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Statistische Analyse der räumlichen und zeitlichen Dynamik der Stamm‐Phloem‐Nekrose (TPN) von Hevea brasiliensis: Keine Hinweise auf eine Pathogenübertragung
Author(s) -
Peyrard N.,
Pellegrin F.,
Chadœuf J.,
Nandris D.
Publication year - 2006
Publication title -
forest pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.535
H-Index - 49
eISSN - 1439-0329
pISSN - 1437-4781
DOI - 10.1111/j.1439-0329.2006.00467.x
Subject(s) - biology , hevea brasiliensis , phloem , transmission (telecommunications) , outbreak , pathogen , botany , physiology , natural rubber , immunology , virology , chemistry , organic chemistry , electrical engineering , engineering
Summary Trunk phloem necrosis (TPN) of Hevea brasiliensis is an irreversible syndrome of the phloem that spreads from the collar towards the tapping cut. It is responsible for the cessation of latex production, the main constraint in rubber plantations worldwide. Numerous investigations have been undertaken to understand the mechanisms of this disease. The apparent linear spread of TPN supported the initial hypothesis of a biotic causal agent for TPN. However, previous and recent aetiological analyses remained inconclusive and the pathogen hypothesis is tending to be abandoned. In this paper we present a complementary statistical analysis of spatio‐temporal epidemiological data collected in a rubber plantation in Côte d'Ivoire. There, four study plots were surveyed each year from 2000 to 2003, with tree‐by‐tree disease assessment. In two plots, the tapping knife was systematically disinfected with sodium hypochlorite to stop any virus or viroid transmission. Based on permutation tests, our analysis confirmed the aetiological results: there was no evidence for spread by pathogen transmission. However, the spatial structure of the disease was clear. These results strengthen the current alternative scenario of a multi‐factor physiological disease caused by an accumulation of exogenous and endogenous stresses. Spatial heterogeneity of the risk factors probably results in the presence of areas of stress that can explain the spatial patterns observed among the TPN cases. The final contribution of this study was confirmation of the curative effect of sodium hypochlorite in the earliest stages of the disease, thus opening the way for control of this disease.