Vol. 15—1961 - NorthEastern Weed Science Society

iss.
BVAWATIONor rIVE HEIBICIDES 101 ULUNG BSDILlSHED POISON IVY
IN .AN A,PPLBORCHARD'nIIEB YEARSFOLlOWINGA SltfGLE TRBA'HNT.
O.car B. Schubert
l
This study is beinl continued to determine the number of years
a slngle herbicide application will give a significant reduction in polson
ivy when compared with unsprayed check.. Additional detans of the experiment
and yearly results have been reported in the Proceedings of the Northeast
Weed Control Conference (I, 2).
Between Augu8t 13 and 17, 1957, ATA, 2,4,5-T Ester, 2,4,5-T.P
2,4,5-T .Amine, and ...... te were applied to well e.tabli.hed poi.on ivy in
a mature apple or~hal'd. All herbicides, except "-ate, were applied at
the rate of 4 pound. active ingredieat per acre. ......te was applied at
the rate of 150 pounds of formulated Amaate per acre. The herbicide.
ware applied with a power apr8Yer at the rate of 200 gallon. of spray per
acre. An operating pres.ure of 15-80 pound. was applied to the three
nozzle ~ delivering a flat fan apray pattern.
The l/looth-acre plots were cla8stfied according to the relative
density of poison ivy, and then gr~ed into twelve repHcations,
each with .imilar poison ivY.tand.. 'Six replicationa composed of six
plot. each warela14 out. around 'tree., and another .is replication. were
lald out in apac8s between tree plote in the tre, row. The herbicides
were applied at random wi.thin eacb replication.·
All sprayed plot. were free of poi.on ivy when observation.
were made in October, 1957. In the fall of 1958, 1959, .nd 1960, the
density of poisoo ivy was recorded for each of the 72 plots as the
number. of .leaf~ st_ that were vll1ble. Stera counts of 20 to 50 would
generally be cOnaidered ltaht •. The apparent decrease in average stem
counts in 1960 compared with 1959 may have arisen from less frequent
mowing of .the orchard cover, hence a smaller number of branchedsteras •.
Differences in weather may also have lnfluenc.a the stem counts. Since
.te. counts or stand are not normally dlstrib~ted it is necessary to
tran.form the .tem counte by adding one to each count and then taking
the square root when making statistical analyses.
In Table I, the average number of poison ivy stems is given
one. two and three years following the application of herbicides.
-_ ............ - ........_-_..... _...- ....
1 Associate Horticulturi8t, West Virainia Unlvere1ty. 1he author is
indeb~d to Dr. R. S. Dunbar, Statistician. for the analy.es of the
data •. lie is alao grateful to the Dow Chemical Company for 2.4,S-T
compounds and to American" Cyan_id Company for the AD u.ed in this
study.