CHAPTER XVIII 



MILL AND ELEVATOR INSECTS AND MILL 

 FUMIGATION 



INSECTS infesting stored grains and their products are often 

 found in mills, elevators, grocery and feed stores, and in homes. 

 The control measures for many of these are somewhat similar. 

 Such treatment is given at some length in the last half of the 

 chapter. 



Mediterranean Flour Moth. This grayish, slender moth 

 (Ephestia kuehniella Zell.) is about three-fifths of an inch long. 

 The female has the characteristic habit, upon emerging from the 

 pupal stage, of remaining for hours with the tip of abdomen and 

 head raised above the level of the body. Approximately 200 

 eggs are laid by each female after mating. They are placed any- 

 where, in cracks, directly in the flour, in spouts, purifiers, or other 

 machinery, or in sacks containing flour or meal. They hatch in 

 from nine to ten days, and the larval life averages forty days. 

 When full grown the larva spins a cocoon about one-half inch 

 long and transforms to a pupa within. Normally there are prob- 

 ably two broods, though there may be more in warm mills. 

 The female moth may also lay eggs in stored products. 



The larva is from white to pink in color, with a reddish-brown 

 head. A few small hairs are found over the body. When full 

 grown it is three-fifths of an inch long and becomes pink in color, 

 which color, however, varies, some specimens being green- 

 ish. There are three dark spots on the side of each segment 

 (Fig. 351.) 



Injury. Wherever this larva crawls, it secretes a silken thread 

 which results in a network, causing the formation of great masses 

 of matted flour or meal through which the thread runs (Fig. 352). 

 These masses may clog spouts or any other machinery throughout 

 the mill, rendering the products unfit for use and sometimes even 

 stopping the machinery. Various sources are responsible for the 

 existence of this pest in flour mills. The more common source 

 of infection is found in returned sacks. Second-hand machinery 

 may be a cause. 



Control Measures. The old adage, "An ounce of prevention 

 is worth a pound of cure," is very applicable here. No sacks, 



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