TWENTY YEARS OF GRAPE BREEDING IN THE TROPICS: THE STRESS PATHOGEN BOTRYODIPLODIA CONFUSED THE ABILITY TO SELECT FOR RESISTANCE TO PIERCE'S DISEASE

A. Ingalls, A.L.G. Jimenez
At the previous meeting, it was reported that the resistance to Pierce's Disease (PD) of the Vitis caribea x V. vinifera hybrids that we had made was beginning to break down at the time that they had reached 8 to 13 years of age. The plants did not show the typical bright colored burns, characteristic of PD, but rather a slow degeneracy and lack of vigor that we thought was another form of the same disease. It was first suspected that there might be a second disease involved when it was found that this was also happening to some thirteen-year-old PD resistant plants sent by Mortenson from Florida. The following year was very dry and in the dry season many plants died or became extremely weak. Their trunks often had longitudinal cracks, were infested with termites, and when cut transversally had hard, pie shaped, black rot similar to Eutypa. Samples were sent to various laboratories, but in no case was Eutypa found. Instead the fungi found in their trunks or roots were: Botryodiplodia sp., Nectaria sp., Phomopsis sp., Pestalotia sp., Schizophyllum sp., Ganoderma sp., Fistolinella sp., Xylaria sp., Stereum purpureum, Rhizoctonia sp., Cylindrocarpon sp., Sphaeropsis sp., Fusaruim sp. In Mexico and the warmer areas of California a similar disease was observed to be caused by Botryodiplodia teobromae. In Costa Rica, Botryodiplodia is the cause of many diseases of tropical fruits especially in the pressence of water stress. By planting on well drained locations, to prevent standing water in the rainy months and by giving supplementary water in the dry seasons to prevent the extremes of water stress, it is possible to mitigate greatly the danger of Botryodiplodia. Combining this with varieties resistant to PD the life span of grapes in the tropics can be extended well over 15 years even in hot spots for PD such as Montezuma, Costa Rica.
Ingalls, A. and Jimenez, A.L.G. (2000). TWENTY YEARS OF GRAPE BREEDING IN THE TROPICS: THE STRESS PATHOGEN BOTRYODIPLODIA CONFUSED THE ABILITY TO SELECT FOR RESISTANCE TO PIERCE'S DISEASE. Acta Hortic. 528, 467-478
DOI: 10.17660/ActaHortic.2000.528.67
https://doi.org/10.17660/ActaHortic.2000.528.67
Vitis caribea, Pierce's Disease, tropical grape, Xylella fastidiosa, Diplodia Botryodiplodia

Acta Horticulturae