378 



mixed. An alternative spray is i lb. of the arsenical in 4 U.S. gals, 

 of water with the addition of 1 U.S. gal. of stock solution of kerosene 

 emulsion. 



Particulars of various investigations are given, during which it was 

 found that the denser the growth, particularly weeds and undergrowth 

 round the stem of the tree, the less was the amount of infestation. 



Satterthw^mt (A. F.). How to control Billbugs destructive to Cereal 

 and Forage Crops. — U.S. Dept. Agric, Washington, B.C., Farmers' 

 Bull. 1003, January 1919, 23 pp.. 24 figs. [Received 8th July 

 1919.] 



A great deal of damage is done to cultivated grasses and cereals 

 in the United States by various weevils of the genus Sphenojjhorus. 

 The damage is most marked in fields nearest to reclaimed swamp 

 land and marshes. Deformity is caused to the plants in two ways ; 

 either the punctured leaves interfere with the growth of the succeeding 

 ones, or when the injury is low down in the stalk sprouting or suckering 

 may be the result. The young grubs may also cause injury by feedmg 

 on the roots. 



The following species are dealt with : Sjyhenophorus jJarmdiis, Gyll. 

 (blue-grass billbug) injures timothy, blue grass, wheat, oats, barley 

 and rye. The grub excavates the stem for about 3 inches at the 

 base or it may eat the root and fibres. Pupation takes place in the 

 corms of timothy grass or in the soil. AVhen attacking rye the grub 

 eats the substance of the stem up to the seco2id joint, passing from 

 there to the roots. The larval and pupal stages average about 23 and 

 8 days respectively. The entire period from egg to adult is about 

 45 days. Submergence for several days in water does not injure this 

 species. 



Sphenophonis zeae, Walsh (corn billbug) very much resembles 

 8. jiarvulns in its habits and life-history. The whole cycle from the 

 egg to the adult is about 52 days, the egg-stage lasting about 9 days, 

 the larval stage 3S, and the pupal about a. week. 



S. aequalis, Gyll. (clay- coloured billbug) is a swamp-inhabiting 

 species. In Illinois and Indiana eggs are laid in the stalk about 

 4 inches above the young bulb, from May to August. The grubs 

 bore doxvTi the stem to the old bulbs, where pupation takes place 

 within the larval excavation, the adults emerging about 21st August, 

 but remaining in the pupal cell during the winter and appearing above 

 ground in the spring. Injury by this species generally results in 

 death of the plant. Adults have been found feeding on maize, 

 millet, foxtail {Chaetochloa spp.), the bullrushes (Scirpiis atrovirens 

 and S. fluviatilis), Cyjyerus strigosr.s and Phragmites. 



S. maidis, Chitt. (maize billbug) injures maize by piercing the stem 

 and eating the tissue and also by excavating the stalk at or below 

 the soil surface for oviposition. After 7 to 12 days the grubs appear 

 feeding on the stalk and main root, in the upper part of which they 

 pupate after about 40 to 50 days. The pupal period lasts about 

 10 to 12 days. The injury dwarfs and sometimes kills the plant. 

 This pest is active from June to September, oviposition taking place 

 in June. The early developing adults migrate for hibernation else- 

 where, but those maturing later remain in the larval excavations, 



