850 EXPERIMENT STATION RECORD. [Vol.36 



the vine variously known as little leaf, curly leaf, and yellow leaf. This dis- 

 ease is known to have been present in California for a number of years, 

 although no printed reference to it has been found that points clearly to its 

 occurrence before 1900. At the present time, it is said to attack vines in 

 various regions from the borders of Sacramento and San Joaquin Counties to 

 the southerly end of the San Joaquin Valley. In seriousness it is to be com- 

 pared with Oidium and phylloxera. 



Affected vines show small, yellowish leaves, short jointed canes, and in severe 

 cases, dead spots on the leaves and gummy secretions in the conducting tissues 

 of the arms and trunks. In severe cases the vines die after a few years. No 

 parasite has been found connected with the disease, and all the evidence seems 

 to show that it is not infectious. The trouble is believed to be associated with 

 local conditions of soil, water, and temperature. No effective method of treat- 

 ment has been demonstrated, although the application of gypsum to the soil 

 is said to have given promising results. 



Control of Oidium or vine mildew, F. T, Bioletti (Proc. Fruit Qrowers' 

 Conv. Cal., 1ft (1915), pp. 147-154). — This is a paper by the author with the 

 discussion thereon. 



It is stated that during 1915 attacks of Oidium have been exceptionally 

 widespread and destructive. The damage was particularly intense in the 

 interior and in regions where it Is usually mild or unknown, rather than in 

 those sections where it Is always present. The unusual severity this year is 

 ascribed to weather conditions. Finely powdered sulphur, applied while the 

 leaves are dry, is recommended. Winter treatments are believed to be in- 

 effective. 



The spraying of yellow pineapple plants on manganese soils with iron 

 sulphate solutions, M. O. Johnson {Hawaii Sta. Press Bui. 51 {1916), pp. 11, 

 figs. 4)- — The yellowing of pineapples on the black manganese soils of the 

 Island of Oahu is said to present a serious problem. Previous work of the 

 station (E. S. R., 27, p. 129) had shown that this yellowing is correlated with 

 the presence of abnormally large quantities of manganese in the soils. 



The author gives an account of experiments for the control of the pineapple 

 yellows by spraying the plants with an 8 per cent solution of iron sulphate. 

 This can be done at a cost for each application of approximately 60 cts. per 

 acre. In a field trial, the rows sprayed with the iron sulphate solution produced 

 more than double the weight of fruit produced by the check rows, while a still 

 greater increase was noted in the proportion of first-grade fruits. 



As a result of his investigations, the author recommends spraying plants 

 with the solution described above when there are any indications of yellowing, 

 repeating the spraying often enough to keep the plants in a green and healthy 

 condition. 



Citrus canker investigations at the Singalong Experiment Station, E. D. 

 DoBYLAND {Philippine Agr. Rev. [English Ed.], 9 (1916), No. 2, pp. 13S-1S5). — 

 Bordeaux mixture having failed to control citrus canker on badly infected 

 nursery stock of C. mitis, C. nobilis, and C. aurantium in 1915, tests were 

 made with 1 part 38 per cent formaldehyde in 120 parts of water and later 

 with a 1 : 100 solution applied to the plants and soil, combined with the removal 

 of the infected leaves and severe pruning. The disease was checked and a 

 healthy growth resulted, subsequent outbreaks of the disease being attributed 

 to the release of infecting material by the turning of the soil. The outbreaks 

 were readily controlled by the use of the same treatment, no new Infections 

 being apparent at the time of the report. 



Further tests with formalin sprays are being made at both the Singalong 

 and the Lamao stations. 



