8. The healhig of wounds is facilitated hy protecting tliemfrom 

 moisture. — Tlie decay of wood is caused by the growth of bacteria, 

 fungi and otlier parasitic organisms. Moisture is necessary to the 

 germination of these organisms. If the exposed surfaces made by 

 heavy pruning are covered with water-proof paint or some anti- 

 septic dressing, the germs and spores of these wood-destroying 

 parasites are kept out. Yery cheap substances are quite effective ; 

 among these are lead, paint, tar and Bordeaux mixture. They 

 should be applied promptly after the wound is made. 



The pruning of grapes, raspberries, gooseberries and currants are 

 matters of special detail. The habits of the plant must be known 

 and the pruner should ask himself in each instance what the par- 

 ticular result is, which he is aiming to secure. 



II. Insects and Diseases. 



9. There are enemies which the fruit-groioer nfiust fight and con- 

 guer if lie %oo\dd succeed in husiness. — Whenever certain classes 

 of plants are cultivated exclusively or largely in any one locality, 

 the insects which feed on them multiply with great rapidity. The 

 conditions for the growth of these insects are more favorable than 

 formerly, food is plenty and the rate of development is out of pro- 

 portion to the increase of the food product. In all great fruit 

 centers, therefore, special methods are employed to destroy the 

 enemies of economic plants — that is, those plants useful to man. 



10. Enemies of the orchard are divisible into tibo classes : those 

 which belong to the animal hingdom / and those which are members 

 of the vegetable hingdom. The onethods of treating these enemies 

 are based on their structure^ habits of growth and the manner in 

 which they attack j9Z<r^/i^5. 



(a) Insect enemies. — Insects which have jaws with which they 

 bite or chew the parts of the plant may be destroyed by sprinkling 

 the plant on which they feed with substances which are poisonous 

 when taken internally. This class of insects is usually the most 

 important one with which the farmer has to deal. To it belong 

 the potato beetle, the canker-worm that defoliates apple trees, the 

 army-worm, the larvse (worms) of the codling-moth, the currant 

 worm and numerous beetles. Chief among poisons used against 



407 



