THE KEPORT OE THE No. 36 



Inferences FiiOM the Above Table and ikom Obskrvations in the Eield. 



First. Corrosive sublimate was the only substance used which gave satisfac- 

 tory or fairly satisfactory results, the results from it being better than the per- 

 centages indicate, because nearly all the injuries Avere on the surfaeo, only a few 

 1 eing deep in the tissues, whereas in the checks a considerable percentage were 

 deep in the tissues. The plants were somewhat older than usual when jiulled. 

 This possibly accounts for surface injuries. 



Second. Tobacco dust alone, or soft coal soot alone, or a combination of the 

 two, or a combination of tobacco dust, sulphur and arsenate of lead powder, gave 

 no control and in most cases seemed to encourage the presence of the insect. 



Third.- Under conditions such as we had last year, corrosive sublimate had 

 a decidedly beneficial result upon the size, shape and quality of the radishes causing 

 them to be smooth-skinned and of good size. On the contrary, toba-cco and soot 

 Ixith acted as fertilizers and gave excellent foliage but inferior form and size of- 

 tlie enlarged part of the root, this being elongate, slender, rough on the surface 

 and unattractive in appearance. 



Fourth. Cori'osive sublimate iP applied stronger than 1-1,000 to young plants, 

 weakens them and causes a distinct shock, though they soon outgTow tliis. The 

 same thing happens to cabbages if the roots, when l)ei ng transplajited, are soaked 

 a couple of minutes in the liquid, yet even then they recover. Too heavy soaking 

 of soil around very young ])lants iji the iield, even with 1 to 1.000 may cause a 

 sickly appearance of foliage for a few days. 



Fifth. Sufficient tests have not been made yet to allow a reliable conclusion 

 to be formed as to the ])est time to apply corrosive sublimate to radishes. 



Sixth. Corrosive sul)limate ap])lie(l within 21 lionrs (<[' sowing the seed 

 a]»pcars to have no injurious effect upon germination. 



How DOES COKROSIVE SUBLIMATE AvV IN TIIF. C'OXTHOL OF TllF. CaBRACE MaiJOOT? 



1. Does it Kill the Eggs? Eggs were jjlaced on blotting pa|>er in pill 

 boxes containing soil freshly saturated with corrosive sublimate 1-1.000. The 

 result was that of 80 eggs treated, 61 or 80 per cent, hatched. In the check, out 

 of 134 eggs, 128 hatched or 95 per cent. Tlie above results represent not a single 

 test, but a series with a few eggs at a time. Thert' seems no doubt therefore, that 

 if the eggs hatch under these circumstances, they would hatch in the field in soil 

 treated with corrosive sublimate. 



2. Does it Kill the Laijv.e? Various metliods were employed to test 

 \vli.ether corrosive sublimate kills the lar\;e in any stage of their growth. 



Out of 190 larv;e treated 83 pujiated. \ remained larva^ to the end of ihe test 

 and 103 or 56.8 per cent, were missing. More would have been missing had they 

 not iji some cases been ])ut in retainers from which they could not escape. 



In the checks, out of 46 larva\. 35 pupated and 11 or 23.8 per cent, were 

 missing, 5 of these by accident. 



Some of the missing treated larvie were doubtless killed, especially the 

 very small larva\ but most of them crawled away and escaped. Where 

 the larvffi were conhned so that they could not escape, it was found that, 

 while a good many died, yet many lived. It was observed however, that there was 

 an evident desire both of large and small larv.T to avoid contact with this liquid 

 compared with water. Our inference is therefore, that control is not to any large 

 extent brought about by the death of tlie larviP from contact with corrosive sub- 



