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THE STUDY OF THE ECONOMIC THRESHOLD OF TOMICUS PINIPERDA (COLEOPTERA: SCOLYTIDEA) ON YUNNAN PINE
Author(s) -
Fang CHEN,
Shaofang SUN,
Panjiang GUO,
Cuilian YANG,
Zhiyong ZHANG
Publication year - 2001
Publication title -
insect science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 45
eISSN - 1744-7917
pISSN - 1672-9609
DOI - 10.1111/j.1744-7917.2001.tb00450.x
Subject(s) - pinus yunnanensis , biology , bark (sound) , economic threshold , pest analysis , population , shoot , bark beetle , population density , forestry , botany , horticulture , ecology , demography , geography , sociology
By careful and long period field investigation of the population density of Tomicus piniperda L. and the growth of Yunnan pine ( Pinus yunnanensis French.), and improved regression analysis, the economic threshold of Tomicus piniperda on Yunnan pine is determined: When the death rate of the trees is not more than 0.52%, the natural control factors can prevent the density of the bark beetle from increasing and no control measure is needed. When the death rate of the trees reaches 0.5%, the corresponding rate of shoots attacked is 0.61% and the mean of invading holes per tree 0.66, the cost for control is equal to the economic loss saved. So, considering both the economic justification and the prevention of the pest density from increasing, when the death rate of the trees is more than 0.5%, the corresponding rate of shoots attacked more than 0.61% and the mean of invading holes per tree more than 0.66, control measure should be taken. The paper also gives formulae for different Yunnan pine forest areas to calculate their own economic threshold according to their special situations.