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HoRNE (A. S.) & Lefroy (H. M.). Effects produced by Su&king 

 Insects and Red Spider upon Potato Foliage. — Ann. A pp. Biol, 

 London, i, no. 3 & i, Jani>ary 1915, pp. 370-386, 4 plates. 



This paper details a series of experiments undertaken to ascertain 

 accurately what eflects are produced in potato foliage by the action 

 of sucking insects. The following species were used in making infesta- 

 tions : Aleurodes vapomriorum, Westw., Tetmnychus telarius, L. (red 

 spider), Rhopalosiphuni solani, Theo., the two Jassids, Eupteryx 

 atropunclata, (ioeze, and Chloriia viridula, Fall. (? C. solani, Koll.), 

 and the Capsids, Calocori,s bipundalus, F., and Lygus pabnlinas, L. 



Definite and similar symptoms, apart from any other cause, were 

 obtained as the result of infesting young plants raised from seed of the 

 "President" variety of potato with the above insects under various 

 experimental conditions as follows : T. telarius, leaves become mottled, 

 plants turn brown and die; A. vaporariorum, effect gradual, plants 

 weakened, but did not die ; R. solani, leaves with discoloured veins, 

 brown and dead leaf-ends, yellowing and death of the plant ; Jassids, 

 white spots, plants did not die ; Capsids, dark brown blotches on 

 leaves and young growth, veins darken, young leaves and shoots 

 killed rapidly. 



These symptoms did not develop in the controls, except where 

 the control plant became infested by the particular insect in the 

 experiment. 



The effect on the foliage tissue in each case is as follows : T. telarius, 

 epidermal and sub-epidermal cells injured ; Aleurod£s, conducting 

 tissue tapped, not followed by vein discolouration ; R. solani, conducting 

 tissue tapped, followed by vein discolouration after nine or ten days ; 

 Jassids, epidermis punctured, assimilatory tissue destroyed ; Capsids, 

 tissue lacerated, causing severance of veins and leaving ragged, 

 irregular pits which rapidly become discoloured, as do also the veins 

 within two days. 



The markings caused by Jassids and Capsids proved distinctive 

 and could be recognised as such, for some time after the injury, but 

 for the safe recognition of Aphid {R. solani) injuries, the association 

 of typical markings with Aphids or their remains is necessary. Evidence 

 was obtained that Aleurodes selects particular plants. Definite 

 symptoms due to Aphids, Jassids and Capsids, correlated with the 

 presence of remains of these insects, have been found in the field crops 

 in several districts in three consecutive seasons. During and after 

 periods of wet weather, the original injuries, especially those caused 

 by Aphids and Capsids, frequently suffer secondary' extension, and 

 the foliage is prematurely destroyed. From field observations, Aphids 

 appear to exhibit a preference for certain varieties or races of potato, 

 but the question of selection has not been experimentally studied 

 by the authors. 



Petherbridge (F. R.). Exomias pellucidus as a plant pest, — Ann. 

 App. Biol, London, i, nos. 3 «fe 4, pp. 390 392, 1 plan. 



On 14th May 1914, an enquiry was received from a nurserv at 

 Fordham, Cambs., concerning the damage done to a number of 

 plants by the weevil Exomias [Barypeithes) pellucidus. A visit was 



