180 



TITRNIPS. 



cation is to be sure that no more than the prescribed quantity 

 of fluid is added to a certain quantity of water. 



Some good may be done by copious syringings with such 

 appHcations as ammoniacal water, tobacco-water, and soft- 

 soap, the strength of the appHcation being proportioned to 

 what the leafage will bear. One part of gas-water or 

 ammoniacal liquor to ten or twelve of water will kill Green 

 Fly, but the strength of the liquor varies so much that 

 experiment is necessary before use to ascertain its power. 



Aphides multiply most quickly in dry weather, and on 

 plants which are sickly from drought, exhaustion by insect- 

 attack, or other causes ; so that all measures of cultivation 

 tending to produce vigorous healthy growth are serviceable in 

 counteracting attack ; and where circumstances allow of the 

 application of liquid manure, or of water to an extent to make 

 the plant-food in the soil available, and push on growth that 

 otherwise was being checked by drought, such treatment 

 would be desirable. 



Where new growth is not l)eing made, and the juices are 

 being constantly abstracted by the Green Fly, the plant 

 necessarily fails, unless extra food is supplied to start it 

 forward. 



Various kinds of Titmice, and especially the Blue Tit, are 

 of service in destroying Aphides ; and the common Ladybird 

 Beetles and their larvse feed on them voraciously. 



Turnip Fly, or Flea Beetle. Haltica {PhjUotreta) nemorum, Linn. 



1 y 



1—3, 71. ncmmun: 4 and 5, eggs ; 6—9, maggot ; 10 and 11, pupa ; 

 all nat. size and magnified. 



This is one of our most destructive kinds of insect attack 

 to Turnips and allied crops. 



The P. nemorum (figured above, magnified, in the act of 



