256 EXPERIMENT STATION RECORD. [Vol 40 



sion centrifuged with 60 per cent methyl alcohol for 10 minutes or mixed with 

 34 per cent ethyl alcohol for 16 hours shows filament extrusion under the action 

 of perhydrol." 



Effect of hydrocyanic acid gas under vacuum conditions on subterranean 

 larvae, E. R. Sasscer and H. L. Saneokd {Jour. Aar. Research [U. S.], 15 

 (1018), No. S, pp. 13S-1S6). — The advisability of fumigating all imported 

 nursery stock at the port of arrival as a requirement for entry, which has 

 been under consideration for the past five or six years, led to the investigations 

 by the Federal Horticultural Board of the U. S. Department of Agriculture here 

 reported. 



It is pointed out that under normal conditions from five to seven million 

 ornamental plants, such as azaleas, rhododendrons, aucubas. conifers, box 

 hushes, bays, etc., arc Introduced annually with halls of earth around their 

 roots. Since it is Impossible t<> inspect and safeguard plants <>f this type 

 without removing the soil from the roots, ami since practical horticulturists 

 have strongly advised against this procedure on accounl of its effect on the 

 plants, the only safe course appears to be fumigation with hydrocyanic acid 

 gas under vacuum conditions. 



The work was carried on with larv:e of the wheat wlrcworm ( Agrintes 

 mancus), green June beetle [Cotinui flitida), white grub ( I.nehn<istcrna sp.), 

 and Japanese i tie (PopUUa japonioa). 



The results show tl Efectiveness of hydrocyanic acid ?as under the vacuum 



process to be Influenced by the water content of the soil. "The death of 100 

 per cent was not obtained with larva' in soaked soil iges ranging from 



0.5 oz. to 3 oz. per 100 cu. ft. of space. Eliminating the soaked-soU tests, by 

 far the best results were secured where a preliminary 15-ln. vacuum preceded 

 an exposure of 1.5 hours under normal atmospheric conditions. Hydrocyanic 

 acid gas in the presence of 26 In. vacuum throughout the entire exposure gave 

 negative results with a di I 1 08. of sodium eyanid per lo<i on. ft. and an 



exposure of one hour. An exposure of the i:a< for one-half hour under 10 IPs. 

 pressure, following a half-hour exposure to a 27 in. vacuum, yielded very indif- 

 ferent results. With our present knowledge of vacuum fumigation with hydro- 

 cyanic acid gas, a dosage i of Bodlum eyanid per loo cu. ft. of 

 space with an exposure of 1.6 hours is nol recommended for plants in foliage. 

 Inasmuch as all larva? in re not killed with dosages Varying from 

 0.5 oz. to 3 oz. per 100 CU. ft. of space, fumigation at the port of entry with a 

 dosage which will not injure the plants can not prevent the Introduction and 

 establishment of all subterranean pests." 



The control of insect pests of cotton, H. II. Ktno {[Wellcome Trap. Re- 

 search I. <il>.] F.nt. Bui. 9 {1918), pp. Ji. — A brief summary of methods of con- 

 trol of insect pests of cotton in Anglo-Egyptian Sudan, Including the pink boll- 

 worm {Pec&nophora [QelechAa] gossypiella) , Egyptian bollworm {Bariot in- 

 suiana), Sudan bollworm (Diparopais txutomea), cotton aphis, Btainer bug 

 {Oayoarerwa hyalinipetvnl*), and a flea-beetle {Niaotre tmiformia). 



Garden and small fruit insects, with notes on spraying in general. A. G. 

 RUGGLES and S. A GRAHAM [Unto. Minn, Col. A;/r. r.rt. DiV, S],rr. Hn! 

 (1918), pp. S2, figs. 50). — The several circulars previously noted i K. s R 

 p. 861) have been brought together in this special bulletin. 



The insect enemies of fruit trees. P. LESN1 I R< 0. Unit. [Porte], 89 (1917), 

 No. 24, pp. 385-88*. pi. I: Jour. Affr. Prat., n. sir.. 31 [1918), Vo. I',, pp. B69- 

 271, pi. 1). — A bri unt is given of the woolly aphis and the more important 



QOCdd enemies of fruil I r. ompanied by a colored plate of the same. 



Papers on deciduous-fruit insects {V. 8. Dept, Iffr. I'ul. 780 {1918), pp. 40, 

 pis. 8, fig. I). — This bulletin consists of three papers, information relating to 



