100 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 15 



lbs. salt to each 100 gals, of water. This gave the best results when 

 applied as late as possible before the eggs hatched. It is believed that 

 the wash acts mainly as a mecharical barrier to the emergence of the 

 3^oung from the eeg, but the salt probably exerts some direct effect also, 

 since the omission of this ingredient lessens the effectiveness of the wash. 

 In our experiments we usually m.ade the application as soon as the buds 

 showed the first sign of green at the tips. Later than this the leaf 

 tips are likely to be more or less iniured from the action of the salt. 

 It is only by the use of the greatest care and thoroughness in covering 

 every sm.allest twig with the wash that successful results are secured 

 and, in practice, we have found it necessary to make two applications 

 to produce the desired eft'ect. The fact that it is almost impossible 

 to get on clay land so early in the spring with a heavy outfit is 

 another disadvantage connected with this method. It is only one that a 

 careful worker, situated on favorable land, can successfully employ. 



2. This insect is one of the m.ost susceptible to sprays in the nymphal 

 stage of an}^ we have had experience with, provided the sorays are 

 applied when the insect can be reached by them. It is useless to attempt 

 control while the leaves are unfolding or while the flower stalks are still 

 fastened together. To do so invites failure, for the insects cannot be 

 reached by the liquid or dust. When the flower stalks have separated 

 out, a careful spraying of nicotine sulphate, ^ of a pint to 100 gals, 

 is most satisfactory. We have not as yet experimented with a reduced 

 strength of this compound, but believe that, provided a proper pressure, 

 etc. is maintained, a weaker strength would be equally effective. 



We were also able to secure very satisfactory results fi'om the use of 

 nicotine dusts. To state the matter briefly, a dust containing 2% 

 or more of nicotine sulphate (40% nicotine) with sulphur as a base gave 

 only slightly poorer results than nicotine sulphate used as a liquid. The 

 addition of lime to this mixture increases its eft'ectiveness, but such 

 mixtures gradually lose their strength and m.ust be kept in air-tight 

 containers. Clay used as a filler in place of sulphur gives a very in- 

 ferior product, frcm an insecticidal standpoint. 



3. The long preoviposition period of this insect seems to offer, indeed 

 to invite, attemipts at control in this stage. We were surprised to find, 

 upon making the attempt, that the different sprays and dusts employed 

 against the nj-mphs could be used with equally telling effect against 

 the adult. 



In addition to spraying and dusting we also made several trials of 

 open air fumigation, after the manner reported to have given good 

 results in Russia. 



Our experim^ents indicate that 360 lbs. to the acre of waste tobacco, 

 free frcm inccmbustible material, will give good control under favorable 



