THE ONION THRIPS. 



About the middle of August my attention was called 

 by Mr. B. P. Ware of Swampscott to serious losses of bis 

 onions from the attacks of a minute insect. The leaves 

 were observed to turn suddenly yellow and to wilt, and 

 the plant die. In this way large patches became infested 

 and turned yellow, until in two or three days these pro- 

 lific insects spread over the whole field. They seemed to 

 increase most rapidly during the unusually dry hot 

 weather that we experienced about the middle of last 

 August. On the 11th of August a whole acre was thus 

 cut off. Mr. Ware informed me that onion plants have 

 been more or less infested in this way for some fifteen 

 years, but the damage done this year was greater y^„ j 

 than ever before. This evil seems wide spread 

 in Essex County, as not in Swampscott alone, but 

 in Lynn, Salem and parts of Danvers, the onion 

 crop had been similarly infested. About $100,- /y' 

 000 worth of onions are raised in Essex County 

 alone, and Mr. Ware judged that at least a tenth 

 part was destroyed by this new pest, so that in f^fv^x 

 one county alone and from one kind of injurious ,. „ . 

 insect we have in one season lost $10,000. The """'^'e'"-*- 

 onion crop is next to the hay crop in value, as it' is sold 

 for cash. 



On examining the specimens brought into the Museum 

 of the Peabod}' Academy of Science, the leaves were 

 found to be covered with hundreds of a minute thrips 

 which by gnawing the surface of the leaves had caused 

 them to turn white in spots, and subsequently yellow; 

 where th^y were most numerous the outer skin of the 

 fieshy leaves was entirely eaten oil', and though it was 

 difiicult to imairine that so minute an insect could have 



