June, lyiS.J Root-knot or Eelworm Attacks. 553 



for the most part had decayed, Hberating the eggs and egg-filled 

 bodies of the female nematodes into the soil. The tops of the 

 tomato plants and as many of the remaining roots as could be 

 found, were removed from the bench. The soil itself, however, 

 was not given a soil treatment, but was allowed to remain in an 

 infested state. 



The foreman in charge of the greenhouses gave directions to 

 place various potted bedding plants on top of this bench, allowing 

 the pots to come in direct contact with the soil which had previous- 

 ly grown the infested tomato crop. The experiment proved an 

 interesting one, for among the potted plants there were a number 

 which became infested, while, on the other hand, a few kinds 

 which were under the same environmental conditions proved 

 non-susceptible to an attack. 



After having stood on top of this bench for more than a month, 

 the following plants showed the development of nodules upon their 

 roots, and upon a microscopic examination revealed the egg-filled 

 nematodes of Heterodera radicicola: Vinca rosea Linn. (Mada- 

 gascar Periwinkle), Chrysanthemum frutescens Linn. (Mar- 

 guerite), Celosia empress (Cockscomb), Matthiola incana Var. 

 annua Voss. (Ten- weeks or Intermediate stocks) , Zeae mayz ( Bur- 

 bank's Rainbow Corn), and Phlox (Phlox annual). The writer 

 also reported Cirsium arvense (Canada thistle), a susceptible 

 host (Science, 40::241, 1914). There were also a large number of 

 other plants whuch were attacked, but only those which proved 

 to be new hosts have been hsted here. 



The eelworm has been previously reported as attacking 

 Zeae mayz by Neal, B. P. L (1S.S9), Burbank's Rainbow corn 

 being a horticultural variety of Zeae mayz. 



The following is a list of potted plants which remained ap- 

 parently unaffected, although they were growing among the in- 

 fested potted plants: Centaurea imperialis (Royal Sweet Sultan), 

 Calundula (Pot marigold, Vaughan's Mammoth Mixture and 

 Eldorado), Salvia Zurich (Dwarf Sage), and Canna varieties. 



The soil which was used in the bench was originally obtained 

 from a nearb}^ orchard, and was probably infested with Heterodera 

 radicicola at the time that it was placed in the greenhouse bench, 

 although it is possible, but not probable, that the organisms 

 gained entrance through the application of infested manure; 

 knowing the source of the fertilizer used, this did not appear to be 

 the case. The soils in many sections of Kansas are badly infested 

 with the eelworm, and the problem of economically combating 

 this pest is becoming a serious problem, especially in the truck- 

 growing regions where entire crops become affected. 



Besides the above hosts, the writer obtained specimens of 

 Carum petroselinum (parsley) from Hutchinson, Kansas, which 



