PLANT ENEMIES 47 



Root Insects. Some of these insects are found on the roots, 

 in which case the plants affected are thought to be diseased. Some 

 of these insects actually chew the roots, while others suck out the sap. 



Borers. There is a group of insects which burrow into the 

 stalks, the bark and solid wood of branches, and even the trunks of 

 trees. The fruit trees are especially attacked by these borers. 

 Peaches, Apples, Currants, Gooseberries, Raspberries, Blackberries, 

 Roses, China Asters, Squashes and many other plants are so affected. 

 They must be dug out. It is difficult to apply an insecticide effec- 

 tive against borers after they get into the plants. Spray the trunks 

 with kerosene emulsion and a caustic solution of soap, caustic 

 potash and carbolic acid. Tarred paper or wire protectors will also 

 keep the insects from laying their eggs. Remove all weeds and 

 suckers and keep clean cultivation. 



Leaf, Flower and Bud Insects. Other insects prefer the 

 leaves and buds. This class is the easiest to control. As in medi- 

 cal work, there is no panacea for all ills, but it is not dangerous to 

 make one general sweeping statement about their control. It is 

 this : Sucking insects are seldom controlled by poisonous insecticides ; 

 their breathing pores along the sides of their bodies must be hit and 

 fiUed with the fluid; they are controlled by contact insecticides. 

 Chewing insects greedily eat the leaves which, if covered with a 

 poison, will kill them. 



CONTACT INSECTICIDES. The following insecticides are 

 effective against sucking insects: 



1. Tobacco or Nicotine Extracts are placed first in the list 

 because they are the most effective. Those having the highest 

 percentage of nicotine are the most valuable. Tobacco extracts 

 are found in both liquid and powder form and should be sprayed 

 upon the plants out of doors according to directions for each sort. 

 The addition of some soap to the tobacco solutions will help to 

 make them adhere to the insect. In the greenhouse, plants may be 

 fumigated by tobacco solutions or by burning tobacco dust. By 

 this method the nicotine is more thoroughly applied than by spray- 

 ing. Nicotine solutions are effective against plant lice or aphids, 

 thrips or any of the softer bodied bugs; the sucking insects. 



2. Soap Solutions for sprays are not as effective as the to- 

 bacco solution and are hardly worthy of use considering the ease of 

 obtaining and the effectiveness of the latter. They are useful for 

 washing scale from plants; for this use iish-oil soap, if possible. 



