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Emigration from elm to currants takes place in July and August and 

 the return of the sexuparae to the elm in November. It is probable 

 that far more damage is done by this pest than is suspected ; benzine 

 poured into holes in the soil at about 10 inches apart and of the same 

 depth as that at which the aphids are found, is said to be an effective 

 remedy ; about 5 cubic cm. is sufficient in each hole, which should be 

 at once closed. Pinus cembra in nurseries near Breda was attacked 

 by Pineus {Chermes) sibiricus, Choi. This pest is generally found 

 where Picea excelsa and P. cembra are growing together. The life- 

 cycle corresponds with that of S. nlmi, only that it lasts two years 

 and the intermediate host plant is a conifer. Pineus hibernates as a 

 stem-mother, not as an egg. In spring the stem-mothers, thickly 

 covered with wax, are to be found on the terminal buds at the base 

 of a needle. The shoots are not so much shortened as in the case of 

 attack by Chermes abietis, and the needles are broadened and scaly 

 at the base and generally the attacked shoot has a more normal 

 appearance. The winged immigrant progeny of the stem-mother and 

 their ^vinged young, the sexuparae, return to the spruce and there 

 lay eggs from which the sexual forms hatch out. The fertilised female 

 lays one egg and from this the stem-mother hatches. Hemichionaspis 

 {Chionaspis) aspidisirae, Sign., was found on the leaves of Asplenium 

 nidus-avis (bird's nest fern) and on Polypodium laevigatum ; the males 

 are white and the brownish females attached to the leaf between the 

 rings of spores are not readily visible. Aspidiotus abietis, Schr., was 

 found on Picea pungens. Tetranychus telarius, L., was constantly 

 reported as a pest, and T. altheae, Haustein, may also have been 

 present. Sulphur in the finest possible powder, mixed with soapy 

 water (6| lb. sulphur and 1 oz. soft soap in 20 gallons of water), was 

 found to be an excellent remedy. Picea remonti was attacked by a 

 Tetranychus not identical with T. telarius and probably T. ununguis, 

 Jacobi, though Oudemans regarded the specimens sent to him as 

 T. carpini, Oud. A pear branch was received thickly covered with a 

 white mass consisting of moulted skins and empty egg-shells. This 

 was determined by Oudemans as Bryobia nobilis, Koch ( = praetiosa, 

 Koch, = speciosa, Koch, = cristata. Dug.). It is doubtful whether 

 Bryobia ribis, Thomas, is identical with B. nobilis or not. B. ribis is 

 not to be found after May on gooseberries, but the author has found 

 B. nobilis on ivy in mid-winter and it only disappeared under the 

 influence of intense frost and a cold wind. Oudemans determined 

 mites from gooseberries sent to him as B. nobilis, but the question 

 of the identity or otherwise of these species and varieties is not 

 finally settled [see this Review, Ser. A, ii, p. 169]. Eriophyes ribis, 

 Nal., and E. pyri, Nal., were frequently reported on black currant 

 and pears ; the former winters in the second and third layer of 

 the bud leaves, and so cannot be reached by carbolineum or other 

 sprays. Against E. pyri, a winter spray of 6 per cent, carbolineum 

 reduced the pest in the following year to very small proportions ; a fine 

 sulphur and soap spray applied early in July also proved useful, but 

 winter treatment is best, because it is very difficult to determine the 

 precise time at which to spray with effect in summer. Serious damage 

 to the leaves of Buxus (Box) was traced to E. unguiculatus. Corn. 

 According to Nalepa, this species causes hairy malformations of the 

 buds, but this was not the case in the specimens sent to the station. 



(C144) D 



