84 MAt^YLAXD AGRICULTURAL EXPERIMEXT STATION. 



are closed. This worm feeds only on the outer leaves of the cabbage. 



REMEDIES FOR CABBAGE WORMS. 



All of the above-mentioned cabbage worms are amenable to 'about 

 the same treatment. In my 1883 Iveport, already referred to, I recom- 

 mend hot water (at a temperature of al:<out 130° F.), pyrethrum powder, 

 200 grains to 2 gallons of water, and kerosene emulsion. I also mentioned 

 the fact 'thiit dry applications of lime, salt, pepper, bran, buckwheat 

 flour, road- dust, soot, or of any other tine powder are efficacious against 

 the r<7/^/^^' worms and quoted Mr. P. T. Quinn's remedy of sawdust, im- 

 pregnated with carljolic acid as well as an anonymous remedy from the 

 JV. V. Tribune of 20 parts superphosphate of lime, 3 parts shell or fresh 

 air-slaked lime and 1 part of carbolic powder. I also mentioned the fact 

 of the efficacy of the arsenical poisons, but stated that few persons Avould 

 use them for fear of their poisonous effects. 



Since that time little has been suggested that is new, but many ex- 

 periments have been made with the remedies mentioned above. Prof. 

 Lawrence Brnuer of Nelu-aska claims that corn meal dusted on the cab- 

 bages causes the worms to fall off and protects the crop until washed off 

 by rain. It should be applied in the morning while the dew is on. 



The best results, however have been reached by a careful, intelligent 

 and sparing use of Paris green and London purple. Many successful 

 cabbage growers are today using these poisons. I am very loath to rec- 

 ommend them, for there is danger unless the greatest care be had. When 

 Paris green is thoroughly and evenly mixed with flour at the rate of one 

 ounce of the green to 100 ounces of flour and dusted through a cloth bag 

 so as to just luake a slight show of dust upon the leaves, the worms will 

 all be killed in the course of 2 or 3 days. Prof. C. P. Gillette has shown 

 that, applied in this way, the average amount of poison on each head will 

 be about one-seventh of a grain. Considering that fully one half of the 

 powder will fall upon the outside leaves or upon the ground he concludes 

 that ajierson will have to eat about 28 heads of cabbage in order to con- 

 sume a poisonous dose of arsenic even if most of the poison remained 

 upon the cabbage after cooking, which of course it does not. 



In spite of this encouraging reasoning, however, and in spite of the 

 fact that no cases of poisoning have been rej^orted, although the remedy 

 is in more or less general use, I hesitate to recommend it except while the 

 plants are young. At this time its use is advisable, where necessary, as 

 none of the jioison can i)ernuinently lodge in the heart or head which is 

 yet unformed. 



From the i)resent outlook pyrethrum mixed with water, as above 

 described, or di-y mixed with flour, is the safest remedy. Prof. James 

 Fletcher of Canada, a careful and reliable experimenter, says concerning 

 this remedy : 



"In the treatment of cabl)age caterpillars, pyrethrum diluted with 

 four times its weight of common flour, and then kept tightly closed for 



