505 



BSrner ( — ) & Janisch (— ). Zur Lebensgeschichte und Bekampfung 

 der " Schwarzen Blattlause." [A Contribution to the Life-history 

 and Control of the " Black Aphids."] — N achrichtenbl . dcittscli. 

 Pflanzenschutzdienst, Berlin, ii, no. 8, 1st August 1922, pp. 65-67. 



As a result of his previous investigations [R.A.E., A, x, 262] the 

 senior author treated as distinct species the following black Aphids : 

 Aphis vihurni on snowball, A. philadelphi on Philadelphus, and A. 

 rmnicis on Rumex, while the name A . eiionymi was used for Aphids on 

 Euonymus. The varying behaviour of the last-named when transferred 

 to herbaceous plants indicated the possibility of further differentiation 

 among them which this year's work has confirmed. During the spring 

 of 1922 black Aphids on Euonymus from various sources were bred for 

 comparison. It was found that they are divisible into two species, 

 differentiated by the length of the hairs (especially on the antennae, 

 fore-legs and sides of the body) and by the food-plants. The short- 

 haired species refused Vicia faha, Chenopodium, Beta and Papaver ; 

 these were accepted by the long-haired species, for which the name 

 A . papaveris is adopted, the short-haired one being called A. euonymi. 



A, papaveris occurs in spring and autumn on Euonymus, on which 

 alone it hibernates, and in summer and early autumn it is found 

 on the plants mentioned above and on Cirsium, Carduus, Fumaria, 

 Urtica dioica, Phaseolus, Umbelliferae, Campanida, Capsella, Rheum, 

 Galium, and Scorzonera. It also occurs on the young shoots of some 

 woody plants, such as grape-vine, Crataegus, Pyrtis and Cydonia. 

 In the open it has never been seen on Rtimex and cannot be bred on it. 

 It also refuses Arctium lappa and Solanum nigrum. It is especially 

 injurious on Vicia faba, Beta, Chenopodium, Papaver and Phaseolus, 

 and curls the leaves of Euonymus, Beta, Chenopodium, stinging 

 nettle, etc. 



A. euonymi occurs in spring and autumn on Euonymus, on which 

 alone it hibernates. In summer and early autumn it is found on 

 Solanum nigrum, Polygonum convolviilus, common thistle, Rumex 

 crispus and Umbelliferae, causing leaf-curl on them. It is not injurious. 



There is a thii'd migratory black Aphid, the autumn, winged 

 individuals of which van der Goot incorrectly described as the alate 

 forms of the snowball Aphid, A. vihurni. Breeding experiments, 

 begun in autumn 1921 with the winged migrants to the common 

 snowball, resulted in large colonies infesting the ends of the shoots 

 and lower surfaces of the leaves without causing any leaf-curl as 

 A . vihurni does. Attempts to transfer the spring forms to Vicia faha, 

 Chenopodium, Beta and Papaver failed. Transference to Arctium lappa 

 succeeded very well ; success was less marked with Rumex and Umbel- 

 liferae. No leaf-curl was produced on these summer food-plants. This 

 last fact and the above limitation to certain plants are biological 

 differences that in conjunction with a morphological difference (the 

 presence of secondary olfactory organs on the fifth antennal joint of 

 the sexupara) justify in the author's view the erection of a new 

 species, A. nwrdivilkoi. It is not injurious, and it hibernates on 

 snowball alone. It is long-haired, like A. papaveris. 



A. vihurni is not a true migratory Aphid. It occurs from spring 

 to autumn on' the common snowball, on wliich it causes leaf-curl and 

 to which alone it is injurious. It hibernates on this plant alone. 

 Transmission to herbaceous plants has succeeded artificially only. 

 It has very long hairs. 



