Vol. 16—1962 - NorthEastern Weed Science Society

Vol. 16—1962 - NorthEastern Weed Science Society Vol. 16—1962 - NorthEastern Weed Science Society

08.06.2015 Views

·168 The yiel? of. U.S. #1 Katahdin potatoes from the untreated plots was 3~9 bushels per a,qre. StatisticaLan~J.yses of the yields indicated' that a .d1!ffElrence of 56 bushels was significant at the 5%level. Inspection of the results showscasoron was the ,only material which significantly reduced yields. 'It can also be seen that in 1960 with. adequate rainfall and fertility the heavier stand of weeds did not reduce the potato yields .....'Ibis is probablY duetQ,the fact that the annual weed"crop"'Iii'late potatoes usually does not becomeestablished until the vines mature, flatten out on the ground and lose manyof their leaves. Thep:-incipal objection' to late, 8,I:IIUl.el weeds is the difficulty they cause 'in the use of mechanical diggers, the increased tuber loss in the field and the amount of soil and debris that must be handled at the grading, shed. Procedure Pre-emergent'herbicide trials, 1961 The area of silt loam available for weed control during this season was not uniform with some low, moist spots and higher, drier ones. The large size of the plots, 15' x 48', helped to bridge some of these areas but some variability was inevitable. The land was in redtop sod the previous. 2 years. Redtop sod always exerts a favorable effect on the succeeding potato crop. Delus and Kennebec potatoes were planted 'on April 26 with 1600 lb/A of 10-10-10-2 (tc) fertilizer. The pre-emergent ,herbicides were applied on May16-17 using a calibrated low gallonage sprayer drawn by a tractor. The rate per acre was 40 gallons of spray. The granular materials were weighed for individual 'plots and spread by hand a,fter mixing with coarse sand. The area was not cultivated until June 26. The rainfall drought injury. Results .was scanty during July but the ,crop showed no evidence .of The amounts of herbicides per acre, weed estimates and yields of U.S. #1 tubers are shown in table 2. The principal weeds were ladysthtllllb and ragweed. Randomweed counts of several one, foot square areas for each treatment indicated that the triazine compounds, atrametryne, ipazine, prometryne and trietazine at the rate of 3 Ib/A of toxicant reduced weed stands considerably. The herbicides svph as dalapon, falone and zytron Whenused alone were not effective on the broadleaved weeds. The falone and zytron, however, slowed 'the initial growth of ladysthumb. DNBPused with these later materialS reduced the stands of ragweed aM ladysthumb. There were very few native annual grass seedlings at this time, and no conClusions were reached about their control. Foxtail and barnyard millet broadcasted over the area after hilling did not become established due to heavy vine cover and the dry July weather. Just prior to hill ing on June 26 the weeds weN pul Ied from random one foot square areas and their dry weights determined~ The weights were lal'gely of 1adysthumb with occasional ragweed and a few annual grass seedlings. !The . dal.apon plots had a .thick cover of 1adysthumb.Th& check, the dal apon and ,.falone trea'bnents still showed considerably ladysthumbat harvest time. Those combined with DNBPwere fairly clean at harvest •. Th~ .~~tatoes were dug on,

0' ~ Table 2. Pre-emergent weed control experiments with Kennebec and Delus potatoes (R.I. 1961). Average Av. # weeds per sq. ft. Gms. Ratin! Active Bu/A June 12. 1961 Dry weight Ladys- Toxicant U.S. #1 Ladys- Annual Weeds/sq. ft. th1,lll Material Ib/A Kennebec Qe1us thumb Ragweed grasses June 26 9126!t 1. D!'eP+Zytron 3+f) .. 646 491 3.0 1.,9 2.8 . 0.21 9.] 2. DNBP+Dalapon 3+3+{4 post-) 674 433 7.2 . 0.2 5.4 0.22 9.~ 3. DtI.'BP+Dal apon 3+3 573 464 0.6 0.2 3.1 0.43 9.~ 4. Zytron 8 508 407 13.4 6.2 1.9 2.93 7 .~ 5. Amiben (gran.) 5 525 388 9.7 4.2 1.5 2.06 7.t. 6. Zytron 5 509 414 12.8 5.8 2.2 3.18 7.e 7. Falone 4 534 388 14.2 5.3 0.3 9.04 4.] 8. Falone 4+{4 post-) 566 390 16.2 6.9 6.1 9.07 I.e 9. De.lapon 4 589 388 24.4 9.3 4.0 22.32 2.~ 10.· P'rometryne 3 654 459 0.6 0.3 1.6 0.48 8.1 ll. Atrametryne 3 539 436 0.3 1.1 1.4 0.33 8.~ 12. Ipazine 3 517 461 0.0 0.0 2.4 0.08 9.~ 13. Trietazine 3 661 441 0.0 0.8 2.5 0.05 9.~ 14. Trietazine 3+{2 post-) 612 406 0.4 0.7 1.2 0.04 9.e 15. No cultivation - 579 390 11.2 6.0 5.6 11.05 1.~ 16. CUltivated - 590 438 - - - - 7.e LSDat 0.05 NS NS *low numbers - high weed cover, 10 = no weeds ) )

0'<br />

~<br />

Table 2. Pre-emergent weed control experiments with Kennebec and Delus potatoes (R.I. 1961).<br />

Average Av. # weeds per sq. ft. Gms. Ratin!<br />

Active Bu/A June 12. 1961 Dry weight Ladys-<br />

Toxicant U.S. #1 Ladys- Annual <strong>Weed</strong>s/sq. ft. th1,lll<br />

Material Ib/A Kennebec Qe1us thumb Ragweed grasses June 26 9126!t<br />

1. D!'eP+Zytron 3+f) .. 646 491 3.0 1.,9 2.8 . 0.21 9.]<br />

2. DNBP+Dalapon 3+3+{4 post-) 674 433 7.2 . 0.2 5.4 0.22 9.~<br />

3. DtI.'BP+Dal apon 3+3 573 464 0.6 0.2 3.1 0.43 9.~<br />

4. Zytron 8 508 407 13.4 6.2 1.9 2.93 7 .~<br />

5. Amiben (gran.) 5 525 388 9.7 4.2 1.5 2.06 7.t.<br />

6. Zytron 5 509 414 12.8 5.8 2.2 3.18 7.e<br />

7. Falone 4 534 388 14.2 5.3 0.3 9.04 4.]<br />

8. Falone 4+{4 post-) 566 390 16.2 6.9 6.1 9.07 I.e<br />

9. De.lapon 4 589 388 24.4 9.3 4.0 22.32 2.~<br />

10.· P'rometryne 3 654 459 0.6 0.3 1.6 0.48 8.1<br />

ll. Atrametryne 3 539 436 0.3 1.1 1.4 0.33 8.~<br />

12. Ipazine 3 517 461 0.0 0.0 2.4 0.08 9.~<br />

13. Trietazine 3 661 441 0.0 0.8 2.5 0.05 9.~<br />

14. Trietazine 3+{2 post-) 612 406 0.4 0.7 1.2 0.04 9.e<br />

15. No cultivation<br />

- 579 390 11.2 6.0 5.6 11.05 1.~<br />

16. CUltivated - 590 438 - - - - 7.e<br />

LSDat 0.05 NS NS<br />

*low numbers - high weed cover,<br />

10 = no weeds<br />

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