Volume 20, Bulletins 222-231. (222) Control of Leafy Spurge, Euphorbia Esula L.; (223) Parasitism of Collectotrichum Lagenarium (Pass.) Ell. And Halst.; (224) Genetics of Resistance to Bacterial Wilt in Maize; (225) Classification of the Organisms Important in Dairy Products: II. Pseudomonas fragi; (226) Design of Agronomic Experiements for Plots Differentiated in Fertility by Past Treatments; (227) Chemistry of Butter and Butter Making: IV. The Relationships Among the Cream Acidity, the Churning Loss and the Churning Time; (228) Inheritance and Correlation of Shape, Size and Color in the Watermelon, Citrullus Vulgaris Schrad.; (229) Influence of Environmental Factors on the Growth of the Corn Plant Under Field Conditions; (230) Oxidized Flavors in Strawberry Ice Cream; (231) Some Kinematic and Dynamic Studies of Rigid Transport Wheels for Agricultural Equipment