898 
Journal of Agricultural Research 
Vol. V, No. 19 
A relatively meager literature dealing with the subject of insects 
as carriers of fungi producing plant diseases has accumulated. Since 
the most important publications upon this subject are summarized in a 
recent excellent paper by Studhalter and Ruggles, 1 an historical review 
is purposely omitted at this time. These authors find that certain 
insects belonging to the orders Hemiptera, Coleoptera, Diptera, and 
Hymenoptera are carriers of the chestnut-blight organism. Because 
of the positive evidence secured in the few studies previously made on 
insects as agencies in the dissemination of plant diseases, it will not be 
surprising if it is found in future investigations that insects are a very 
important factor in the dispersal of many plant-pathogenic fungi. 
The insects used in these tests were collected in diseased peanut fields 
near Eutaw, Thomasville, Marion Junction, Greensboro, and Auburn, 
Ala., and placed in sterile test tubes or flasks plugged with cotton. 
After being brought into the laboratory, each insect was dropped into 
a measured amount of water, in case it was desired to determine the 
number of conidia upon its body. After agitating the tubes vigorously 
a drop of the wash water was examined under the low-power lens of a 
microscope, the number of conidia in the drop were counted, and from 
this the total number of conidia was estimated. 
In case fecal discharges were examined, each deposit was macerated in 
a drop of water on an object slide, and a count was made with the aid of 
the low-power lens. Because of the presence of undigested bits of plant 
tissue and the impossibility of one's being sure that no conidia escaped 
notice and that none were unwittingly counted twice, these determina¬ 
tions can not be exact. They very closely approximate the true number, 
however, since several counts of the same slide were made and the average 
taken as the final number. 
A total of 75 insects collected in five different counties has been 
examined in the course of these tests, 54 of which gave positive results. 
Four orders of insects—namely, Orthoptera, Lepidoptera, Coleoptera, and 
Hemiptera—were represented among the positive tests. Of the 56 grass¬ 
hoppers and katydids examined, 38 were found to be bearers of Cercospora 
personaia . No attempt has been made to classify these Orthoptera, 
but several different genera were represented. Of the roasting-ear 
worms, Heliothis obsoleta, which were examined, nine were found to void 
conidia of Cercospora in their feces. Eight members of the Coleoptera 
were examined, six of which gave positive results. Three of these were 
lady beetles, Megilla maculata; one a blister beetle, Epicauta vittata; 
and the other two were fireflies, Chauliognathus sp. A single member 
of the Hemiptera, one of the leaf hoppers, was examined and found to 
be a carrier. 
1 Studhalter, R. A., and Ruggles. A. G. Insects as carriers of the chestnut blight fungus. Penn. Dept. 
Forestry Bui. 12, 33 p., 4 pi. 1915. 
