Ml. Desprezloustau et K. Wagner, INFLUENCE OF SILVICULTURAL PRACTICES ON TWISTING RUST INFECTION AND DAMAGE IN MARITIME PINE, AS RELATED TO GROWTH, Forest ecology and management, 98(2), 1997, pp. 135-147
A three-year study was carried out on the influence of silvicultural i
ntensification on infection and damage caused by Melampsora pinitorqua
, the twisting rust fungus, in maritime pine, Pinus pinaster Air. The
silvicultural practices studied were phosphorus fertilisation, the mod
e of stand establishment (either seeds or plants), and pine density. G
rowth and nutrition variables were also measured. Infection and damage
were the most important in the first two years, which could reflect h
igher resistance with aging. At the end of the experiment, when pines
were 4 years old, the planted, fertilised pines turned out to be the m
ost damaged and the tallest, while the sown, non-fertilised pines were
the least damaged and the smallest. Final damage was mainly explained
by the damage observed in the earlier years. Annual damage was signif
icantly correlated with infection percentage, more closely in the firs
t year of observation. Higher susceptibility of the planted pines was
associated with better growth and was explained by a greater amount of
susceptible tissues. Under our experimental conditions, this explanat
ion could not be retained for the fertilisation effect. However, phosp
horus fertilisation induced changes in the nutritional status of pines
. A significant positive correlation was observed between the phosphor
us and potassium content on one hand and the susceptibility and damage
on the other hand. Density effects were seldom observed in the experi
ment, either on growth or susceptibility variables. The positive relat
ion between pine growth and rust damage, as confirmed in this study, e
mphasises the need for an integrated management of intensively managed
pine stands, taking into account the disease hazard. (C) 1997 Elsevie
r Science B.V.