PREVENTION AND DESTRUCTION OF INSECT PESTS. 515 



contains such noxious species as the raspberry weevils (0. picipes 

 and 0. suloatus) and the plum weevils (0. fuscipes and 0. tene- 

 bricosus). They all hide away during daylight, coming out at night 

 to feed. We can best catch these depredators by "jarring" the 

 trees over tarred sacks or boards at nights, when the weevils fall oil' 

 and are caught in the tar beneath. Jarring may generally be em- 

 ployed for this group of beetles. Arsenical spraying is also said to 

 kill them. Some other weevils (Bruchidce) attack seeds, living in 

 the larval state in them, such as the pea weevil {Bruohiis pisi). All 

 infested seed should- either be steeped in carbolic water or fumigated 

 with bisulphide of carbon for some hours, when all signs of insect 

 life will be destroyed. 



Such are some of the many ways by which we can prevent insect 

 attack. Cleanliness and the judicious rotation of crops loill to a 

 large extent keep them in check ; whilst, where we can, s%ich animals 

 as pigs, fowls, guinea-fowls, &o., may be employed on infested land 

 after a bad attack, especially in orchards, where they will be seen 

 greedily devouring all manner of grubs that come in their way. 



Substances used for the destruction of insects, or insecticides, are 

 now employed with great success. — Insectifuges are mixtures used 

 for keeping insects off a crop — preventive washes or powders. 

 Insecticides may be liquid or dry ; the liquid washes are always 

 preferable to the dry powders. To destroy insects by washes or 

 spray fluids we must carry one thing in our mind — namely. How do 

 the insects to be killed devour their food ? are they provided with a 

 biting or a sucking mouth ? 



There are' six chief types of washes now in use — namely, (1) Arseni- 

 cal washes ; (2) Tobacco toashes ; (3) Paraffin emulsions ; (4) SulpMir 

 lime washes ; (5) Soft-soap and Qiiassia washes ; (6) Caicstic or winter 

 washes. 



1. Arsenical waslies are three in number — viz., Paris green, London 

 purple, and Arsenate of lead. These poisonous washes are only of 

 use for leaf-eating larvae and beetles. As to the respective merits 

 of each, arsenate of lead stands first, as it has a lesser tendency to 

 burn the leafage, a feature which has too often attended the use of 

 Paris green. Arsenate of lead is mixed in the following manner : 

 dissolve 2 ounces of arsenate of soda (commercial) in a little water, 

 then dissolve 7^ ounces of acetate of lead also in water. Add the 

 arsenate of soda to 10 gallons of water, and then after stirring well 

 add the dissolved acetate of lead and mix the whole well together. 

 It may also be obtained as a paste (Swift's, Berger's, Voss', &c.) 



