39 



affect them unpleasantly for a short time, but they would uniformly 

 recover, and either proceed again to eat or crawl away to another 

 plant. In no case were worms injured unless spray was delivered di- 

 rectly upon them. Eating- of the plants after they had been sprayed 

 did not affect them. These experiments occupied several days and 

 were duplicated. 



Tests in small Jars. — This was a duplicate test on Plusia brassioce and 

 Pieris rapce. The liquid was applied with a feather and in sufficient 

 quantity to moisten the entire body of the worm. In dilutions up to 1 

 to 5 it killed both; weaker solutions occasionally killed one or more 

 rapw but not brassicce. 



In breeding Cages. — In this test the above was duplicated on larger 

 scale. Liquid was applied as spray and until all worms were thoroughly 

 drenched. They were placed on parts of a small cabbage-head, so that 

 each box very nearly represented an out-door experiment and enabled 

 me to be much more certain of results obtained. 



Up to 5 dilutions 80 per cent, of rapce were destroyed and 10 per cent, 

 of brassicce, there not being much difference in the strength of liquid 

 as to efficacy. Weaker solutions did little or no injury to either. P. bras- 

 sicce was not treated with emulsion at all in the field, but from effect 

 on rapce am sure that the conditions were essentially those of outside 

 experiments. The amount of drenching with this liquid which bras- 

 sicce could stand was certainly remarkable. In previous test jars were 

 covered. Liquid in each case was taken from same jar of emulsion. 

 I had no trouble in making a good emulsion that was stable in what- 

 ever dilutions I chose to use it. 



On Cabbage Plant-louse. 



Wherever used on this insect, even in weakest solutions (1 to 16), 

 the emulsion destroyed all that were touched by it. 



On White Grubs. 



A solution of 1 part emulsion to 4 parts water was used quite ex- 

 tensively on the larvae of the May beetle, Lachnosterna fusca. The re- 

 sults were far from satisfactory. Where used on the lawn the grubs 

 descended 2 or 3 inches and were unharmed. Some few appeared a little 

 sick, and occasionally a black spot was observed on some of them, but 

 none were destroyed. After conducting this test for twenty days it was 

 abandoned. Several boxes were arranged with loose soil and grubs 

 placed in these for experiment. Here where they were only lightly 

 covered with loose soil the emulsion destroyed nearly every one in 

 twenty-four hours. The liquid was sprinkled on in these tests suffi- 

 ciently to moisten the surface thoroughly. 



Lime and salt were also tried over the lawn and in boxes. On the 

 lawn where they washed through, the grubs immediately descended out 

 Of reach. iSone were actually killed on the lawn that I could observe, 



