- 9 ,
CONTROL. OF PEACH BOREZRS
j. G. Rodriguez
The most important enemies of the peach tree are the peach tree borer and the
lesser peach tree borer. The former is the most common and the most destructive,
causing heavy losses in Kentucky orchards. These species are closely related and,
except for habit, are difficult to distinguish.
Injury Borers may be identified by the fact that the peach borer attacks the
base of the trunk, from Z or 3 inches below the surface to about a foot above the sur-
face while the lesser peach tree borer attacks the upper part of the tree trunk, the
crotches, or any wounds in the bark. jelly -1ike gum, including sawdustlike frass,
exudes from the borings of either borer and this is an indication of infestation.
I_;.ife History. Both borers overwinter as small worms in bark crevices or in
portions of the trunk in which they feed; they resume burrowing and feeding in early
spring. The more advanced of the peach tree borer l`arvae attain full growth, about 1
inch, by the middle of l\/[ay. They then spin silken, dirt and gum-covered cocoons on
the surface of their burrows or in the soil, and change to the pupal stage. The first _
moths emerge in late june and continue emerging through September., They are clear-
winged, blue and orange moths resembling wasps. The moths of the lesser peach tree
i borer may also be mistaken for wasps but they may emerge somewhat earlier.
C_on_t1j>_h The summer treatment is the same for the control of both species.
Use 4 lb of 50 percent wettable DDT per 100 gallons of water and spray only the trunks,
including the crotches. Apply july l, August 1, and September 1. lf the lesser peach
tree borer is also present, it may be advisable to begin the treatments about june 24.
lf a heavy infestation of either exists, spray at 3week intervals. Care should be taken
to assure thorough coverage of the trunks; remove all trash, weeds, or grasses from z
around the tree trunks.
The fall treatment of paradichlorobenzene (PDB) applied at soil level is effective
only on the peach tree borer. Apply PDB crystals about October 1, when the soil is dry.
Clear trash from the base of the tree trunk, remove gum if present and place a band of
crystals around the trunk, taking care to allow at least 2 inches between the band and
the trunk. One ounce of PDB is advised for treating a full grown tree and from l/2. to
3/4 oz on trees from 3 to 5 years old, depending upon the size of the tree. Do not use
more than l l/2 oz on any tree. Cover the crystals with about 3 inches of fine soil,
piling it towards the trunk, and compact the mound with the back of the shovel. Re-
move the soil after four weeks from trees less than four years of age; on older trees
the mounds may be removed in the spring.
For lesser peach tree borer control, paint the wounds with a mixture of PDB
dissolved in crude cottonseed or linseed oil. Warm 2 qt of oil, dissolve 1 lb of the PDB
crystals and apply with a paint brush. Make this treatment about October 1 and apply
only to the area of the wound. lt is not necessary to remove gum, frass, or loose bark
V from the infested area.