LESSONS ON POTATOES FOR RURAL SCHOOLS. 19 
3. Types of cultivators: Weeder, disk cultivator, corn cultivator, 
two-horse cultivator for large fields. 
Cautions : 
1. Careless tillage may work great injury upon the crop, as potato 
plants are more tender than weeds. 
2. In using weeder or tooth harrow great care must be taken to pre- 
vent the teeth from injuring the sprouts. 
3. In later growth the roots are in danger from too deep or too 
close cultivation. The greatest development of the roots in the 
plowed area is from 5 to 10 inches below the surface. 
4. The danger of injury to the potato plant is greatest at blossom- 
ing time, when the exhausting effects of blossoming and forming 
tubers at the same time are very heavy. 
Practical exercises. — This lesson should essentially be a guide to 
proper practice in potato cultivation. Many of the pupils will have 
potatoes as a home project, others will assist in the home work on 
the farm where potatoes are raised. The principles laid down in this 
lesson should be put into careful practice in either case. 
A field trip to a potato farm would be valuable to the class. If 
the projects are under the supervision of the school, the teacher 
should try to visit each home as soon as possible to observe the 
progress of the projects. If the teacher is working in cooperation 
with the county or State club leader, it will be especially helpful to 
make these visits at the same time the official representative makes 
his visits to the work. In all cases this cooperation should strengthen 
the school work if it is well carried out. 
Correlations. — The written reports, summaries, and costs of pro- 
duction as completed in the project work will furnish ample correla- 
tions in language and arithmetic. In case there is no project, the 
same reports on the work of the pupil on the home farm will furnish 
the same material. 
LESSON XL 
Subject. — Potato-crop pests — Insects and diseases, how to combat 
them. 
Problem. — To learn to identify the chief potato insect pests and 
diseases and to discover proper methods of control. 
Sources of information. — Farmers' Bulletins 544, 557, and 868; 
bulletins from State college of agriculture. 
Illustrative material. — Spraying charts. Illustrations of spraying 
apparatus. Samples of sprayers may often be borrowed from a 
farmer in the district or loaned by the local dealer. Samples of 
fungicides and insecticides. Illustrations or exhibits of the pests to 
be controlled. Samples of potato plants affected with the common 
fungus diseases may be brought to class for a study of the charac- 
teristics of the disease. 
