188 



STATE BOARD OP AGRICULTURE. 



/^ O ? 



^ig. 38 — BaiTed-winsed onion maggot, enlarsred. (iMom Riley 

 and Howard, Insect Life, U. S Dept. of Agr., Bureau of Ent J 



REMEDIES. 



The fact that the insects pass the winter in the bulb, at once sug- 

 gests the first measure to be taken. Destroij all injured onions in the 

 fall. All young and growing onions should be pulled up and destroyed 

 as soon as they show 

 signs of infestation, 

 and liberal applica- 

 tions of commercial 

 fertilizers should be ap- 

 plied to stimulate rap- 

 id growth, for mag 

 gots always prefer 

 slow^-growing and sick- 

 ly plants to vigorous 

 ones. 



Apply carbolic-acid 

 emulsion diluted thirty 

 times, along the rows 

 as soon as the plants 

 get nicely above ground. 

 This has shown the best 

 results and is highly 



recommended by Professor M. V. Slingerland against the common mag- 

 gots. Repeat at intervals of about a week, as long as there is danger, 

 and practice rotation on general principles. Commence early, just as 

 soon as the first young onions sliow the presence of the maggots. 



IXSECTS AFFECTING TUB TOPS. 

 Cuion Thrips (Thrips tabaci) . 



Tiniest of all the insects mentioned in this paper, is the onion 

 thrips. A little larger tlian a printed period and very active, it is so 

 small and quick in its movements, that it is usually overlooked. The 

 injury is brought about by the great numbers that collect on the plants. 

 On the onion, the thrips prefer the axillary portion of the plant, where 

 two leaves join. They scrape the soft material off the leaves, giving 

 them a grey or hoary appearance, sometimes noticeable at quite a dis- 

 tnnce. The leaves or tops decay if the weather turns wet and tlie 

 keeping qualities of the bulbs are impaired. 



The immature insects are usually more abundant than the adults, they 

 are about one-twenty-fourth of an inch in size, and yellowish-green in 

 color. See fig. 39. The body is long and slender, with six legs and six- 

 jointed antennae. The feet, like those of all true thrijis are destitute 

 of claws. The adult is shown in fig. 39, at rest with the wings closed, 

 as that is the position in which it is most often seen. The general color 

 is dirty yellow with dusky markings. The antennae are seven-jointed 

 in the adult. The extremely narrow wings are fringed with long hairs 

 giving them a feathery appearance. The time required for each gen- 

 eration is said to be about six days in the South, llere in Michigan, 

 more time will, no doubt, be required, at any rate, a number of broods 

 are developed each year. 



An extended account of this pest is given by Mr. Theo. Pergande of 



