243 



Attempts to produce the disease by inoculation, with a needle, of freshly 

 prepared juice and the insertion of freshly crushed fragments of 

 mosaic leaves into slits on the leaf petioles and crown were unsuccessful. 

 There is also no evidence of seed transmission of the disease. The 

 virus retains its vitality throughout the silo period, which is the only 

 means of overwintering thus far known. Aphids are able to carry 

 the infection, and in cage experiments healthy plants were infected 

 by Myzus persicae. The incubation period of the disease on seed 

 beets under greenhouse conditions is about 24 days, and on seedling 

 plants from 12 to 18 days. 



Severin (H. H. p.). Minimum Incubation Periods of Causative Agent 

 of Curly Leaf in Beet Leafhopper and Sugar Beet. — Phytopathology. 



Lancaster, Fa., xi, no. 10, October 1921, pp. 424-429, 1 lig. 



From the experiments here described it is evident that EiUettix 

 tenella. Baker (beet leaf-hopper) is non-infective when it hatches 

 from the e^g, neither is it a mechanical carrier of curly leaf even in mass 

 infection of a beet. The causative agent of the disease requires at 

 least four hours for incubation in the leaf-hopper at an average tempera- 

 ture of 100° F., with a minimum of 94'^ and a maximum of 103°, and 

 at least five days in the beet at an average temperature of 72-8° F., 

 with a minimum of 53-3° and a maximum of 93-6°. 



Adams (J. F.) & Manns (T. F.). The Corn Ear Worm and Kernel 



Rot of Corn. — Phvto pathology, Lancaster, Pa., xii, no. 1, January 

 1922, pp. 25-26." 



Injury to maize by the corn ear- worm [Heliothis obsoleta, F.] has 

 been constantly followed by the occurrence of infection by Fnsarium 

 moniliforme and Ccphalosporium sacchari. Observations show that 

 this moth is capable, in the course of its injury to the ear, of furthering 

 the source of infection when established. 



Leach (J. G.). Leafhopper Injury of Potatoes. — Phytopathology, 

 Lancaster, Pa., xii, no. 1, January 1922, p. 37. 



A new pathological condition of potatoes is described as being 

 prevalent during 1921 in Minnesota. It is characterised by a pro- 

 nounced shortening of the leaf petioles with consequent crowding 

 of leaflets. Empoasca niali (potato leaf-hopper) was continually 

 associated with this condition, and has been proved by experiment 

 to be responsible for it. Sufficient data have not yet been obtained 

 to justify conclusions as to the nature of the disease or its relation to 

 hopper-bum. 



Godfrey (G. H). The Stem and Bulb infesting Nematode.— PA^/o- 



pathology, Lancaster, Pa., xii, no. 1, January 1922, pp. 52-53. 



Tylenchus dipsaci {devastatrix) occurs in America on red clover, 

 lucerne, strawberry and daffodils. In Europe it is a serious pest 

 of daffodils and hyacinths. Attention is drawn to the necessity 

 of watching for it generally on all susceptible plants and promptly 

 reporting any new occurrence. 



