6 MASS. EXPERIMENT STATION BULLETIN 415 



type. Seed should be obtained from a reliable seed concern. Ornamental varie- 

 ties of sunflowers, of which there are many, are not of agricultural value since 

 they produce very little seed. 



JUMBO UAMMOTB RUSSIAN 



Figure 4. Typical Seed Varieties. 



Diseases and Pests 



A rusting of the lower leaves of the sunflower plants was the onl}- ailment 

 encountered in our trials. In severe cases the leaves turned brown completely 

 and died. However, there was no evidence that the disease materially reduced 

 the yield of the crop. Control measures consist of rotating the crop and plowing 

 under the stalks. 



Sunflower seeds are subject to infestation by the weevil. However, very little 

 damage from this cause has been noticed in Massachusetts. This pest seems to 

 develop in the head and inside the hull of the seeds before the seeds are fully 

 mature. Seed which appears to be free from weevil when harvested may, after 

 a month's storage, show weevil holes bored from within, which damage the grade 

 of the crop. After the weevils leave the hull, they apparently never again bother 

 the seed; hence it is possible to determine the weevil damage at this time, for it 

 will not be any greater a year or so thereafter. 



Some pest trouble has been observed in which slight damage has been caused 

 by an insect boring into the heart of the plant stalk and eating out the pith; but 

 this insect does not touch the seeded head. 



Birds sometimes pick some of the seeds out of the sunflower heads where only a 

 few plants are grown. The loss of seed due to birds is negligible, however, if the 

 area of sunflowers is large and not surrounded by woods. 



