Unsuccessful Brood Development of the White-Pine Weevil
| Autor: | H. M. Kulman, D. M. Harman |
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| Rok vydání: | 1967 |
| Předmět: | |
| Zdroj: | Journal of Economic Entomology. 60:1216-1220 |
| ISSN: | 1938-291X 0022-0493 |
| DOI: | 10.1093/jee/60.5.1216 |
| Popis: | Many white pine, Pinus strobus L., leaders killed by the white-pine weevil, Pissodes strobi (Peck), do not yield a new brood of weevils. Brood development was considered “successful,” A , if weevils emerged from the attacked leaders and “unsuccessful” if weevils did not emerge. Unsuccessful brood development was classified as B , dead leaders; C , live leaders so badly damaged that laterals took the leader position; D , live leaders with a conspicuous reduction in growth; and E , live leaders bearing large scars. Leaders in categories A, B , and C always caused crooked trees. If leaders in categories D and E died or were broken by wind, the damage caused crooked trees. Unsuccessful brood development was commonly observed in white pines in Wisconsin, Ohio, Maryland, West Virginia, Tennessee, North Carolina, Virginia, Minnesota Pennsylvania, and New York. In the 6 last-mentioned States, quantitative data were taken showing that about ⅓ of the weevil-caused crooked trees in open natural stands and plantations, and about ½ of the crooked trees in understory stands, were associated with unsuccessful brood development. In stands with a high frequency of unsuccessful broods, the average number of weevils reared per producing leader was less than in stands with a lower frequency of unsuccessful broods. It was concluded that unsuccessful brood development was a rather uniform phenomenon on the basis of data from more than 70 stands scattered throughout most of the range of white pine in the United States. |
| Databáze: | OpenAIRE |
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