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grubs [Laclinostema spp.], army worms, grasshoppers or chinch bug 

 [Blissus leucopferus], the estimation of damage is comparatively simple ; 

 but where injury is inconspicuous, as in the case of scale-insects, corn 

 root aphis [Aphis maidiradicis], Hessian fly, chinch bug in wheat, 

 and the joint worm [Isosoma tritici], it is far more difficult to calculate. 

 In some cases, where the damage is restricted to a definite area, it 

 is possible to obtain an accurate estimate of injury by comparing 

 yields of that area with a similar uninfested area in previous years 

 as well as the year of injury, consideration being given to the dimatic 

 conditions in the two areas. Where the injury is widespread, the only 

 known method is to compare the yields during the season of injury 

 with previous seasons' yields, taking into consideration the insect 

 injuries of previous years and comparableness of climatic conditions 

 and acreage. In the case of injury by Hessian fly and joint- worm, 

 comparison can be made with previous years, but there is no basis 

 to compute accurately the injury in individual fields, since there is 

 no reliable comparison between infestation and injury. It is pro- 

 posed to obtain positive data another year concerning these insects 

 by enclosing large areas during their oviposition period, two to be 

 kept free from infestation and two to be infested by introduction 

 of the respective insects. It is hoped that others may make similar 

 tests with other insects. In order to obtain reliable results it is 

 essential to continue the experiments over a period of years. If, 

 for example, recommendations for sowing wheat with regard to 

 Hessian fly infestation had been based on the 1918 experiments 

 only, they would have been inaccurate, since the fly-free date in 

 1918 was earlier than the normal. Continuity of observation is also 

 very necessary in assisting the entomologist to predict the likelihood 

 of an insect outbreak in a succeeding year and to determine the 

 seriousness of such a possible outbreak. Thus a study of the likely 

 hibernating quarters of the chinch bug in a certain section of the 

 country extending over a large area for several consecutive years 

 is necessary to enable the entomologist, by surveys each autumn, 

 to determine with reasonable accuracy the probabilities of an outbreak 

 of the insect and the extent and degree of the probable infestation 

 in the following season. 



McCoLLocK (J. W.). Eleodes opaca, Say, an important Enemy of 

 Wheat in the Great Plains Area. — Jl. Econ. Entom., Concord, N.H., 

 xii, no. 2, April 1919, pp. 183-194, 1 plate. 



The Tenebrionid beetle, Eleodes opaca, Say, caused considerable 

 injury in Western Kansas in 1908, since when several well-marked 

 outbreaks have been reported. This " false wireworm " has a wide 

 distribution throughout the Great Plains area, the most severe out- 

 break occurring in the autumn of 1917, when whole fields were 

 destroyed. The reason that no previous records of injury are available 

 is probably due to the fact that the larvae of this beetle have been 

 mistaken for true wireworms [Elateridae]. The larvae destroy the 

 wheat seed before germination, usually in the autumn, although 

 damage has also been reported in the spring to wheat several inches 

 high. Other food-plants of E. opaca are oats, barley, sorghum and 

 maize. It is believed that the adult beetles feed on the wheat heads 

 and grain. 



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