252 



AGRONOMY 



FIG. 182. Scale insects on 

 a maple leaf 



kinds, often covering every available spot. The scale is a 

 waxy substance secreted by the insect, and under this it lives, 

 sucking the juice from the tree and multiplying rapidly. If 

 not eradicated, it will ultimately cause the death of the plant. 

 Strong sprays that can be used when 

 the plant is dormant are most useful in 

 combating this pest. The lime-sulphur 

 spray used against fungous pests is also 

 effective against this one, although it 

 can be used in winter only. 



Preventing attacks of insects. It is 

 more difficult to protect plants from 

 winged insects than from creeping ones, 

 since the former can go from one plant 

 to another through the air. Creeping 

 insects may be trapped or repelled in 

 numerous ways. The foliage of plants 

 likely to be attacked may be sprinkled with ashes or slaked 

 lime. Bands of sticky paper or tar may check the advances 

 of climbing species, and whitewashing the trunks of trees will 

 discourage many others. Small plants may be screened, but, 

 in general, poisons and sprays are most effective. Bands of 

 cotton fastened about the trunks of trees some distance from 

 the ground are favorite hiding places for many insects, which 

 may thus be easily caught and killed. 



Poisons for chewing insects. For all kinds of chewing insects 

 one of the poisons adapted to the purpose should be used. Of 

 these the most useful for general purposes in the small garden 

 is white hellebore, which may be procured at any drug store. 

 This may be sprayed on the infested plants in the proportion 

 of 1 ounce to 3 gallons of water, or it may simply be dusted 

 on the foliage when wet with the dew. White hellebore is 

 not so poisonous as some of the other remedies used, but 

 its convenience serves to recommend it. Paris green, an 



