Gum pocket - Gummy pitting disease of trifoliate orange: Considerations about its etiology
The terms "Gum pocket", "wood pitting" and "gummy pitting" have been used to describe a characteristic disorder of trifoliate orange. Affected trees show gum pockets, which develop only in the bark and wood of the trifoliate orange rootstock. This disorder has been reported in Argentina, South Africa, Australia and Italy. The association of the disease with a viroid-like RNA with the electrophoretic mobility of CVd-III was recently demonstrated. Viroid infected clementine trees grafted on trifoliate orange were monitored for the presence of gum pockets and malformations of the bud union. Trees showing gum pocket symptoms were identified in all the viroid-infected treatments as well as in some uninoculated controls. The presence of symptoms was more frequently observed (50% and 54%) on trees infected with CVd-I and CVd-IlI respectively, than in the other treatments. The symptoms appeared to be associated with trees showing a shouldered stock overgrowth. No symptoms were observed on seedlings of trifoliate orange infected with the same viroid sources. These observations suggest that gum pocket symptoms may be of physiological or stress origin. The observations made on viroid infected trees maintained for at least ten years in field trials indicate that viroid infection may act simply by enhancing the development of non specific symptoms.
| Main Authors: | , , |
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| Format: | conference_item biblioteca |
| Language: | eng |
| Published: |
IOCV
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| Subjects: | H20 - Maladies des plantes, Citrus, viroïde, symptome, étiologie, http://aims.fao.org/aos/agrovoc/c_1637, http://aims.fao.org/aos/agrovoc/c_15856, http://aims.fao.org/aos/agrovoc/c_7566, http://aims.fao.org/aos/agrovoc/c_15588, http://aims.fao.org/aos/agrovoc/c_603, http://aims.fao.org/aos/agrovoc/c_7252, http://aims.fao.org/aos/agrovoc/c_714, http://aims.fao.org/aos/agrovoc/c_4026, |
| Online Access: | http://agritrop.cirad.fr/487517/ |
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