October, ’20] 
METCALF: TOBACCO FLEA BEETLE CONTROL 
399 
be shaken slightly to remove the excess poison. Care must be taken not 
to shake them too violently or too much of the poison will be removed. 
After a few bundles are dipped look at the first bundles and notice 
whether the leaves are completely and uniformly covered with a dry 
white powder. If large drops of water have collected here and there 
on the leaf it means that the plants should be shaken a little bit more 
as they are removed from the poison. Tobacco plants can be set prac¬ 
tically as rapidly in this way as by the old method, for the additional 
labor involved is very slight indeed. 
The other factor involved was to determine just what strength of 
arsenate of lead solution to use. Apparently the tobacco plant, when 
properly hardened off before transplanting, will stand almost any 
amount of arsenate of lead. Plants have been dipped in solutions of 
arsenate of lead as strong as 20 pounds of dry powder to 50 gallon of 
water without any injurious effects appreciable. However, solutions 
as strong as this are not necessary and this past year we carried on a 
series of experiments to determine whether 1 pound or 2 pounds of 
powdered arsenate of lead to 10 gallons of water would give the better 
results. Briefly the results of an inspection made two weeks after the 
plants had been transplanted may be summarized as follows: 
Treated with Arsenate of Lead One Pound to Ten Gallons of Water 
Per Cent 
Plants not inj ured. 51.3 
Plants slightly injured. 35.4 
Plants badly injured. 5.6 
Plants replanted. 2.6 
Plants badly sun scalded. 5.1 
Treated with Arsenate of Lead Two Pounds to Ten Gallons of Water 
Per Cent 
Plants not injured. 63.0 
Plants slightly injured. 22.6 
Plants badly injured. 1.0? 
Plants replanted. 3.6 
Plants badly sun scalded. 9.8'. 
Check 
Plants not injured. 0.0' 
Plants slightly injured. 7.1 
Plants badly injured. 91.1 
Plants replanted. 1.1 
Plants sun scalded. .7 
Analyzing the above results we find a total effectiveness for the one 
pound of lead of 78 per cent, counting both the uninjured and slightly 
injured, as effectively treated and assuming on the basis of the check 
that only 90 per cent of the plants would be badly injured in this time 
