Investigation of Wine Grape Cultivar and Cluster Developmental Stage Susceptibility to Grape Ripe Rot Caused by Two Fungal Species Complexes, <i>Colletotrichum gloeosporioides</i>, and <i>C. acutatum</i>, and the Evaluation of Potential Controls

Ripe rot of grape is caused by two fungal species complexes: <i>Colletotrichum gloeosporioides</i> and <i>C. acutatum</i>, both of which cause disease on a variety of crops, such as strawberry and apple. To investigate effect of cultivar and cluster developmental stage on the development of ripe rot, controlled environment and field studies were conducted during 2013-2014. We have identified that a certain level of infection could can take place on most cultivars tested from bloom to the near harvest. In most of the cases, significant cultivar and cluster developmental stage interaction effects were observed (<i>P</i> < 0.05) for the development of disease symptoms in both studies. In general, susceptible cultivar (Cabernet Franc, Cabernet sauvignon, and Chardonnay) demonstrated fluctuations of disease susceptibility among cluster development stages, while resistant cultivars (Merlot) showed consistently low level of the disease throughout the season. To investigate the effect of eleven ten modes of action for control of <i>C. gloeosporioides</i> and <i>C. acutatum</i>, two methods, alamarBlue® assay and inoculation on fungicide-treated detached fruits, were used. Protective fungicides (mancozeb, captan, and copper) as well as some of newer formulations such as azoxystrobin and tetraconazole were identified as excellent products against ripe rot of grape. Four additional materials were identified as good potential candidates to investigate further. The information gained from these studies will help growers to determine the critical period for ripe rot management and chemicals to be applied for management. With better control of cluster rot pathogens, Virginia growers can experience an increase in yield and wine quality.

Name thesis:degree_name

Master of Science in Life Sciences

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Plant Pathology, Physiology, and Weed Science

Department dc:contributor.department

Plant Pathology, Physiology, and Weed Science

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2016

Author dc:creator

• Oliver, Charlotte

Chair dc:contributor.committeechair

• Nita, Mizuho

Committee members dc:contributor.committeemember

• Baudoin, Antonius B.
• Bush, Elizabeth Ann
• Yoder, Keith S.

• Colletotrichum gloeosporioides
• Virginia
• Colletotrichum acutatum
• Grape ripe rot

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Dc Identifier Other

etd-04282016-113249

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/77504