. A manual of injurious insects [microform] : with methods of prevention and remedy for their attacks to food crops, forest trees, and fruit : to which is appended a short introduction to entomology. Insect pests; Agricultural pests; Entomology; Insectes nuisibles, Lutte contre les; Ennemis des cultures, Lutte contre les; Entomologie. 212 BIRCH. BIRCH. Gall Mite, rhytoptus (? sp.). Gall Mite of the Birch, mag., nat. length two-hunclreclths of an inch; egg, also greatly magnified; deformed shoot (smaller than life). The "Witch-knot, or great bunch of twigs looking like a large bird's nest
. A manual of injurious insects [microform] : with methods of prevention and remedy for their attacks to food crops, forest trees, and fruit : to which is appended a short introduction to entomology. Insect pests; Agricultural pests; Entomology; Insectes nuisibles, Lutte contre les; Ennemis des cultures, Lutte contre les; Entomologie. 212 BIRCH. BIRCH. Gall Mite, rhytoptus (? sp.). Gall Mite of the Birch, mag., nat. length two-hunclreclths of an inch; egg, also greatly magnified; deformed shoot (smaller than life). The "Witch-knot, or great bunch of twigs looking like a large bird's nest fallen at random amongst the branches of the Birch, may frequently be noticed; and amongst the various forms of galls caused by Phytopti this neculiar growth of twigs in the Birch tree is of some interest, from the attack of the Gall Mites producing an increased development of woody growth from the infested buds, instead of—as is usually the case—leaf- galls, or diseased leaf-buds alone. As far as I am aware up to 1876 this special attack had not been studied, and the following observations on the origin and progress of this diseased formation were taken by myself in part from so-called " "Witches' Brooms " growing in Saver- nake Forest, near Marlborough, and also from growths on Birch trees planted by the roadside at Spring Grove, near Isleworth, which (probably from the unsuitableness of the situation) suffered so much from Gall Mite that, whilst resident there in 1876 and 1877,1 was able to trace the effects of the infestation from the beginning.* The Phytoptm causing the diseased growth is greyish- white, cylindrical, and rarely exceeding one two-hundredth of an inch in length, and a quarter of that measure at its * In the 1st Edition of my ' Manual,' I gave a short note regarding this attack, which was all that space would permit, but now, as Ihe infestation is oi .,ome interest, I reprint by permission most of the information, together with the figures
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectentomology, bookyear1
