1919 



ENTOMOLOGICAL SOCIETY. 



57 



been called to our attention only recently, are old and well-known reprobates more 

 familiarly known to us as the southern corn root worm or bud worm [Diahrotica 

 12-punctata) , and the northern corn root worm {D. longicornis). They are com- 

 monly pests of corn plants when in the larval stage, but as the " silk bug " it is the 

 beetle that causes the damage and in an entirely different manner for it appears 

 just as the ears are silking, cutting off the silk before the kernels become fertilized, 

 thus causing the production of barren ears. One would expect the corn plant 

 to be injured by the larvae of these beetles earlier in its growth but such seems 

 not to be the case, at least the corn shows no' apparent injury. The probable reason 

 for this is because the land is overflowed every winter and large amounts of rich 

 humus are deposited, leaving the ground so rich that corn is planted year after 

 year and the plants make such rapid growth that they overcome all injury to the 

 root system inflicted by the larvae of these two beetles. 



We have no remedy for these pests under the conditions just given. As already 







Pig. 10. — Field of cane damaged by White Grubs f, lAuimostrrna spp. i 



stated the farmers prefer to grow corn on the ground year after year, giving 

 the one species {D. longicornis) at least, ideal conditions for reproducing itself. 

 Poisoning the beetle appears to be out of the question, but there is a likelihood of 

 reaching them by the use of repellant dust sprays. More information on the life 

 history and habits of the species under these conditions, new to us, is necessary 

 before the problem can be intelligently attacked. 



The White Grub (Lachnosterna spp). 



Since the common white grubs have been serious pests in the northern states, 

 this problem has been given considerable attention at the Lafayette Laboratory. 

 The general results bearing on their economic relartions have been published, 

 and the natural enemies have been fully discussed in a paper soon to be issued. 

 Many interesting data on their ecological and taxonomic relations have been, and 



