Vol. 16—1962 - NorthEastern Weed Science Society

230
UndoubtAldlythe three oult:I.vations and the' two hoeihgs on the weedy plots
during the season added to the effeotiveness of the ohemioal treatments. The
stands of quaokgrass in the oont:r9.1.».lotsw.ere reduoed by about 60 percent from
June to September as a result of these operations.
Control of ~uaJ. Weeds An abundanoeof annual we.19dsand bindweed (COnvolvulus
arvans!s) Vided the plot areas ~ The annual weeds were predominantly ragweed
fAmtrosia arte~iifolia),orabgrass (Digitaria ean~alis) and yellow foxtail
~ lutescens). Ratings of these and other annua weeds are shown in Table 3.
Fall appli'cations of amitrol, silllazine, atrazine and propazine all appeared
to deorease the. stands of annual weeds, especially in June. Beoause of the '
oompetition offered by the nutgrass in plots of these treatments, however, little
can be said of t-heir real value. Dalapon had little effaot on the annual weed
population althOUgh EPTCappeared to control bindweed.
G~anular simazine, applied at 3 lbs./A aft~r planting provided satisfactory
control of annual.weeds for the season. Bindweed did 'not persist in plots
treated with combinations of atrazine, propazine or simazine in the fall and
granular simazine in the spring.
Plantin s Nona.of the treatments injured"any
~o~~e~n~u~r~s~e~ry~p~an~~s-s~e~r~o~u~e~y~.~~e~~o~r~sythia were slightly disoolored by the
atrazine treatmlilnts but th~ injury appeared to be temporary. The forsythia grew
vigorously, and made more growth in the treated plots than in the controls
(Table 3). The forsythia grew poorly in these plots where annual weedS and/or
nutgrase were not controlled.
The oats sown in September yielded information on residual activities o~
the triazine herbioides. Qats are very sensitive to the triazines. The Only
plots with pronounced injury to the oats were the combinations of simazine at
3 or 5 lbs./A in, the fall ",ith simazin,e at 3 lbs./A in the spring.
Summary
Combinations of fall and spring pre-planting treatments with a post-planting
application of simazine in the spring were tested for their effects on quackgrass
and nutgrass in nuraery liners. A pre-planting, ,soil-incorporated treatment with
EPTCat 5 lbs.!A'controlled the first crop of nut~ass but had little etrect on
nutgrass germination after two months. Repeated applications of EFTCmay be
needed for seasonal control. Simazine greatly suppressed growth of nutgrass
during the summe~.
With periodic cultivation and weedlng,.. fall applications of atrazine and
propazine at 4 1'c;s./A and simazine at 3 or 5 lbs./A provided good centrol of
quackgrass for the season. Seasonal control of annual weeds and excellent
?ontrol of quackgrass waS obtained when these treatments were followed by a
post-planting application of,grapular simazine at 3lbs.!A.
None of the herbicide treat~nts seriously af!ectedthe newly-plantod
nursery stock.