. The large larch sawfly (Nematus erichsonii) [microform] : with an account of its parasites, other natural enemies and means of control. Insect pests; Tenthrède du mélèze; Larch; Insectes nuisibles, Lutte contre les; Larch sawfly; Mélèze. M il none of those (11) emerging from the cocoons rontraeted the fungous disease. After 21 days no more adults emergef these, nine eventually developed the typical Isaria and the moss also began to be covered with numerous Isaria colonies. This experiment confirms my other oliservations and indicates that the disease may \n> artificially introduced
. The large larch sawfly (Nematus erichsonii) [microform] : with an account of its parasites, other natural enemies and means of control. Insect pests; Tenthrède du mélèze; Larch; Insectes nuisibles, Lutte contre les; Larch sawfly; Mélèze. M il none of those (11) emerging from the cocoons rontraeted the fungous disease. After 21 days no more adults emergef these, nine eventually developed the typical Isaria and the moss also began to be covered with numerous Isaria colonies. This experiment confirms my other oliservations and indicates that the disease may \n> artificially introduced even at so late a stage in the development of the larch sawfly. Infection takes place in nature, no doubt, much ; "Although none of my experiments were made under strictly natural conditions, that is to say in the open air, y ^ the observation that the fungus Isaria is regularly fmuul year after year ui r larch tn-es when once it has been found, may indicate that the results really closely show what takes place in ; The above results and observations are confirmatory of my belief and observations as to the method of infection. They also indicate that the fungus is an important factor in the control of the disease, which is supported by my own and Mr. Mangan's observations under forest conditions. In certain the number of coeen as high as twenty-five per cent. Such a percentage of infection was oljserved by me in one locality in Cumberland in January, 1 -i. The adoption of any prai,..able measures against a pest of the nature of the larch sjiwfly when it is widely spread ane made for the presence jf the diaracteristic larva? or their green excrement "pellets" which can often be found when the larvffi are beyond reach or sight. It may be iM) to control or eradicate the pest in its earlier stages when a few trees only are attacked. Plnnting. In replanting or afforesting areas pure stands of larch should be avoided
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectinsectp, bookyear1912
