THE GARDEN MAGAZINE 



23 



41. The scale follows the veins. (About natural size) 42. Plum twig badly infested. (About natural size) 



43. Infested plums, showing reddish discoloration 



young, results in almost continuous breeding 

 from the latter part of June till into October 

 and, under certain conditions, November 

 and even December. The period of activity 

 is longer in the southern than in the northern 

 States, and the destructiveness of the insect 

 correspondingly greater. This species has 

 been recorded upon a large number of food 

 plants, but is very injurious to compara- 

 tively few. The fruit-trees — peach, pear, 

 plum, cherry and apple — are preferred in about 

 the order named. Currant-bushes are very 

 subject to injury, and among ornamentals 

 none are worse affected than Japanese quince. 

 Lilacs, snowberry, willows and some other 

 ornamentals are also liable to serious injury. 



The method of spreading is of considerable 

 importance, particularly in places where the 

 scale has not become established. It is con- 

 veyed long distances almost entirely upon 

 plants. The danger of budding from infested 

 stock is greater, since the scale has a marked 

 tendency to gather about buds and other 

 rough portions of the bark. Aside from this, 

 the pest can spread only by the crawling 

 young being carried either by birds, other 

 insects, winds or animals. The first three can 

 hardly be controlled. Great care should be 

 taken during the breeding season not to 

 allow men and teams which have been work- 

 ing among infested trees to go directly to 

 uninfested ones, since the scale is easily con- 

 veyed in this manner. 



This insect is difficult to control not only 

 because it is exceedingly prolific, but largely 

 on account of its ability to withstand the 

 action of various insecticides, and particularly 

 because of its extended breeding-season. 

 It is a sucking insect, and, as stated above, 

 draws its nourishment from underlying tis- 

 sues, consequently the application of arsenical 

 poison or any similar material which lies 

 upon the surface of the plant and must be 

 taken into the stomach has practically no 

 effect. It can be controlled only by the use 

 of some substance powerful enough to pene- 

 trate the scale and destroy the underlying 

 insect. A large number of materials have 

 been employed for this purpose. The nearly 

 naked, crawling young are unprotected, and 

 on that account easily killed. The great 

 difficulty of attempting to check the insect in 

 this stage is that young are produced during 

 an extended period, and therefore the best 

 results have been obtained by the use of 

 materials strong enough to penetrate the 

 sheltering scale of the adult, and such sub- 

 stances are so strong that they can be applied 

 to deciduous trees only when in a dormant 

 condition. The best results, as a rule, have 

 been obtained by early spring applications, 

 preferably deferring the treatment till shortly 

 before the buds begin to open. 



A wide variety of materials have been 

 employed, prominent among which may be 

 mentioned whale-oil soap solution, kerosene 

 emulsion, crude petroleum and its emulsions, 

 and the lime-sulphur washes. The whale- 

 oil soap solution at the rate of two pounds to 

 one gallon of water is fairly effective though 

 costly, and in commercial orchards has quite 

 generally given way to other materials. 

 Both kerosene and crude petroleum, in pure 

 and mechanical emulsions, have been em- 

 ployed to a considerable extent, but in most 

 cases they likewise have been displaced by 

 the cheaper, safer lime-sulphur washes 

 which, as a rule, have been most success- 

 fully employed. There are many formulae 

 for these latter, some of which have been 

 used for years and others developed within 

 twelve months. 



A thoroughly safe, well-tried wash may be 

 prepared as follows : Take 20 pounds of lime 

 and 15 pounds of flowers of sulphur; bring 

 a few pails of water nearly to a boil in a large 

 iron kettle; add the lime, following imme- 

 diately with the sulphur; stir so as to inti- 

 mately mix, and keep the combination boiling 

 rapidly for at least thirty minutes, then re- 

 move and strain through a wire screen such 

 as ordinary mosquito-netting, and dilute to 50 

 gallons with cold water. This is one of the 

 simplest methods of making the wash, and 

 when properly prepared and very thoroughly 

 applied the results have been most gratify- 

 ing, as a rule. 



This material can be made in a similar 

 manner by steam boiling — that is, forcing a 

 jet of steam into a barrel containing the ma- 

 terials, and this method of preparation is a 

 very convenient one for those possessing 

 steam-engines or desirous of making large 

 amounts of the wash. Some lime-sulphur 

 washes do not require any boiling water, 

 and a method developed by Professor Lowe, 

 and subsequently used by Professor Parrott, 

 calls for the above-mentioned quantities of 

 lime and sulphur and about 4 to 6 pounds of 



44. Spraying San Jose scale in Mr. J. H'. Hale's 

 orchard in Connecticut. Running the mixture into 

 the pumping barrel from the supply platform 



caustic soda to 50 gallons of water. The lime 

 is slaked preferably with warm water, and 

 while the reaction is in progress the sulphur, 

 which has previously been made into a thin 

 paste, is added and thoroughly mixed with 

 the slaking lime. The caustic soda is then 

 put in and water supplied as needed, the 

 whole being stirred thoroughly. After the 

 chemical action has ceased, the mixture may 

 be strained and diluted as stated above. 



In spite of the poor results reported from 

 applications of lime-sulphur washes during 

 the past season in New Jersey, we feel that 

 in most sections of the country this material 

 is by far the best for controlling this pernicious 

 insect. It is not only cheaper, but when 

 thoroughly applied appears to be fully as 

 effective as any other, and there is far less 

 danger of injury to the trees. The kerosene 

 limoid spray may possibly be equally valu- 

 able, but it cannot be recommended for more 

 than experimental work till it has been further 

 tested. The question of what apparatus to 

 use for spraying is also important. Select 

 a stout, preferably iron pump, with broad 

 valve-seats, because high pressure is needed 

 and lime-sulphur washes are extremely 

 caustic and therefore injurious to any but 

 well-made pumps. A power outfit is advis- 

 able wherever extensive applications must be 

 made. Ten to twenty or thirty feet of hose 

 and a six- to eight-foot extension nozzle may 

 be classed with the necessities. Most essen- 

 tial of all is a thoroughly reliable man to hold 

 the nozzle, because, unless the trees are very 

 well covered with the spray mixture, poor 

 results are likely to follow. It is advisable, 

 before spraying, to cut the trees back as much 

 as possible, and in sections where the scale is 

 prevalent, low heading will doubtless become 

 popular because of the greater ease in fight- 

 ing this pest. Another important point is to 

 spray with the wind whenever conditions 

 permit, making the application on the other 

 side of the trees when the wind is blowing in 

 an opposite direction, since it is almost im- 

 possible to thoroughly spray a tree, par- 

 ticularly a large one, without the aid of a. 

 favorable breeze. Spraying outfits are rather 

 expensive, and the man with a few trees. 

 will undoubtedly find it much cheaper to hire: 

 his spraying done; and in some cases, at 

 least, co-operative neighborhood work will 

 prove the most economical and satisfactory 

 method of controlling this dangerous pest. 



The article on "Spraying Tall Shade 

 Trees " in the February rumber of Country 

 Life in America shows the kind of power 

 spraying outfits used by progressive park 

 superintendents, describes a new way of 

 making a living out-of-doors, and the new 

 type of neighborhood organization to get the 

 best spraying done for the least money. 



