beech trees grow in massachusetts, us.
beech trees grow in massachusetts, us.
where do beech trees grow in the us?
massachusetts
the beech scale is monophagous, being found only on beech trees, and sucks sap from the parenchyme tissue of the bark. the small wounds produced when it feeds allow the "nectria" fungi to invade infested trees. the insect colonises beech trees that are aged at least thirty years. studies have shown that younger trees produce defensive chemicals which deter infestation. a ladybird beetle "chilocorus stigma" feeds on this scale and is common throughout most of the eastern united states, but this predator does not reduce scale populations sufficiently to control infestations. persistent severely cold weather may kill beech scale and air temperatures of -37 °c have been shown to be lethal to insects not protected by snow. although trees are weakened when supporting scale colonies, this does not usually cause mortality, which only occurs after the trees have been invaded by the "nectria" fungi. it usually takes three to six years of infestation by the scale insect before the fungus reaches critical levels. where beech bark disease becomes established, most of the larger trees will die. some trees seem to be partially resistant to the disease and a small number seem to be completely resistant. this may be partly due to the fact that trees with smooth bark provide fewer cracks and crevices in which the scale insect can flourish.
cryptococcus fagisuga
in 1998, by comparing the dna coming from common beech trees, dwarf beech trees from verzy, common purple beech trees and purple dwarf beech trees from the süntel, anita gallois working in the laboratory of biology and plant physiology in reims university brought to light that these morphological differences are indeed there because of a genetic factor, a result that confirms the hypothesis of a mutation.









































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