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| Author: | W.J. Swart |
| Keywords: | bacteria, phytoplasma, virus, diagnosis, fungi, pathogen |
Abstract:
Cactus pear (Opuntia ficus-indica) originates from arid and semi-arid areas in Mexico, but is presently cultivated in more than 20 countries for fruit and fodder.
Intensive monoculture of cactus pear in new geographic areas will inevitably result in the appearance of new disease problems which, if not managed properly, will impact negatively on yields.
Worldwide, very few systematic studies of cactus pear diseases have been conducted and current knowledge is mostly based on tenuous identification of biotic agents such as fungi and bacteria associated with symptoms.
However, proof of their true pathogenic ability is scant and the possibility that they are not primary pathogens, but at best secondary or opportunistic, is high.
The management of diseases must therefore be based more on a proactive approach rather than reactive or “knee-jerk” responses, as is presently the case.
A prerequisite for a proactive approach is strict phytosanitary regulation governing the import of propagation material.
Furthermore, in the event of disease occurring in a cactus pear orchard, careful diagnostic procedures are crucial for successful identification of the primary cause, as well as any predisposing factors, and their combined management.
Genotypic characterisation of cactus pear cultivars using molecular markers will facilitate breeding strategies for disease resistance.
An integrated and holistic strategy, where the focus is on investigating all biotic and abiotic factors that can affect the overall health and productivity of a cactus pear crop, is ecologically more sound and sustainable than present reactive approaches to dealing with cactus pear diseases.
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