2003 focused on evaluation of experimental compounds for broad-spectrum fungal disease control and testing new materials for managing fire blight. Fungicide testing on apples included 7 tests of 71 treatments. The experimental fungicide Pristine, a mixture of pyraclostrobin and boscalid from two chemical classes, gave excellent control of scab, Brooks spot, sooty blotch, and flyspeck and good control of mildew and fruit rots. Experimental fungicide V10116, gave excellent control of scab, and good mildew control but was weak on Brooks spot, sooty blotch, and flyspeck and its mixture with Induce russetted Golden Delicious fruit. Alternating Scala (pyrimethanil) with Flint gave good scab and mildew control. Mixtures and alternating schedules involving KP481 (a mixture of famoxadone and cymoxanil) were only fair for scab control under heavy pressure but gave good control of Brooks spot, sooty blotch, flyspeck and rots. Cuprofix, a
copper formulation registered to include two summer applications on apples, gave good control of Brooks spot, and rots and suppression of sooty blotch and flyspeck. Applied in mid-summer, Cuprofix caused some phytotoxic responses on leaves and fruit but still might find some applicability on apples produced for the processing market where fruit finish is not as much of a concern. A fire blight test of 11 treatments on apple involved two antibiotics and three biocontrol agents (Serenade, QRD 141, and Brotomax). The three biocontrol agents gave significant suppression of blossom blight; gentamycin was more variable and less effective. A fungicide test on peach and nectarine involved 14 treatments under heavy leaf curl, brown rot and scab pressure. Pristine, V10116, USF2010 and a mixture of Elite + Flint gave excellent brown rot control, comparable to Indar. Elite + Flint and provided V10116 excellent scab control; Scala was ineffective on peach scab. A bud swell application of Ziram for
leaf curl control helped to suppress peach scab a month later.
Impacts
Ongoing fungicide evaluations are essential to tree fruit disease management in view of the development of resistance to current materials and potential loss of older, useful materials through withdrawal of registration. The heavy fire blight infection years in Virginia in 2001-02 and heavy wet weather disease pressure in 2003 reiterate the erratic and unexpected demands on the fruit industry and emphasize the need for ongoing testing of new materials and novel approaches for economical, environmentally sensitive tree fruit disease management.
Publications
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2003. Comparison of fungicides for broad spectrum disease control on Redhaven peach, 2002. F&N Tests 58:STF001.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2003. Test of an experimental fungicide and Cuprofix for disease control and fruit finish on three apple cultivars, 2002. 2 p. F&N Tests 57:PF027.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2003. Evaluation of experimental fungicides for broad-spectrum disease control on Stayman, Idared, and Granny Smith apples, 2002. F&N Tests 57:PF026.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2003. Fire blight blossom treatments on Golden Delicious and Rome Beauty apples, 2002. 1 p. F&N Tests 58:PF025.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2003. Full season evaluation of concentrate applications of registered fungicides on Golden Delicious apple, 2002. F&N Tests 58:PF028.
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Progress 10/01/01 to 09/30/02
Outputs
Apple disease management research in 2002 focused on testing novel methods for managing fire blight and evaluation of experimental compounds for broad-spectrum fungal disease control. Fire blight studies on apple involved two tests of 19 treatments and 19 demonstration/test plots in commercial orchards. Starner (S-0208) gave strong suppression of blossom blight in a strong, inoculated test. Starner and Serenade (QRD 137) served as mixing partners for reducing potential for resistance to streptomycin but neither added much blossom blight suppression compared to streptomycin alone. Over a 2-yr period, the plant growth regulator prohexadione-Ca (Apogee) has given 85 percent suppression of shoot blight strikes when applied at petal fall on king bloom in nine tests in commercial orchards. Hail injury, in the 3-wk period following bloom, was a factor in secondary infection in all of these tests. Fungicide testing on apples included 6 tests of 66 treatments. The experimental
fungicide BAS 516, a mixture of compounds from two chemical classes, gave excellent control of scab, mildew, Brooks spot, sooty blotch, and flyspeck. Cuprofix, a copper formulation recently registered to include two summer applications on apples, gave good suppression of Brooks spot, sooty blotch, flyspeck, and rots. Cuprofix, applied in mid-summer, caused some phytotoxic responses on leaves and fruit but still might find some applicability on apples produced for the processing market where fruit finish is not as much of a concern. Fungicide testing on peaches involved one test of 10 treatments on peaches.
Impacts
Ongoing fungicide evaluations are essential to tree fruit disease management in view of the development of resistance to current materials and potential loss of older, useful materials through withdrawal of registration. The heavy fire blight infection year in Virginia in 2002 reiterates the need for ongoing testing of new materials and novel approaches such as the use of the PGR, Apogee for suppression of this devastating disease.
Publications
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2002. Evaluation of fungicide schedules for brown rot control on peach and nectarine, 2001. F&N Tests 57:STF23.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2002. Evaluation of fungicide schedules for leaf curl and scab control on peach and nectarine, 2001. F&N Tests 57:STF24.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2002. Evaluation of experimental fungicides and mixtures on Golden Delicious apple, 2001. F&N Tests 57:PF34.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2002. Registered fungicide schedules for broad spectrum disease control on Ginger Gold, Idared and Stayman apples, 2001. F&N Tests 57:PF35.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2002. Comparison of experimental and strobilurin fungicides on Redspur Delicious apple, 2001. F&N Tests 57:PF33.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2002. Comparison of biocontrol, oil-related and conventional fungicides on Idared apple, 2001. F&N Tests 57:PF31.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2002. Comparison of bio-rational and potential organic production treatments on three apple cultivars, 2001. F&N Tests 57:PF32.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 2002. Scholar as a post-harvest fungicide dip treatment for Loring peaches, 2001. F&N Tests 57:STF21.
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Progress 10/01/00 to 09/30/01
Outputs
Apple disease management research in 2001 focused on testing novel methods for managing fire blight and evaluation of experimental compounds for broad-spectrum fungal disease control. Fire blight studies on apple involved one test of 11 treatments and 13 demonstration/test plots in commercial orchards. The plant growth regulator prohexadione-Ca (Apogee) gave 88-96 percent suppression of shoot blight strikes by suppressing shoot susceptibility when applied 24 days before natural infection due to hail injury. A second Apogee application in the affected orchards suppressed late season infection and potential overwintering cankers. Fungicide testing included 6 tests of 64 treatments on apples. Under relatively heavy disease pressure, the recently registered strobilurin fungicides, Sovran (kresoxim-methyl) and Flint (trifloxystrobin), showed potential for management of scab, mildew, sooty blotch, fly speck and apple fruit rots. The protectant fungicides captan, mancozeb,
metiram, and ziram worked well as mixing partners for these fungicides. The experimental compound BAS 516 gave good control of scab, mildew, and summer diseases. MANA 131 80WDG was a strong protectant fungicide active for control of sooty blotch, flyspeck and fruit rots. Fungicide testing on peaches and nectarines involved two tests of 17 treatments. Fludioxonil gave excellent control of brown rot and Rhizopus when applied to peaches as a post-harvest dip treatment.
Impacts
Ongoing fungicide evaluations are essential to tree fruit disease management in view of the development of resistance to current materials and potential loss of older, useful materials through withdrawal of registration.
Publications
- YODER, K. S., A. E. COCHRAN II, A. DEMARSAY, W. S. ROYSTON, JR., and S. W. KILMER. 2001. Evaluation of bloom treatments for fire blight suppression on Golden Delicious and Rome Beauty apples, 2000. F&N Tests 2001:PF36.
- YODER, K. S., R. E. BYERS, A. E. COCHRAN II, A. DEMARSAY, W. S. ROYSTON, JR., and S. W. KILMER.. 2001. Suppression of fire blight infection of apple shoots by Apogee, 2000. F&N Tests 2001:PF39.
- YODER, K. S., A. E. COCHRAN II, W. S. ROYSTON, and S. W. KILMER. 2001. Mixed fungicide schedules for broad spectrum disease management on Granny Smith, Idared and Stayman apples, 2000. F&N Tests 2001:PF40.
- YODER, K. S., A. E. COCHRAN II, W. S. ROYSTON, JR., and S. W. KILMER. 2001. Concentrate applications of experimental fungicides on Golden Delicious apple, 2000. F&N Tests 2001:PF41.
- YODER, K. S., A. E. COCHRAN II, W. S. ROYSTON, JR., and S. W. KILMER. 2001. Season-long disease management by experimental and registered fungicides on Idared apple, 2000. F&N Tests 2001:PF42.
- YODER, K. S., A. E. COCHRAN II, W. S. ROYSTON, JR., and S. W. KILMER. 2001. Carry-over of leaf curl in 2000, following full-season treatments on Redgold nectarine in 1999. F&N Tests 2001:STF10.
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Progress 10/01/99 to 09/30/00
Outputs
Apple disease management research in 2000 focused on testing novel methods for managing fire blight and evaluation of experimental compounds for broad-spectrum fungal disease control. Fire blight studies on apple involved three tests of 21 treatments. The plant growth regulator prohexadione-Ca (Apogee) suppressed fire blight incidence by reducing shoot susceptibility when apple shoots were challenge-inoculated 7, 14, and 21 days after application. Early suppression occurred before visual effects were evident, suggesting a physiological mode of action in addition to growth reduction. Fungicide testing included 9 tests of 71 treatments on apples. Under relatively heavy disease pressure, the recently registered strobilurin fungicides, Sovran (kresoxim-methyl) and Flint (trifloxystrobin), showed potential for management of scab, mildew, sooty blotch, fly speck and apple fruit rots. However, Flint and Sovran were commercially inadequate for control of quince rust in an
unusual epidemic year, and will require alternating or tank-mixing with sterol-inhibiting or dithiocarbamate fungicides in areas where quince rust is a threat. The experimental compound TM-41501 gave good control of scab, mildew, and quince rust. MANA 131 80WDG was more active than Captan 50W for control of sooty blotch, fly speck and fruit rots. A bacterial formulation, QRD 132, was equal to sulfur for powdery mildew control and had a surprising effect on quince rust. In a 3-yr study of the cumulative effect of powdery mildew incidence on apple yield, yield was significantly reduced on untreated trees which had 59% foliar mildew incidence compared to treated trees with 32% incidence. Two additional applications of sulfur at a cost of $104/ha were estimated to give a return of $2,394/ha over the 3-yr test period.
Impacts
Ongoing fungicide evaluations are essential to tree fruit disease management in view of the development of resistance to current materials and potential loss of older, useful materials through withdrawal of registration. Solid economic evidence for losses to powdery mildew provides a basis for management decisions.
Publications
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 2000. Evaluation of experimental fungicides and apogee for fungal disease effects on three apple cultivars, 1999. Fungic. Nematic. Tests Vol. 55:46-47.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 2000. Evaluation of strobilurin and other experimental fungicides on Stayman and Idared apples, 1999. Fungic. Nematic. Tests Vol. 55:44-45.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 2000. Sequential application schedules of experimental and registered fungicides for season-long apple disease control, 1999. Fungic. Nematic. Tests Vol. 55:43.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 2000. Suppression of fire blight infection of apple shoots by Apogee, 1999. Fungic. Nematic. Tests Vol. 55:38-39.
- Yoder, K. S. 2000. Effect of powdery mildew on apple yield and its economic management in Virginia. Plant Disease 84:1171-1176.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 2000. Concentrate applications of experimental fungicides on Golden Delicious apple, 1999. Fungic. Nematic. Tests Vol. 55:41-42.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 2000. Effects of copper, dithiocarbamate, and Vangard fungicides on Nittany apple, 1999. Fungic. Nematic. Tests Vol. 55:40.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 2000. Evaluation of experimental and registered fungicides for disease control on Redhaven peach and Redgold nectarine, 1999. Fungic. Nematic. Tests Vol. 55:67-68.
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Progress 10/01/98 to 09/30/99
Outputs
Apple disease management research in 1999 focused on evaluation of experimental compounds for broad-spectrum disease control and testing of novel methods for managing fire blight. Fungicide testing included 7 tests of 67 treatments on apples and one test of 14 treatments on stone fruits. Under relatively heavy disease pressure, recently registered fungicides Sovran (kresoxim-methyl) and Flint (trifloxystrobin) and experimental materials RH-7592 (fenbuconazole, and TM-41501 showed potential for management of scab, mildew, sooty blotch, fly speck and apple fruit rots. Vangard (cyprodinil) is now registered and provides a new mode of action for management of apple scab. In the third year of a study testing the cumulative effect of powdery mildew incidence on apple yield, yield was significantly reduced on untreated trees which had 59% foliar mildew incidence compared to treated trees with 32% incidence. Fire blight studies on apple involved three tests of 19 treatments.
The plant growth regulator prohexadione-Ca (Apogee), currently under registration review as reduced-risk material, provided a novel means of reducing fire blight incidence by suppressing shoot susceptibility when apple shoots were challenge-inoculated 10 and 20 days after application.
Impacts
Ongoing fungicide evaluations are essential to disease management in view of the development of resistance to current materials and potential loss of older, useful materials through withdrawal of registration. Findings regarding the economic impact of apple powdery mildew on yield helped to refine the economic thresholds for this disease, clarifying when and how frequently fungicides are need for its management.
Publications
- Pfeiffer, D. G., J. C. Killian and K. S. Yoder. 1999. Clarifying the roles of white apple leafhopper and potato leafhopper (Homoptera: Cicadellidae) in fire blight transmission in apple. J. Entomol. Sci. 34: 314-321.
- Byers, R. E. and K. S. Yoder. 1999. Prohexadione-calcium inhibits apple, but not peach, tree growth, but has little effect on apple fruit thinning or quality. HortScience 34:(14-18, in press).
- Yoder, K. S. 1999. Suppression of apple shoot susceptibility to fireblight by prohexadione-Ca (Apogee). Phytopathology 89:S88. (Abstr.)
- Yoder, K. S., S. S. Miller and R. E. Byers. 1999. Suppression of fireblight in apple shoots by prohexadione-calcium (BAS 125 W) following experimental and natural inoculation conditions. HortScience 34:(11-13, in press).
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 1999. Evaluation of concentrate applications of strobilurin fungicides on Golden Delicious apple, 1998. Fungic. Nematic. Tests Vol. 54:33.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 1999. Evaluation of copper and dithiocarbamate fungicides on Nittany apple, 1998. Fungic. Nematic. Tests Vol. 54:37.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 1999. Experimental fungicides and mixtures for full season apple disease management on three apple cultivars, 1998. Fungic. Nematic. Tests Vol. 54:34-35.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 1999. Protective treatments for fireblight management on Rome Beauty and Golden Delicious apple blossoms and shoots, 1998. Fungic. Nematic. Tests Vol. 54:40-41.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 1999. Suppression of fireblight infection of apple shoots by Apogee, 1998. Fungic. Nematic. Tests Vol. 54:38-39.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, and S. W. Kilmer. 1999. Brown rot, leaf curl and scab control by registered and experimental fungicides on Loring peach and Redgold nectarine, 1998 Fungic. Nematic. Tests Vol. 54:67-70.
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Progress 10/01/97 to 09/30/98
Outputs
Apple disease management research in 1998 focused on evaluation of experimental compounds for broad-spectrum disease control and testing of novel methods for managing fire blight. Fungicide testing included 7 tests of 61 treatments on apples and two tests of 19 treatments on stone fruits. Under relatively heavy disease pressure experimental materials RH-7592, Sovran (kresoxim-methyl, BAS 490F), Flint (CGA-279202) and TM-41501 showed potential for management of scab, mildew, sooty blotch, fly speck and apple fruit rots. Vangard (cyprodinil, CGA-219417) is now registered and provides a new mode of action for management of apple scab. In the third year of a study testing the cumulative effect of powdery mildew incidence on apple yield, yield was significantly reduced on untreated trees which had 59% foliar mildew incidence compared to treated trees with 32% incidence. Fire blight studies on apple involved three tests of 23 treatments. The plant growth regulator
prohexadione-Ca (Apogee, BAS 125 W) reduced shoot tip susceptibility and suppressed fire blight incidence when apple shoots were challenge-inoculated one, two, and three weeks after application and had a synergistic effect with streptomycin when BAS 125 W was applied one week before inoculation and followed by streptomycin the day of inoculation. Indar, Elite, Abound and experimental material Elevate (TM402) suppressed leaf curl when applied at bloom and gave excellent brown rot control as pre-harvest treatments on peaches and nectarines. Indar and Abound applied in post-bloom and mid-season sprays also gave good control of scab on peaches and nectarines. Ongoing fungicide evaluations are essential to disease management in view of the development of resistance to current materials and potential loss of older, useful materials through withdrawal of registration.
Impacts
(N/A)
Publications
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., S. W. Kilmer and J. E. Scott. 1998. Control of powdery mildew and scab by experimental fungicides on Golden Delicious apple, 1997. Fungic. Nematic. Tests Vol. 53:40.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., S. W. Kilmer and J. E. Scott. 1998. Two-year treatment regime effects on powdery mildew on Ginger Gold apple, 1997. Fungic. Nematic. Tests Vol. 53:45.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., S. W. Kilmer and J. E. Scott. 1998. Fungicide combinations for disease control on Stayman, Idared and Ginger Gold apples, 1997. Fungic. Nematic. Tests Vol. 53:41-42.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., S. W. Kilmer and J. E. Scott. 1998. Integrated fungicide schedules for suppression of powdery mildew and other diseases on Idared apple, 1997. Fungic. Nematic. Tests Vol. 53:43-44.
- Yoder, K. S., A. E. Cochran II, W. S. Royston, Jr., and S. W. Kilmer. 1998. Disease control by registered and experimental fungicides on Redhaven Peach and Redgold nectarine, 1997. Fungic. Nematic. Tests Vol. 53:71-72.
- Byers, R. E. and K. S. Yoder. 1998. Prohexadione-calcium inhibits apple, but not peach tree growth, but has little effect on apple fruitlet thinning or fruit quality. HortScience (in press).
- Killian , J. C., D. G. Pfeiffer and K. S. Yoder. 1998. Clarifying the roles of white apple leafhopper and potato leafhopper in fireblight transmission in apple. Journal of Entomological Science (in press).
- Yoder, K. S., S. S. Miller and R. E. Byers. 1998. Suppression of fireblight in apple shoots prohexadione-calcium (BAS 125 W) following experimental and natural inoculation conditions. (HortScience) (in press).
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Progress 10/01/96 to 09/30/97
Outputs
Research in 1997 focused on evaluation of experimental compounds for broad-spectrum disease control, incorporation of biofungicides into a practical usage pattern, and testing of novel methods for managing fire blight. Fungicide testing included 8 tests of 62 treatments on apples and two tests of 19 treatments on stone fruits. Experimental materials RH-141647, RH-7592, BAS 490F, and fluazinam showed potential for management of scab, sooty blotch, fly speck and apple fruit rots, and Vangard potential for apple scab management. The biofungicide AQ10 gave apple mildew suppression comparable to sulfur and was incorporated in a compatible schedule with dodine for scab management or myclobutanil for scab, rust and mildew management. In the second year of a study testing the effect of powdery mildew incidence on apple yield, yield was significantly reduced on untreated trees which had 72% mildew incidence compared to treated trees with 6-16% mildew incidence. Fire blight
studies on apple involved three tests of 26 treatments. The plant growth regulator BAS 125W suppressed fire blight incidence and canker length when apple shoots were challenge-inoculated two weeks after application and had a synergistic effect with streptomycin when BAS 125W was applied two weeks before inoculation and followed by streptomycin 8 days before inoculation. Indar, Elite and experimental materials Abound and TM402 gave excellent brown rot control as pre-harvest treatments on peaches and nectarines. Indar applied in mid-season also gave good control of scab on peaches and nectarines. Ongoing fungicide evaluations are essential to disease management in view of the development of resistance to current materials and loss of older useful materials through withdrawal of registration.
Impacts
(N/A)
Publications
- BYERS, R. E. and YODER, K. S. 1997. The effect of BAS-125W on apple tree growth, fruit quality, and fireblight suppression. HortScience 32:557. (Abstr.)
- YODER, K. S., COCHRAN II, A. E., ROYSTON, W. S., and KILMER, S. W. 1997. Control Of scab and summer diseases by experimental and standard fungicides on Starking Delicious apple, 1996. Fungic. Nematic. Tests Vol. 52: 40-41.
- YODER, K. S., COCHRAN II, A. E., ROYSTON, W. S., and KILMER, S. W. 1997. Cover spray fungicide suppression of summer diseases and fruit scab on three apple cultivars, 1996. Fungic. Nematic. Tests Vol. 52: 42-43.
- YODER, K. S., COCHRAN II, A. E., ROYSTON, W. S., and KILMER, S. W. 1997. Effects of Ziram, Thiram, and Captan on disease control and coloring of Red Delicious fruit, 1996. Fungic. Nematic. Tests Vol. 52: 44.
- YODER, K. S., COCHRAN II, A. E., ROYSTON, W. S., and KILMER, S. W. 1997. Combinations involving AQ10 Biofungicide and SI fungicides for early season disease control on Stayman, Idared and Granny Smith Apples, 1996. Fungic. Nematic. Tests Vol. 52: 45-46.
- YODER, K. S., COCHRAN II, A. E., ROYSTON, W. S., and KILMER, S. W. 1997. Effectiveness of experimental fungicides for disease control on Loring peach and Redgold nectarine, 1996. Fungic. Nematic. Tests Vol. 52: 63-64.
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Progress 10/01/95 to 09/30/96
Outputs
Research in 1996 focused on evaluation of experimental compounds for broad spectrum disease control and incorporation of biofungicides into a practical usage pattern. Fungicide testing included 6 tests of 53 treatments on apples and one test of 12 treatments on stone fruits. Experimental materials RH-141647, BAS 490F, GWN-4485 and fluazinam showed potential for management of scab, sooty blotch, fly speck and apple fruit rots, and CGA-219417 potential for scab management. The biofungicide AQ10 gave apple mildew suppression comparable to sulfur and was incorporated in a compatible schedule with dodine for scab management or with myclobutanil for scab, rust and mildew management. A 3-yr study was initiated to test the effect of powdery mildew incidence on apple yield. Aspire biofungicide was somewhat varible when tested as a postharvest dip treatment for Penicillum blue mold of apple. Indar and experimental material RH-128274 gave excellent brown rot control on peaches
and nectarines. Rovral was highly effective for brown rot on peaches but less effective on nectarines. Ongoing fungicide evaluations are essential to disease management in view of the developement of resistance to current materials and loss of older useful materials through withdrawal of registration.
Impacts
(N/A)
Publications
- YODER, K.. and COCHRAN II, A.. and ROYSTON, W.. and KILMER, S., 1996, Control ofPenicillium blue mold by Aspire biofungicide on Golden Delicious apples, 1995: Fungic. Nematic. Tests Vol. 51:39 YODER, K.. and COCHRAN II, A. and ROYSTON, W.. and KILMER, S.. and LAYMAN, J., 1996, Powdery mildew and summer disease cont. by exper. fungicides on three apple cultivars, 1995: Fungic. Nematic. Tests Vol. 51: 34-35.
- YODER, K. S.. and COCHRAN II, A.. and ROYSTON, W. S.. and KILMER, S. W.. and LAYMAN, J.
- C., 1996, Disease control by concentrate fungicide applications on Golden Delicious apple, 1995: Fungic. Nematic. Tests Vol. 51: 33 YODER, K.. and COCHRAN II, A.. and ROYSTON, W.. and KILMER, S.. and LAYMAN, J., 1996, Broad spectrum disease control by reg. and experimental fungicides on Loring peach, 1995: Fungic. Nematic. Tests Vol. 51: 58-59 YODER, K. S.. and COCHRAN II, A. E.. and ROYSTON, W. S.. and KILMER, S. W.. and LAYMAN, J.
- C., 1996, Suppression of apple powdery mildew by biofungicide AQ10, 1995. B & C Tests for Control of Plant Diseases 11:37
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Progress 01/01/93 to 09/30/94
Outputs
Fungicide and bactericide testing at Winchester included l3 tests of 84 treatments on apple and 2 tests of 21 treatments on peach. Under moderate disease pressure fluazinam gave good control of apple scab, sooty blotch and Brooks spot. CGA-219417 and RH-0611 gave good control of scab. On blossom-inoculated Rome apple test trees streptomycin continued to give good control of fireblight compared to copper materials and Aliette. Rovral gave excellent control of Alternaria leaf blotch when applied three times to Red Delicious in southwest Virginia. On peaches Elite, Rovral, Orbit, EXP l0566A and EXP l0370B gave good control of brown rot when applied 3 wk and l wk before harvest. In a l990 planting of 25 scab-resistant cultivars which have been treated occasionally with sulfur as the only fungicide, Dayton, Enterprise, Liberty, Williams' Pride and six numbered selections had less than 5% of the leaves infected with cedar-apple rust and 5% or less of the leaf area
affected by powdery mildew throughout the 3-yr period.
Impacts
(N/A)
Publications
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Progress 01/01/92 to 09/30/93
Outputs
Fungicide and bactericide testing at Winchester included ll tests of l05 treatments on apple and 2 tests of l5 treatments on peach and nectarine. On apples experimental compound RH-7592 gave good control of scab, mildew, sooty blotch and fly speck. Summer applications of Ziram reduced storage scald. Development of latent bitter rot infection was inhibited by post-harvest dip treatments of Aliette, Aliette + Rovral and Rovral + Captan. Mean fireblight canker length was reduced by post-inoculation treatment with streptomycin in combination with Regulaid or LI-700. On peach and nectarine RH-7592 2F gave good control of brown rot and Rhizopus rot. In a l990 planting of 25 scab-resistant cultivars which have not been treated with fungicides, Dayton, Enterprise (Coop 30) and two numbered selections from the Purdue collection have had l0% or less of the leaves infected with cedar-apple rust or powdery mildew in l992 and l993. Named cultivars or Coop selections which had
20% or more of the leaves infected with powdery mildew in l992 or l993 were Liberty, Williams Pride, Coop 25, Coop 27, Coop 29 and Coop 3l.
Impacts
(N/A)
Publications
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