452 JOURNAL OF ECONOMIC ENTOMOLOGY [Vo\. 6 



lack of sanitation in the fields, the froghopper is a difficult pest to 

 control and is rendered all the more difficult because of the lack of 

 vulnerable places in its life history. 



The nymphs are found only on the roots of cane, where no insecticide 

 can reach them. The adults are of such small size and are so active, 

 that their collection by boys is impracticable. It might be possible 

 to reduce their numbers b>' Imrning the trash in which their eggs are 

 deposited, but as the eggs are also deposited in the ground and it is 

 usually in the moister trash which is closest to the ground and most 

 difficult to burn, that most of the eggs are deposited, this practice 

 would only destro}^ much-needed hunms, and leave the major portion of 

 the eggs undestroyed. As all ordinary methods of control are imprac- 

 ticable, a most novel and unusual plan of campaign has been adopted. 



The fungus, Metarrkiziwn anisoplia' Sorokin, produces a fatal 

 disease of froghoppers and other insects called the Green ]\Iuscardine. 

 When the fungus spores are widely diffused throughout a cane field, 

 a heavy mortality of the froghoppers follows, if the moisture and 

 temperature conditions are favorable. At the beginning of the rainy 

 season, when the froghoppers begin to become most abundant, the 

 conditions for the growth and development of the fungus are ideal. 

 Although attempts to use fungus diseases in comVjating insects 

 have been made elsewhere, never before has the growth of large 

 amounts of fungus spores and their thorough distribution throughout 

 a field to kill the insect pests of the crop growing there been attempted 

 on so large a scale. The spores of Metarrhiziuin are grown on layers 

 of cooked rice spread out on trays three feet square, ten of Avhich 

 trays are contained in a culture cabinet. As about 70 pounds of the 

 mixture of spores with the proper amount of cassava starch for field 

 dusting are produced from one cabinet ; on several estates in Trinidad 

 as many as four of these cabinets are in operation, and as the length 

 of time for the maximum production of spores is only three weeks, 

 it is apparent that the commercial production of spores has been made 

 practical. The application of spores in the field is made from a blower 

 mounted on a railroad flat car. The pioneer work in the devising of 

 large-scale, commercially practical methods of growth and application 

 of fungus spores has been done by Mr. J. B. Rorer, Pathologist of 

 the Trinidad Board of Agriculture. To his recent article in "Phyto- 

 pathology," April, 1913, pp. 88 92, one may be referred for the details 

 of the work. 



The practical results of this field dusting are somewhat inconclusive, 

 as few of the cabinets were put into operation till towards the end of 

 the rainy season last year, and most of the dusting has been done 

 during the dry season when conditions are not optimum for the pro- 



