101 



POTATO. 



Potato-stem Borer. Hydrcecia micacea, Esp.* 



On July 20th, in the past season, Mr. W. Sim, of Gourdas, Fyvie, 

 Aberdeenshire, N.B., to whom I have been previously indebted for 

 very carefully observed notes of insect attack, forwarded me some 

 observations of damage caused to Potato stems (to a serious extent) by 

 the borings of a kind of moth caterpillar within them, of which he 

 forwarded a sample. 



The piece of Potato stem sent accompanying was bored for about 

 seven inches. That is, the boring sent was about that length, but it 

 might have been longer, as the stem was cut through at the lower 

 part, so that some of the tunnelling was removed. At the upper part 

 there was some frass from the workings of the caterpillar. With this, 

 and the moth caterpillar accompanying, Mr. Sim sent the following 

 notes: — 



" I beg to enclose you specimen of larva which is not described, to 

 my knowledge, in your works on injurious insects. They are destructive 

 to the growing crop of Potatoes, especially in gardens, and perhaps the 

 failure of that crop may be sometimes due to them. I have observed 

 some extent of damage done here every season for some years, but I 

 am not aware what is the originator of the evil. When the Potatoes 

 are in a growing state, and the haulms nearly at the full height, a 

 plant may be seen here and there with leaves withered up and the 

 stem fallen over. A careful examination of the prostrate plant with 

 hollow stem invariably shows that the damage is due to the enclosed 

 pest, which is found feeding inside." 



On August 9th Mr. Sim sent me the following communication, 

 which it will be observed is of interest as giving the approximate date 

 of the termination of attack : — 



"I have looked over the Potato crop as you advised, and have 

 found in the fallen stems a few more of the destructive grubs like the 

 specimen I sent you. Their season of work is now over, but I will 

 try and rear a moth for you." 



On October 17th following, Mr. Sim was accordingly good enough 

 to send me specimens of the moths, with the note of these moths being 

 reared from caterpillars taken from injured Potatoes, also the date of 

 pupation and the date of the appearance of the moths, as follows : — 



" I have much pleasure in sending the Potato moths which I have 



* A description of the moth, which is known jDopularly as the "Kosy Rustic," 

 will be found at p. 103; but it is not figured, as the specimens (apparently from 

 circumstances noted) were stunted in growth. 



