20 
fields of limited area, which are low and poorly drained or underlaid 
with “hardpan” (a ferruginous sandstone), seem predisposed to pro- 
duce the disease. Trees set out on such soils never develop normally, 
but contract die-back in its worst form. These frequently remain for 
years in a stunted condition, each year’s growth as formed dying back. 
Such trees finally die if allowed to remain untreated. Often consider- 
able loss is incurred by planting and fertilizing groves on these die- 
back soils. The symptoms of die-back are the same whether due to 
excessive fertilization or to improper soil conditions, and it is probable 
that the real cause will be found to be the same in both cases. Both 
forms of the disease appear to be greatly aggravated by excessive cul- 
tivation, which apparently destroys the surface roots and forces the 
tree to feed lower down. 
Treatment.—When die-back is due to the excessive use of highly 
nitrogenous organic fertilizers, an effective remedy consists in simply 
ceasing to cultivate and allowing all weeds to grow. In fertilizing 
omit entirely all highly nitrogenous organic manures, but use about the 
normal quantity of potash and phosphoric acid. As the tree recovers 
a small amount of nitrogen should be given, preferably in the form of 
nitrate of soda or sulphate of ammonia, until the tree is brought up to 
its normal condition. If the disease 1s produced by the close proximity 
of privies, chicken houses, barns, ete., removing these will usually 
result in the recovery of the affected trees. In the case of barns 
which can not be removed it has been found effective in some cases 
to dig trenches between the trees and the barn to prevent the feeding 
roots from running under the former. Of course the caution in regard 
to the use of organic nitrogenous fertilizers given above is applicable 
in this casealso. When the malady is caused by planting on die-back 
lands, treatments vary according to the character of the soil. If the 
grove is on low, wet soil, thorough drainage will usually be found an 
effective remedy without other treatment. If the soil is underlaid 
with hardpan, mulching the trees with pine straw, oak leaves, or some- 
thing of this nature, and stopping cultivation will allow the feeding 
roots to develop near the surface and usually bring about a cure. The 
latter has been found an effective treatment in many instances. Good 
drainage is also beneficial in such cases. 2 
SCAB OR VERRUCOSIS OF THE LEMON AND OTHER CITROUS FRUITS. 
The introduction of this disease into the United States is compara- 
tively recent. It first appeared in Florida about the year 1884 and 
spread rapidly over the State and to Louisiana. Although many 
thousands of trees affected with scab have been sent to California, it 
seems that the disease is unable to exist there permanently. The rea- 
son for this will appear later. The malady also occurs in Australia 
and Japan, from which latter country it was undoubtedly introduced 
into America. So far it is not known to occur in Europe or Africa. 
