57 



Labor. Laborers receive from $1.75 to $2.50 per day. Man and team, $3.50 

 to $5. 



Troubles. Two diseases, blight and scab; an insect, codling worm; and an 

 occasional late frost are the chief obstacles to pear culture. Scab and worms 

 can be controlled by spraying. Blight is a very serious enemy and has ruined 

 thousands of acres of pears in California and elsewhere. Pear planting is 

 somewhat hazardous on account of this disease, although it can be fairly well 

 controlled by very careful work. Control is effected by very thorough removal 

 of affected parts, especially during the winter. The disease is extremely 

 infectious. Partially resistant trees are being developed. Special information 

 should be sought in blight control. 



POTATO CULTURE 

 By JOHN W. GILMOEE, Professor of Agronomy 



The principal regions are in the delta lands of San Joaquin and Contra 

 Costa counties, and the Salinas Valley of Monterey County. Those desiring 

 to investigate this industry would do well to visit the regions in the vicinity of 

 Middle River, Holt and Stockton for the delta country, Blanco and Salinas 

 (Monterey County) and Sebastopol (Sonoma County) for the other regions. 

 There is, also, a considerable acreage in Los Angeles, Orange, and Imperial 

 counties. 



The delta region consists of lowlands which for a long period of time have 

 been inundated by the high waters of the Sacramento and San Joaquin rivers. 

 They have been overgrown by juncus (tule) and other marsh plants. These 

 marshes have been reclaimed by constructing levees along the water courses 

 and then by electrically driven pumps the water has been removed to a level 

 sufficiently low to grow crops. The soil consists of partly decomposed vegetable 

 matter mixed with sediment from the overflows, and in this form it is loose 

 and friable and permits the ready movement of water. The soil is well suited 

 not only to potatoes, but to onions, asparagus, beans, and barley. 



Because this soil is very rich in organic matter, and because of its loose 

 texture and abundance of moisture, diseases that affect the potato thrive 

 readily. These do not often materially damage the first crop, but they are 

 sufficiently prevalent to infest and multiply in the soil, so that future crops 

 are often greatly reduced. The disease causing the most trouble is the 

 Rhizoctonia. It infests the soils from year to year, and while it affects the 

 tubers it does not render them unfit for use. Its principle effect is upon the 

 young shoots which after becoming thoroughly diseased die before the tubers 

 are formed, but too late in the season for replanting. The only effective 

 remedy against this disease now known is to plant the land to non-affected 

 crops until the disease is starved out. It is estimated that this disease causes 

 an annual loss to potato growers in this region of from 20 to 25 per cent of 

 the crop, or a money loss of nearly, if not fully, a million dollars. 



Wilt disease (caused by Fusarium and Verticilium) is also very common in 

 this region and attacks both the tubers in the soil and the growing stems just 

 below the surface. The disease has the effect of cutting off the water supply 

 to the growing parts of the plants from the roots. The disease also produces 

 conditions favorable for the infestation of the tubers and stems by other 

 diseases. The use of disease-free tubers for seed and the witholding of potatoes 



