304 



a strong lens it was possible to see mites actually blown on to young 

 shoots and leaves, and when their movements were followed, it was 

 found that eventually they made their way to the petiole mostly along 

 the veins, which are smooth and over which they made rapid progress. 

 On reaching the base of the petiole they disappeared between its upper 

 surface and the main stem, where the bud eventually appears. 

 Dissection of such a leaf base showed that a small colony of mites had 

 established itself in this position. E. ribis therefore feeds and repro- 

 duces on these succulent inner surfaces until the buds, which are 

 almost invisible, are large enough to be entered. As the season 

 advances, the tissues of the lower leaves of the young shoots harden. 

 This causes most of the mites to leave those leaf bases which no longer 

 give them nourishment and to migrate to those nearer the growing 

 shoot. They also creep in between the minute bud and the main stem, 

 and it is in this position that they are usually found when present iu 

 the older leaf bases of the shoots. Examination of the bud scales which 

 persist for some considerable time round the bases of the new shoots 

 shows that the mites take shelter there ; they also collect in the leaf 

 scars and probably feed on the oil glands there. At the end of May, 

 the buds of the current year's gro\\i;h are entered by the mites, and 

 it is within them that the life-history is continued until the migratory 

 period in the spring of the following year. The impossibility of obtaining 

 uninfested stock interfered with an experiment to find out to what 

 extent new shoots are infested by mites carried by the wind, and the 

 presence of some disease — probably bacterial — and the ravages of the 

 parasitic fungus, Botnjtis eriophyes, interfered with another experiment 

 imdertaken to find out to what extent infestation occurs from a big 

 bud to the shoot growing from it. 



Taylor (Miss A. M.). Eriophyes ribis (Nal.) on Ribes grossularia. — 

 Jl. Agric. Science, Cambridge, vi, no. 2, May 1914, pp. 129-135, 

 1 fig. [Reprint received 13th May 1915.] 



When Ribes grossularia (the gooseberry) is attacked by Eriopihyes 

 ribis, Nal., no abnormal growth of the buds takes place, as is the case 

 with Ribes 7iigrum [see above], but while the tissues of the expanded 

 leaves and shoots of the latter show no sign of injury, they are severely 

 blistered and deformed on the gooseberry. The mite only migrates 

 by the agency of the wind, when on the gooseberry, to a limited extent, 

 the general method being that of crawhng from the scale leaves of the 

 attacked bud to the shoot developing from it. An examination of the 

 attacked bud of the gooseberry shows that no mites are present in the 

 true leaves of the bud, but that they collect on the succulent portions 

 of the scale leaves which surround them. They are found here from 

 the time when the buds are entered in early summer mitil the spring 

 of the following year. Large bhsters, which are characteristic of an 

 attack by E. ribis on this host, are formed on the surface of the scale 

 leaves. These fall off, when they have served their purpose of protect- 

 ing the embryonic shoot which they enclose. The injury is therefore 

 not permanent and the bud remains normal, because the mites do not 

 enter the true leaves and deform them. The blistering and deformation 

 of the expanded leaves and shoots of the gooseberry are due to the 



