CHAPTER XIV 

 INSECTS INJURIOUS TO THE HOP-PLANT * 



The Hop-plant Borer t 



THE Hop-plant Borer is sometimes the occasion of a consider- 

 able loss to the hop industry, Mr. Chas. R. Dodge having estimated 

 upon the basis of the census of 1879 that it then amounted to 

 $600,000 annually in New York State alone. The moths have 

 been taken from Ontario and New England south to the District 

 of Columbia, and west to Wisconsin, and also from Colorado and 

 Washington, but the larvae have never become injurious in the 

 hop-fields of the Pacific Coast. " It is probable that it is a north- 

 ern form, and confined, as it seems to be, to a single food-plant, it 

 will be found only where this plant is known to grow." 



Life History. Many of the moths emerge from the pupae in the 

 fall and hibernate over winter, while others do not transform till 

 spring, passing the winter in the pupal stage in small cells in the 

 ground near the roots of the plant which the larvae have infested. 

 The moths appear during May, and the females deposit their globu- 

 lar, yellowish-green eggs upon the tips of the hop-vines just as they 

 begin to climb. " The egg hatches in a few days and produces a 

 minute slender greenish larva, spotted with black, which immedi- 

 ately burrows into the vine just below the tip, and spends a part of 

 its life in the vine at this point. The vine soon shows the effects of 

 the insect's work; instead of pointing upward, embracing the pole 

 readily and growing rapidly, the. tip points downward, will not 

 climb, and almost entirely ceases growing. This appearance is 

 called by growers a ' muffle-head.' When the insect attains a 



* " Some Insects Affecting the Hop-plant," L. O. Howard, Bulletin No. 

 7, n. a., Division of Entomology, U. S. Dept. Agr., p. 41. 

 f Hydroecia immanis Grt. Family Noctuidoe. 



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