542 



Trehkrne (R. C). Some Notes on the Fruit Worms of British 

 Columbia.- — Separate from Scienlific Agriculture', ]\Iarch 1921, 

 4 pp., 5 figs. [Received 20th September 1921.] 

 Owing to the great similarity tliat exists between the various fruit- 

 infesting larvae in Canada, these notes are given as a guide to their 

 ready determination. The species dealt with are the Tortricids, 

 Eucosma (Tmctocera) ocellana (apple bud moth), Cydia pomonella 

 (codling moth), Peronca {Acleris) maximana, Tortrix {Archips) 

 rosaceana, T. (A.) argyrospila and Enarmonia prunivora (lesser apple 

 worm) ; the Gracilariid, Marmara pomonella (apple fruit miner) ; 

 the Gelechiids, Anarsia lineatcUa (peach twig borer) and Aristotelia 

 fragariae (strawberry crown borer) ; the Occophorid, Epicallima 

 dimidieUa ; the Pyralids, Plodia interpundclla (Indian meal moth), 

 and Mineola tricolorella ; and the Geometrid, Rachela bniceata (Bruce's 

 measuring worm). A key to certain families, adapted from Fracker, 

 is also given. 



Crawford (H. G.). The European Corn Borer. — Separate from 

 Scientific Agriculture, March 1921, 4 pp., 2 figs. [Received 

 20th September 1921.] 

 The present situation with regard to Pyrausta niibilalis, Hb., in 



the United States and Canada is reviewed and general recommendations 



for protecting non-infested areas and for dealing W\i\\ those already 



infested are made. 



Skaife (S. H). Some Factors in the Natural Control of the Wattle 



Bagworm. — 5. African Jl. Sci., Johannesburg, xvii, no. 3-4, 

 July 1921, pp. 291-301, 15 figs. 



Very little is known about the early mortality of AcanthopsycJie 

 jimodi (wattle bagworm), although this is one of the most important 

 factors in the natural control of this moth, as a far greater number 

 is destroyed during that period than by the various natural enemies 

 that are present during the later stages. The Ichneumonid, P/iilopsyche 

 abdominalis, Morley, which is a parasite of A. junodi, has apparently 

 two generations a year. The adults emerge over a prolonged period 

 from March to October, and the generations overlap. Larvae and 

 pupae were found in the bags of the host in March, and in April eggs 

 and young larvae occur simultaneously. 



Carcelia evolans, Wied., is the commonest Tachinid parasite of 

 A. junodi. When mature the parasitic larva leaves the body of the 

 host and either pupates in the bag, or drops to the ground and pupates 

 in the soil. Adults emerge from March to October, and there are 

 possibly two generations a year. C. evolans is in turn parasitised by 

 a minute Chalcid. About 20 per cent, of the bagworms that 

 survive the early stages are destroyed by insect parasites, of which 

 Hymenoptera are more than three times as efficient as Tachinids. 



The action of the fimgous disease, Isaria psychidae, is somewhat 

 impaired by the attacks of a secondary parasitic fungus, Mclanospora 

 parasitica. The polyhedral wilt disease of the gipsy moth in America 

 is also highly destructive to A. junodi, as are also other diseases of 

 an obscure nature. The virulence of these diseases, however, is largely 

 dependent on climatic conditions. The excessive humidity during 

 the warmer months either sets up physiological disturbances that 

 cause the death of the larvae, or else weakens them and renders them 

 peculiarly liable to disease. 



