Vol. 15—1961 - NorthEastern Weed Science Society

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of scintillation solution, dispersed by shaking, and counted at 5°C. for 30
minutes (or to a count of 100,000 if this was reached first).
C 14 standard solutions and scintillation blanks were used, and the
counting efficiency (which was determined for each counting run) varied from
54% to 57%. . .
Although other workers have reported that dalapon is easily leached
from plant tissue, the sample preparation procedure was checked to determine
whether or not a disproportionate amount of dalapon-2-€14 remained
in the solid portion. Samples were ground, dispersed in 10 mI, of water and
centrifuged. An 8 ml, aliquot was removed, 8 ml, of water were then added,
and the solids redistributed by shaking. This was centrifuged and another
8 rot aliquot removed. This was done a total of four times. The va rtous
aliquots were examined by liquid scintillation counting. By successive extractions,
it was determined that the dalapon-2-C 14 vias readily equilibrated
in the system.
RES ULTS AND DISCUSSION
Results obtained using different dalapon-2-C 14 and wetting agent combinations
in the leaf immersion uptake test are shown in Table 1.
Table 1.
The Uptake of Dalapon-W ettfng Agent Solutions
By the Third Leaf of Five-Leaf Quackgrass Plants Through Leaf Immersion
- - - - - - - - - -%-V"ettlng Agent - uptake In - -UPtaiein - E"vi"pO"ratlOn
Formulation in Solution 24 hrs. 48 hrs. in 72 hrs ,
------------------------------------
Dalapon alone 0.0 O. 11 ml, 0.23 ml. 0.11 ml,
Dalapon plus P-26-2 0.05 0.31 0.67 0.12
0.1 0.58 >2.0 0.09
0.2 0.98 >2.0 0.10
Dalapon plus Tergitol 0.05 0.44 0.71 0.11
TMN 0.1 0.49 >2.0 0.13
0.2 0.83 >2.0 0.11
- - - - - - - - - - - - --- - - - - - - - - ......- - - - ---- -.. "- -" .......­