38 BULLETIN 746, U. S. DEPARTMENT OP AGRICULTURE. 



in Louisiana as compared with Porto Eico makes it more difficult 

 to determine its effect on the moth borer. 



EFFECT OF FLOODS. 



Complete flooding of cane fields for long periods seems to have a 

 great influence on the infestation of the moth borer. For four years 

 observations have been made on a plantation near Morgan City, 

 which was under water for some weeks in the spring of 1912. In the 

 fall of 1912 the infestation on this plantation was 4 per cent. In the 

 fall of 1913 it was 6 per cent, only slightly higher than in the year 

 of the overflow. In the fall of 1914, however, the infestation had 

 reached 68 per cent, while in 1915 it was 87 per cent. It seems that 

 the moth borer was much reduced in numbers by flooding, but that 

 the numbers increased rapidly the second year after the inundation. 



EFFECT OF IRRIGATION. 



Though floods seem to reduce the percentage of infestation, it has 

 not been observed that irrigation has any effect. Observations have 

 been made on the nonirrigated plantations of Louisiana and on the 

 irrigated properties of the lower Rio Grande Valley of Texas. No 

 difference in the infestation which can be traced to irrigation has 

 been noticed. 



FUNGOUS DISEASES. 



Although a fungous disease on the larvae of Diatraea saccharalis 

 was studied by J. R. Picard (120) at the Louisiana State University 

 in 1903, its occurrence under natural conditions is very rare. Larvae 

 are sometimes attacked in the insectary, especially when kept in tin 

 boxes, but all attempts to inoculate healthy larvae have failed and it 

 is probable that the fungus is only saprophytic. One such diseased 

 larva of D. zeacolella sent in by Mr. A. G. Davis from Chipley, Fla., 

 was submitted to Mr. Alden T. Speare, Mycoentomologist of the 

 Bureau of Entomology. He reported that "the fungus seems to be 

 very close to Aspergillus 'parasiticus, which I found to be parasitic 

 upon the sugar-cane mealybug in Hawaii. There is no doubt that 

 the fungus is an Aspergillus, but I would venture no specific name 

 at present. A. flavus has been found to be parasitic upon sugar-cane 

 mealybugs in Louisiana and in Porto Rico, but this is the first record 

 to my knowledge of an Aspergillus on Diatraea, hence I can not 

 vouch for its parasitism." 



The fungus parasite Cordyceps barberi is recorded by Van Dine 

 (169) from Porto Rico, and by Bodkin (17) from British Guiana 

 on both the larva and the pupa of Diatraea. The present writers 

 planned to experiment with this disease but they were unable to 

 obtain cultures or diseased specimens. 



