VIII Journal of Agricultural Research Voi.vi 



Citrus Canker 



Page 



Plate VIII. Fig. i. — Grapefruit leaf showing young Citrus cankers. Fig. 2. — 

 Old Citrus canker on Satsuma leaves. Figs. 3, 4. — Seedling grapefruit 

 branches affected with Citrus canker. Fig. 5. — Severe canker infection of 

 branches of Citrus trifoliata 100 



Plate IX. Fig. i. — View of lower side of leaves of seedling grapefruit artifi- 

 cially inoculated with Pseudomonas cilri. Fig. 2 . — Top view of plant shown 

 in figiu-e I. Fig. 3. — Spongy white cankers on leaf and twig of seedling 

 grapefruit produced by artificial inoculation. Fig. 4. — Citrus canker on 

 Satsuma leaves resulting from artificial inoculation with Pseudomonas citri. 

 Fig. 5. — Photomicrograph of section of young, open canker on grapefruit. . 100 



Plate X. Fig. i. — Natural Citrus canker infection on leaves of Citrus trifoliata. 

 Fig, 2. — Matm-e cankers on fruit of Citrus decumana. Fig. 3. — Canker on 

 seedling grapefruit leaves, entrance having been effected through abrasions 

 made by thorns. Fig. 4. — Yotmg spongy cankers on fruit of Citrus decu- 

 mana. Fig. 5. — Phoma soda on cellulose agar showing dissolution of cellu- 

 lose. Fig. 6. — Mature cankerous areas on leaves of Dxmcan grapefruit. . . . 100 



Plate XI. Fig. i. — Cankers on old grapefruit leaves which have enlarged 

 during the second growing season. Fig. 2. — Citrus canker resulting from 

 immersion of leaves in a bacterial suspension. Fig. 3. — Culture of Phoma 

 socia showing pycnidial formation in concentric rings. Fig. 4. — Dilution 

 poured plate of Pseudomonas citri on green-bean agar. Fig. 5. — Photo- 

 micrograph of pycnidium of Phoma socia taken in reflected sunlight. 

 Fig. 6. — Photomicrograph of pycnidia of Phoma socia taken in diffuse 

 light 100 



Insect Injury to Cotton Seedlings 



Plate XII. Fig. i. — Cutworm injury to cotton seedlings; produced in breed- 

 ing cages. Figs. 2, 3. — Cutworm injury to cotton seedling 140 



Plate XIII. Fig. i. — Cutworm injury to cotton seedling. Fig. 2. — Tussock 

 larva feeding upon cotton leaf. Fig. 3. — Injury produced by a nearly 

 full-grown tussock larva when confined in a screen cage containing potted 

 cotton plants 140 



Plate XIV. Cotton leaves showing grasshopper injury 140 



Plate XV. Fig. i. — Underside of cotton leaf showing grasshopper injury. 



Fig. 2. — Cotton leaf showing grasshopper injury 140 



Plate XVI. Fig. i. — Injury to terminal bud of cotton by lepidopterous larva. 



Fig. 2. — Two cotton plants from laboratory garden with leaves removed. . 140 



Watermelon Stem-End Rot 



Plate XVII. Watermelons, showing the effect of inoculation with species of 

 Diplodia: Fig. 1. — The upper four melons were held as checks; the 

 lower five are melons nine days after having been inoculated with a culttue 

 of Diplodia sp. Fig. 2. — A watermelon nine days after having been in- 

 oculated with a culture of Diplodia tuhericola E. and E 152 



Crowngall Studies Showing Changes in Plant Structures due to a 



Changed Stimulus 



Plate XVIII. Teratoid cro\vngalls produced in Pelargonium spp 182 



Plate XIX. Teratoid crowngalls produced in castor-oil plant. Fig. A. — A 

 red-stem variety. Leaves reflexed; axis distorted; and feeble shoots 

 developing out of the axillary tumors. Fig. B. — A green-stem glaucous 

 variety 182 



