THE GKEEN MUSCABDINE FUNGUS. 27 



of material was some months later ajiplied at Rio Piedras not only 

 to cane, hut aronnd the hases of a niimher of eoeonut trees, wiiidi 

 had been severely attacked by PliyUophaga sp. Infected insects 

 have never been recovered. 



CONCLUSIONS. 



As a result of the tie'ld observations and tlie varied experiments 

 carried out l)y the members of th(- Station staff and others who have 

 I)een (connected with the project, the conclusion seems justified that 

 tile green muscardiue will not serve as a practical means of control- 

 ling the white grubs or ]\Iay-beetles in Porto Rico. 



It is true that in confinement various stages of PliyUophaga sp]». 

 are subject to attack, as are also other cane pests, 1>ut even in tiiese 

 instances the disease has not been virulently parasitic. No positiv<» 

 results have been obtained in the field tests and it appears that the 

 fungus is indigenous, but so dependent upon humidity and otiier 

 natural conditions that it is a negligible factor in controlling iuscci 

 pests and will remain so. 



This conclusion is borne out by the reports of workers in Java, 

 both Rutgers (i^l) and Groenewege (11) stating that while consid- 

 erable numbers of insects were attacked in confinement, results iii 

 the field were so absolutely dependent upon the weather tliMt no 

 artificial attempts .(t dissemination of the disease would avail. Tiic 

 favorable results obtained in Samoa in the control of the coconul 

 beetle may be easily accounted for by the fact that conditions a]>- 

 proximated confinement, the piles of debris retaining moisture, sn 

 that for all practical purposes they were no different than so many 

 insect cages. None of the Torto Rican insects l(Mid themselves tn 

 this method of trapping. 



In Trinidad nmst favorable results have been re]>orted, it is tine 

 hut in this ca.s(! the insect pest involved has an entirely ditfcicui 

 mode of life from the May-l)eetles, which it is thought will account 

 foi- the (litferciice in the efficiency of the fungus in tlie two regions. 

 It is also quite possible that the weather conditions |)i-evailing at 

 times of severe froghopper infection may favor the fungus. 



It does not seem advisal)l(^ to carry out any further work witir 

 the green inuscardine in I'orto Kico. at least in connection with tlu- 

 white-grubs or May-beetles. 



