24 



As regards remedial measures, winter shelters such as bands and 

 ties on the trunks, cracks in the bark, etc., should be examined and 

 cleaned. In spring and summer infested fruits and injured twigs 

 should be removed. Kerosene emulsion with insect powder is a useful 

 remedy and should be sprayed thrice in May, July and August and 

 twice in June. Various methods of protecting the fruit, such as 

 covering them with paper bags, are considered, but are not recom- 

 mended on account of their cost. 



Kajitani (K.). Soju no Gaichu Chimadara-yokobai ni genin suru 

 Sanji no Koku-han. [Black Patches on Silkworms caused by a 

 Mulberry-infesting Leaf-hopper, Zygina mori, Mats.] — Dainihon 

 Sanshi-Kwaiho [Jl. Japan Silk Assoc.,] Tokyo, xxviii, nos. 333 

 and 334, 1st October and 1st November, 1919, pp. 712-715 & 

 794-798. 



The fact that black patches occur on silkworms owing to the attacks 

 of various enemies has already been recorded [R.A.E., A. vi, 502 ; vii, 

 152]. Somewhat similar symptoms are caused by a leaf-hopper, 

 Zygina mori, Mats., which is a common pest of mulberries. The 

 Chinese race of sikworms is more liable to attack than the indigenous 

 Japanese one, but the pupa is not affected. 



The black patch produced by this insect is characterised by being 

 circular or elliptical in shape with a jagged edge and is usually of a 

 lighter colour in the centre. It can be distinguished from similar 

 symptoms caused by other organisms in the following points. The 

 patches caused by pebrine are irregular, or polyhedral in shape and are 

 usually darkest in the centre ; those caused by the gold-tail moth 

 [Ardornis chrysorrJioea] have smooth edges ; those caused by the mite 

 (Pedicnloides) are larger and rather irregular, and are found usually on 

 the ventral surface. 



Yagi (N.). Sanyo ni mii daseru Shishu no Dani. [Four Species of 

 Mites found on the Silkworm Pupa.] — Dainihon Sanshi-Kwaiho 

 [Jl. Japan Silk Assoc], Tokyo, xxviii, no, 334., 1st November, 

 1919, pp. 787-790, 1 plate. 



The mites recorded on silkworm pupae, in addition to Pediouloides 

 are : — Tyroglyphus sp., a Canistrinid, Gamasus sp., and Cheyletus sp. 



Amari (S.). Pedicvloides-Dsini ni yoru Sanji, Sangyo, Sanga no Hanten 

 ni tsuite (Yoho). [On the black Patch in Silkworms caused by a 

 Mite, Pediculoides (Preliminary Report)]. — Dainihon Sanshi- 

 Kwaiho [Jl. Japan Silk Assoc], Tokyo, xxviii, no. 334, 1st 

 November, 1919, pp. 790-792. 



The author has observed that all stages of Bombyx mori, when 

 infested by a mite {P edict doides) [R.A.E., A, vii, 152] exhibit black 

 patches on the body. In 1917, the experiment of placing the mites 

 on healthy silkworms proved negative, although the hosts died. In 

 1919, the experiment was repeated with silkworms that were about 

 to moult, with the result that black patches made their appearance. 

 The development of these symptoms seems to be independent of tem- 

 perature pnd may be produced at any time of year. They may also 



