ECONOMIC ZOOLOGY ENTOMOLOGY. 677 



also given on fumigation and inspection under the law and the construction of fumi- 

 gation houses. Brief abstracts are also given of the inspection laws of other states. 



Injurious insects, F. Cobboz (Chron. Agr Vaud, t8 \ 1905), Nos. 11, pp. ?6 

 12, pp. 290-2'J-i). — An accounl i- presented of the habits, life history and means of 

 comhating cabbage inaL r !_ r "t, Ortalis cerasi, onion 111.11:^11, larvae of crane Hie-, planl 

 liee on apple, peat-, plum, peach, cherry, ami gooseberry, Lecanium perricse, ami 

 oyster-shell bark-louse. 



Field experiments and observations on insects injurious to Indian corn, 

 s. A. Forbes (Illinois sin. Bui. 104, pp. 95- 152, fig. I). — Corn suffers considerable 

 injury from year to year from the attacks of timothy billbugs, of which Spin nophoms 

 parvulus was perhaps the most important species observed in the work reported in 

 this bulletin. 



In timothy fields neat- infested corn from 50 to 7"> per cent of the timothy bulbs 



were infested. Adjaeent corn fields were injured SO that the yield u a> reduced from 

 60 to 20 bu. per acre. Careful observations in one field indicated that billbugs had 

 affected about 29 per cent of the hills of corn, diminishing the number of stalks to the 

 extent of 14 per cent and the number of ear- 40 per cent. In this field the total loss 

 was estimated at 18 per cent of the crop. A large proportion of this injury may be 

 prevented according to the author's observations by early fall plowing of the timothy 

 sod, and it is recommended that corn should nut he planted on timothj sod recently 



plowed. 



The corn-root aphis was carefully studied from the standpoint of its life history 

 and also with regard to successful remedial measures against it. In this study 

 observations were made on the agency of ants | Latiw alienus) in carrying the root 

 lice from place to place. In work on insecticide remedies against this pest it was 

 found that by means of disking the ground 3 or more times before the corn was 

 planted the number of hills infested by ants w r as reduced by 64 per cent and those 

 nfested by the root lice by 82 per cent. 



In one instance a single treatment with the disk harrow, as soon as the ground was 

 dry enough to be worked, reduced the number of insects in the held by !'t) per cent. 

 This remedy is, therefore, strongly recommended on account of the fact that the 

 extra tillage is not only effective in destroying the corn-root aphis hut is of advantage 

 in putting the soil in better condition for the corn crop. Incidentally, it was observed 

 that infested corn land planted once to oats becomes freed of the root aphis. 



Elaborate experiments were carried out in determining suitable insecticide methods 

 in controlling chinch bugs. In the use of barriers it was demonstrated that chinch 

 bugs could be effectively kept in check for 4 weeks by means of a strip of coal tar 

 which cost at the rate of ^L'2.40 a mile. In dry years the harrier must he kept intact 

 for 10 days and in wet years perhaps as long as 30 days. It was found necessary to 

 pour fresh tar along the line about .". times every 2 -lays. In case the harrier, for 

 any reason, should prove ineffective the chinch hugs may be destroyed by the use of 

 kerosene emulsion. For this purpose a 4 per cent emulsion was found highly 

 effective and not injurious to the corn. 



The emulsion was used at the rate of about 2 gal. per acre and was simply flirted 

 upon the corn by the hand.. A single treatment was, in some cases, sufficient to 

 reduce the chinch bugs below the danger point It required a man about 2 hours to 

 treat an acre which w.mld give an average of about 5 acres for a day's work. Whale- 

 oil soap at the rate of ^ lb. to 1 gal. of water is also found to he a safe and successful 

 insecticide for the destruction of chinch bugs, hut its cost is about 3 times that of the 

 kerosene emulsion. 



The literature relating to the use of the gasoline blast lamp in the destruction of 

 insects is reviewed in considerable detail. The author had already tested this device 

 in the destruction of other insects and experiments are reported in the bulletin of its 



