40 NEW YORK STATE MUSEUM 



are interesting since they show just what forms were present in 

 the wheat fields last summer. 



In addition to the parasites mentioned above, there is a wing- 

 less species known asBoeotomus subapterus Riley, which 

 was not obtained and appears to be exceptionally efficient in Mis- 

 souri. Platygaster herrickii Pack, is recorded as a com- 

 mon parasite and a European species, Entedon epigonus 

 Walk., should be of assistance in checking this pest. P t e r o m - 

 a 1 i s p a 1 1 i p e s Forbes is another species which preys upon the 

 Hessian fly. 



An abundance of parasites means very few midges later and 

 comparative immunity from injury in all probability. Wheat stub- 

 ble or chaff containing numerous parasitized " flaxseeds " should 

 never be burned, since this may result in more real damage than 

 if nothing be done. 



Preventive and remedial measures. Late sowing. The most 

 important preventive is to delay sowing till after the flies have de- 

 posited their quota of eggs and perished. This means in New 

 York State delaying sowing, as a rule, till September 20th or a 

 little later. It will be seen by referring to a preceding paragraph 

 that the precipitation in August and September may have an im- 

 portant influence in determining the time when the flies will appear. 

 Rains in late summer and early fall mean an early emergence of 

 the flies, and if the moisture does not come too soon, a correspond- 

 ingly early disappearance. Should the rains be early enough to 

 permit the development of a supplementary brood on volunteer 

 plants before the main wheat crop is up, there may be a large in- 

 crease in the number of flies attacking the grain. It requires, under 

 the most favorable conditions, only about 30 days to produce a 

 generation, hence this danger is far from theoretical. 



Resistant varieties. Experience in 1900 and 1901 in western 

 New York showed that varieties such as number 8, Dawson's golden 

 chaff, white chaff, Mediterranean, red Russian, prosperity and 

 democrat withstood attack very successfully, while the beardless, 

 weak-stemmed white wheat known as number 6 was very seriously 

 injured and, in many cases, totally destroyed. Resistance is only 

 comparative and a wheat immune in one locality may be rather 

 seriously affected in another. The only safe way is to sow resist- 

 ant varieties even though the non-immune wheats are better pro- 

 ducers. 



Good culture. Culture counts for much in growing a good crop 

 of wheat. The field should be thoroughly prepared and the land put 



