247 



Fexton (F. A). Progress Report on the Season's Work on the 

 Production oJ Potato Tipburn. — //. Ecoii. Ent., Concord, N.H., 

 xW, no. I, February 1921, pp. 71-83, 2 figs. 



The following are the author's conclusions as given in this paper : — 



Tipburn or hopper-burn of the potato is produced through the agenc\- 

 of Empoasca malt. All nymphal stages of the leaf-hopper are capable 

 of producing symptoms of the disease. The older the nymphs, the 

 greater the amount of injury done, nymphs in the first and second 

 instars being incapable of producing any effect on the leaf unless in 

 numbers. The greater the number of nymphs on a leaf, the sooner the 

 injury develops and the more rapidl}' the leaf or plant is killed. The- 

 adult hopper is not nearly so effective as any of the nymphal stages, 

 but will produce the disease when concentrated in large numbers on 

 a given plant. The disease is produced to the same extent and just as 

 soon under such diverse environmental conditions as t vpe of soil, amount 

 of moisture in the soil, presence or absence of sunlight, or reduced leaf 

 transpiration. Tipburn as a disease is localised, being confined te> 

 that part of the plant exposed to the attack of the leaf-hoppers, whether 

 this be a leaflet or entire branch. 



Other insects known to feed on potato, such as nymphs of the buffalo 

 tree-hopper [Ceresa hubalus], tarnished plant-bugs [Lygns praiensis^ 

 Aphids and flea-beetles, produce a type of injury characteristic of the 

 individual species concerned, but in no way resembling tipbiu'n. 



Bordeaux mixture prevents tipburn by repelling the ovipositing 

 female leaf-hoppers. 



Flint (W. P.). Chinch-bug Resistance shown by certain Varieties of 



Com. — //. Econ. Ent., Concord, \.H.,x\y, no. 1, February 1921, 

 pp. 83-85. 



Certain strains of maize show greater resistance to attack bv chinch- 

 bugs [Blissus leucopteriis] than others, but it is apparently impossible 

 to develop a strain that will be sufficiently resistant to the attack of 

 the nearly full-grown insects of the first generation when they leave the 

 wheat fields at har\'est time. If the resistant strains are grown on 

 fertile soil and protected from attack by the first brood, moderate 

 yields may be expected. So far " White Democrat " maize shows 

 the greatest resistance, but further tests are to be conducted. 



Felt (E. P.). European Corn Borer in New York State. — Jl. Econ. 

 Ent., Concord, N.H., xiv, no. 1, February 1921, pp. 85-89. 



Observations made in New York State during the past season indicate 

 a continued, though not excessive, spread of the European corn borer 

 [Pyrausta nuhilalis]. Special attention is being given to improviui;- 

 the method of handling the maize crop in order to anticipate possible 

 serious damage, and quarantine measures are being enforced in 

 co-operation with the Federal Government. 



The amount of injury does not necessarily stand in direct relation 

 to the amount of stubble infestation, the direction of the prevailing 

 winds and the proximity of earlier infested fields being important 

 factors in this connection. 



