Vol. 16—1962 - NorthEastern Weed Science Society

Residue analysis of potatoes treated withtrietazine
for weed control. l
C. E. Olney, R."S. Bell and T. W. Kerr2
The compoundtrietazine, 2-chlor0-4-diethylamino-6-ethylamino-s-triazine,
is a new herbicide being tested for the control of annual grasses and other
weeds in potato fields. The present investigation was undertaken to determine
whether measurable amounts of this herbicide would accumulate in potato tubers
following applications in the field.
The tubers analyzed were obtained from an experiment on herbicidal weed
control reported by Bell et al (1) elsewhere in this journal. The potatoes
were planted in late April, 1961 using four randomly replicated plots per
treatment. While both the Delus and Kennebec varieties were exposed to the
treatments, residue data were obtained from the latter variety only. The
treatments and the amounts of trietazine (active ingredient) applied as sprays
and the occasions when tuber samples were taken for residue analysis are presented
in table 1. The pre-emergence treatment was made on May16, the posthilling
on June 27, and the vines-down on August 15. Harvest of the potatoes
was September 27 and 28.
On each of the 4 sampling dates, 4 pounds of potatoes were obtained at
random from each of the 4 replicates. These were then halved lengthwise and
the halves diced into half-inch cubes, from which a representative 200 gram
sample was taken. After homogenizing in a blender, each sample was tumbled
with chloroform and filtered through anhydrous sodium SUlfate. The extracts
were stored at 25Of. for future analysis.
The analytical method was supplied by the Geigy Chemical Company(2). It
is based m the conversion of trietazine to hydroxytrietazine by acid hydrolysis
Table 1. Residues of trietazine in potato tubers following application in
various treatments. Kingston, R.I. 1961.
Treatment
Active toxicant
Pre-emergent 3
Pre-emergent plus post-hilling 3 + 2
Post-hilling 3
Post-hilling plUS vines down 3 + 2
and the determination of the latter by its
line technique.
Residue (p.p.m.) in tubers
on dates indi,atedl
189