Botrytis cinerea Gray Mold

As noted by Zoecklein et al. (1995), Botrytis cinerea is unique among grape parasites in that, depending on the conditions of infection, the grapes may be used to produce some of the world s most sought-after dessert wines or be sold as distilling material. 

Where warm, sunny and windy weather follows the primary infection by Botrytis, free water in the cluster evaporates and the fruit begins a process of dehydration. Although mold and bacterial growth continues to consume a portion of the grape s sugars and acids, this is countered by dehydration, such that there is a net increase in both, a situation referred to as noble rot. 

Where conditions within and surrounding the cluster remain wet and the relative humidity high ( 90%), berry dehydration does not occur. Thus, the concentration of grape sugars either remains the same or decreases. In this scenario, growth of Botrytis and secondary molds, native yeast, and bacteria rapidly ensues, resulting in sour bunch rot. 

Because mold spores are ubiquitous, controlling germination and growth by use of pesticides may be part of the answer but not the complete answer. Inherent properties of the fruit as well as cultural practices play a significant role in mold infections. The grapes themselves may be more or 

Canopy management may also mitigate or make worse the potential for Botrytis infection. Generally, dense canopies which minimize air circulation and light incursion favor a relatively humid environment which increases the potential for mold growth. Open canopies not only favor air circulation but spray penetration as well (English et al., 1990). 

---

Botrytis cinerea is responsible for gray mold disease in more than 200 host plants. This necrotrophic fungus displays the capacity to kill host cells through the production of toxins and reactive oxygen species and the induction of a plant-produced oxidative burst. Thanks to an arsenal of degrading enzymes, B. cinerea is then able to feed on various plant tissues (Choquer and others 2007). 

Liu, Z., Zeng, M., Dong, S., Xu, J., Song, H., and Zhao, Y. (2007). Effect of an antifungal peptide from oyster enzymatic hydrolysates for control of gray mold (Botrytis cinerea) on harvested strawberries. Postharvest Biol. Technol. 46, 95-98. 

Li et al., 2006a] organs is often linked to the genetic diversity in resistance to gray mold (Botrytis cinerea) [Sbaghi et al., 1996 Borie et al., 2004] and decay caused by Rhizopus stolonifer [Sarig et al., 1997]. 

Adrian M, Jeandet P, Veneau J, Weston LA, Bessis R. 1997. Biological activity of resveratrol, a stilbenic compound from grapevines, against Botrytis cinerea, the causal agent for gray mold. J Chem Ecol 23 1689-1702. 

Gray mold rot is caused by Botrytis cinerea, which results in a pale brown discoloration and sunken lesions on the tuber surface. At high relative humidities, the surface becomes covered with white mycelium and subsequently with gray-brown spores (Johnson, 1931). The interior of the tubers discolors and softens. The organism can cause serious storage losses even at low temperatures. 

Plant volatiles have been surveyed to find safe and environmentally friendly postharvest fumigants. Hexanal (171), 1-hexanol (172), ( )-2-hexen-l-ol (173), (Z)-6-nonenal (174), ( )-3-nonen-2-one (175), methyl salicylate (176), and methyl benzoate (177) exhibit potential to control the gray mold, Botrytis cinerea 02 (E)-2-hexenal (178), carvacrol (179), ( )-cinnamaldehyde (180), and citral (181) exhibited consistent fungicidal activities against Penicittium expansum, the cause of blue mould of pear.103 ( )-2-hexenal (178), carvacrol (179), and citral (181) were also effective against Monilinia laxa, the cause of brown rot in stone fruit.104... 

Diethofencarb is highly toxic to benzimidazole-resistant isolates of B. cinerea, whereas its toxicity to the benzimidazole-sensitive isolates is weak. In contrast, MBC inhibited the growth of wild type isolates at a low concentration but had low toxicity to resistant isolates. In pot tests, diethofencarb was effective for gray mold caused by resistant isolates of Botrytis cinerea, but was not effective for wild type isolates. Diethofencarb has systematic activity in plants and both preventive and curative activity in controlling gray mold. 

Gray Mold (Botrytis cinerea). This fungus in certain parts of Europe is a harmful parasite of the vine, injuring seriously leaves, shoots and growing fruit. The only injury of this kind noted in California is in the callousing beds of bench grafts. 

Gray mold (Botrytis cinerea). (After Ravaz.)... 

This phytoalexin helps the plant resist attack by gray mold (Botrytis cinerea). Another possibility is to use a phytoalexin made by a chemical synthesis apart from the plant. Novartis sells a benzothiadiazole (Actigard) that elicits systemic resistance to bacterial and fungal pathogens.189... 

---