Vol. 16—1962 - NorthEastern Weed Science Society

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whether or not these apparent cases of enhanced control are meaningfUl should
await further evaluation.
In the field tests (Tables 2 to 4) against populations of mixed speoies,
certain trends seem apparent. Most combinations provided weed control
better than eXpected. In general, greatest benefit seemed to be imparted to
the lower dosages of dimethyl tetrachloroterephthalate. Differences between
actual weed control and expected control appeared to increase with time. In
other words, the oombinations responded less to dosage and provided longer
control than the herbicides applied alone.
TABIE 1
Relative Effectiveness of Dimethyl Tetrachloroterephthalate
Alone and Combinedwith CDECand with NPA­
Greenhouse Test
Dosage, Ib./aore
Dimethyl
tetrachloroterephthalate
other
2
o
CDEC2
2
2
o
2
NPA2
2
o
Per cent
Pigweed
control 11
Actual Expected
85 81
81
87
53
o
53 93
78
Barnyard grass
f.ctual Expected
96 81
38
11= Actual per cent control based on fresh weight.
= == = = = = = = = = = = = = === = = = = = = = ===== == = = = =::;: = =
TABIE2
Relative Effectiveness of Dimethyl Tetrachloroterephthalate Alone
and Combinedwith DNBPin Field-Grown Lima Beans
Dosage. 1b. lacre
Dimethyl
tetrachloroterephthalate
8
4
8
4
4
DNBP
o
70
9.3
%weed control, days after treatment 1I
40
Actual Expected
95
66
4 .CJ8
42 93
85
o 4 41
2
97
80
78
36
51
49
Actual Expected
80
30
11= At 40 days the check was'4 per cent covered by pigweed, purslane,
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