84 



by hand-picking in spring as soon as signs of damage are 

 apparent. 



(2) In Commercial Plantations : Spraying. Magpie cater- 

 pillars are easily killed b'y means of lead arsenate, but a 

 difficulty arises from the fact that this insecticide is very 

 poisonous and cannot be used when the gooseberries are fruit- 

 ing. Lead arsenate spray should, therefore, be applied either 

 (1) just before the flowering period, or (2) at the end of August 

 to kill the young caterpillars. The time available for the work 

 during the first period is very short, as it is necessary to wait 

 until as much foliage as possible has been produced, while, on 

 the other hand, spraying must cease before bees have begun 

 to visit the flowers. It is possible that a second application of 

 lead arsenate might be given directly after the flowers have set, 

 but the berries swell so rapidly tHat there would be a risk of 

 poisoning the fruit unless the work was carried out rapidly and 

 with discrimination. 



If spraying be deferred until the end of summer, the nozzle 

 should be directed as much as possible on to the undersides 

 of the leaves. 



When an attack has not become apparent until it is too late 

 to use lead arsenate, then hellebore (which loses its poisonous 

 properties rapidly) may be used within three weeks of the 

 time when the fruit is to be gathered. Pyrethrum, which must 

 be fresh, is non-poisonous, and may be applied at any time. 

 There axe also various non-poisonous proprietary compounds 

 to be bought from most horticultural firms. 



(3) Formula. 



A. Lead arsenate paste* ... ... \ Ib. 



Water 10 gallons. 



B. Hellebore powder* 2 Ib. 



Water 10 gallons. 



C. Pyrethrum powder ... ... 2 Ib. 



Water 10 gallons. 



In mixing lead arsenate it is best to work up the paste into 

 a thin cream with a little water, subsequently adding the 

 remainder. 



Sprays B and G are improved by the addition of \ Ib.-l Ib. 

 of soft soap to each 10 gallons, and when being used, they 

 should be kept well shaken up. Half-a-pound of soap will 

 be enough unless the water is hard, when the full quantity 

 may be allowed. 



* Load arsenate and Hellebore are poisonous to man and animals 

 ,ud should be kept under lock and key. Spocial tubs should be 

 reserved for mixing the ?pray fluid. 



