Symptoms of grapevine trunk diseases in Northern Midwest vineyards. Cankers were often associated with skips in the cordons but had rarely wedge-shaped discoloration (A). Cankers more often had irregular shaped xylem reactions (B). Pycnidia were sometimes observed fruiting from cankers (B) and bleached canes (C). Dieback symptoms are common and the result of successive skips starting from tips of cordons (D). Pruning wounds were associated with minor (E), moderate (F), and severe (G) vascular streaking symptoms. Near completely healthy vascular tissue observed in wild Vitis riparia vines (H). Infrequent shallow cracks (I), several shallow cracks (J), and deep cracks (K and L) were associated with minor to moderate (I), moderate to severe (J), and severe (K) vascular symptoms. Winter injury often results in deep cracks on the trunk (L). Observations included cankers (ck), skips in the cordons (sk), bleached canes (bc), dieback (db), pruning wounds (pw), shallow cracks (sc), deep cracks (dc), black spotting (bs), black lines (bl), brown-red wood streaking (br), brown to black necrotic streaking (bn), discolored xylem (dx), sometimes healthy tissue (h), and white rot (wr). Bars = 1 cm.

Contexts in source publication

Context 1

... diseases can be difficult to diagnose due to their sporadic symptom display and similarity of external and internal symptoms. Such symptoms may include interveinal foliar chlorosis and necrosis or tiger striping, generalized dieback, apoplexy or sudden death, gummosis, vascular streaking, wedge-or V-shaped vascular discoloration, cankers, and wood decay (Fig 1) [16]. GTDs cause serious grapevine health and economic problems and can be found in all grape growing regions of the world [17][18][19]. ...

Context 2

... cause serious grapevine health and economic problems and can be found in all grape growing regions of the world [17][18][19]. In the Northern Midwest United States (NMW), growers often struggle with unproductive cordon sections commonly referred to as "skips in the cordon" or "blind wood" (Fig 1A and 1B). Cordon skips come at the cost of vineyard managers with lower yields and require retraining new cordons. ...

Context 3

... many NMW vineyards are now reaching a decade in age since their first vines were planted, the characteristic cordon skip (Fig 1A and 1B) and dieback ( Fig 1D) symptoms of GTDs have begun to appear. In addition, the compounding effect that GTDs and winter injury have on vines is becoming a major concern (Fig 1L). ...

Context 4

... many NMW vineyards are now reaching a decade in age since their first vines were planted, the characteristic cordon skip (Fig 1A and 1B) and dieback ( Fig 1D) symptoms of GTDs have begun to appear. In addition, the compounding effect that GTDs and winter injury have on vines is becoming a major concern (Fig 1L). ...

Context 5

... many NMW vineyards are now reaching a decade in age since their first vines were planted, the characteristic cordon skip (Fig 1A and 1B) and dieback ( Fig 1D) symptoms of GTDs have begun to appear. In addition, the compounding effect that GTDs and winter injury have on vines is becoming a major concern (Fig 1L). In many other parts of the world where grapes are grown, surveys have been conducted to characterize the region-specific composition of GTD pathogens. ...

Context 6

... sample collection was targeted towards symptomatic grapevines showing skips in the cordons, generalized dieback, reduced productivity, vascular discoloration, vascular decay, or apoplexy (Fig 1). A few externally asymptomatic vines were also collected for comparison. ...

Context 7

... symptoms of GTDs following the terminology of Mugnai et al. 1999 [16] included brown-red wood streaking in a clearly defined wedge-shape from the cambium to pith which is indicative of canker fungi were observed in few of our samples. Cankers more often occurred in irregular forms and were associated with skips in the cordons (Fig 1A and 1B). Centrally diffuse brown-red wood as well as brown to black necrotic streaking originating from the pith was often associated with pruning wounds (Fig 1E-1G) and cracks (Fig 1I-1L). ...

Context 8

... more often occurred in irregular forms and were associated with skips in the cordons (Fig 1A and 1B). Centrally diffuse brown-red wood as well as brown to black necrotic streaking originating from the pith was often associated with pruning wounds (Fig 1E-1G) and cracks (Fig 1I-1L). All samples collected had discolored xylem to some extent and nearly completely healthy vascular tissues were only observed in some cross-sections of wild riverbank grapevines in forest and urban environments not included in this survey ( Fig 1H). ...

Context 9

... more often occurred in irregular forms and were associated with skips in the cordons (Fig 1A and 1B). Centrally diffuse brown-red wood as well as brown to black necrotic streaking originating from the pith was often associated with pruning wounds (Fig 1E-1G) and cracks (Fig 1I-1L). All samples collected had discolored xylem to some extent and nearly completely healthy vascular tissues were only observed in some cross-sections of wild riverbank grapevines in forest and urban environments not included in this survey ( Fig 1H). ...

Context 10

... diffuse brown-red wood as well as brown to black necrotic streaking originating from the pith was often associated with pruning wounds (Fig 1E-1G) and cracks (Fig 1I-1L). All samples collected had discolored xylem to some extent and nearly completely healthy vascular tissues were only observed in some cross-sections of wild riverbank grapevines in forest and urban environments not included in this survey ( Fig 1H). Cross-sections near pruning spurs often showed discolored wood symptoms without being preceded by diffuse brown-red wood or brown to black streaking ( Fig 1E). ...

Context 11

... samples collected had discolored xylem to some extent and nearly completely healthy vascular tissues were only observed in some cross-sections of wild riverbank grapevines in forest and urban environments not included in this survey ( Fig 1H). Cross-sections near pruning spurs often showed discolored wood symptoms without being preceded by diffuse brown-red wood or brown to black streaking ( Fig 1E). Concentric black spotting, the result of longitudinal streaking, was also frequently observed, and in some cases, black spotting would begin to coalesce into shorter black lines ( Fig 1F). ...

Context 12

... near pruning spurs often showed discolored wood symptoms without being preceded by diffuse brown-red wood or brown to black streaking ( Fig 1E). Concentric black spotting, the result of longitudinal streaking, was also frequently observed, and in some cases, black spotting would begin to coalesce into shorter black lines ( Fig 1F). Most samples had severe mottled expression of vascular symptoms especially for brown-red wood streaking, brown to black necrotic streaking, and discolored xylem ( Fig 1G). ...

Context 13

... black spotting, the result of longitudinal streaking, was also frequently observed, and in some cases, black spotting would begin to coalesce into shorter black lines ( Fig 1F). Most samples had severe mottled expression of vascular symptoms especially for brown-red wood streaking, brown to black necrotic streaking, and discolored xylem ( Fig 1G). Severe symptoms were sometimes associated with several points of origin from shallow cracking from winter injury or hail damage ( Fig 1J). ...

Context 14

... samples had severe mottled expression of vascular symptoms especially for brown-red wood streaking, brown to black necrotic streaking, and discolored xylem ( Fig 1G). Severe symptoms were sometimes associated with several points of origin from shallow cracking from winter injury or hail damage ( Fig 1J). Rarely, if ever, have GTD foliar symptoms been observed in the NMW which possibly may be the result of our overall young vineyards or different climate. ...

Context 15

... wood samples collected had some degree of internal vascular symptoms including externally healthy samples (Fig 1). From 172 samples with various symptoms that included cankers and vascular discoloration, dieback as well as pruning wounds and cracks from cold injury or other environmental stresses yielded 640 isolates. ...

Context 16

... etiology of these Diaporthales pathogens on grapevines has been previously well characterized [76]. In addition to symptoms of internal wood discoloration, pathogenic species of Cytospora and Diaporthe can induce symptoms of cane bleaching (Fig 1C). They also produce asexual fruiting bodies known as pycnidia which can be found on all affected tissues (Figs 1B, 1C and 4). ...

Context 17

... grapevines this could be considered "winter sunscald", not to be confused with sunscald of grape berries in the summer. Like extreme cold weather exposure, winter sunscald can also result in both shallow and deep frost cracks depending on severity (Fig 1I-1L). Additionally, winter sunscald of grapevines results in a blackened appearance of the bark on the south to southwest facing side of the vine (Fig 1L). ...

Context 18

... extreme cold weather exposure, winter sunscald can also result in both shallow and deep frost cracks depending on severity (Fig 1I-1L). Additionally, winter sunscald of grapevines results in a blackened appearance of the bark on the south to southwest facing side of the vine (Fig 1L). In either case of winter injury often the roots and the lower trunk of vines are protected by the insulating snow covering. ...

Context 19

... of occlusions in response to pathogenic infections can lead to extensive hydraulic failure resulting in external foliar symptoms and often vine death [89,90]. In cross sections the defense response of the grapevine host is seen as a continuum of brown-red wood to brown-black necrotic tissue (Fig 1). Lighter vascular discoloration indicates more recent responding tissues and likely the front of pathogen spread. ...

Context 20

... primarily pectinolytic active pathogens degrade gels in xylem vessels and spread longitudinally by spores through the small spaces between tyloses partially occluding xylem conduits [92]. Longitudinal spread of these pathogens is seen in cross section by the host defense response as black spotting and black lines (Fig 1F) [16]. Genomes of Cytospora spp. ...