PLATE 5 



I. — Influence of relative amount of sand and clay on lohacco rootrot: A, unin- 

 fested series: B, infested series — 



I A, uninfested soil, three-fourths clay ajid one-fourth siuTid; 



1 B, infested soil, three-fourths clay and'one-fourth sand; 



2 A, uninfested soil, one-half cla}-- and one-half sand; 

 2B, infested soil, one-half clay and one-half sand; 



3 A, uninfested soil, three-fourths sand; 



3B, infested soil, three-fourths sand; 



4A, uninfested soil, all sand; 



4B, infested soil, all sand. 

 II, III. — Influence of soil fertility on amount of tobacco rootrot: II, infested 

 series; III, uninfested series — 



I A, infested soil, no treatment; 



2A, infested soil, 3.5 gms. of nutrient salts; 



3A, infested soil, 7.0 gms. of nutrient salts; 



4A, infested soil, 14.00 gms. of nutrient salts; 



5A, im'ested soil, 28 gms. of nutrient salts; 



6A, infested soil, 56 gms. of nutrient salts. 



Note increasing injur\'^ from nutrient salts beginning at pot 3A. 



iB, uninfested soil, no treatment; » 



2B, uninfested soil, 3.5 gms. of nutrient salts; 



3B, uninfested soil, 7.0 gms. of nutrient salts; 



4B, uninfested soil, 14.00 gms. of nutrient salts; 



5B, tminfested soil, 28 gms. of nutrient salts; 



6B, uninfested soil, 56 gms. of nutrient salts. 



Note injury from nutrient salts in pots 5B and 6B. 

 IV. — Relation of compactness of soil to injury caused by Thielavia basicola: 



lA, infested soil, loosely packed; 



iB, uninfested soil, loosely packed; 



2A, infested soil, very compact; 



2B, uninfested soil, very compact. 

 V. — Influence of transplanting infected seedlings in healthy soil: 



A, Pennsylvania Broadleaf infected geedlings; 



B, Pennsylvania Broadleaf healthy seedlings; 



C, White Eurley infected seedlings; 



D, WTiite Burley healthy seedlings; 



E, Northern Hybrid (a resistant type) infected seedlings, 



F, Northern Hybrid (a resistant type) healthy seedlings. 



