. Circular. Insect pests; Insect pests. Avards noted similar injury in several of the smaller public parks of this cit}', shoAving- that the attack was not local, although more severe on the department "rounds, which had attracted the but- terflies from afar, doubtless owing to the much larger jjarkage, .Caterpillars kept under observa- tion had "sjoun up" for pupation by September ;>, but at this time there Avere still many young larva> present in garden plats, and there was eA'idence that they had been at Avork at least as late as the middle of August, Avhile the age of
. Circular. Insect pests; Insect pests. Avards noted similar injury in several of the smaller public parks of this cit}', shoAving- that the attack was not local, although more severe on the department "rounds, which had attracted the but- terflies from afar, doubtless owing to the much larger jjarkage, .Caterpillars kept under observa- tion had "sjoun up" for pupation by September ;>, but at this time there Avere still many young larva> present in garden plats, and there was eA'idence that they had been at Avork at least as late as the middle of August, Avhile the age of the larva indicated that the butterflies had appeared to lay their eggs late in July, but evidently not earlier. The cause of this iuA^asion Avas appar- ently that the summer of 1005 Avas an unusually hot one. Heat favors an increase of insects of this type. Prevailing southerly Avinds, however, Avere probably more potent factors in causing this migration from the Gulf region northward, since .the summer of 1906 Avas still warmer, but Avith much greater humid- ity, and under these condi- tions only one ]Dupa was found during that en- tire year. The attention of the Avriter Avas attracted to injury by this spe- cies by the large irregular areas Avhich were cut away from the margins of the canna leaAes, It was then noticed that the larva (fig. 1) begins operations by cut- ting a small, more or less oblong strip about one-half inch long from the edge of a leaf and fold- ing it neath^ over on the loAver sur- face, (See fig. 2.) "Within this flap, which is nearly flat, the larA'a liA'es concealed, feeding aboA'e and beloAv its retreat. As it increases its groAvth the larva makes large incisions in the leaf's edge, Avith a correspondingly large flap (fig. 3). It is not until the larva is considerably larger that it forms'large tubular retreats. (See Fig. ].—The larsor canna loaf - roller {Cali>o(lcs clhtiii^} : Full - .urown larva. About one-tliird on- larscd. (Orislnal.).
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectinsectp, bookyear1904
