8 BULLETIN 1229, IT. S. DEPARTMENT OF AGRICULTURE. 



that became affected as a result of such inoculations. Attempts to 

 inoculate other hosts with the Hypochaeris strain have thus far 

 failed. Further inoculation experiments, designed to get some in- 

 formation as to the possibility of these wild strains passing over to 

 cultivated hosts, are under way at the present time. 



ECONOMIC SIGNIFICANCE. 



Many different crops are subject to infection by the stem nematode, 

 according to foreign literature. Among these are alfalfa, barley, 

 beans, buckwheat, flax, garlic, hyacinth, narcissus, oats, onion, peas, 

 potato, rye, strawberry, and many others of less importance. Many 

 of these crops are cultivated in western Oregon and Washington. The 

 general belief in Europe is that there are distinct biological strains 

 of the nematode. It is not known at the present time whether or 

 not the American strains can adapt themselves to new hosts. The 

 mere fact of the existence of the disease in so many hosts seems to 

 imply this possibility. 



SUMMARY. 



The stem nematode Tylenchus dipsaci has been found rather abun- 

 dantly in the Pacific Northwest on the wild strawberry (Frag aria 

 ckiloensis) and on the false dandelion (Hypochaeris radicata). 



The wild-strawberry strain of nemas occurs along the west coast 

 of Oregon near the seashore, from Coos County to northern Tilla- 

 mook County. The Hypochaeris strain was found from the south- 

 ern part of Lincoln County, Oreg., to Long Beach, Wash., being 

 almost universally present in western Oregon. 



Judging from natural occurrence, the two strains appear to be 

 entirely independent of one another. 



The symptoms of the disease on either host are swelling and 

 crinkling of the leaves and stems, resulting in extreme cases in 

 marked twisting and bending. Where an abundance of infection is 

 present in the crowns the plants are often killed. In strawberry 

 plants the stolons and the flowering parts are swollen and distorted 

 also. 



Several species of Fragaria are capable of becoming infested. The 

 strawberry strain can be' transmitted to red-clover seedlings. At- 

 tempts to transmit the Hypochaeris strain to other hosts have failed 

 thus far. 



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