A lot of wire worms (_Iulus_ sp.) brought in from potato hills were
put into a tin can with about three inches of soil and some potato
cuttings, and the soil was thoroughly moistened with kainit, one ounce
to one pint of water. Next morning all the specimens were dead. A
check lot in another can, moistened with water only, were healthy and
lived for some days afterward.
A number of cabbage maggots placed on the soil impregnated with the
solution died within twelve hours.
To test its actual killing power, used the solution, one ounce kainit
to one pint water, to spray a rose bush badly infested with plant
lice. Effect, all the lice dead ten hours later; the younger forms
were dropping within an hour.
Sprayed several heads of wheat with the solution, and within three
hours all the aphides infesting them were dead.
Some experiments on hairy caterpillars resulted unsatisfactorily, the
hair serving as a perfect protection against the spray, even from the
atomizer.
To test its effect on the foliage, sprayed some tender shoots of rose
and grape leaves, blossoms, and clusters of young fruit. No bad effect
observable 24 hours later. There was on some of the leaves a fine
glaze of salt crystals, and a decided salt taste was manifest on all.
Muriate of potash of the same strength was tested as follows: Sprayed
on some greenhouse camellias badly infested by mealy bugs, it killed
nearly all within three hours, and six hours later not a living insect
was found. The plants were entirely uninjured by the application.
Thoroughly sprayed some rose bushes badly infested with aphides, and
carried off some of the worst branches. On these the lice were dead
next morning; but on the bushes the effect was not so satisfactory,
most of the winged forms and many mature wingless specimens were
unaffected, while the terminal shoots and very young leaves were
drooping as though frosted. All, however, recovered later.
The same experiment repeated on other, hardier roses, resulted
similarly so far as the effect on the aphides was concerned, but there
was no injury to the plant.
Used this same mixture on the caterpillars of _Orgyia leucostigma_
with unsatisfactory effect, and with the same results used it on a
number of other larvæ. Used on the rose leaf roller, _Cacæcia
rosaceana_, it was promptly effective.
Tested for injury to plants, it injured the foliage and flowers of
wisteria, the younger leaves of maple and grape, and the finer kinds
of roses.
From these few experiments kainit seems preferable to the muriate, as
acting more effectively on insects and not injuriously on plants. For
general use on plants it is not to be recommended. It is otherwise on
underground species, where the soil will be penetrated by the salts
and where the moisture evaporates but slowly, and the salt has a
longer and better chance to act. The best method of application would
be a broadcasting in fertilizing quantity before or during a rain, so
as to carry the material into the soil at once. In cornfields infested
with grubs or wire worms, the application should be made before
planting. Where it is to be used to reach root lice, it should be used
when the injury is beginning. When strawberry beds are infested by the
white grub, the application should be made when cultivating or before
setting out.
The potash salts have a high value as fertilizers, and any application
made will act as a stimulant as well as insecticide, thus enabling the
plants to overcome the insect injury as well as destroying the insect.
In speaking on this subject in Salem county, I learned from farmers
present that those using potash were not troubled with the corn root
louse to any extent, and also that young peach trees have been
successfully grown in old lice-infested orchards, where previously all
died, by first treating the soil with kainit of potash.
* * * * *
A meteorological station has been built on Mont Blanc, at an elevation
of 13,300 feet, under the direction of M. Vallot. It required six
weeks to deliver the materials. The instruments are self-registering
and are to be visited in summer every fifteen days if possible, the
instruments being left to register between the visits. In the winter
the observatory will be entirely inaccessible. This is the highest
scientific station in Europe, but is 847 feet lower than the Pike's
Peak station in Colorado.
* * * * *