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  ef · ’ ;‘ ii
V Q ' The Army-worm. 439   ;
3 , - I FUNGUS ENEMIES.   `
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Z ° During wet seasons by far the most destructive enemy of the  
H  . army—worm is a species of Fmpusa,* one of the parasitic fungi.  
W In both 1907 and 190,8, the worms were observed in large  
E numbers sticking tothe heads and blades of timothy and other liffi
f  { plants, generally head down and with the forward part of  
[I I  the body raised at a slight angle from the surface upon which lg,
G   the body rested. ·Thcse dead worms were flaccid at first and  
__ A black, finally drying up and shrivelmg to a mere wisp, upon Tjfil
_ which was found a rather scant growth of the fruit (conidia)  
Q l of the fungus by which the disease spreads. The conidia are I  
S , small, elongate oval, generally with a couple of oil droplets  
d   in the interior. Quite often eggs of the Tachina fly noted  
,1 ‘ above were present on these dead worms,`but I think the fungus  
G had the best of the argument in these cases, perhaps attacking  
G p the grubs of the parasite as well as the army-worm.  
S * During excessively hot spells of weather, worms confined in  
I the Insectary sometimes died from what appeared to be a bac-  
9 , terial disease, resembling that described by Forbes for the red-  
h   necked apple tree caterpillar (Daltena aninistrel. The fluids _ 
1_ l. of such worms contained large numbers of a round organism  
,_ r , (a Micrococcus), which was easily cultivated on nutrient gcla- { 
{E   tin (agar). I found no fungus on the worms dead of this l 
ls ; disease, and assume for the present that it is due to the Micro-  
k coccus. . ?` 
6 In the field both in Illoodford and Fayette counties the dead  
,. t worms clinging to grasses invariably bore the conidia of the  
I- i Empusa, though from the toughness of the skin of the army-  
  A worm, the threads bearing them push through somewhat spar-  
,6 V The occurrence of fungus diseases among the worms was in  
,7 ,, 1908 very- largely responsible for a decided reduction in the  
G i number of insects of the early brood completing their trans-  
t, _A formations. Not more than half of the worms. reached ma-  
5_ " turity, and of succeeding broods the nuinbcr escaping the prcda— ·  
4.1.4.1,..  
E   I *Prefesser R. Thaxter, who haslmade a special study of the genus, i  
’ ij suggests that this species is E. virescens. Most of the eonidia are, gg
  however, provided with two oil droplets suggesting E. dipterigena and ·  
F E. aphidis. The resting spores have not been observed, which renders  
·l determination difficult,  
 
 
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