324 



or seven U.S. gals, of boiling water per cubic foot of infested soil in 

 shallow benches. The percentage of germination and the size and 

 vigour of the plants grown in the treated soil showed a marked increase, 



Byars (L. p.). Experiments on the Control of the Root-knot Nematode, 

 Heterodera radicicola (Greef) Mueller. I. The Use of Hydrocyanic- 

 Acid Gas in Loam Soil in the Field. — Phytopathology, Baltimore, 

 Md., ix, no. 2, February 1919, pp. 93-103, 1 plate. 



Experiments were made in Florida in 1916 and 1917 to eradicate 

 Heterodera radicicola from fields by means of the introduction into 

 the soil of hydrocyanic acid gas. Though apparently more efficient 

 than most chemicals when used on a small scale this substance failed 

 on large areas. The experiments were made at the rate of 3,600 lb. 

 and 5,400 lb. respectively per acre. The same effect is obtained 

 with both the powdered or liquid form of the poison. Particulars 

 are given of each experiment. 



Byars (L. P. ). The Nematode Disease of Wheat caused by Tylenchus 

 tritici (Steinbuch) Bastian, and its Control. — Phytopathology, 

 Baltimore, Md., ix, no. 1, January 1919, p. 51. 



Great damage to wheat in 1918 by the eelworm, Tylenchus tritici, 

 occurred in all parts of the United States, especially Virginia. The 

 wheat spi'celets developed hard galls filled with larvae of this Nematode. 

 From these galls they escape to the soil and settle between the leaf 

 sheaths near the bud of the young seedlings and are thus passively 

 elevated to the spike. Here they enter the flowers, where they produce 

 galls in which they remain until they reach maturity when oviposition 

 takes place in the gall. This pest may be kept in check by the use 

 of clean seed, crop rotation, etc. The sound grain may be separated 

 from the galls by A. G. Johnson's salt brine method for removing 

 ergot from rye. 



RuGGLES (A. G.). Life History of an Oak Twig Girdler, Agrilus arcuatus. 

 Say, and var. torquattis, Lee. — 17th Rept. Minnesota State 

 Entomologist, Agric. Expt. Sta., Univ. Farm, St. Paul, 1st December 

 1918, pp. 15-20, 3 figs., 1 plate. [Received 21st May 1919.] 



Local damage to oak trees is recorded in Minnesota, due to a small 

 Buprestid larva identified as Agrilus arcuatus, Say, var. torquatus, Lee, 

 which burrows beneath the bark at the tip of the twigs. A similar 

 species, A. bilineatus, Web. [see this Review, Ser. A, iii, p. 331], infests 

 the same species of oaks, particularly Quercus rubra, L., and attacks 

 the trunk and larger limbs, while A. arcuatus works downward, often 

 cutting off branches 8 feet long. 



The adults appear throughout July. The eggs are usually laid 

 singly on the side of the twig near the terminal bud, and hatch in 

 about 10 days, the larva at once entering the bark and burrowing 

 in the cambium during July, August and September. In May and 

 June of the year following oviposition they are still working just 

 beneath the bark, but in July, August and September they burrow 

 to the centre of the twig? and work back to the bark during October, 

 often encircling a main branch, which dies during the following year. 



