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Impact of external factors on the population dynamics of beech scale ( Cryptococcus fagisuga ) (Hom., Pseudococcidae) in beech ( Fagus sylvatica ) stands during the latency stage 1
Author(s) -
Lunderstädt J.
Publication year - 1998
Publication title -
journal of applied entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 60
eISSN - 1439-0418
pISSN - 0931-2048
DOI - 10.1111/j.1439-0418.1998.tb01505.x
Subject(s) - beech , fagus sylvatica , infestation , biology , thinning , flushing , botany , horticulture , agronomy , ecology , endocrinology
Within a natural occurrence of beech on weathered lime stone in the hilly region of southern Lower Saxony, the infestation dynamics of Cryptococcus fagisuga as dependent on the flushing status of its host, Fagus sylvatica , were investigated from 1988 to 1995 during the latency stage. Employing subpopulations on microstands with different water supply and under different silvicultural treatment but with equally good nutritional status, the infestation dynamics of the scale were compared by means of a differential analysis. Independent of the year of observation, the microstand, and the silvicultural treatment, beeches with a bhd < 10 cm flushed quicker and showed a lesser degree of infestation than beeches of bhd 10–20 cm and > 20 cm. In almost all cases the beeches of the higher diameter classes on the strongly thinned plots were attacked markedly stronger than the corresponding ones on the moderately thinned plots. Increasing infestation was promoted by a decreasing flushing status on dry stands and by an increasing flushing status on moister stands. With heavier thinning or stronger self‐differentiation on the more humid stands, heavier infestation was promoted too by decreasing flushing status. The gradual transition was stopped when an equilibrium was reached comparable to the level of infestation of strongly thinned stands on dryer locations.