Early Botrytis Rot of Grapes: Time of Infection and Latency of Botrytis cinerea Pers. in Vitis vinifera L.

Abstract

The effect of five rootstock cultivars and two pruning methods with two crop loads each on Botrytis cinerea Pers. rot of Vi tis vinifera L. cv. Chenin blanc was investigated. The effect of these factors on bunch compactness, berry skin strength, pedicel strength, total soluble solids and nitrogen content of berries was also investigated to determine the correlation between these parameters and botrytis rot. The most rot occurred with Chenin blanc on Ramsey, 110 Richter and 101-14 Mgt when spur pruned, while the least rot occurred with Chenin blanc on 99 Richter when cane pruned. Rootstock cultivar had a significant effect on bunch compactness, berry skin strength, pedicel strength, cane mass and crop mass while rootstock cultivar and pruning method had a significant effect on total nitrogen and total soluble solids of berries. Except for bunch compactness none of the other parameters appear to have any direct effect on botrytis rot. Control of bunch rot of grapes caused by Botrytis cine-rea Pers. is achieved mainly by chemical means. This is an expensive operation; the total cost in South Africa for wine and table grapes is estimated at R2,0 million per season. As a result of the rise in cost of chemical control as well as the fact that strains of B. cinerea resistant to some of the fungicides have occurred, it is unlikely that practical control of botrytis bunch rot can be achieved by the use of fungicides alone. It is known that many cultivation practices which are likely to increase vine vigour, e.g. excessive nitrogen fertilisation, vigorous rootstocks and irrigation, will increase the susceptibility of grapes to B. cinerea (Bra-nas, 1960; Champagnol, 1969; Delas, 1972; Dry & Smart, 1982). Christensen (1981) found that by increasing the number of nodes per vine from 40 to 60 in the case of Chenin blanc, a significant decrease in botrytis bunch rot occurred. Practical experience in European viticultural areas has shown that choice of rootstock and scion cultivar as well as fertiliser application level, are very important factors with regard to control of bot-rytis bunch rot (Dry & Smart, 1982). The present study was carried out to determine the effect of certain cultivation practices, viz. the use of certain rootstock cultivars, pruning method and crop load on the incidence of botrytis rot of Chenin blanc. The effect of these factors on bunch compactness, as well as pedicel strength, berry skin strength, nitrogen and sugar content of berries was also evaluated in order to determine if a relation exists between these parameters and botrytis bunch rot. MATERIALS AND METHODS A fourteen-year-old vineyard at Robertson, consisting of five rootstock cul ti vars viz. Ramsey, 99 Richter, 110 Richter, 101-14 Mgt and Jacquez with Chenin blanc as scion, was used in this study. Vines were trellised ac'cording to the Perold system as described by Zeeman (1981). A randomized block design in which each rootstock cultivar was replicated four times was used. Each plot consisted of four rows with seven vines per row. Two prunin...

Desfolha precoce como estratégia de controle da podridão de Botrytis cinerea na videira Cabernet Sauvignon em regiões de altitude

“…Esses períodos antecederam em sete dias o início da maturação da variedade Cabernet Sauvignon, pois apesar das infecções de B. cinerea ocorreram a partir da florada, seus sintomas são visíveis apenas no início da maturação da uva, podendo no período de latência colonizar cada vez mais a baga sem a exteriorização dos sintomas (16). Nenhuma das épocas de desfolha proporcionou atraso na epidemia, como pode ser visto pelos valores de IAS, TAMID e TAMDS (Tabela 1).…”

Application of differential display RT-PCR to the analysis of gene expression in a plant-fungus interaction

“…dead or senescent plant tissues from which it spreads into healthy tissues [19]. Wounds can serve as entry sites [8,35] but direct penetration of healthy plant tissues by infection pegs differentiated from appressoria or from the tips of germtubes also occurs frequently [20,26]. Research on the fungal processes involved in pathogenesis has focused on extracellular enzymes with a presumed role in the infection process, such as a cutinase [27], an aspartic protease [23] and a large number of cell wall-degrading enzymes [ 13,24].…”

Gray mold caused by Botrytis cinerea limits grape production in Chile

“…McClellan and Hewitt (1973) were the first to demonstrate the infection of B. cinerea through the stigma at the stylar end of the flower. B. cinerea remained latent at the stylar end of the grapes, restarting to grow after veraison, causing early rotting at berry maturity.…”

“…This infected floral debris is often retained in the grape clusters and provides inoculum for berry infection during ripening or even later during storage and transit (Calvo-Garrido et al, 2014a;Jacometti et al, 2010;Keller et al, 2003;Latorre and Vásquez, 1996;Latorre et al, 2001;Nair, et al, 1988Nair, et al, , 1995Pezet and Pont, 1986;Viret et al, 2004;Wolf et al, 1997). It is possible that the abundance of pollen and stigma exudates during flowering increases the level of colonization of floral debris (McClellan and Hewitt, 1973).…”