Fumigant applicators must wear protective clothing and stand upwind
from the point of application. The proper amount of the chemical is ap-
plied to the lowest hole first, leaving enough space for the plug. A tight
fitting preservative treated plug is driven into the hole. Care must be ex-
ercised to avoid squirting the fumigant from the hole while driving the
plugs. The applicator should continue to work up the pole one hole at a
Decay fungi recolonize vapam-treated poles in about five years, but the
fungal population remains low for at least nine years. These poles
should be retreated every nine years by placing additional fumigant in
the same hole.
The effectiveness of wood fumigants for long term insect control is un-
certain. Vapam may control subterranean termites, however, carpenter
ants are known to reinfest wood shortly after fumigant application, per-
haps because of the decreased fumigant concentration.
NAVFAC Specification TS-20312 provides additional guidance on pole
fumigation requirements. Application of wood preservatives requires
DOD or State certification (See Section 2.0).
5.0 POLE TOP PROTECTION. Pole top deterioration is caused by
decay fungus and weathering action. Depressions, splits, and checks cre-
ate water holding pockets which cause wood to expand and contract,
freeze and thaw and subsequently split and check. These conditions
present an ideal condition for decay fungi. When left unchecked, the
pole top continues to deteriorate until pole topping or removal is neces-
Pole top products are now available which effectively protect pole tops
from weathering. decay fungi and ultimately degradation.
Pole tops (caps) are designed to keep the roof portion of poles free of
moisture thus preventing attack by decay fungi. Preservative fluids are
also available which should be applied to the pole tops prior to capping
6.0 POLE STRENGTH RESTORATION. Woodpeckers, carpenter
ants, decay fungi and termites can cause extensive damage to wood
poles. Left unheeded they can cause serious damage and result in early