Vol. 15—1961 - NorthEastern Weed Science Society

PRE-fREATINGSOILS, APOSSIBLE.TECfiNIQU1Fon \In:],]-INGVEGl,TABLES
,
R. D. Sweet and Joseph Cialone
Department of Vegetable Crops, Cornell University, rthac~, d.Y.
A selective herbicide tha.t will kill a wide range of weed species without
danger to the crop, and one whose performance is not unduly influenced by
either soil or environment, is the goal of many llorkers. Obviously, there are
very few such chemicals available at present for weeding' vegetable crops.
Thus, there is a need for additional techniques by which weeding can be accomplished
safely without resorting to costly hand labor.
The purpose of this report is to present a few limited research r€sults
regarding the feasibility of pre-planting chemicals treatments for several
vegetable crops.
Experimental
In a series of preliminary tests on sandy loam soil, certain individual
plots from earlier treatments were utilized by replanting the initial crop.
The plots chosen had given excellent weed kill but had seriously damaged or
killed the first planting. The soil was raked by 'hand just prior to the second
planting. A summary of these preliminary test results is presented in Table 1­
From these observations, it was clear that several chemicals having high initial
weed killing ability, but which injured crops, might possibly be rendered nontoxic
in a sufficiently short period of time to warrant their use as preplanting
treatments.
As a partial follow-up of these results, greenhouse tests are being conducted
with 7442and 8043to determine if possible the specific length of time
they remain toxic. Rates of 4 and 6, and 2 and 4 pounds for 7442and 8043
respectively were sprayed on flats filled 2" deep with greenhouse potting soil.
One series was planted immediately to timothy and broccoli. A duplicate series
was planted at weekly intervals for four successive weeks. Hercules 8043lost
its toXic action in approximately three weeks. However, 7442still showed
toXicity in the fifth planting.
A field test was conducted in which plantings of several vegetables werE:
made at time of treating and at one and two weeks later. The individual plots
were 6' x 15' and each contained spinach, cabbage, lettuce, carrot sand
tomatoes. A separate series was used for each planting date. There were two
replications. Crop response and control of weeds were rated approXimately six
weeks after the first planting. In ("eneral, weed control was excellent for
all materials. However, galinsoga was prevalent and this pest was not controlled
by either EPTC or St. 2061. The plots were not re-worked between the
initial treatment and the subsequent plantings.
Paper No. 452 of the Department of Vegetable Crops, Cornell University.