Progress 10/01/99 to 09/30/05
Outputs
Disease resistance and susceptibility of two 5-replicate, 26-cultivar plantings were evaluated at Winchester. Over the 10-year period of the project, prevailing local weather patterns and disease pressures resulted in excellent comparison of the 50+ cultivars. Wet weather facilitated strong comparison of cultivars to scab, rusts, Brooks spot, sooty blotch, flyspeck and fruit rots and years with drier weather facilitated evaluation for mildew susceptibility. In 2004, without fungicides, fruit from 10 scab-susceptible cultivars were nearly a total loss due to scab-cracking and subsequent rots but the 11 scab-resistant cultivars in the 1999 planting had no fruit loss from scab. Coop 29, NY 79507-72, NY 75413-30, NY 43334-35, and Dayton shows some resistance to scab and cedar-apple (CAR) and quince rust (QR). NY 65707-19 and 79507-49 are resistant to scab and CAR but are susceptible to quince rust; scab-resistant cultivars Scarlet OHara and CQR10T17 are very susceptible to
CAR. Ambrosia, Coop 39, Pinova, and Scarlet OHara are also susceptible to quince rust. Dayton, Hampshire, September Wonder Fuji, NY 65707-19, and NY 79507-49 are quite resistant to mildew. Cameo, NY 65707-19, NY 79507-72, Coop 39, Runkel, and Pink Lady showed susceptibility to Brooks spot. Over the 10-year course of the project, interesting results emerged regarding the effect of accumulated wetting hours (AWH) on presence of sooty blotch and flyspeck on test cultivars which ripened from mid-July to November. What might be mistakenly viewed as field resistance by a cultivar was actually an escape from the disease because there were not enough AWH for the earlier ripening cultivars that year. However, grouping the cultivars by ripening date and AWH at that date allowed a fair comparison of innate susceptibilities of cultivars ripening during similar weather conditions. For example, in 2004 the 250-hr AWH threshold for presence of the sooty blotch and flyspeck fungi on fruit was met in
mid-June, allowing early ripening cultivars Zestar and NJ109 to escape the appearance of these diseases on the fruit surface. NY 79507-72 (3 Sept), Coop 39, Corail, CQR10T17 (16 Sept), Scarlet O Hara (21 Sept) and NY 65707-19 (27 Sept) had fewer rots than others harvested about the same time. This was consistent for NY 79507-72 in 2001-03 and for Coop 39 in 2002-03. Considering equal weighting of ratings for early season and summer diseases throughout the evaluation period, Pristine, a scab-resistant, early ripening cultivar, ranked the highest (most resistant) in the 1995 planting and NY 79507-72, a scab-resistant cultivar ripening in early September, ranked highest in the 1999 planting. In some years severe foliar and fruit scab on the susceptible cultivars limited the value of the fruit quality data because diseases probably affected fruit drop, starch production, firmness, etc. This work was supported in part by Virginia Agricultural Council and the Virginia Apple Research
Program. We will continue some aspects of this project, including cooperative publication of cumulative results, through participation in the recently established NECC-1009 project.
Impacts
Diseases are important limiting factors for production of apples in different regions of the USA. Disease susceptibility assessment in successive years provides a baseline for expected performance in a typical year in the mid-Atlantic region and contributes to a solid database for the geographical area covered by this project. Advanced knowledge provided by this project about disease susceptibility and resistance of new cultivars helps to guide planting and disease management decisions in Virginia and the region, leading to a potential reduction in fungicide usage. Disease resistance is a particularly useful consideration in certified organic fruit production.
Publications
- Brown, M. W., S. S. Miller, and K. S. Yoder. 2005. Stink bug feeding preferences among apple cultivars. J. Amer. Pomol. Soc. (in press).
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Progress 10/01/03 to 09/30/04
Outputs
Disease resistance and susceptibility of two 5-replicate, 26 scion/rootstock plantings are being evaluated at Winchester, now focusing mostly on the cultivars in the 1999 planting. Wet weather facilitated strong comparison of cultivars to all the major apple diseases. Without fungicides, fruit from 10 scab-susceptible cultivars were nearly a total loss due to scab-cracking and subsequent rots but the 11 scab-resistant cultivars in the planting had no fruit loss from scab. Coop 29, NY 79507-72, NY 75413-30, NY 43334-35, and Dayton have some resistance to scab and cedar-apple (CAR) and quince rust (QR). NY 65707-19 and 79507-49 are resistant to scab and CAR but are susceptible to quince rust; scab-resistant cultivars Scarlet OHara and CQR10T17 are very susceptible to CAR. Ambrosia, Coop 39, Pinova, and Scarlet OHara are also susceptible to quince rust. Dayton, Hampshire, September Wonder Fuji, NY 65707-19, and NY 79507-49 are quite resistant to mildew. NY 65707-19, NY
79507-72, Coop 39, Runkel, and Pink Lady showed susceptibility to Brooks spot under relatively light disease pressure. A wet summer gave a good test of summer disease susceptibility, and grouping the cultivars by ripening date and accumulated wetting hours (CWH) at that date allowed a fair comparison of innate susceptibilities of cultivars ripening during similar weather conditions. The 250-CWH threshold for presence of the sooty blotch and flyspeck fungi on fruit was not met in mid-June, allowing early ripening cultivars Zestar and NJ109 to escape these diseases. NY 79507-72 (3 Sept), Coop 39, Corail, CQR10T17 (16 Sept), Scarlet O Hara (21 Sept) and NY 65707-19 (27 Sept) had fewer rots than others harvested about the same time. This was consistent for NY 79507-72 in 2001-03 and for Coop 39 in 2002-03. Hampshire and September Wonder Fuji did not have enough fruit to evaluate disease incidence in 2004. Severe foliar and fruit scab on the susceptible cultivars limited the value of the
2004 fruit quality data. Diseases probably affected fruit drop, starch production, firmness, etc. Hampshire has not had fruit at harvest the past three years.
Impacts
Disease susceptibility assessment in successive years provides a baseline for expected performance in a typical year in the region and contributes to a solid database for the geographical area covered by this project. Advanced knowledge provided by this project about disease susceptibility and resistance of new cultivars is helping to guide planting and disease management decisions in Virginia and the region, leading to a potential reduction in fungicide usage.
Publications
- No publications reported this period
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Progress 10/01/02 to 09/30/03
Outputs
Disease resistance and susceptibility of two 5-replicate, 26 scion/rootstock plantings are being evaluated at Winchester, this year focusing mostly on the cultivars in the 1999 planting. Wet weather facilitated strong comparison of cultivars to all the major apple diseases. Without fungicides, fruit from ten scab-susceptible cultivars were a total loss due to scab-cracking and subsequent rots, but the 11 scab-resistant cultivars (SRC) in the planting had no fruit loss from scab. Coop 29 and NY 79507-72, Dayton and NY 75413-30 have some resistance to scab and cedar-apple (CAR) and quince rusts. NY 65707-19 and 79507-49 are resistant to scab and CAR but are susceptible to quince rust while SRCs Scarlet OHara and CQR10T17 were the most heavily infected with CAR. Ambrosia, Chinook, Coop 39, Corail, and CQR12T50, and Cripps Pink (Pink Lady) are also CAR susceptible, comparable to Golden Delicious and York. Ambrosia, Hampshire, Jubilee Fuji, NY 65707-19, and NY 79507-49 are
quite resistant to mildew. The highest wetting hour (CWH) total in the past ten years gave a good test of summer disease susceptibility. Grouping the cultivars by ripening date and accumulated wetting hours allowed a fair comparison of innate susceptibilities of cultivars ripening during similar weather conditions. Because the 250-CWH threshold for presence of the sooty blotch and flyspeck fungi on fruit was met in late May, early ripening cultivars were more affected by these fungi than they were in previous years. Under moderate pressure, NY 65707-19, Coop 39, CQR12T50, NJ 109, Scarlet OHara and Zestar were quite susceptible to Brooks spot. NY 79507-72, NY 79507-49, Coop 39, CQR10T17 and Scarlet OHara had fewer rots than others harvested about the same time. This was consistent for NY 79507-72 in 2001 and 2002 and for Coop 39 in 2002. Severe russet on BC-8S-26-50 prevented growth of flyspeck. Severe foliar and fruit scab on the susceptible cultivars limits the value of the 2003
fruit quality data. Diseases probably affected fruit drop, starch production, fruit firmness, etc. This work is supported in part by Virginia Agricultural Council.
Impacts
Disease susceptibility assessment in successive years provides a baseline for expected performance in a typical year in the region and contributes to a solid database for the geographical area covered by this project. Advanced knowledge provided by this project about disease susceptibility and resistance of new cultivars is helping to guide planting and disease management decisions in Virginia and the region, leading to a potential reduction in fungicide usage.
Publications
- Yoder, K. S. 2003. Controlling diseases in home apple plantings in Virginia. Grandiflora 9:17-26.
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Progress 10/01/01 to 09/30/02
Outputs
Disease resistance and susceptibility of two 5-replicate, 26 scion/rootstock plantings are being evaluated at Winchester. This year we focused mostly on the cultivars in the 1999 planting. Weather was more favorable for mildew development than for scab, but wetting in June promoted development of summer diseases and late season scab. Coop 29, NY 65707-19, and NY 79507-72, appear to have resistance to scab and the rusts. NY 79507-49 is resistant to scab and cedar-apple (c-a) rust but is susceptible to quince rust. Hampshire, NJ90, Runkel and Zestar also appear to be resistant to c-a rust on foliage, comparable to McIntosh. Ambrosia, Hampshire, Jubilee Fuji, NY 65707-19, and Zestar demonstrated considerable resistance to mildew under relatively heavy pressure. As in 2000 and 2001, the scab-resistant cultivar CQR10T17 was the most heavily infected with c-a rust; Ambrosia, Chinook, Coop 39, CQR12T50, and Cripps Pink (Pink Lady) were also heavily infected with c-a rust,
comparable to Golden Delicious and York under this year's sustained pressure. Brooks spot infection was light this year, and only NY 65707-19 had significant infection. The cumulative wetting hour total provided good test conditions for summer diseases. Zestar apparently ripened early enough to escape sooty blotch and flyspeck. NY 65707-19 was low in rot incidence in 2001 and 2002. Coop 39, NY 65707-19, NJ 90 and McIntosh were cultivars that ripened in September with fewer than 10 percent rots. All trees in the 1995 planting have survived; two of the trees in the 1999 planting have died.
Impacts
Disease susceptibility assessment in successive years provides a baseline for expected performance in a typical year in the region and contributes to a solid database for the geographical area covered by this project. Advanced knowledge provided by this project about disease susceptibility and resistance of new cultivars is helping to guide planting and disease management decisions in Virginia and the region, leading to a potential reduction in fungicide usage.
Publications
- No publications reported this period
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Progress 10/01/00 to 09/30/01
Outputs
Disease resistance and susceptibility of 26 scion/rootstock tree sets are being evaluated at Winchester. The test orchard was planted in 1995 with 5-replicate blocks of test trees interplanted with Fuji border trees. All trees have survived the 5-yr period. Another planting, initiated in 1999, has 23 cultivars, eight of which are known to have some disease resistance. In both plantings, fungicide use is minimized to ensure a strong test of comparative susceptibility. The 2001 effort was directed toward evaluation for summer disease susceptibility for the 1995 planting and all fungal diseases for the 1999 planting. The cumulative wetting hour total provided good test conditions for summer diseases. The threshold for sooty blotch (SB) and flyspeck (FS) development was reached in mid-June and sooty blotch was observed in the test block by 15 June and SB was observed in the test block by 9 July. All cultivars had some SB/FS in 2000 in contrast to seven cultivars which
escaped SB/FS and rots in 1999; in 2001 only the earliest ripening cultivars, Pristine, Sunrise, Zestar escaped SB/FS. In the 1999 planting Coop 29, NJ 90, NJ109, NY 65707-19, NY 75907-49, and NY 75907-72, are quite resistant to scab and cedar-apple rust. Hampshire, Runkel and Zestar also are quite resistant to cedar-apple rust on foliage. Jubilee Fuji, Zestar, and Ambrosia are resistant to mildew. As in 2000, CQR10T17 was most susceptible to cedar-apple rust. NY 65707-19 and Scarlet O'Hara are the most susceptible to Brooks spot. All but four of the trees in the 1999 planting have survived.
Impacts
Disease susceptibility assessment under differing disease pressures in successive years provides a baseline for expected performance in a typical year in the region and contributes to a solid data base for the geographical area covered by this project. Advanced knowledge provided by this project about disease susceptibility and resistance of new cultivars is helping to guide future planting and disease management decisions in Virginia and the mid-Atlantic and Southeast regions, leading to a potential reduction in fungicide usage.
Publications
- No publications reported this period
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Progress 10/01/99 to 09/30/00
Outputs
Disease resistance and susceptibility of 26 scion/rootstock tree sets are being evaluated at Winchester. The test orchard was planted in 1995 with five replicate blocks of test trees interplanted with Fuji border trees. All trees have survived the 5-yr period. Another planting, initiated in 1999, has 23 cultivars, eight of which are known to have some disease resistance. In both plantings, fungicide use is minimized to ensure a strong test of comparative susceptibility. Year 2000 effort was directed toward evaluation of the 1995 planting for summer diseases. An unusual quince rust infection period at bloom provided a good opportunity for checking susceptibility to this erratic but sometimes damaging disease. Ratings conducted on the tree in July and on harvested samples suggest that some affected fruit may have dropped or rotted before normal harvest. Pristine (1% incidence) and Orin (7%) ranked lowest and Fortune (56%) ranked highest in orchard counts. In postharvest
ratings, Yataka, NY 75414-1, Orin, Sunrise, and Pioneer Mac all had less than 10% of the fruit with quince rust symptoms. Golden Delicious, Cameo, Enterprise (resistant to cedar-apple rust), Fortune, and Shizuka had more than 25% of the fruit affected. The highest cumulative wetting hour total in six years provided heavy summer disease pressure for the 1995 planting. The threshold for sooty blotch (SB) and fly speck (FS) development was reached in mid-June and sooty blotch was observed in the test block by 30 June. All cultivars had some SB and FS in 2000 in contrast to seven cultivars that escaped these diseases and rots in 1999 because they were harvested before the diseases could develop during drier weather in 1999. Sansa and Arlet were less affected by SB, FS and rots than other cultivars which ripened in August 2000; NY 75414-1 was less affected by SB (% area) and Pioneer Mac had fewer rots than other cultivars which ripened in early September; Yataka and Creston had less area
affected by SB than some other cultivars which ripened in late September. Fortune, which had appeared to be relatively less susceptible to FS in 1999, was very susceptible in 2000, possibly because it was harvested earlier and had less color to obscure these diseases in 2000. Many wetting periods during the summer months were at warmer temperatures favorable for bitter and Bot rot development. Fuji had fewer rots than several other cultivars harvested late in the season. In the 1999 planting Coop 29, CQR12T50, NY 65707-19, NY 75907-49, NY 75907-72, Scarlet O' Hara and Silken appear to have good resistance to scab, cedar-apple rust and powdery mildew. Hampshire, NJ 90 Runkel and Zesta also appear to be resistant to cedar-apple rust on foliage. The scab-resistant cultivar CQR10T17 was the most heavily infected with cedar-apple rust. Hampshire, NY 75907-49, and Runkel were not defoliated in spite of heavy disease pressure from scab, mildew, cedar-apple rust and Golden Delicious leaf
blotch. All but four of the trees in the 1999 planting have survived.
Impacts
Disease susceptibility assessment under differing disease pressures in successive years provides a baseline for expected performance in a typical year in the region and contributes to a solid data base for the geographical area covered by this project. Advanced knowledge provided by this project about disease susceptibility and resistance of new cultivars is helping to guide future planting and disease management decisions in Virginia and the mid-Atlantic and Southeast regions, leading to a potential reduction in fungicide usage.
Publications
- Yoder, K. S. 2000. Effect of powdery mildew on apple yield and its economic management in Virginia. Plant Disease 84:1171-1176.
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Progress 10/01/98 to 09/30/99
Outputs
Disease resistance and susceptibility of 26 scion/rootstock tree sets were evaluated at Winchesterin a test orchard planted in 1995. All trees have survived the 4-yr period. Another planting of 21 different cultivars was set in 1999. Fungicide use is minimized to ensure a test of susceptibility. Following are brief observations about selected NE-183 cultivars: Creston-very susceptible to cedar-apple (c-a) rust; Cameo- unusual susceptibility to Brooks spot; Enterprise- immune to scab, resistant to c-a rust and mildew; good fruit size and firmness; vigorous tree; Gala Supreme- surprisingly resistant to scab, c-a rust, and mildew; good fruit flavor and size; an abnormal growth in the stem cavity may have been frost related in; some cracking at lenticels and at injury sites with rains following drought; Ginger Gold- interesting cultivar for mid-August but very disease susceptible, especially to mildew; Goldrush- immune to scab but moderately susceptible to mildew and
highly susceptible to c-a rust; raised lenticels, with some cracking two years; low vigor; Honeycrisp- not too susceptible to scab but may be susceptible to rots, severe storage breakdown two years, Although unique in texture and flavor, color is poor; NY 75414-1- immune to scab and resistant to c-a rust and mildew; poor fruit finish, severe fruit cracking in 1999; Orin- very susceptible to scab and fruit not very attractive but excellent flavor; Pristine- immune to scab, resistant to mildew, moderately susceptible to CA rust; very early ripening; heavy bloom in 3rd leaf, bruises easily; Shizuka- very susceptible to c-a rust. Although Sansa foliage has been relatively resistant to scab, cedar-apple rust, these trees were confirmed to have latent viruses and Tomato Ringspot Virus, raising a question about the value of the Sansa data.
Impacts
Disease susceptibility assessment under differing disease pressures in successive years is providing a baseline for expected performance in the region and contributes to a solid data base for the geographical area covered by this project. Advanced knowledge provided by this project about disease susceptibility and resistance of new cultivars is helping to guide future planting and disease management decisions in Virginia and the mid-Atlantic and Southeast regions, leading to a potential reduction in fungicide usage.
Publications
- No publications reported this period
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Progress 10/01/97 to 09/30/98
Outputs
Disease resistance and susceptibility of twenty-six scion/rootstock tree sets were evaluated at Winchester. The test orchard was planted in 1995 with five replicate blocks of test trees interplanted with Fuji border trees. All trees have survived the 3-yr period. Fungicide use was minimized to ensure a strong test of comparative susceptibility. In 1998 the planting was challenged with the heaviest scab and cedar-apple rust pressure in four years' testing. The cultivars that are most resistant to foliar mildew, scab and rust include NY 75414-1, Gala Supreme, and Enterprise. Goldrush and Pristine were found to be immune to scab but will require fungicides to manage rust, and mildew. Under heavy scab pressure in 1998, Honeycrisp exhibited high resistance on leaves and fruit. Fortune had no scab or rust on foliage but 20% of the fruit were infected with scab. Golden Supreme, Sunrise, Suncrisp, and Pioneer Mac were resistant to rust but susceptible to scab and mildew.
Ginger Gold is the most susceptible to mildew. Fruit for disease evaluations of several of the cultivars was more limited in 1998. Fruit from 1997 and 1998 crops indicate differential cultivar susceptibility to Brooks spot. Cultivars harvested after Brooks spot first appeared on Ginger Gold 17 Aug, which did not have Brooks spot symptoms either year were Honeycrisp, Fortune, NY 75414-1, Sansa and Pioneer Mac. Cultivars with Brooks spot both years were: Braeburn, Cameo, Fuji Redsport #2, and Goldrush. Cameo had the highest Brooks spot incidence both years. Additional years of testing will confirm whether cultivars without Brooks spot symptoms are resistant or have merely escaped infection to this point. Although Sansa foliage has been relatively resistant to cedar-apple rust and 'leaf spots', an unusual, chlorotic leaf symptom present on Sansa throughout the growing season has led to early defoliation of older leaves each year 1995-1998. Disease susceptibility assessment under
differing disease pressures in successive years is providing a baseline for expected performance in a typical year in the region and contributes to a solid data base for the geographical area covered by this project. Advanced knowledge provided by this project about disease susceptibility and resistance of new cultivars is helping to guide future planting and disease management decisions in Virginia and the mid-Atlantic and Southeast regions, leading to a potential reduction in fungicide usage.
Impacts
(N/A)
Publications
- Jones, A. L., A. R. Biggs, R. K. Kiyomoto, R. McNew, D. A. Rosenberger, and K. S. Yoder. 1998. Susceptibility of apple cultivars in the NE-183 project to apple scab, 1997. Biological and Cultural Tests for Control of Plant Diseases 13:35.
- Kiyomoto, R. K., A. R. Biggs, W. Copes, R. McNew, D. A. Rosenberger, and K. S. Yoder. 1998. Foliage susceptibility of 23 apple cultivars in the NE-183 trial to cedar-apple rust, powdery mildew, and leaf spots, 1997. Biological and Cultural Tests for Control of Plant Diseases 13:36.
- Yoder, K. S. 1998. Disease resistance and susceptibility of new and old apple in cultivars in Virginia. Mountaineer Grower 548: 9-18.
- Yoder, K. S. 1998. Disease resistance and susceptibility of new and old apple in cultivars in Virginia. Proc. of the 102nd Ann. Meeting of the Virginia State Horticultural Soc. Pp. 12-19.
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Progress 10/01/96 to 09/30/97
Outputs
Disease resistance and susceptibility of twenty-six scion /rootstock tree sets were evaluated at Winchester, Va. The test orchard was planted in 1995 with five replicate blocks of test trees interplanted with Fuji border trees. All trees have grown well during the 3-yr period. Fungicide use was minimized to ensure a strong test of comparative susceptibility. The relatively dry 1997 season increased mildew pressure and reduced scab pressure compared to the 1995 and 1996 seasons. These cultivars are ranked in order of resistance to foliar mildew incidence based on the 3-yr evaluation period: NY 75414-1, Gala Supreme, Sansa, Yataka, Sunrise, and Enterprise. For the 3-yr period, Ginger Gold was the most susceptible to mildew, followed by Suncrisp, Pioneer Mac, Golden Delicious and Braeburn. Nearly all of the cultivars in the test planting bore fruit in 1997. Cultivars which have had less than 2% of the leaves infected by scab or cedar-apple rust over the 3-yr period and
no scab infection on fruit in 1997 were Enterprise, Gala Supreme, NY 75414-1 and Sansa. With the 1997 harvest and fruit evaluation still in progress, there are some preliminary indications of differential Brooks spot susceptibility on cultivars harvested after Brooks spot first appeared 2 Sept. Cultivars harvested after 2 Sept which did not have Brooks spot symptoms were Honeycrisp, Fortune, NY 75414-1, Sansa and Pioneer Mac. Cultivars with Brooks spot included: Braeburn, Golden Delicious, Yataka, Arlet, BC8M15-10, Cameo, Fuji Redsport #2, Gala Supreme, Goldrush, Orin, Senshu and Suncrisp. Additional years of testing will confirm whether cultivars without Brooks spot symptoms are resistant or merely escaped infection this year. Although Sansa foliage has been relatively resistant to cedar-apple rust and "leaf spots", an unusual, chlorotic leaf symptom present on Sansa throughout the growing season has led to early defoliation of older leaves each year 1995-1997. Knowledge about
disease susceptibility and resistance will guide future planting and disease management decisions leading to a reduced fungicide usage. Disease susceptibility assessment under differing disease pressures in successive years provides a baseline for expected performance in a typical year in the region and contributes to a solid data base for the geographical area covered by this project.
Impacts
(N/A)
Publications
- YODER, K. S., BIGGS, A. R., KIYOMOTO, R. K., MCNEW, R. and ROSENBERGER, D. A. 1997. Foliage susceptibility of 23 apple cultivars in the NE-183 trial to scab, powdery mildew, cedar-apple rust, and leaf spots, 1996: Biological and Cultural Tests for Control of Plant Diseases 12: 42-43.
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Progress 10/01/95 to 09/30/96
Outputs
Disease resistance of twenty-six scion/rootstock tree sets was evaluated at Winchester. The test orchard was planted in 1995 with five replicate blocks of test trees. Fungicide use was minimized to ensure a strong test of comparative susceptibility. The new cultivars Enterprise, Gala Supreme, Goldrush, Honeycrisp, Fortune, NY 75414-1, Pristine, and Sansa all had less than 2% leaf scab infection. Ginger Gold (23%) and Pioneer Mac (20%) had the most scab, followed by Yataka, Cameo, and Fuji Red Sport #2. A commercial standard, Golden Delicious had 11% of the leaves infected with scab. Frequent rains in May and June reduced incidence of the dry weather disease, powdery mildew to only 8% compared to 23% in 1995. Yataka, Fuji Red Sport #2, NY 75414-1 and Sunrise showed high mildew resistance both years. BC8M15-10, Honeycrisp, and Orin had 35-40% incidence in 1995 but only 5-7% in 1996. Ginger Gold was again the most most susceptible to mildew with 35% leaves infected. An
unususl, chlorotic leaf symptom present on Sansa in 1995 and 1996 again led to early defoliation of older leaves. The test trees have grown well and will likely start to bear next year, promising opportunity for evaluation of susceptibility to important fruit diseases such as rots. Knowledge about disease susceptibility and resistance will guide future planting and disease management decisions, leading to a reduced fungicide usage.
Impacts
(N/A)
Publications
- ROSENBERGER, D.. and YODER, K.. and BIGGS, A.. and KIYOMOTO, R.. and MCNEW, R., 1996, Comparative susceptibility of 23 apple cultivars in the NE-183 trial to powdery mildew and cedar apple rust, 1995, B & C, tests 11:36
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