THE CUREANT BUD-MITE, OR CURRANT GALL-MITE. 297 
mobile to penetrate the buds without injury to the plants. Hot water, at 
a low temperature, and hydrocyanic acid gas will kill the mites, but 
these latter will be treated of separately, as they scarcely come under the 
above heading. 
Ivwiersion of Branches i)i Hot Water. — I find that the immersion of 
the diseased branches in hot w^ater for various lengths of time at certain 
given temperatures is undoubtedly fatal to the mites. And in order to 
ascertain the lowest temperature at which the mites could be killed, I 
made a series of experiments descending from the boiling point (212° F.) 
to 115°. The result is given in the tables which follow : — 
Table I. — Immersion of Black Currant Branches infested with Phytoptus 
RiBis IN Hot Water. 
Temperature Time of Immersion 
1 sec. 
5 „ 
10 „ 
175° 
10 „ 
30 „ 
170° 
60 „ 
165° 
5 „ 
10 „ 
160° 
30 „ 
60 „ 
150° 
5 „ 
j> 
10 „ 
30 „ 
145° 
60 „ 
140° 
30 „ 
>> 
60 „ 
135° 
60 „ 
130° 
30 „ 
J) 
1 min 
2 „ 
120° 
1 „ 
j> 
2 „ 
115° 
1 „ 
>i 
2 „ 
)> 
5 „ 
Results 
No mites killed. 
All mites killed, form destroyed. 
Many mites living. 
All mites killed, form destroyed. 
Mites all living. 
Mites in centre of bud living. 
Mites all dead, form retained. 
Mites all dead, form destroyed. 
Mites all living. 
>> 5? M 
Mites all dead, form retained. 
Mites all living. 
Mites all dead, form retained. 
Mites all dead, forms of many retained 
Mites all living. 
Many mites killed. 
Mites all killed, form retained. 
In nearly all those instances where the mites " retained their form " 
but showed no signs of life the branches were set aside for future exami- 
nations, which were made on the fifth and fourteenth days after immer- 
sion. The result is given in Table II. : — 
Table II. — Further ExAmNATioN of Specimens treated under Table I. 
Tempera- 
ture 
Time of 
immersion 
Condition of the mites on the 5th day- 
after immersion 
140° F. 
1 min. 
Mites still retaining their form 
135° 
1 „ 
'» M M 
130° 
2 „ 
" 5> M 
130° 
1 „ 
'» J> J> 
115° 
5 
Condition of the mites on the 14th 
day after immersion 
Dried up 
Mites still retaining their form 
It will be seen that in five instances the mites did not show any signs 
of life on the fourteenth day after the immersion, when, with one excep- 
