Minnesota Plant Diseases. 



parts of the insect-body, build up a mycelium which consumes 



all of the interior of the host except the chitinous skin. It 



thus stores up an enormous amount of nutrient material in the 



form of a storage organ or sclerotium, which is an exact cast, 



not only of the external form of the insect but also of the in- 



ternal organs. When this storage organ has rested for some 



time, and when conditions of moisture and temperature are 



favorable, it sends up, 



usually one or more, 



rarely two, stalks, 



which come above 



ground. Here they 



form a club-s h a p e d, 



bright-orange - colored 



body which may easily 



be mistaken for a club 



fungus. Close exam- 



ination shows this 



body to contain nu- 



merous small holes 



just as in the head of 



the stalk on the germi- 



nating ergot, and these 



holes again communi- 



cate with pear-shaped 



cavities, which are the 



s p o r e-sac capsules. 



Api i 



ne bdCS aiSO COmam 



pi o-li t 1rmcr tVirAarl 



Clglll Jllg, UiredU- 



shaoed SOOreS divided 



into numerous cells, 



each of which is able to form a germ thread and thus infect 

 other grubs or caterpillars. Sometimes the storage organ 

 does not produce a sac-capsule-bearing stalk, but produces in 

 one of several ways a great abundance of accessory spore forms 

 which are pinched off from threads in enormous numbers. 

 This happens if one places a freshly developed storage organ 

 in a moist chamber, or it may happen in nature where one 

 finds frayed-out branches or strands from the storage organ 



FIG. 56. A caterpillar tungus. The insect-shaped 

 bodies are fungus casts of threads which form a 

 storage organ; raising from these are club-shaped 

 bodies which are covered above with fine warts. 

 These warts are the tops of the sac-spore-capsules. 



