Vol. 16—1962 - NorthEastern Weed Science Society

Since rec1root is only one of the IIIaJlYweed species Pr"ent in potato f1e1ds~ the
results are not particularly" de:f1n1t1ve. If, however~ redroot is the principal
pest, certain chemicals can either be el1m1ntted or tried at much higher rates.
The principal value of the data is to point out that for pre-emergence use, the
research worker has a Wide lattitude in choosing chemicals whic probaly will
not be toxic to potatoes.
Judging from the weed results obtained with theee compounds in other teets,
the authore Suggelilt that particular attention be paid to the following new
compounds: DipheJ:l8m1d,TrifluraliD~ Du Pont 326 and Hercules 7531.
Summary~ COnclusions
177
Two ex;per1ments wel'$ conducted • the effectivElQ4!Ss and safety of preand
post-emergence applications of several herbicides, on potatoes.. One 'test was
on muck~ the other on graveely" 108lIl.. Two tests were .conducted to evaluate new
chemicals as to their· potential tor selective weeding of potatoes. One of these
was conducted on muck and one on m1neral soil.
1. Muck soils· gre$tly reduced the herbic1.dal effectiveness ot Herct,Uee 8043,
Dacthal, Zytron, and HolD and Haas 11'-34. On the otb$r band CDEC+CDAA activity
was much improved on muck as compared to that obtained on mineral so11. .
2. In contrast to previous work by the authors Hercules 7175 was toxic to
potatoes.
3. Both chemicals and crop shading markedly influence weed populations at
harvest.
4. NO chemical was tound to be toxic to swampor perennial smartlll!led,
Polygonum cocc1neum.
5. A large number ot distinctly different chemicals are safe for preemergence
and post -emergence use on potatoes.
6. Of the newer chemicals, Diphenam1d~ Triflural1n, Du Pont 326, and
Hercules 7531 are especially outstanding for pre-emersence use. It is not known
how potatoes wUl react to Du Pont 326 and Trifluralin it they are used
post -emergence.