Vol. 15—1961 - NorthEastern Weed Science Society

2.60.
than the emulsion and in other ins taneea the reverSe ,.,as true. 't'he late season -'
estinlates also indicate that treatment interval after seeding was not of great
importance particularly with tile dry formulation. lhe one exception was with
redtop:'and colonial' bent where the late emulsion treatments were less damaging
than those ap~lied at the firstop'lecond int.~al •.
One very significant observation came to light when making the November
readings. This observation may negate some of the data presented in table 2.
It"fas'found that those grasses spreading by stolons and those that tiller pro­
fusely; namely· the Agrostis' species and the red fescues, did. not form normal
roots' as they increased in size. Thoie roots arising ,front nodes of the stolons
and from the crowns as the plants enlarged would prolifetate,' thicken and remain
short. Often all enlarged tip would result on contact with the soil. iI'ewof
thesero'ts were' able to penetrate into the'soil. In sc:ae illstances where roots
appeared to develop normally they failed to enter the soil but grew laterally
under the'organic mat at the surface of the moist soil. Although the plants in­
crease4in si~e and gave the appearance of being normal they could readily be
lifted from the soil. They were able: to persist'during the favorable fall grow­
ing season.
The' same phenomenon wasobset'Ved on a few crabgrass plants that had gennin­
ated prior to treatment in $ome of the ~lots. The roots formed prior to the
chemicnlapplication appeared normal and were able to sustain gro,.,th of the
plant but roots formed at the surface were malformed and failed to penetrate the
soil.
The bluegrasS8s,spreading by rhizomes, did not appear adversely effected
in theb' spread and no root abnormalities 'fete observed. The tall fescue and
ryegrass also appeared normal.
Simlnaq: ~. Conclusion;
Eight grasses were seeded in normal prepared seedbeds and. at standard rates
on i~.,ri126,196G.' . At intervals 'of' 2',' '4, 6, and 8 weeks after seeding an emul­
sifiabl~ concentrate and vermiculate£ormu~ation of Zytron was applied to these
': grasses 'at the rate 'Of20'pounds of actIve nmterial per acre. Periodic observat
ions and stand.' countawere Malle during the growing season. '
j •• !. .
On the basis of the preliminary work the' folloYing conclusions have been
drawn:
1:.' Seedliiig turf' maybe 'se''v'erely injured, by lytron application at the
rate of 20 pounds' per'acre. '," ':, .
2~ 'The emulsifiable concentrate" of Zytron gave more immediate injury
than did the dry formulation.
3. At the first treatment colonial bentgrass and redtop were most sus­
ceptiltle .to injury follo,.,ed btthe bluegraS8&S, red fescues , tall fescue and
1>erennial rye grass in tha torder.