44 
mature worms in all the experiments, it is evident that they strongly 
resist the effects of the powder, and if ample opportunity is given to 
escape to the ground or loose earth, may often entirely overcome its 
influence and recover. Whether on corn or cotton, it must be admitted 
that the protection is only temporary. This is shown by the fact that 
in some of the experiments undisturbed individuals entered bolls with 
impunity soon after dusting and after the first worm had retreated, or 
even the same worm going back and feeding upon the boll from which 
it had been driven, presumably, by the pyrethrum. 
As has been noted, there is a certain benefit derived from the appli- 
cation of the powder to young corn before tasseling. It is just to con- 
sider that the pyrethrum was at a disadvantage, in that it was not ap- 
plied early enough to catch the worms before they had become so 
nearly grown or had entered far into the bud. If it had been applied 
earlier a much greater per cent of the worms then present would 
doubtless have been destroyed. Such being the case, the use of pyre- 
thrum may prove to be a decided advantage in cooperation with the plan 
of planting corn as traps for egg deposition, and hence the worms 
when these are hatched. This can be done by thoroughly applying 
pyrethrum of about one-half or third dilution with lime to the corn 
plants at a time when the worms are found to be about half grown. 
By doing this the time of cutting out corn to destroy the worms it con- 
tains will be delayed for a time longer, and hence also be exposed to the 
depositions of the moth for a greater period. Experiments in this 
direction will be taken up extensively this season. 
The powder being thus limited in its efficacy, especially on cotton, it 
is not surprising that decoctions of the powder prove to be even less 
effective. As will be noted from the experiments with the decoctions 
when compared with the record of the checks upon the same, little 
more was accomplished than to temporarily arrest the feeding of the 
worms. It is true some of the worms changed bolls during the after- 
noon, and others which were in bolls came out, but it must also be 
noted that the same action was taken by other worms which were un- 
der observation and which had not been sprayed. There is some ques- 
tion, therefore, that the decoction was directly accountable for the 
action of the worms upon which it was sprayed. 
This doubt is further increased from the fact that it was often noted 
in worms which had been marked for observation that they very fre- 
quently changed bolls or even plants during midday or afternoon. 
OTHER VEGETABLE INSECTICIDES. 
The work upon vegetable insecticides was assigned almost entirely to 
Prof. Jerome McNeill, Fayetteville, Arkansas. He has been as unfor- 
tunate as myself in being unable to obtain plenty of Boll Worms to ex- 
periment with. Progress was further impeded by unpropitious weather. 
For this reason the greater portion of the time was occupied in collecting 
