Sintomas de "exocortis" em limoeiro cravo
Exocortis symptoms on rangpur lime
S. Moreira
SUMMARY
Exocortis or scaly butt is considered a typical bud-union effect disease of citrus plants. Evidence is accumulated that the causal agent of exocortis is a virus which is symptomless in many stock-scion combinations, except when the rootstock is the trifoliate orange (P. trifoliata) or some trifoliate hybrids (citranges).
In the rootstock tests at Limeira Experiment Station every plant of Baianinha (a little Washington Navel) orange and Marsh Seedless grapefruit budded on trifoliate showed exocortis symptoms before they were 5 years old. This same rootstock budded to Pera (a late variety) and Washington Navel oranges didn't show any symptom of exocortis. At Tietê Experiment Station the exocortis symptoms were brought about on trifoliate rootstock when the tops were Baianinha, Maracanã and Hamlin oranges. If the tops were Pera orange, Willow Leaf mandarin or Eureka lemon no symptoms showed up.
In those tests the Rangpur lime rootstock showed exocortis-like symptoms at the same age and only when budded to those same symptomless infected varieties. The stunting of the trees and the scaling of the butt were less conspicuous than in trifoliate diseased combinations.
The similarity of the symptoms and the accordance in that the same top varieties caused the disease on the two stocks give us the evidence that the Rangpur lime tissues are intolerant to exocortis virus.
After the ravage made by the tristeza disease in the citrus orchards of the State of São Paulo the Rangpur lime is being the main stock used by the nurserymen. Only the exocortis-virus free clones should be budded on it.
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Recebida para publicação em 18 de novembro de 1954.
Datas de Publicação
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Publicação nesta coleção
24 Maio 2010 -
Data do Fascículo
1955
