232 NEBRASKA STATE HORTICULTURAL SOCIETY. 



2. Shot-hole: perforation of leaves: 



3. Wilting: "Damping off," "Wilt," etc. 



4. Necrosis: death of parts, as leaves, twigs, stems, etc. 



5. Reduction in size: dwarfing or atrophy. 



6. Increase in size: hypertrophy. 



7. Replacement of organs by a new structure. 



8. Mummification. 



&. Change of position. 



10. Destruction of organs. 



11. Excrescences and malformations. 



Galls: Pustules, tumors, corky outgrowths, crown galls, etc. 

 Cankers: Malformations in the bark generally resulting in an 



open wound. 

 Punks or conchs and other fruits of fleshy fungi. 

 Witches' brooms. 

 Rosettes. 



12. Exudations. 



Slime flux. 



Gummosis: Especially for stone fruits. 



Resinosis: Especially for coniferous trees. 



13. Rotting. 



Dry rot and soft rot: the "gangrene" of plant tissue. 



Root rots: Alfalfa, beets, cherry, etc. Generally woody or fleshy 



roots. 

 Stem or trunk: Dry rot of trees; rot of modified stems like 



rhizomes, bulbs, or tubers. 

 Bud. 

 Fruits: fleshy fruits of various kinds. 



It is quite common to find the foliage of trees, in the western part 

 of the state, showing a pronounced yellow cast instead of the normal 

 green color. This yellowing is especially prominent in the regions where 

 the soil is decidedly alkaline or where there is a seepage of ground 

 water from high irrigation ditches to a lower level, or where both of 

 these conditions prevail. The conspicuous sickly yellow com plants that 

 may be found in the early part of the season upon flooded fields or in 

 water-logged soils is another example of this marked symptom of disease. 

 The lack of sufficient iron in the soil will cause a plant to pass into 

 what is technically termed a chlorotic condition, that is, the leaf green 

 or chlorophyll is either not developed at all or only to a slight extent 

 These chlorotic plants can often be restored to their normal condition 

 by supplying them with iron. The occasional white plants that appear 

 in corn fields are some of our plant "albinos" and are suffering from 

 rather complex disturbances of their nutrition. Another physiological 

 trouble, the "mosaic disease," common in the tomato and the tobacco 



