SPRAYING FRUIT-TREES. 



43 



stirred each time the knapsack or engine is 

 filled. The strainers with which all spraying 

 machines should be furnished must have ex- 

 tremely fine meshes, and all liquids must be 

 passed through them before use, otherwise the 

 nozzles will be continually blocked and cause 

 endless trouble. 



Insecticides must either kill the insects imme- 

 diately by contact, or poison them through their 

 food. For the former it is difficult to find a 

 compound that will destroy the pests without 

 injury to the plant. The insects which infest 

 plants can be classed in two groups, namely 

 "sucking" and "biting" insects, indicating 

 roughly both the habits of the pests and the 

 best methods for their destruction. The suck- 

 ing insects comprise those that absorb the juices 

 of the foliage, as the numerous form of aphis, 

 red spider, &c. ; while the biting insects include 

 those which consume the leaf itself, as the hosts 

 of caterpillars and other larvse. 



The direct method should be employed for 

 the sucking insects, for the destruction of which 

 petroleum (paraffin), particularly in the form of 

 an emulsion with soft soap, is extensively used. 

 Where injury to foliage has resulted from its 

 use this has been traceable to neglect of ordi- 

 nary precautions. One of the simplest pre- 

 parations we have tried is the following: — 

 Dissolve two quarts of soft soap in a gallon of 

 hot water, and while it is still warm add a quart 

 of petroleum, stirring the whole together, pre- 

 ferably with a hand-syringe. To this add 20 

 gallons of soft water. This mixture is destruc- 

 tive to aphides of all kinds, while with the 

 addition of about 2 ozs. of liver of sulphur the 

 efficacy of the wash against red spider is 

 increased. 



Quassia extract with soft soap is also largely 

 used against sucking insects, but it varies in its 

 effects, and is not so reliable as the petroleum 

 mixture. The Quassia mixture can be obtained 

 ready for use on a small scale, but for extensive 

 work it is cheaper to make it. The Quassia 

 chips should be first steeped in enough cold 

 water to cover them for two hours, and then 

 boiled for ten hours, adding 10 lbs. of chips to 

 each 10 gallons of water, which can afterwards 

 be diluted to 100 gallons; to this, \ lb. of soft 

 soap for every 10 gallons is added, previously 

 mixed as already directed. 



The indirect method, i.e. poisoning the food 

 of the pests, is applied for the multitude of 

 "biting" insects which soon render the trees 

 leafless or injure the fruits if unchecked. For 

 this a mixture of Paris green and lime in water 



is used, and notwithstanding occasional injuries 

 to the tree foliage, it is one of the most effective. 

 It is a powerful poison, and therefore great care 

 is required in handling it. It is sold both as a 

 powder and as a paste, the latter form being 

 preferable in all respects, and this can be em- 

 ployed at the rate of \ lb. with 1 lb. of fresh 

 lime to each 100 gallons of water. The Evesham 

 Committee of fruit-growers a few years since 

 recommended the use of " 1 oz. of Paris green 

 to 8 gallons of water for growing foliage, or 



1 oz. to 6 gallons of water when the foliage is 

 matured ". The weaker mixtures, however, are 

 usually effective, and are less likely to injure 

 the trees. It should be impressed upon oper- 

 ators that Paris green does not dissolve in 

 water, and therefore requires frequent agitation 

 to keep it thoroughly mixed. Owing to its 

 poisonous nature it must not be sprayed over 

 fruit blossom, or the bees will be killed; nor 

 over fruit within a few weeks of the time for 

 gathering it. The best time for the first appli- 

 cation is immediately after the flowers have set 

 and when the young leaves are expanding, and 

 subsequently as occasion demands until the fruit 

 is approaching maturity. 



London Purple, a somewhat similar poison 

 to Paris Green, varies more in its composition, 

 is more uncertain in its effects on insects, and 

 more frequently injures the foliage. Its advan- 

 tages are that it is very finely divided and more 

 easily mixed. It can be used at the rate of 

 6 ozs. of London Purple and 12 ozs. of lime to 

 100 gallons of water. 



Arsenate of lead has been tried in America 

 with satisfactory results as a destroyer of cater- 

 pillars. It is prepared by mixing from 1 to 



2 lbs. of the arsenate with 150 gallons of water. 

 Extremely useful mixtures can be made with 

 this and petroleum emulsion, or with Bordeaux 

 mixture, thus securing a wash containing the 

 properties of several. 



Fungicides. — The only fungicide in general 

 use on a large scale for fruit-trees and orchard 

 spraying is the Bordeaux mixture, and this is 

 most efficacious. The mixture used consists of 

 12 lbs. of copper sulphate and 8 lbs. of quick- 

 lime to 100 gallons of water. The copper 

 sulphate is placed in a coarse canvas bag and 

 suspended in the water to dissolve gradually, 

 the fresh lime is mixed with water to form a 

 paste, and is then added. Another form is that 

 in which copper sulphate, lime, and treacle are 

 mixed at the rate of 10 lbs. of each to 100 gallons 

 of water; the treacle causes the liquid to adhere 

 to the foliage. Soft soap is occasionally substi- 



