August, '16] HYSLOP: TRIPHLEPS AND CORN-EAR ROT 437 



in about three days, the insect reaching maturit}^ in about fifteen days. 

 As this insect is known to hibernate in the rubbish in the corn fields, 

 the conchision at which I have arrived is almost evident: The insects 

 spending considerable of their time in the rubbish in the fields become 

 infected with the disease, they oviposit in the corn silk, infection enters 

 at the point of oviposition and travels down the corn silk to the ovary 

 of the corn. The evidences in favor of this conclusion are : the charac- 

 teristic starting points of discoloration of the kernel at the base of the 

 corn silk, the fact that the disease will occur on several points of the 

 ear often distant from the tip, and that the disease is not one of the 

 forms which attack the plants through the roots and fibro vascular 

 system nor can be introduced by air-borne spores alighting upon ex- 

 posed parts of the ear. In fact, in many cases ears were badly rotted 

 wherein the husk was tight and extended considerably beyond the tip 

 of the ear. 



Should this hypothesis prove to be the fact, Triphleps insidiosus 

 will assume quite a different role than it has assumed in the past. It 

 has been recorded as a very beneficial insect as far back as 1881 when 

 Riley^ recorded this insect as a natural enemy of Blissus leucopterus. 

 In 1900 Dr. S. A. Forbes^ gives this insect as a natural enemy of Blissus 

 leucopterus, Phylloxera, Thysanoptera, eggs of Heliothis ohsoleta and 

 larva; of Diplosis sorghicola, and Garman and Hewitt add Coccidcc and 

 Aleyrodes vaporarium. As a noxious insect, this is not the first record 

 by any means. It has been recorded as damaging plants as far back 

 as 1888 in an unsigned article published in Garden and Forest, August 

 22, wherein it was stated that many of the Chrysanthemum collections 

 around Boston were being seriously damaged by this insect piercing 

 the ends of the shoots and causing the leaves to curl up and wither. 

 Dr. E. P. Felt^ records this insect as doing damage to squash vines, 

 and Professor Herbert Osborn found them damaging the blossoms of 

 red clover. It is possible that the injury in these cases is purely physi- 

 cal, destroying the plant tissue by withdrawing the sap. It is not im- 

 possible, however, that, in these cases also, parasitic fungi introduced 

 by the mouthparts or ovipositor of the insect were largely responsible 

 for the destruction of the plant tissues. 



The probabihty of the transmission of Diplodia and Fusarium by 

 Triphleps insidiosus serves to accentuate the remedial measures gener- 

 ally suggested in combating these diseases; not replanting fields to 

 corn that have borne a diseased crop, and destroying the leaves and 

 stubbles in all infested fields. It is not even advisable to use this Utter 



lAmer. Agri. Tec. 1881, Vol. 40, p. 515. 



2 Bui. 60, 111. Agri. Exp. Sta. 



3 Am. Garden, Sept. 10, 1898. 



4 



