Vol. 16—1962 - NorthEastern Weed Science Society

There are a number of reaso~ for unders{anding the mode
fenuron in tree-killing and for,recognizing its effects at various
of acHonor
stages.
419
Observations during 1961 of the trees treated with fenuron in the
fall of 1960 indicate that about' 80 per cent of t*irihave been surely Idlled.
The same problema of inadequate dOsage or poor d1i1tr:l.bution for multi-stemmed
and large trees appeared again in the 1960 fenuron program. However, no valuable
trees were damaged with :f'entiron, except onelSat-ge wolf oak., Fenuron from
four nearby treated trees ap~ntl;y was taken up 'by its perimeter roots on
one side and the whole tree defoliated late in 196!L. '
('
Two general conclusiopswere made from the 1960 program. Fir&t~
fenuron could have been used more Y.!.dely in place"bt the 2,4,5-T and so4fum
arsenite, with consequent redUction in laborarii'l. :I.lire-sprouting. Resti-l'tS
with fenuron would have been be'1;ter on larger and :Jz1Ulti-stemmed.trees w:Il1lh
higher dosage and wider scattering over the root tone.
!!.he 1961 Experiment~"'
On the basis of 1960 success, fenuron w~used in 1961 for weeding
10 different forest areas, ranging in size from slightly under an acre up to
25 acres. The total was 61 acres, requiring 318, pounda of fenuron pellets or
only ab?ut five pounds per acre. The first ap:plic,tion was made in Mar~h, on
snow, ~d the work continued throuP Sept ember 20,r'" During the summer a 'few
modifications in application were adopted. Fenuroo'Wll.s applied in the dbttventional
manner on' the ground, and, for close work~" tn various homemade jellies
or pastes in hatchet cuts. Dosage for so11 applieation was differentia-bed for
various size trees, up to a full ounce of pellets, for a 30-inch swamp maple.
The, spoon was abandoned for hand applicll-tion. Ex~pt for close work, the
pellets were slightly scattered at tree bases, in~ead of being concentrated
in a heel print. In most areas, the duff was scuttedaway so the :pelle1;SWe1'e
put on bare soil, and then a duff covering was kicked over them. (A tabu}.ation
of these 10 "commercial-sc~e" treatments is, ,available from the authOr.)
In the first nine, and. a first :pll.rtof tIle tenth, of the fieldis,
injury symptoms from "Dybar" fenuron, weed and brush'killer were quite evident
before the seasonal changes of foliage by the ,mid.dle of October. In each case
all the smaller weed trees (up to six inches d.b.1i}') with few ~cept1ans., were
defoliated. ' . ,
" ~
On the majority of these weed trees, a s:econd crop of lee:vee ~
started~ as occurs in the spring When,a late frost 'freezes early leaves,' In
most cases, the second crop of,1eaves also showed chlorosis. That is, the
chemical, either remaining in the ground, or, w4at:)s more likely, rema.1n1ng
in the tree systems, was interfering with the proclliction of the second crop of
leaves. The inner wood of the trees was still cle~, White, and seemed alive.
Although definite results will not be evident until 1962, the I
preliminary shm.>:ingwas excellent ~
~ of Action"'!
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