16 Farmers’ Bulletin 1257. 
factorily. Generally these waters come from deep wells in the lime- 
stone formation and are termed “ hard,” but some, which come from 
surface wells, are as a rule brackish. Certain oil emulsions when 
combined with these “hard” waters may prove at times unsatis- 
factory, in that the calcium and magnesium salts present in the water 
tend to break up the emulsion, causing the oil to be set free during 
spraying. This free oil is detrimental to mango foliage and causes 
severe burning. Where a grower has knowledge of such separation, 
spraying operations should be discontinued and the trouble remedied. 
Where separation of oil occurs in using an oil emulsion with the 
water a grower has available, the water should first be softened by 
means of caustic potash fish-oil soap. This soap has been found to 
be satisfactory when 3 or 4 pounds are used to a 125-gallon tank of 
ordinary hard water. After the water has been softened, the oil 
emulsion should be added to the tank. There are a number of oil 
emulsions which contain the proper stabilizers, so that when the 
emulsion is combined with hard water no separation occurs, thus 
doing away with the additional expense and labor of softening. As 
a preliminary precaution it is advisable to test the spray before start- 
ing operations in the field. Barring a few difficulties which a grower 
may experience in the use of oil emulsions with hard water, the 
emulsions will prove to be most efficient sprays for the control of 
scales attacking the mango in Florida. 
Oil emulsions during the dormant season on the mango at a 
strength of 1 part to 70 parts of water have proved very satisfactory. 
Two applications during the winter, with an interval of three weeks 
between, are recommended. These applications should be so timed, 
however, as not to interfere with spraying for the red spider or 
thrips. It has been found that the use of 40 per cent nicotine sul- 
phate solution, at the rate of 1 part to 900 parts of spray, with the 
diluted oil-emulsion sprays, gives satisfactory results against the 
scale insects and thrips and temporary relief from the red spider. 
THE TESSELLATED SCALE. 
Another soft-bodied scale, often found infesting the mango in 
Florida, is the tessellated scale® (fig. 8). It is oval in shape but 
broadly rounded posteriorly. It is of a‘dark-brown color, with a 
decidedly mosaic appearance on the upper surface. It is not so 
generally distributed in Florida as the mango shield scale, being 
found only in a few localities on the east and west coasts of Florida. 
The writer has taken it at Little River, Oneco, Palm Beach, and 
Miami. 
5 Bucalymnatus tessellatus Sign. 
