THE NATIONAL NURSERYMAN. 
55 
SOME PRACTICAL RESULTS. 
Inspection of Nurseries and the Treatment of Nursery Stock— 
Young Grafts May be Sprayed with Green Arsenite—Experi¬ 
ments with Plant Sice—Methods of Fumigation. 
Victor H. Lowe of the New York Experiment Station has 
prepared a bulletin on the inspection of nurseries and the 
treatment of nursery stock. What he says of the New York 
nurseries will apply in a general way to those of other states. 
He makes the following brief summary of his investigations : 
Most of the nurseries inspected have been found practically 
free from insect pests of a serious nature. Ten important 
species have been found at different times, however, in suffi¬ 
cient numbers to do serious injury. In all cases efforts were 
at once made to clean out the stock thus infested. The most 
important insect which attacks nursery stock in this state is 
the San Jose scale. It is important to nurserymen not only 
because of the injury which it may do to the infested stock, 
but because it is greatly dreaded by both dealers and fruit 
growers alike. Hence stock from a nursery which is known 
to have been once infested, does not find a ready sale. 
Experiments in dipping and spraying young nursery trees 
indicate that plant lice may be controlled in the nursery by 
dipping the curled tips of infested trees in a solution of whale 
oil soap, i pound to 7 gallons of water. The work should be 
done early in the season. Flea beetles attacking your.g pear 
and apple trees may be held in check by spraying with green 
arsenite, 1 pound to 100 gallons of water, and the canker worm 
will succumb to the same treatment. 
The experiments in fumigating nursery stock with hydro¬ 
cyanic acid gas, when the stock is piled in the cellar for winter 
storage, indicate that this method may prove practical, thus 
avoiding the necessity of building special fumigating houses. 
PLANT LICE. 
Regarding treatment of plant lice Mr. Lowe says : 
The injury was usually caused to seedling and one-year-old 
fruit trees. The lice attacked the tender leaves at the tips of 
the young trees soon causing them to curl so badly that the 
insects could not be reached with a spray. In the nursery in 
which the experiments were made the infested trees, prin¬ 
cipally sweet cherry, apple and pear trees, showed serious in¬ 
jury from the effects of the lice. The experiments were under¬ 
taken with a view to determining a practical method of check¬ 
ing the injurious work of the lice. It was evident that spraying 
would not be a success and so dipping the infested trees in a 
solution of whale oil soap and water was resorted to. It might 
at first seem that this method would be impractical because of 
the time and labor involved, but it should be remembered that 
the lice appear on comparatively few trees first, others becom¬ 
ing infested from these later in the season, and hence if they 
are successfully treated more serious injury by the lice may be 
prevented. 
All of the trees used in the experiments were seedlings, one- 
year-olds and two-year olds. As the lice were congregated on 
the leaves at the tips it was necessary to wet only this portion 
of the tree. The dipping of the stock was found to be a very 
simple matter. Three or four men carrying pails filled with 
the solution passed through the blocks and, picking out the 
infested trees, bent them over carefully and dipped their tips 
into the solution taking care to hold them long enough to wet 
all of the lice. It was found unnecessary to spend more than 
two minutes to a tree. 
Experiments. About a thousand trees were used in ex¬ 
periments, which for convenience may be divided into six 
blocks. Blocks I and II were sweet cherries badly infested 
with the black cherry aphis, Myzus cerasi. Blocks III and 
IV were apples also badly infested, but with the apple aphis, 
Aphis mali. Blocks V and VI were standard pears infested 
with a species of plant lice, Aphis sp. Blocks I, III and V 
were treated the same day, a bright, warm day about the 
middle of July, with a solution of whale oil soap, 1 pound to 3 
gallons of water. Blocks II, IV, and VI were treated within 
two days of this time, under practically the same weather con¬ 
ditions, with a solution of whale oil soap, 1 pound to 7 gallons 
of water. But one application was made in each case. 
Results. —In nearly every case where the stronger soap 
solution, 1 pound to 3 gallons, was used, the leaves were more 
or less injured. The pears were injured most, while there was 
not much difference between the apples and cherries. So far 
as could be ascertained, all of the lice on these trees were 
killed. The weaker solution, 1 pound to 7 gallons, did not 
injure the foliage in any instance, but proved fully as effectual 
as the stronger solution in killing the lice. These treated trees 
were not seriously infested again during the season. 
Conclusions. —The above experiments indicate that, when 
young nursery trees become so badly infested with plant lice 
as to make spraying impractical, they may be successfully 
treated by dipping the curled tips in a solution of whale oil 
soap, 1 pound to 7 gallons of water. The expense and labor 
were so slight as to be factors of but little importance. When 
thoroughly done, but one treatment is necessary under ordinary 
circumstances. 
SPRAYING YOUNG GRAFTS. 
Most of these experiments were conducted against a large 
species of flea beetle, Systena hudsonias Forst. The beetles 
were very abundant during June and July on apple and pear 
grafts in a nursery near the station. The beetles fed vora¬ 
ciously on both upper and under surfaces of the leaves, eating 
away the tender tissue and causing them to wither and die. 
About twenty-five per cent, of the grafts were killed before 
the experiments were commenced and a whole block of 20,000 
apple grafts was seriously threatened. The beetles were also 
doing serious injury in a small block of two-year-old apples 
and a larger block of two-year-old pears in the same nursery. 
Green arsenite was used in all the experiments and in each 
case sufficient lime was used to make the mixture “milky” in 
appearance. A barrel and pump, mounted on a small stone 
boat which could be easily hauled between the rows by one 
horse, was used. To each lead of hose a V was attached so as 
to support two short lengths of hose. Two men followed the 
pump spraying two rows at a time, thus requiring three men to 
do the work. Improved Vermorel nozzles were used. 
Experiments. —Block 1 ; one-year-old apple grafts sprayed 
June 16, with green arsenite, 1 pound to 150 gallons of water. 
June 18 this block was again sprayed but the poison was used 
at a strength of 1 pound to 100 gallons of water. June 25 a 
third application was made, the poison being used at the same 
strength. Block II ; two-year-old apple trees sprayed June 18 
and again June 25, with green arsenite, 1 pound to 100 gallons 
of water. Block III ; two-year-old pear trees sprayed June 18 
and again June 25 with green arsenite as in Block II. Block 
