REPORT OF TEE ENTOMOLOGIST AND BOTANIST 211 



SESSIONAL PAPER No. 16 



No reports of injury were received in 1906 from Nova Scotia, where considerable 

 injury was done in 1904. 



The Small "White Cabbage Butterfly, Pontia rapes, L. — This well-known enemy 

 of the cabbage was remarkably abundant and destructive in Manitoba during the sum- 

 mer of 1906. 



Aweme, Man., September 20. — ' The larva; of Pontia rapoe were more abundant 

 this year in our district than I have ever known them to be, and, as a result, in those 

 districts where the use of pyrethrum insect powder was not known, cabbages were 

 seriously and in some places wholly destroyed. Here a couple of dustings of the pow- 

 der a week apart, mixed according to your directions, completely exterminated the 

 caterpillars, so that no further damage was done, and we had a good crop. Turnips 

 wild mustard, wild radish, and even the notorious Stinkweed, were also attacked, as 

 well as, I suppose, many other cruciferous plants which I did not notice.' — N. CfJinnLE. 



Norquay, Man., September 25.—' The Cabboge Butterfly has descended on us as 

 a scourge; every cabbage patch I know has been destroyed, also mignonette in the 

 flower garden. Later they attacked Swede turnips rather savagely. I note your remedy 

 (insect powder and flour) which I will have ready for them next year.' — W. II. 

 Holland. 



Macgregor, Man., October 25. — ' The White Cabbage Butterfly appeared suddenly 

 this year in immense numbers, and the caterpillars entirely destroyed the cabbage 

 crop. There were but four cabbages at our local show on the 3rd instant ; two of these 

 were completely riddled by the caterpillars, and the .other two, although not so bad, 

 were injured to some extent. I saw no tickets attached to any of them. What I 

 would like to know, is : Are these butterflies likely to turn up again next season, or 

 are they only occasional visitors? They are distinct from the cabbage butterfly that is 

 in Ireland and they seem to be harder to deal with, as the n-^'-ibs get into the centre of 

 the cabbage, while those in Ireland live on the outer leaves.' — T. Rowan. 



Cypress River, Man., March. 1907. — ' Last year tho White Cabbage Butterflies 

 were so numerous as to be quite a plague in this part of Manitoba, and no one here 

 had a cabbage for winter use. The whole cabbage was like a skeleton. I tried quick 

 lime (that was a specific in the old country), but it was of no avail here; and then I 

 trind salt, but they seemed to like that all the more, and then I tried ashes.' — John 

 Marten, Sr. 



The caterpillars of the Small White Cabbage Butterfly, commonly known as 

 Cabbage Worms, are, when full grown, about an inch long, of a velvety green colour, 

 with a broken yellow line along each side and an unbroken one down the middle of 

 of the back. The eggs are laid on the leaves on any part of the plant and on both 

 sides of the leaves. The young caterpillars hatch after about a week and at once feed 

 on the soft tissues close around the egg from which they have emerged. As they grow 

 larger, they bore into the heads of the cabbage and do a large amount of injury, com- 

 pared with their size. Being of the same green colour as the leaves, they are difficult 

 to detect and may be in large numbers upon the plants wilhout being noticed, except 

 for their injuries. After feeding for about a fortnight ,the chrysalis condition is as- 

 sumed, and in about a month after the eggs are laid the butterflies appear. There are 

 two regidar broods during the growing season and, besides this, sometimes a late 

 supplementary brood of which the caterpillars are found as late as November. Cruci- 

 ferous plants of nearly all kinds are attacked by this insect, as well as plants belong- 

 ing to the Caper and ^fignonette families, which are closely allied to the Cruciferse. 



This insect, which has now spread right across the Dominion and is every year 

 the cause of enormous losses, not only in crops of cabbages, but also in turnips, swedes, 

 and rape, is a comparatively recent importation from Europe. The first records of 

 its occurrence in America were about 1860, when it was observed near Quebec; and 

 it is supposed that it was brought across the Atlantic on some of the ships running 

 into Quebec from European ports. 



16—14* 



