Florida Agricultural Experiment Station


be worked away from the root crown with a trowel and a pointed
stick until a shovel can be used. One half of a posthole digger
makes an excellent implement to remove the soil under the root
crown when the lateral roots lie close together.
 If it is practicable to treat the tree, all dead roots should then
be cut out, using a mallet and chisel or gouge to trim them back
to the root crown (Fig. 23). Special effort should be made to
remove all oak or other foreign tree roots that may be encoun-
tered under the citrus trees being treated. All dead roots of
either citrus or other trees which are cut out should be followed
out to the ends and removed in their entirety. All bark lesions
that may occur on the base of the trunk, root crown, lateral roots,
or taproot in case the latter is not entirely dead, should have the
dead or infected bark cut out back to healthy bark and cleaned
off down to the wood. Particular care should be taken to exam-
ine for lesions under the lateral roots, especially where they leave
the root crown. Where lesions have ceased activity and have
become limited by a callus formation at their margins it will
suffice merely to scrape off the dead bark down to the wood. All
pieces and chips of wood and bark cut out should be collected
in a container and piled at some convenient point for burning
later. A piece of heavy paper placed under the tree will prove
helpful in collecting the chips and small pieces of wood and bark
cut out, which, if allowed to remain, may act as sources of in-
fection. All trees not worth treating should be dug up, care be-
ing taken to remove and burn all roots. Where attacked trees
are removed, it is advisable to leave the excavations open for
a few months before replanting.
 After completing the surgical treatment of the tree the root
crown should be left exposed for aeration and drying for a
few clear days, after which the treated areas should be brushed
clean of sand and inspected for any bark infections that may
have been overlooked, and all exposed wood surfaces should then
be painted with a durable waterproof wound dressing. After
this has dried the excavation may be filled in completely or the
immediate root crown may be left exposed indefinitely if prefer-
red. If the tops of the trees have died back they should be de-
horned proportionately and pruned of all dead wood. The lo-
cation of the treated trees should be recorded and they should
be inspected periodically to detect any subsequent development
of the root-rot fungus.