Over de economische betekenis van insektenplagen in bossen (Cephalcia alpina Klug en Diprion pini L.)
During 1952-1956 a study was made of the loss of increment and the consequent financial losses caused by the 1941-1950 outbreak of the spinning larch sawfly (Cephalcia alpina Klug) in Japanese larch and the 1950-1951 outbreak of the pine sawfly (Diprion pini L.) in Scots pine. Growth losses were compared for different degrees of defoliation. The financial losses were calculated and compared with the cost of control operations, to estimate how severe the insect attack must be to justify chemical control.Sample plots in the provinces of Drente, Gelderland and Overijssel showed that loss of increment increased with degree of defoliation. Losses of increment in Japanese larch were less on richer loamy soils than on sandy soils. It was presumed that low vigour of Japanese larch and Scots pine, probably indicated by small annual increment of the tree for a few years before an insect attack, favours this attack, and thus defoliation. This would mean that the method of calculating the loss of increment was incorrect. Further research was greatly needed.
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| Format: | Doctoral thesis biblioteca |
| Language: | Dutch |
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Staatsdrukkerij
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| Subjects: | forest damage, insect pests, insects, netherlands, bosschade, insecten, insectenplagen, nederland, |
| Online Access: | https://research.wur.nl/en/publications/over-de-economische-betekenis-van-insektenplagen-in-bossen-cephal |
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