THE WHITE-GRUBS INJURING THE SUGAR CANE IN 



PORTO RICO. 



1. LIFE-HISTORIES OF MAY-BEETLES— Continued. 

 By EuGEXE G. Smyth, Acting Entomologist, Insular Experiment Station. 



THE SUGAR CANE WHITE-GRUB— Continued. 



Infection by the Metakrhizium Fungus. 



Infection of Phyllophaga vandinei n. sp.* in the experimental 

 jars and boxes by the green museardine fungus, Metarrhiziuni anis- 

 opliae (also known as Entomoptliora anisopliae and Isaria destruc- 

 tor), has been noted of every stage except the pupa. The number 

 of specimens that developed the disease, as compared to the total num- 

 ber kept in confinement under close observation, may be summed up 

 in the following table: 



Of 853 adults kept in confinement, 81 became infected, or 9.5 per cent. 

 Of 1,502 eggs kept in confinement, 10 became infected, or .66 per cent. 

 Of 852 grubs, 1st instar in confinement, 3 became infected, or .36 per cent. 

 Of 209 grubs, 2d instar in confinement, 3 became infected, or 1.43 per cent. 

 Of 117 grubs, 3d instar in confinement, 16 became infected, or 13.67 per cent. 

 Of 48 pupae kept in confinement, none became infected. 



The majority of diseased specimens were adults, which is possibly 

 accounted for by the fact that they, moving about freely in the jars, 

 are more apt to transmit the disease from one individual to another 

 than are larvae or eggs. 



The stage in which the highest per cent of individuals became 

 infected was the third instar of the grub, in which infection was 

 necessarily contracted from the soil, which is lielieved to have con- 

 tained large numbers of spores. 



The degree of susceptibility to infection by the disease was, among 

 the immature stages of the beetle, lowest in the pupal stage and 

 highest in the third instar of the larval stage. 



The following conclusions have been reached regarding attack of 



* The habits of this species, and suggestions for control, were discussed in the Third 

 Report of the Board of Commissioners of Agriculture of Porto Rico (pp. 42—47), under 

 the name "Lachnoaterna grande," and its life-cycle (except pre-oviposition) given in the 

 Fourth Report (p. 47) under the same name. 



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