74 JOURNAL OF THE 



NOTES ON THE ORCHARD SCOLYTUS. 



[Scolytus rugulosus. Ratz.) 



By G. F. ATKINSON. 



Some interesting things in the habits of the orchard scolytus 

 have come under my observation during the past year. This is a 

 minute beetle which infests peach, plum and cherry trees\ and has 

 done considerable damage to fruit growers recently in this country, 

 and notably so in the South. 



The weight of opinion seems to favor the view that the beetle at- 

 tacks only diseased trees. It sometimes attempts to bore into 

 healthy trees for the purpose of depositing eggs, but is driven out 

 by the exudation of the gum. I have seen sound limbs of healthy 

 peach trees badly punctured in this way, but no evidence of eggs 

 being deposited or of the larvae at work. I am led to believe that in 

 some cases this may lead to a diseased condition of the tree and 

 thus afford suitable material for the beetle to work upon. 



The number of annual generations in this latitude is probably two. 

 I have noticed that the late spring (May) and ear^y autumn (Sept.) 

 are two periods during which numbers of beetles excavate the gal- 

 leries to deposit the eggs. 



The female beetle seems to exhibit great maternal affection. The 

 galleries in which the eggs are deposited are from i to f inch in 

 length. The opening is just the size of the beetle, but the gallery 

 a very little larger in diameter. When the eggs are deposited the 

 female retreats to the entrance and remains here with the posterior 

 part of the body even with the outer bark of the tree When 

 touched she will crawl in a short distance, and return when the dis- 

 turbance ceases. She remains here night and day guarding her 

 eggs and young with a maternal fondness rarely seen. I have ob- 



^Scolytus rugulosus in branches of Pear Trees which were killed by Pear 

 Blight. Can. Ent., Vol. i6, p. i6i, by Dr. H. A. Hagen. 



Peach Yellows. Houghton Farm. Exp. Dept. Appendix to Series HI, 

 No. ^. D. P. Penhallow. 



Minute Borers in Cherry, Peach and Plum Trees. Prof. C. V. Riley in Am. 

 Entomologist, Vol. Ill, p. 298. 



Georgia Crop Report for August, 1884, p. i6. 



