08 CORN AND ORASS. 



found as early as June in the ears, and also in the sheathing- 

 Icaves of the stem. The injury is caused by the Thrips draw- 

 ing away the juices by its sucker-Hke jaw-apparatus, and thus 

 the grain shrivels and becomes abortive. 



Prevention and Eemedies. — It is stated that Thrips do 

 most mischief to late-sown Wheat, the early-sown crop being 

 too hard at the time the Thrips appear for them to injure it, 

 and though it appears quite impossible to do anything to 

 check Thrip-attack when once established in the Wheat-ears 

 (by reason of the minuteness of the insects), yet a good deal 

 may be done in the way of prevention. 



'' The circumstance that Thrips are to be found in autumn 

 (and still later) in large numbers in rotten roots, or in stubble, 

 and in similar lurking-places, and also in the next spring 

 before the development of the insect from the egg can have 

 taken place, speaks for the hybernation of the Thrips in its 

 perfect state, and also points to where attack comes from.*" 

 The perfect insects are thus preserved, and next spring the 

 females being furnished with wings, have full power to fly, or 

 to be carried by any light breezes from their wintering places, 

 to neighbouring Corn or Grass, where they will start new 

 attack. Therefore, any measures for destroying their lurking- 

 places would be sure to be of service. 



Also these insects are to be found near marshes, and in the 

 damp hot weather accompanying thunderstorms they have 

 been noticed as especially injuring the crop in the part of a 

 field to the north of a high hedge, and also the Potato Thrips, 

 figured above, have been noted as most abundant on plants 

 sheltered from the wind. 



From these observations it would seem that a well-drained 

 soil, properly cultivated and free from weeds, with surround- 

 ing hedges well trimmed down, so that the sun and wind 

 might have free play, would be the best preventive, by in- 

 ducing an early ripening of the Corn that would be beyond 

 the power of the insect to injure, and would also do away with 

 the damp close places which in some cases at least it has 

 been found to infest. 



Deep ploughing, so as to bury the Thrips well down, or 

 dressings of gas-limo, or anything to poison the surface of the 

 land, would be useful where the Corn was known to have been 

 badly infested. 



Piemoval of waste pieces or headlands of wild Grass would 

 also be desirable, as these serve as propagating grounds, as 

 well as winter shelters, from which the Thrips come out on 

 the Corn. 



* Sec ' Piaktische Insckten Kuuilc,' by Dr. E. L. Taschenberg. 



