. 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. Buds of Birch infested by Gall Mite. The infested buds figured above, magnified at fig. 1, may be distinguished by their spheroidal shape, greater size, and loosely imbricated irregular scales, from the natural growths, which are smooth and lanceolate in general
. 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. Buds of Birch infested by Gall Mite. The infested buds figured above, magnified at fig. 1, may be distinguished by their spheroidal shape, greater size, and loosely imbricated irregular scales, from the natural growths, which are smooth and lanceolate in general outline. A few months later (about the beginning of February), a touch to one of these distorted buds will often throw off all the diseased scales, and at their bases the coming growth will be found in the numerous minute round buds set close together on the common thickened centre, as shown (magnified) at fig. 2. The growth of the knot from these embryo buds is the work of years; but Avliilst the tree is still bare of leaves it may be found in every stage of progress: the shortened shoot beset with swollen buds, as (magnified) at fig. 3 ; the compound form, where many buds have grown close together so as to present a hard cluster, with a few shoots starting from it (figured page 212), and so onwards, till the Witch-knot is fully formed, a mass sometimes more than a yard in diameter. In November I found the four-footed Acaras {Phytoptus) to be present in an active state, amongst the inner scales, in numbers that might be counted by dozens or scores; and about the beginning of February I found numerous egg-like bodies amongst the diseased leaf-scales, from which Phytopti were shortly after disclosed, occasionally perishing whilst partly excluded from the pellicle, so as to give ample oppor- tunity for examination. These eggs were bluntly ovate (as. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - colorat
Size: 1340px × 1864px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectentomology, bookyear1
