310 



rather than the Concord variety, are due to a confusion with a closely- 

 allied species, the lesser grapevine flea-beetle, H. {A.) xvoodsi, sp. n., 

 hitherto usually determined as a small form of H. chalyhea. The 

 various stages of both species are described. H . woodsi is also single- 

 brooded, but emerges late enough in the season to have the appearance 

 of a second brood of H. clialybca. Its eggs are deposited singlv, or 

 sometimes as a cluster of two or three on the underside of the leaf. 



There is hardly any other insect that can cause such se\'ere injury 

 to the grape crop as that of which //. chalybea is capable when the 

 buds are swelling. H. woodsi, which emerges later, is less destructive. 

 Both species are sporadic in their occurrence from season to season. 



A number of predatory enemies contribute to their natural control. 

 Of these, the Carabid, Lehia viridis. Say, is the most important. 

 L. nrnata, Lee, and Harpalus erythropiis, Dej., were found in very 

 small numbers in leaf mould imcler wild grape-vines, and fed upon 

 pupae and prepupae in confinement. A brown ant, Mvrmica scabri- 

 nodis, Xyl., sub-sp. schenchi, Emery, var. enicryana, Forel, destroyed 

 a large amount of larval and pupal material intended for rearing 

 work. A number of birds also eat grape-vine flea-beetles. 



Where vineyards are liable to injury, vigilance in early spring is 

 essential, as the voracity of the beetles makes prompt action necessary. 

 A spray application of lead arsenate, \\ lb. powder or 3 lb. paste to 

 50 U.S. gals, water, is ordinarily recommended for large areas, but 

 if the infestation is severe and rains can be avoided, double the strength 

 may be used In small areas the most effective and cheapest measure 

 is handpicking. The larvae of H. n'oodsi, and most of those of 

 H. chalybea, may be readily destroyed by the usual sprays applied 

 against the grape-berry moth {Polychrosis viteana) and the grape- 

 vine rootworm {Fidia viticida). Very rarely a spray application 

 before the grapes bloom will be advisable to destroy the earliest 

 larvae of H. chalyhea. These measures have probably caused the 

 grape-vine flea-beetle to change its status from that of a first-class 

 pest twenty years ago to one of second-rate importance. 



\\'oGirM (R. S.). Fumigation of Citrus Plants with Hydrocyanic 

 Acid: Conditions influencing Injury. — U.S. Dcpt. Ai;ric., Wash- 

 ington, D.C., Bull. 907, 20th October 1920, 43 pp., 1 fig., 4 plates. 

 [Received 27th April 1921.] 



In dealing with injur}' due to fumigation \\ith hydrocyanic acid 

 gas, scant attention has hitherto been given to the pre-fumigation and 

 post-fumigation environments, and the results of a study of the 

 influence of heat and light under these conditions are here recorded. 



Sunshine is the chief pre-fumigation factor that increases injury ; 

 it is more active at high temperatures. In darkness or diffused light, 

 temperatures up to 100° F. do not appear to increase injury unless 

 the fumigation or post-fumigation temperatures exceed 80° F. 



The environment after fumigation is almost as important as that 

 during the actual treatment. Sunshine is most destructive to plants 

 exposed immediately after treatment, and affects them deleteriously 

 at least two hours afterwards. Temperatures of 80° F. or above 

 injure plants more than lower temperatures. The fumigation of 

 citrus plants is best done below 80° F. 



Diftused light before, during, or after fumigation exerts no more 

 deleterious eft'ect than darkness. ^loisture on citrus plants does not 



