240 MINNESOTA STATE HORTICULTURAL SOCIETY. 



curly leaf from ordinary, poor conditions in the plants which 

 have a similar appearance. In some districts the disease has 

 been causing considerable damage. The affected plants are 

 usually shorter than the healthy ones. The plant may be very 

 bushy in appearance. The leaves are usually smaller than 

 normal and yellowish in color or mottled, with green and yel- 

 low patches alternating. The parts of the leaf between the 

 veins are quite often raised, giving the leaf a peculiar curled 

 appearance. The exact cause of this condition is not known 

 though diseased plants seem to incur in groups in the field. In- 

 vestigations are being carried on in co-operation with the Horti- 

 cultural Department to determine whether it is capable of spread- 

 ing through a field and whether it can be transmitted by the use 

 of cuttings from diseased plants. We do know it affects the gen- 



Crovvn gall of raspberries. 



eral vigor of the plants and, consequently, materially reduces 

 the yield. 



Raspberry plants should be obtained from localities where 

 the disease is not serious and planted in well drained, not too 

 heavy soil of medium texture. Judicious applications of barn- 

 yard manure may be of value. If possible, applications of 

 water during dry weather may be of assistance. If, however, 

 in spite of these precautions, plants show marked signs of the 

 trouble, they should be pulled up at once and burned to prevent 

 a possible infection of nearby healthy plants. 



Gray bark, or spur blight, anthracnose, crown gall and yel- 

 lows, or curly leaf, then comprise the list of the more important 

 diseases of the raspberry in Minnesota. 



Investigational work on these diseases is well under way. 

 All of the information which is needed before definite control 

 measures can be prescribed is not yet available. The Section 

 of Plant Pathology of the Department of Agriculture at the 

 University is making a determined effort to get this informa- 

 tion. It solicits the co-operation of berry growers. They can 

 render valuable service by reporting diseases, submitting speci- 



