Vol. 15—1961 - NorthEastern Weed Science Society

114.
Carrot yields are not presented in Table 2 for the band cultivated
control and granular dicryl treatments, because weed competition in these plots was
sufficiently intense to prevent the development of any marketable carrots. Prometone,
completely inhibited carrot seed germination.
The most promising treatment in this trial was liquid or granular amiben
which resulted in carrot yields significantly higher than the currently recommended
varsol treatment. Amiben performance in the 1959 carrot trial was rather mediocre.
Meteorological data for both years indicates that rainfall after application may be
the reason for the variable performance. In 1959, no precipitation occurred until
7 days after amiben application when 0.3 in were recorded, while in 1960 0.71n were
recorded shortly after application and 0.8 in were recorded in the following week.
Another possible explanation could be that in 1959 amiben application was made 5 .
days after planting, while in 1960 it was applied immediately .fter planting.
For the past 2 years, CIPC at rates of 6 to 8 Ib/A has given effective
weed control during the early part of the season. The main disadvantage of this
chemical appeared to be its short residual weed control period.
Dicryl and solan were promising selective herbicides for carrots in
this trial. Dicryl was a more effective weed killer at the rates used than was
solan. Barnyard grass was the predominant weed not controlled by these herbicides.
§nap Bean~ Pre-planting incorporated herbicide treatments were applied on May27,
1960. The following day, Tendergreen snap beans were"planted in the experimental
area. Pre-emergence treatments were applied immediately aft·er planting, and postemergence
treatments were applied on June 4 when the beans were mainly in the 2 leaf
stage. The post-emergence treatments were scheduled fpr application shortly after
bean emergence but unsuitable weather conditions for spraying necessitated the delay.
The weed population consisted mainly of commonlambsquarters, redroot pigweed,
commonpurslane, field bindweed, field horsetail and barnyard grass. The fresh weed
weight and marketable bean yield data presented in Tab~e 3 were obtained from 25 ft
of the middle row in each plot. The weed weight data were obtained at the time. of
the final bean harvest on August 2.
EPTCand R.2061 pre-planting incorporated and liquid or granular amiben
pre-emergence were the outstanding treatments evaluated in this experiment. Amiben
was a much more effective herbicide in 1960 than in 1959.
DNBP6 lb/A liquid or granular and CIPC 6 Ib/A pre-emergence treatments
produced excellent early season weed control. However, inacequate weed control was
observed during the harvesting period which has been a constant shortcoming of these
treatments.
Considerable bean stunting was observed after the post-emergence
application of DI~P and DNBPcombined with CDECor CDAA. These treatments applied at
emergence in 1959 gave excellent weed control. This suggests that application timtpe
may be one of the critical f~ctors preventing the general use of this treatment.
The Niagara 5996 chemical appeared to lack sufficient selectivity at a
rate which would give adequate weed kill.