31 



withp:r-tip. 

 The smaller twigs of the sweet orange and grape fruit are very 

 frequently and severely attacked. In a great many cases the death 

 of twigs from an attack of wither-tip is supposed to be the result 

 of die-back. This may, however, be easily distinguished from 

 die-back, as indicated on page 26. It not infrequently happens 

 that die-back and wither-tip occur on the same twig. Any ma- 

 terial weakening of the health of the tree is very likely to induce 

 an infection ; this, however, is not a necessary antecedent to in- 

 fection. The fruits of these two varieties appear to be exempt 

 from attack. 



PREVENTIVE AND REMEDIAL MEASURES. 



TRKATME>.'T TO PREVENT LEMON-SPOT. 



The loss from spotting of lemons may be greatly reduced, if not 

 entirely prevented, by spraying with fungicides, such as potassium 

 sulphid, ammoniacal solution of copper carbonate, and Bordeaux 

 mixture. 



The particular fungicide to be used will depend on the specific 

 form in which the disease manifests itself. For lemon-spot 

 sulphur spray* may be used after the lemons have been picked. 



The spraying may be done by first placing a layer of lemons 

 one or two deep on the curing bed, then spray this thoroughly, 

 place upon these another layer of lemons one or two deep and 

 again spray, continuing the placing of lemons and spraying until 

 the amount of fruit needed to fill the bed has been supplied. After 

 this the lemons should be allowed to dry thoroughly before the 

 cover is placed upon the bed. It is quite probable that the sulphur 

 spray or the potassium sulphidf will also be helpful in the progress 

 ofcolouringthelemons. Sulphur spray and potassium sulphid being 

 mild fungicides, there is no danger of producing lot by their use. 



Ammoniacal solution of copper carbonate^ may also be used to 



* Preparation of sulphur sriray. — Place 30 pounds of flowers of sulphur in a 

 wooden tub large enough to hold 25 gallons. Wet the sulphur with 3 gallons of 

 water ; stir it to form a paste. Then add 20 pounds of 98 per cent, caustic soda 

 (28 pounds should be used if the caustic soda is 70 per cent.) and mix it with the 

 sulphur paste. In a few minutes it becomes very hot, turns brown, and becomes 

 a liquid. Stir thoroughly and add enough water to make 20 gallons. Pour off 

 from the .'^ediraent and keep the liquid as ;i stock sohitioii in a tighn barrel or keg. 

 Of this solution use 4 quarts to 50 gallons of water. 



t Use 1 ounce of potassium sulphid to 2 gallons of water. 



X To prepare ammoniacal solution oj copper carbonate. — Put 3 gallons of water in 

 a wooden or an earthen vessel, pour 3 pints of ammofia (2G° B.) ii this, and stir 

 it to mix the two evenly. Take 8 ounces of copper carbonate and shake it into the 

 ammonia water, stirring the liquid for a while. If a considerable part of the 

 copper carbonate remains undissolved, the liquid may be left to settle ; if, how- 

 ever, all or nearly all of the copper carbonate is dissolved, more of it should be 

 added in the manner previously described until a considerable amount remains 

 undissolved ; then it is set aside as stated before. After th'e prcctpinate has settled, 

 use the clear blue liquid. The undissolved copper carbonate may then be treated 

 with more ammonia and water, fresh copper carbonate being added whenever the 

 residue becomes less than an ouncH. The solution should not be kept for more 

 than a day or two, and when used 1 gallon should be diluted with 16 or 20 gallons 

 of water. 



