THE MONTHLY BULLETIN. 271 



Soils and their treatment will be discussed by some of the highest 

 authorities on the subject; two sessions or more will be devoted to the 

 potato industry; the causes that hinder success in potato production 

 will be discussed by those Avho know; pear blight which is laying so 

 heavy a hand on our fruit growers, will be ably considered by scientific 

 authorities and by orchardists who have successfully controlled this 

 most obdurate of bacterial diseases, and there will be a symposium on 

 the outlook of the various fruits grown in the State by men who have 

 made a success of their culture. ]\Iiss Lillian D. Clark of Berkeley will 

 have charge of the women's sessions, and this is enough to insure their 

 success. We hope and believe that these sessions will fall no whit below 

 the interesting meetings held by the ladies at the Los Angeles conven- 

 tion. i\Ioiulay and Tuesday, July 26th and 27th, will be given to 

 matters of special interest to the county horticultural commissioners, 

 their deputies and inspectors; Thursday, the 20th, will be devoted in 

 part, at least, to an automobile trip through the famous Santa Clara 

 \' alley, and on Saturday the convention will adjourn in a body to meet 

 at the Exposition in San Francisco. Here special pains will be tfiken 

 to explain the great ])lant exhibits, and in the evening an address will 

 be given by Dr. John Coulter of the Chicago University. Saturday 

 will be "Horticultural Day" at the Expo.sition.— A. J. C." 



"Little leaf" disease of fruit trees.^ — For years a mysterious disease 

 has been troubling fruit trees in parts of the State, being particularly 

 bad in the San Joaquin Valley, and attacking all stone fruits, as well 

 as ai)ples, pears, vines aiul prol)al)ly certain kinds of shade trees. 



This disease is described in Bulletin 218 on California Plant Diseases, 

 by Ralph E. and Elizabeth H. Smith, of the Agricultural Experiment 

 Station at Berkeley, under the name of "Little Leaf" or "California 

 Yellows." Various causes have been assigned for the trouble, such as 

 nematodes, light soil, lack of nitrogen in the .soil, unfavorable climatic 

 conditions, etc., but as yet the fruit grower is in the dark as to the 

 exact cause, and consequently at a loss to know what may l)e done to 

 remedy the trouble. 



Recently the writer inspected orchards in Stanislaus, Fresno, Tulare, 

 San Bernardino and Riverside counties, so that some idea might be 

 gained of the distribution of the trouble, both in the San Joaquin 

 Valley and south of the Tehachapi. In the three first mentioned coun- 

 ties the seriousness of the disease was such as to cause alarm. Hundreds 

 of acres of peaches are producing little and there are many cases of 

 trees or portions of trees dying Avhere the little leaf condition is preva- 

 lent. Trees badly affected set practically no fruit at all, and if a small 

 amount does set it is almost sure to fail to develop into first class fruit. 

 While the worst orchards were observed in very light sandy soil, there 

 were some cases where the soil could not be classed as extremely light 

 or sandy. In fact in one case there was considerable clay present. 



In Riverside and San Bernardino counties very little of the disease 

 was seen on peaches; in fact in the Upland-Ontario section of San Ber- 

 nardino County, where the soil is almost pure sand in places, none of 

 the disease was seen. In the vicinity of Victorville apple trees com- 

 monly show the characteristic little leaf condition seen in the San Joa- 

 quin Valley. 



