Summary About half the number of stumps of recently felled Scots pine (Pinus sylvestris L.), selected so as to be evenly distributed over the plots concerned, were barked. Equal numbers of these and of the unbarked stumps were uprooted later, and the larvae, pupae and adults of Hylobius abietis L. and other insects in the stumps and roots were counted. Other readily obtainable data were also collected. In one experiment, cages were put over the stumps to trap the emerging H. abietis adults. On comparing the Hylobius populations in the two categories of stumps it was seen that barking at the beginning of the oviposition period or about 1, 2 and 6 months before it, did not result in a significant reduction of the numbers developing in and emerging from the stumps and roots. Even clearing the soil round the stumps and main roots, carefully barking the stumps to a greater depth than usual, replacing the soil and treading it down did not produce that effect. Nor was it obtained by barking at a time during the larval stage when the greatest possible number of larvae could be destroyed. The latter experiment was carried out in both thinned and cleared plots, the others in either of the two types of plots. It is concluded from a study of the literature on the subject and from these results that the efficacy of barking as a control measure against H. abietis is unproven and that some of the obvious modifications of the method are definitely ineffective. There was no consistent difference between the numbers of Hylobius developing in stumps in cleared or in thinned plots. The time required for development and emergence from the stumps and roots was 14–18 months, presumably corresponding to a two‐year cycle from one egg stage to another. In some individuals the underground period was either 3–6 or 12 months. Most adults appear above ground in August. Less than 10 % of the eggs reached the adult stage on one cleared plot, the greatest mortality occurring in the early larval stages. Normally no H. abietis will be present in the stumps after the second summer after felling. The latter statement also applies to all Scolytids in clear‐felled plots; in thinned plots small numbers may persist after that. Hylastes ater Payk. was the most numerous of these Scolytids. Where the adults of that species could choose between freshly barked and unbarked stumps greater numbers of them invaded the former, but the difference in numbers was offset later by the greater mortality in the brood in the barked stumps. It is believed, however, that the total mortality in the barked and unbarked stumps together remained the same, and that even the barking of all the stumps in a given area would not have affected the total mortality. Barking prevents pine‐shoot beetles (Myelophilus piniperda L., Scolytidae) from breeding in the stumps, but not many are likely to do so under the conditions prevailing in the Netherlands; so the operation is not considered worth the expense. Other Scolytids regularly found in the stumps were Hylastes opacus Er., H. atten...
Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.