&IREST RESEARCH NOTES 

NORTHEASTERN FOREST EXPERIMENT STATION 

Upper Darby , Pennsylvania 

No* 33 

May 1951, 

Effect Of Sterilizing Treatments On Survival 

And Growth Of Hybrid Poplar Cuttings 

Fungus diseases of poplars might be spread to new 

locations if hybrid poplar cuttings (now being test-planted 

in various parts of the ~ortheast) were not sterilized before shipment. hong these diseases are the canker-producing 

fungi Septoria musiva and Dothic,fiza populea and the leafblotch fungus Septotinia populiperda. 

A method of sterilization was needed that would not 

e harm the planting stock. To find such a method, an experiment was made to test a number of fungicidal treatments on 

cuttings. Of the fungicides tried, mercuric chloride, 

Cere an M, and Semesan were found to be effective sterilizers. 9 

Treated cuttings were tested in field planting3 at 

the Beltsville Experimental Forest in Maryland to determine 

whether the treatments had any hamful affect on survival or 

growth. The cuttings were planted 1 foot apart in rows 

3 feet apart. Each treatment (and untreated control) was 

represented by 100 cuttings. All cuttings of each treatment 

were assigned to a row at random. The placement of clones . , in each row was also at random. 

l~or details of the treatments, see Forest ~ebearch 

Note No. 32 or Waterman, A. M., and Aldrich, K. F., Additional information on the surface sterilization of poplar 

cuttings, U. S. Dept. Agr. Plant Dis. Rptr. 38 (2) : 96-100, 

1954. 

See also: Ford, H. F., and Waterman, A. M., Effect 

of surface sterilization on survival and growth of fieldplanted cuttings, U. S. Dept. Agr. Plant Dis. Rptr. 38 (2): 

101-1059 1954. 

Mention of these commercial products is not to be 

construed as endorsement of them by the Forest Service or 

the Department of Agriculture. 

1 

i 
1 

~ei~ht~ 

growth 

Clone (Populus hybrid) 

Number Parentage 

Table 1.--Effect of fungicidal treatment on the averam survival 

and height growth of different hybrid-poplar clones 

grown in field plantinas' 

'e 

'~iducial lMts for comparison of clonal means: Survival data--l% level = 25.0; 

5% level = 18.5. Growth data--no significant differences at 5% level. 

%ased on surviving cuttings. 

Table 2.--Effect of fungicidal treatment on the averam 

survival and height growth of cuttiws mwn 

in the field for one season e 

Percent Inches 

OP- 8 P. nima x P. laurifolia 68 29.6 

10 P. nim x P. trichocarpa 74 24.3 

28 P. charkowiensis x P. trichocarpa 68 46.0 

P. maximowicdi x P. berolinensis 82 36.8 

45 52 P. maximowiczii x P. niara plantierensis 64 34.5 

201 P. deltoides virginiana x P. trichocarpa . 60 42.2 

221 P. deltoides virginiana x P. caudina 52 31.0 

283 P. niara x P. laurifolia 76 33.4 

302 P. nim betulifolia x P. trichocarpa 90 36.1 

J 

Average 

survival 

~ei ghtl 

growth Treatment 

J 

Percent Inches 

'H&2 38 21.3 

HgCl2 (rinsed) 46 W.8 

Ceresan M 76 26.3 

Semesan 94 49.2 

Untreated controls 99 35.7 

based on sunriving cuttings. 

The planting was machine-cultivated and later hoed as 

necessary during the growing season. Artificial watering 

was used four times to supplement inadequate rainfall. At 

the end of-the growing season, the height of the rooted 

trees was measured to the nearest $ inch, and data on survival were taken. 

Results 

Clonal differences.--Some clones showed significantly 

better survival than others (averages for all treatments). 

Clones 232 and 313 did poorly; none of these cuttings sure 

2 

I 

Average 

survival 
vived the unrinsed mercuric chloride treatment. Clone 45, a 

fast gmer and consistently good in other experiments, survived well. There were no significant differences in the 

average height growth of all clones for all treatments 

(table 1). 

Treatment differences.--The most important result was 

the relative effects of the various treatments on survival 

(table 2). Cuttings treated with mercuric chloride showed 

poorest survival. The next most toxic treatment was mercuric chloride with rinsing. Rinsing lessenedthe harmful effect, but this treatment did not sterilize so well, according to Waterman. Of the cuttings treated with Ceresan M, 

24% died. The Semesan treatment had no harmful effect on 

survival. Survival in that treatment was as good as in untreated controls. 

In the field tests two of the treatments, unrinsed 

mercuric chloride and Ceresan M, resulted in significantly 

less growth than the other two treatments. The most effective sterilizing treatments, Semesan and Ceresan M, differed 

significantly in their effect on height growth. The greatest 

average height growth was by cuttings treated with Semesan. 

Since Semesan was found to be effective for sterilizing hybrid-poplar cuttings to prevent spread of fungus 

diseases, and since tNs chemical has no harmful effects on 

the hybrid--poplar cuttings, it can be used safely for this 

work. For most effective results, the poplar cuttings 

should be completely immersed in a 1% water suspension of 

Semesan for 20 minutes. No rinsing is necessary. 

---HAROLD F* FORD 

Agriculture-Forest Service-Upper Darby, Pa.