THE NATIONAL NURSERYMAN 
133 
Damping-Off of Coniferous Seedlings 
])aniping-()ir of coniferous seedlings, in the opinion of 
forest pathologists ofthe U. S. Department of Agriculture, 
causes losses ordinarily considerably heavier than the 
nurseryman realizes. Very young seedlings decay and 
disappear so soon after infection that the number of dead 
seedlings visible at any one time is but a small part of the 
total loss. Furthermore, many of the seedlings are killed 
immediately after the seed sprouts and before the seed¬ 
lings appear above the soil surface. Many failures hither¬ 
to attributed to poor germination, in the opinion of the 
specialists, are due in reality to the work of the damping- 
olf parasites in the sprouting seed, underground. The 
high price of most evergreen seed, which ranges from a 
minimum of 50 cents per pound for western yellow pine 
to ^2 to $4 per pound quoted for native spruces, and even 
$5 to flO per pound for Norway pine, makes the loss of 
young seedlings a serious expense. 
Control Measures 
To assist nurserymen in controlling damping off, the 
U. S. Department of Agriculture conducted extensive ex¬ 
periments in various sections of the country. The 
methods employed in these experiments and the success 
attending their use are reported fully in Professional 
Paper No. 453, The Control of Damping-Off of Conifer¬ 
ous Seedlings, by Carl Hartley, forest pathologist, and 
Roy G. Pierce, forest assistant. Bureau of Plant Industry. 
Following is the summary of the 32-page bulletin 
devoted to this topic: 
(1) By damping-off is meant the killing of very young 
seedlings by parasitic fungi. It is the most serious diffi¬ 
culty encountered in raising coniferous seedlings. 
(2) To decrease losses from the disease excessive 
moisture and shade should be avoided. Caution must be 
used in following this recommendation or many seedlings 
may be killed by drought or by white-spot injury to the 
base of the stem. Damping-off can often be decreased by 
putting beds on very sandy soil. Seed should not be 
sown any thicker than necessary. It appears better to 
sow broadcast than in drills. Late fall sowing results in 
decreased losses at some nurseries and is worth trial. 
Proper attention to all of these measures will decrease 
the losses from damping-off, but at most nurseries they 
are not sufficient really to control the disease. 
(3) The addition of lime, wood ashes, and in some 
cases nitrogenous fertilizers seems to increase damping- 
off. Soil alkalility appears to favor the disease. No 
effect has been noted from green manures. The use of 
unrotted stable manure has had very bad results; 
properly rotted manures seem less objectionable. Tank¬ 
age, charcoal, and cane sugar are the only nondisin¬ 
fectant substances which have to date given any hope of 
disease control. 
(4) Soil disinfection has so far proved the best method 
of combating damping-off. Of many methods tested, 
treatments with sulphuric acid, copper sulphate, zinc 
chlorid, and formaldehyde have proved the most satis¬ 
factory. The disinfectants, however, behave quite diff- 
erenlly at different nurseries. The acid has on the whole 
giv('n the best j’esiilts. Heat disinfection lias been only 
pailly ellective. Disinfection by acid or copper sul¬ 
phate is clieajier than by the other methods commonly 
recommended. 
(5) In addition to decreasing damping-off after the 
seedlings come up, the chemical disinfectants above 
mentioned, when properly used, cause an increase in the 
apjiarent germination and are very helpful in controlling 
weeds. This latter effect alone at some nurseries pays 
the entire expense oi the treatment. Sulphuric acid, has 
furthermore, at some places resulted in marked increases 
in the late season growth of pines. 
(6) In some soils formaldehyde kills dormant seed, and 
the other three most satisfactory disinfectants at some 
nurseries kill the root tips of germinating seedlings. By 
proper precaution, all such injury may he prevented. 
(7) The results obtained to date show that it is entirely 
possible and practicable to control darnping-off by soil 
disinfection. Unfortunately, the varying behavior of dis¬ 
infectants at different places renders it impossible to 
recommend any single treatment which will be every¬ 
where successful. 
THE MADAGASCAR BEAN 
By S. L. Watkins, Pleasant Valley, Califoiiiia. 
Some years back we obtained this bean from a seeds¬ 
man in Australia, with a recommendation that it was 
absolutely the most prolific bean ever grown. 
The beans themselves are very large—a mottled purple 
and crimson splashed white. 
Madagascar beans are especially adapted to warm cli¬ 
mates, where they form large tuberous roots and live year 
after year. They are rank, vigorous growers, with 
heavy powerful foliage and singularly beautiful purple 
crimson and white flowers, borne in dense, long racemes, 
similar to wisteria blooms; these blooms are soon fol¬ 
lowed by enormous pods ten to eighteen inches in length, 
containing ten to twenty large beans. The amount of 
beans each plant will yield in a warm climate is simply 
marvelous, but these beans are more especially adapted 
for use as a shell bean, as they are deliciously rich and 
nutritious. 
It is estimated that in a warm situation and good soil, 
two plants of this bean will supply a large family witli 
this delicious and wholesome vegetable for nine months 
of the year. This bean can also be picked young, and 
the pods boiled whole as per tlie manner of string beans. 
Madagascar beans thrive and hear well in cold climates,* 
but the perennial roots would be killed out each winter, 
so that new seed would have to be sown each season. 
Again a one year plant will only yield about one third 
the amount of beans that a strong powerful two or three 
year perennial root would. 
