561: 



Eoot-attacking insects include Rhabdopterus picipes, Oliv. (cranberry 

 root-worm) [see this Bevieiv, Ser. A, iii, p. 672 and vi, p. 553] and 

 white grubs, including Phytalus georgianus, Horn, Dyscinetus trachy- 

 pygus, Burm., and Lachnosterna grandis, Sm., which are found 

 occasionally in cranberry bogs, but are not of much importance. 

 For infestations of small areas it is advisable to take up vines and turf 

 on the infested areas and plant new vines. For larger areas, holding 

 the winter flowage until 15th July would probably rid the bog of grubs. 



Feytaud(J.). Les Tenthredes du Poirier, [Pear-tree Sawflies.] -Bull. 

 Soc. Etude Vulg. Zool. Agric, Bordeaux, xvii, nos. 9-10, 

 September-October 1918, pp. 102-103, 



The life-histories of, and injuries due to, the larvae of Neurotoma 

 (Lyda) fiaviventris, Retz., and Eriocampoides limacina, Retz., have 

 already been noticed [see this Review, Ser. A, ii, p. 478]. They are 

 both parasitised by various Ichneumonids, the former chiefly by Ophion 

 mercator, F. , and the latter by Mesoleius excavatus, Prov. , and Tryphon 

 trwnslucens, Ratz. 



Stahl (C. F.) &; Carsner (E). Obtaining Beet Leaf-hoppers non- 

 virulent as to Curly-top. (Preliminary Paper.)— JL Agric. Research, 

 Washington, B.C., xiv, no. 9, 26th August 1918, pp. 393-394. 



A method of obtaining non-virulent leaf-hoppers with certainty 

 and relative ease has been evolved from tests conducted to verify 

 earlier conclusions as to the infectivity of leaf-hoppers [see this Review, 

 Ser. A, V, p. 492]. This consists in removing the young nymph from 

 a diseased to a healthy plant before it has had an opportunity to feed, 

 a proceeding rendered possible by the manner in which the egg of the 

 leaf-hopper hatches. The eggs are laid mainly in the petioles of the 

 leaves, and in hatching the nymph forces its way, anterior end first, 

 from the egg-case and through the slit made by the ovipositor. When 

 the body of the insect reaches a position more or less perpendicular 

 to the plant surface the appendages begin to unfold, and during the 

 latter part of this operation the nymph may be lifted off and transferred 

 to a healthy plant by means of a small camel's-hair brush. 



In the first experiment, begun on 19th April 1915, three lots of 

 nymphs, numbering 7, 9, and 15 individuals, respectively, were 

 transferred as they hatched to three healthy beet plants in separate 

 cages, the insects being left on the plants until after they had become 

 adults. All three plants remained healthy. On 3rd July the insects 

 of two of the lots were caged on two separate plants afi'ected with 

 curly-top. After 17 days they were again caged on two healthy 

 plants, both of which developed the disease. 



These and similar results show conclusively that uninfected insects 

 23laced on healthy beet plants will not produce curly-top. Their 

 special interest lies in the possibility of obtaining a supply of leaf- 

 hoppers known positively to be non-virulent, which may be used to 

 determine whether or not plants other than beets harbour the virus 

 •of curly-top. 



