APHIDID^E. 303 



by simply "cutting down" the young thorns and burning the prim- 

 ings. In transplanting such thorns previously cut down, care must 

 be taken to lift plants with the best possible roots, and encourage as 

 much as possible by attention and good management. This plan I 

 have adopted with considerable success. However, under ordinary 

 circumstances, it is certainly not advisable to cut down quicks the 

 same year as they are planted, inasmuch as the shoots produced are 

 not so strong as from those grown for a season prior to cutting off. 

 When the young thorns are cut off the same season, or, perhaps, 

 rather the same day, as they are planted, they are exposed to con- 

 siderable .risks. In the first place, the shoots are weak, and not able 

 to withstand insect attack, as for example the aphis on the shoots 

 during the summer, and also prior to the commencement of growth 

 by the clay-coloured weevil (Otiorrhynchus sulcatus). The shoots, 

 being comparatively weak, are more apt to be destroyed by rabbits 

 or choked by weeds. Hence it is better to cut off the second year, 

 wherever this method coincides with good local husbandry. 



If young thorns in nursery-lines are very badly attacked with this 

 species, and if such attacked quicks are not strong enough to go out, 

 or otherwise not convenient to put out, 

 it would also be well to cut them down 

 in the nursery-lines, burn the tops, and 

 dig in manure between the rows, so that 

 a strong bushy thorn may be produced 

 by another year. 



Aphis padi (Reaum.) 



This insect is very common on the 

 young shoots of Primus padus (bird- 

 cherry). Fig. 283 shows the injuries, 

 or rather the gregarious habits, of this 

 species ; but later on in the year, say 

 about the middle of July, nearly every terminal twig of the bird- 

 cherry bush has been killed. It is therefore evident that severe in- 

 juries accrue from this species, as the development of the bush has to 

 depend upon growth being produced in the latter end of the season. 



The apterous viviparous female is of a yellowish-green colour, some- 

 what variegated with oval stripes, and more or less stained with a 



Fig. 2S3. Aphis padi on bird-cherry. 



