236 EXPERIMENT STATION RECORD. 



Tin cans versus pots for seedling' plants, E. V. Wilcox (Hawaii St a. Press 

 Bui. .'/J, pp. 8, figs. 2). — Obsei-vations of yonug seedling plants, such as papaya, 

 mango, avocado, etc., have shown that they grow more rapidly and with greater 

 vigor in tin cans than in ordinary florist's pots. The author here reports a 

 series of experiments conducted to determine the cause of difference in growth. 

 Special attention was paid to a study of the factors of evaporation and stimu- 

 lation due to the tin and solder of the cans. A portion of the pots and cans 

 was paraffined in order to render the above factors as nearly alike as possible 

 in both kinds of containers. Observations were made of the loss of water by 

 evaporation and transpiration, and measurements were made of plant growth 

 in the different containers. 



The results of these experiments show that it is impossible to maintain the 

 moisture content of the soil in florist's pots as uniform as in tin cans, at least 

 without watering them 3 or 4 times daily. In these experiments 5-in. pots 

 containing 760 gm. of soil lost about 29 gm. of water daily by evaporation, while 

 tin cans holding the same amount of soil lost about 12 gm. daily. The lateral 

 movement of water through the side of the pot tends to bring the roots to the 

 outside wall of soil where the variation in moisture content is greater. It was 

 found that plants gi'own in untreated tin cans showed a better color and a 

 more rapid growth than those in paraffined cans. Hence, it is concluded that 

 the better growth of plants in tins is due in part to the more uniform moisture 

 conditions and in part to a stimulating effect of the tin it-self. 



Since porous flower pots must be imported into Hawaii at great expense and 

 danger of breakage, the above results appear to warrant the use of rejected tin 

 cans from the pineapple canneries, where they may be obtained at little cost. 

 It has been found in practice that where plants in pots require watering every 

 day, plants in cans will thrive well when watered every third day. 



Suggestions on preparation and use of spray formulas, G. M. Bentley 

 (Tennessee Sta. Bui. 99, pp. 61-82, figs. 7). — This bulletin comprises a compila- 

 tion of suggestions on the preparation and use of various insecticidal and fungi- 

 cidal formulas. The subject matter is discussed under the following general 

 headings : Preventives, insecticides for biting insects, insecticides for sucking in- 

 sects, combined insecticides and fungicides, fumigants, fungicides, spraying to 

 kill weeds, and herbicides. Concise directions are also given for the treatment 

 of insect pests and fungus diseases, together with the restrictions that have been 

 made on the shipment of various articles coming from any State partially in 

 fested with the Mexican cotton boll weevil. 



The composition of irrigated and nonirrigated fruits, J. S. Jones and C. W. 

 CoLVER {Idaho Sta. Bui. 75, pp. 53). — This bulletin reports an analytical study 

 of orchard and small fruits, with special reference to the effect of irrigation 

 on those compounds which materially influence quality in fruit. Although the 

 attempt has been made to compare similar varieties of fruits growing both 

 under irrigation and nonirri^ation, data were secured with regard to as many 

 varieties as possible whether grown under both conditions or not. The prin- 

 cipal determinations made include total solids, acidity, invert and cane sugar, 

 nitrogen, ash, and waste. The leading commercial districts of Idaho were 

 represented and all samples were grown at elevations less than 3,000 ft. The 

 analyses are here grouped and discussed under the 3 divisions of drupaceous, 

 pomaceous, and small fruits. 



Summarizing the results it appears that there is a fairly well-defined tendency 

 for apricots, cherries, nectarines, peaches, plums, and prunes to elaborate 

 greater percentages of solid matter when grown in the nonirrigated sections. 

 With the exception of Italian and Petite prunes, however, such differences in 

 sugar and acid are too small to seriously affect taste. There was a remarkable 



