June, ’23] 
FENTON AND TRUNDYI BORDEAUX FOR LEAFHOPPERS 
315 
In preliminary tests 1 it was shown that Bordeaux mixture is toxic to 
the nymphs of Empoasca mali Le B. The following account summarizes 
experiments that not only substantiate the above statement, but also 
indicate that it is poisonous to the young of three other common species 
of injurious leafhoppers, namely: Erythroneura comes Say, E. tricincta 
Fitch, and Empoa rosae Linn. 
Three different combinations of self-prepared Bordeaux and three 
types of proprietary mixtures of this compound were used in these tests. 
As shown in Table I, the commercial brands acted somewhat more 
rapidly than the others, all being toxic without exception. The average 
length of life of the nymphs when feeding from leaves coated with these 
materials varied from two to three days. In contrast the checks lived 
for an average period of one week. Over 500 individuals of this species 
were kept under observation on sprayed potato leaves, and in not a 
single instance did one mature, unless very near the transformation 
stage when placed in the vial. Approximately a sixth of them moulted 
once, and in two cases two moults were observed. The majority died 
before ecdysis. On the other hand a relatively large proportion were 
reared to maturity in the vials on unsprayed leaves. 
Table I. Effect of Bordeaux Spray Upon Empoasca mali Nymphs 
Number of Days Insects Lived 
Number 
Treatment 
Maximum 
Minimum 
Average 
of tests 
4-4-50 
8 
1 
3.12 
164 
4-4-50+Kayso 
5 
1 
3.15 
20 
8-4-50 
4 
1 
2.95 
61 
Glidden 
6 
1 
2.39 
78 
Grasselli 
6 
1 
2.37 
67 
Sherwin-Williams 
7 
1 
2.08 
56 
Untreated 
17 
1 
7.24 
61 
As previously shown, 2 the five instars vary in susceptibility to this 
spray compound, the first succumbing most rapidly, the fifth being the 
most resistant (Table II). Adults seem to be comparatively immune 
to this mixture, for several of them have been kept alive as long as 15 
days while feeding on sprayed leaves. The effect at this stage is, 
chiefly of a deterrent nature. 
Benton, F. A. and Hartzell, A. Journal of -Economic Entomology, Vol. 15 
pages 295-298, 1922. 
2 Fenton, F. A. and Hartzell, A. loc. cit. 
