Vol. 16—1962 - NorthEastern Weed Science Society

WEEDCONTROLANDTHE IMPROVEMENT OF SEEDLINGSTAN~
Colen C. 1ITyatt 11and J.
Introduction
D. V11ieonY
127
IN DIRECT-SEEDEDTOMATOES
Experiments conducted in 1960indicated that Vapam and Allyl Alcohol
were two chemical compounds that might be expected to give a considerable
degree of weed control and at the same time increase the stand of seedlings
in the dil"ect-seeding of tomatoes up to the time ot blocking and thinning. In
the 1960 trials these two materials were mixed with the 10p three inches' of
soil with a tractor-mounted rotary tiller in bands approximately 16 :Inches
wide. In some instances the treated band was coveNd with a polyethylene tarp.
About 12 to 14 days later tomatoes were seeded into the treated bands of soil.
Because of the favorable results obtained in the 1960 experiments it was
decided to continue the experimentation.
Procedure
Vapam (sodium n-methyl dithiocarbamate), Allyl Alcohol and Tillam
(propy1ethyl-n-butythiocarbamate) were included in the 1961 tests. In
addition, various types of mulches or sealants were added to the treated bends
of soil in an effort to evaluate their effectiveness in slowing down the
escape of the Vapam and Allyl Alcohol from the so11 and thus improve their
performance in killing weeds and fungi in the surface imh or so of soil.
Tillam was also mixed with the soil alone and in combination with Vapam and
Allyl Alcohol to increase the degree of weed control. The treatrents used
and the results obtained at Bowling Green and ',~o~, Ohio are indicated in
Table 1.
The soil was thoroughly disked and harrowed to put it in gio d physical
condition before it was treated. The treatments were applied in cooperation
with personnel from the U.S.D.A. Engineering Laboratory located at Wooster,
Ohio, with tractor-mounted equipment designed and developed by that laboratory.
The chemical compounds used were incorporated (mixed) nth the top 3 inches of
soil in bands 16 inches wide, where so indicated, by spraying them on the
surface just ahead of the tilling equi.pmenb; In a few instances where the
rotary tiller was not used about 2 inches of soil 1'I8rethrown over the sprayed
band by means of carefUlly mounted dis ca, In both meth>ds of application the
soil was smoothed and packed somewhat in a rounded mound about 2 inches h1~er
in the center 'han at the edges. If the treated band was to be covered w:l.th a
polyethylene tarp, this covering was then laid and the edges covered (sealed)
by means of specially mounted discs. After 4 or 5 d~s thetarp was removed.
If liquid sealants were to be employed, these were applied by placing the
selected sealant in a paint sprayer operated by compressed air fran Which it
was sprayed on the treated band of soil. These so-called sealants were left in
place and the seed drilled through the mulch some 10 Dr 11 days after the
treatments were applied.
y Research Horticulturist, H. J. Heinz Company, Pittsburgh, Pa,
Y Professor of Plant Pathology, Ohio Agricultural Experim"nt Station,
V"oos~er, Ohio