380 



of S. phoeniciensis, "which cannot complete its life-cycle on wheat or 

 barley, the removal of all grasses from the neighbourhood of these 

 fields will reduce its numbers, or potatoes or cotton are suggested as 

 alternative crops. 



AiNSLiE (G. G.). The larger Corn-Stalk Borer.— Z7.>S. Dept. Agric, 

 Washington, B.C., Farmers' Bull. no. 1025, February 1919, 12 pp., 

 8 figs. [Received 8th July 1919.] 



Much of the damage due to Diatraea zeacolella, Dyar, was pre\iously 

 attributed to D. saccharalis cramhidoides, F., which it greatly resembles 

 in Hfe-history and habits, except that the latter feeds on maize and 

 sugar-cane indiscriminately, whereas D. zeacolella rarely attacks 

 sugar-cane [see this Review, Ser, A, iii, p. 184]. The eggs hatch 

 in about 7 to 10 days and give rise to the larvae of the first 

 generation of the season, being laid in batches of 2 to 25 about May 

 on the under-side of leaves. The larvae begin feeding on the leaves, 

 descending later to the stalk, where they attain full growth and pupate 

 usually in the second or third joint from the ground. The larval 

 stage lasts 20 to 30 days, pupation requiring from 7 to 10 days. The 

 second generation, of which the eggs are laid in similar positions on 

 the lower leaves or stem, hibernates in the larval stage in the extreme 

 lower tip of the tap-root below the ground. 



The natural enemies of this moth include an egg parasite, Tricho- 

 gramma minutum {pretioswn, Riley), and ChaaUognathus pennsyl- 

 vanicus, De G., as well as an undetermined fungus. Remedial measures 

 suggested are crop rotation and clean cultivation, including the 

 destruction or ploughing under deeply of the maize roots containing 

 the hibernating larvae. 



Byars (L. p.). The Eelworm Disease of Wheat and its Control— U.S. 



Dept. Agric., Washington, B.C., Farmers' Bull. 1041, March 1919, 

 10 pp., 10 figs. [Received 8th July 1919.] 



The disease caused by the Nematode, Tylenckus tritici, has been 

 causing a great deal of damage to wheat in the United States, especially 

 in Virginia [see this Review, Ser. A, vii, p. 324]. Diseased plants are 

 recognised by a marked wrinkling, rolhng and distortion of the upper 

 leaves. The plants either die or produce dwarfed, diseased heads. 

 As the plant becomes ripe, the larvae become dried out and motion- 

 less, in which condition they can remain ahve for many years. 



This eelworm was probably introduced with imported seed from 

 foreign countries, and can easily be spread by the interchange of 

 seed ; it can also be carried by means of infested soil clinging to the 

 feet of men and animals or to farm implements. Surface waters 

 that may carry galls or free Nematodes should not be allowed to 

 pass from infested territory to uninfested areas. All infested land 

 should be planted with crops other than wheat for 2 or 3 years ; by 

 this time the Nematode should be starved out, as it is not known 

 to attack seriously any other crop. 



Seed can be rendered free from galls by pouring it slowly into a 

 solution of 40 lb. of common salt dissolved in 25 U.S. gals, of water, 

 making a 20 per cent, salt solution ; this should be vigorously stirred, 

 when the sound grain will sink and the galls, light kernels and trash 



