149 



Preventive measureg-In the summer of 1894 experiments with vari- 

 ous fungicides were carried on at Stanton and Citra, with a view to 

 find a preventive of the disease. The copper fungicides, i. e., Bor- 

 deaux mixture and ammonical solution of copper carbonate, were 

 found to almost wholly prevent the disease if properly applied. In 

 two plats of lemon trees at Stanton, sprayed with Bordeaux mixtures 

 (6 pounds of copper sulphate and 3J pounds of lime to 50 gallons of 

 water), melanose was absolutely prevented, the most careful search 

 failing to disclose a single fruit showing the characteristic spots. The 

 sprayings were made once a week and twice a week, respectively, for a 

 term of ten weeks, beginning February 3. On an orano^e tree sprayed 

 at the same time with the lemons the treatment was equally effective. 

 However, both the lemon trees and orange trees were somewhat injured 

 by the Bordeaux mixture, probably largely because of the numerous 

 sprayings given. On adjoining unsprayed lemon trees from 2 to 4 per 

 cent of the fruits and a larger per cent of the foliage were considerably 

 spotted with the disease. Perhaps half the spoted fruits were so badly 

 disfigured as to be unsalable. In a plat of lemon trees sprayed weekly 

 with ammoniacal solution of copper carbonate (5 ounces to 50 gallons), 

 beginning February 24 and continuing eight consecutive weeks, no 

 melanose could be found on any of the sprayed trees. However, very 

 little developed on the unsprayed trees adjoining this plat. 



In another series of experiments at Citra, several plants of very badly 

 infected orange trees were sprayed wivh Bordeaux mixture (6 pounds 

 of copper sulphate and 3^ pounds of lime to 80 gallons of water). In 

 one of these plats sprayed twice, April 19 (shortly after flowering) and 

 May 16, melanose was almost wholly prevented. Only two slightly 

 spotted fruits were found on the entire plats of twenty- five large trees. 

 Certainly not one-tenth of 1 per cent of the fruit showed even a trace 

 of the disease. On the adjoining unspraj^ed trees fully 90 per cent of 

 the fruit was diseased, some 50 per cent of it being very badly dis- 

 figured. In these experiments the trees also were injured to some ex- 

 tent, probably largely because of the abundance of scale insects on 

 sprayed trees. As melanose was absolutely prevented by Bordeaux 

 mixture of the strength above, it is highly probable that weaker sprays^ 

 would be equally effective. It is likely that more sprayings will be 

 necessary in treating melanose on the lemon than on the orange be- 

 cause of the more extended flowering period of the former. Although 

 the experiments were mostly with Bordeaux mixture, which has proved 

 fully effective in preventing the malady,it is very likely that ammonia- 

 cal solution of copper carbonate will be the most practical remedy, be- 

 cause it is not so apt to injure the trees and will probably prove aB 

 efi'ective as Bordeaux mixture 



The following is a summary of practical directions for keeping mela- 

 nose in check : In treating the lemon for melanose, spray with Bor- 

 deaux mixture(^) or ammoniacal solution of copper carbonate. ( ^ ) Spray 

 first about a month after the beginning of the spring blooming, or 



(1) Take 6 pounds of copper sulphate and 3 pounds of good lime to 80 gallons of 

 water. Slack the lime carefully and dissolve the copper sulphat* ; then dilute ©aeh 

 constituent with water to 26 gallons and mix. Add 6 pounds of soap, dissolved in 

 as many gallons of hot water, and finally add enough water to bring the mixture 

 Hp to 80 gallons. A resin soap suitable for adding to fungicides can be prepared 



