. An annotated list of the important North American forest insects. Forest insects. 10 Farmers' Bulletin 1259. DISTRIBUTION. Leconte's sawfly occurs throughout the eastern United States, the accompanying map (fig. 10) indicating localities from which the species has been recorded or specimens received. TREES ATTACKED. This species seems to have a preference for jack pine,^ red pine,^ and scrub pine,* each of which furnishes a local host in some part of the eastern United States through- out which the insect occurs. Its attack is not limited to these spe- cies, however, for it is also found on
. An annotated list of the important North American forest insects. Forest insects. 10 Farmers' Bulletin 1259. DISTRIBUTION. Leconte's sawfly occurs throughout the eastern United States, the accompanying map (fig. 10) indicating localities from which the species has been recorded or specimens received. TREES ATTACKED. This species seems to have a preference for jack pine,^ red pine,^ and scrub pine,* each of which furnishes a local host in some part of the eastern United States through- out which the insect occurs. Its attack is not limited to these spe- cies, however, for it is also found on or recorded from white pine,^ K 7 i • '^V ^ ^^^' scotch pine,*' loblolly pine,^ shore rV \ ) l^Ov^\^\!'^ pine,^ silver pine," mugho pine,^" western yellow pine," longleaf pine,^^ Austrian pine,^^ and Amer- ican larch.^* PERIODICAL OUTBREAKS. Leconte's pine sawfly, like most insect enemies of forest trees, ap- pears and disappears periodically. For several years this species will be very abundant, then for a few years it will be rare. The cause for this periodic disappearance has not been determined, but the low records of parasitism indicate that some factor other than parasitism plays an important role. NATURAL ENEMIES. Eight species of insect parasites and an infectious disease have been found killing this sawfly. None of these enemies, however, has been found widely enough distributed or abundant enough to account for the periodic disappearance of the species, and it is certain that neither any nor all of these natural checks are sufficiently numerous or effective to justify disregard of the artificial control measures Fig. 10.—Map showing localities where Leconte's sawfly is known to occur. - Piniis banksiatta. ^ P. rcsinosa. * P. iHrginiana. ^ P. strobus. * P. fiylvesPris. 'P. taeda. ^ P. contorta. " P. monticoUt. '"P. m ugh us. ^ P. ponderosa. ^ P. palustris. '3 P. austriaca. " Larix Please note that these images a
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