344 Plums and Plum Culture 



count of it need be given here. It may be said briefly 

 that the San Jose scale is amenable to proper treat- 

 ment, and not more difficult of extermination than 

 many other insect pests. Kerosene emulsion, whale- 

 oil soap, kerosene and water, crude petroleum, or pure 

 kerosene will kill it if thoroughly applied. 



Borers sometimes attack plum trees, but not so 

 frequently as apples and pears. The peach-tree borer, 

 which is quite a different insect from the species work- 

 ing on apples, also attacks plums.* The damage from 

 borers is sometimes serious; but seldom so except In 

 neglected orchards, where all sorts of pests always 

 multiply. 



The remedies and preventives for borers in plum 

 trees are the same as those generally employed in 

 fighting borers in the apple orchard. The first pre- 

 ventive measure is clean culture. Weeds and grass 

 standing about the trees invite the moths to come 

 thither and lay their eggs. Secondly, the trunks should 

 be kept clean of dead and scaly bark. Patches of sun- 

 scald or canker are especially attractive to the borer. 

 Thirdly, various washes are advised to keep the trunks 

 clean and to prevent the young borers from getting 

 into the trees. These are usually of lye or strong soap. 

 The action is the same for all. The potash, or other 

 alkali, keeps the trunk free from certain parasitic 

 growths. If strong and carefully applied, it is very 

 effective. The solution used and recommended by the 

 writer is made by dissolving a pound of concentrated 

 lye or potash in a large pail of water (three to five gal- 

 lons). This solution is very strong and must be 

 handled with caution. It may be put onto the trees 

 with a large paint brush, an old broom trimmed down, 

 or a convenient bunch of rags tacked to the end of a 



*See especially M. V. Slingerland, Cornell Experiment station Bul- 

 letin 176. 1899. 



