532 



Fenton (F. a.) & Ressler (I. L). Artificial Production o! Hopper- 

 burn. — //. Econ. Ent., Geneva, ISl.Y., xv, no. A, August 1922, 

 pp. 288-295, 1 fig. 



Experiments with regard to the aitificial production of hopperburn 

 are described [R.A.E., A, x, 177]. 



Inoculations with hypodermic needles gave varjdng results, probably 

 owing to some difference in procedure not noted at the time. 



It is now thought that the nymphs of Empoasca mali contain less of 

 the toxic substance than the adults, as the abnormalities produced by 

 the inoculation of the crushed nymphs are less severe than when the 

 crushed adults are used [cf. R.A.E., A, ix, 247]. 



Fenton (F. A.) & Hartzell (A.). Effect of Bordeaux Mixture on 



Empoasca mali. — //. Econ. Ent., Geneva, N . Y ., xv, no. 4, August 

 1922, pp. 295-298. 



Bordeaux mixture, 4-4-50, is decidedly repellent to the adults of 

 Empoasca mali and is toxic to the nymphs ; recent experiments have 

 also shown it to be cumulative in its effects [cf. R.A.E., A, ix, 31, 247 ; 

 X, 354]. The addition of IJ pints Black-leaf 40 to every 100 gals, of 

 spray did not materially increase its deterrent effect. 



Beyer (A. H.). Experiments on the Biology and Tipburn Disease of the 

 Bean Leaf-hopper with Methods of Control. {Empoasca mali, 

 Le Baron). — -//. Econ. Ent., Geneva, A^ ¥., xv, no. 4, August 

 1922, pp. 298-302. 



Biological studies were carried out in the northern portion of Florida 

 during 1921, where an overwintering period of Empoasca mali was 

 noticed, whereas in the southern part of the State there is apparently no 

 overwintering period. All stages were taken on castor bean, and an 

 outbreak was also recorded on garden beans {Phaseolus vulgaris) as 

 early as 24th March. In the northern part of the State the earliest 

 occurrence was on cowpeas on 20th August. 



At Gainsville, in the south, the first individuals were found at the 

 beginning of March feeding on poke weed {Rivina Intmilis). The first 

 Qgg scars were found on 10th March, and the first n3miphs on 18th March. 

 A total of six generations were reared in an outdoor laboratory in 1921 . 

 The life of the adults ranged from 32 to 64 da5/s during the summer flight 

 and the incubation period from 5 to 9 days. Young bean plants are 

 affected a few days after colonisation of the nymph stages on them. 

 Hot, dry weather apparently hastens the burning of the plants, while 

 humid weather and moist soil retard it, but neither the type of 

 soil nor sunlight are of importance in minimising burning. The 

 natural enemies of the leaf-hopper include spiders, a mite, the small red 

 ant, Dorymyrmex pyramicus, and the fungus, Entomophthora sphaero- 

 sperma, which the author has succeeded in artificially cultivating and 

 disseminating. 



As the method of applying sprays for the control of E. mali is as 

 important as the kind of material used, the author has devised a spray- 

 ing attachment that has many advantages over the common method. 

 It consists of a canvas- covered cylinder at least 36 in. long and 24 

 in. in diameter, containing an opening 8 in. wide, running the full 

 length of the cylinder. This opening is turned downward to serve 

 as a passage for the base of the plants as the cylinder passes over the 



