Text Appearing Before Image: F-519939-40 Figure 93.—The native elm bark beetle, Hylurgopinus rufipes: top, adult; bottom, gallery pattern. Text Appearing After Image: Winter is spent in the bark of elm trees in either the larval or adult stages. Overwintering adults emerge during May and fly to living trees and feed in the bark. Later they fly to dead and dying trees, broken limbs, or recently cut logs or limbs to breed. Usually, dying or fairly moist dead limbs at least 2 inches in diameter are selected. Entrance holes are made in bark crevices or under overhanging bark flakes and they penetrate directly to the surface of the wood. A biramous egg gallery is constructed with the arms extending away from the entrance hole at various angles (fig. 93). The gallery may be constructed horizontally, but is most often inclined from the horizontal. Galleries may be constructed entirely in the bark, or they may scar the wood slightly. Eggs are laid on both sides of the gallery, sometimes very close together. Young larvae feed away from the gallery, usually following the grain. Pupation occurs in cells at the end of the larval tunnels in the bark. There appears to be two gen- erations per year in the southern portions of the insect's range. In the northern portions there may be only one or one and a partial second (410). When the adults emerge from elms dying from Dutch elm dis- ease, they often carry spores of the disease-causing fungus on their bodies. When they bore into the bark of healthy elms to feed or hibernate, some of the spores rub off onto the walls of their tunnels, inoculating the tree with the disease. In most parts of the United States, the spread of the disease by the native elm bark beetle is secondary to its spread by the much more abundant smaller European elm bark beetle. Farther north in Canada, 251
Note About Images
Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.
Cette image est issue de la collection The Commons du site Flickr. Les organismes y partageant leur collection déclarent qu'à leur connaissance, aucune restriction de droit d'auteur ne fait obstacle à leur diffusion, pour l'une des raisons suivantes :
l'œuvre est dans le domaine public car les droits d'auteur ont expiré ;
l'œuvre a été rattachée au domaine public pour d'autres raisons, tel que le non respect des conditions nécessaires pour renouveler des droits d'auteur ;
l'organisme est détenteur des droits d'auteur mais ne ne souhaite pas exercer son contrôle ou ;
l'organisme possède des droits suffisant pour permettre à des tiers d'utiliser ces travaux sans aucune restriction.
Merci d'ajouter des bandeaux de licence supplémentaires à cette image si des informations plus spécifiques sont disponibles à propos du statut de cette image. Consultez Commons:À propos des licences pour plus d'informations.
No known copyright restrictionsNo restrictionshttps://www.flickr.com/commons/usage/false
Cette image a été originellement postée sur Flickr par Internet Archive Book Images à l'adresse https://flickr.com/photos/126377022@N07/20946246870. Elle a été passée en revue le 26 septembre 2015 par le robot FlickreviewR, qui a confirmé qu'elle se trouvait sous licence No known copyright restrictions.
26 septembre 2015
Légendes
Ajoutez en une ligne la description de ce que représente ce fichier