162 FROGHOPPER BLIGHT OF SUGAR-CANE. 



The nymphs can be cruslied in their fi-oth or hand collected by gangs 

 of children, but both methods are expensive and only possible on a small 

 scale. 



The adult froghopx>ers are sometimes collected by hand, but this is 

 laborious (p. 143). 



Spraying with kerosene emulsion has been recommended by Gough, 

 but no field trials have ever been made (p. 148). 



Light traps catch large numbers of adults, but only about 1 per 

 cent, of these are females. Bright lamps are but little more attractive 

 than oil lamps, and green and red lights are found to attract fewer 

 adults than white, and no greater percentage of females. Lights 

 near the ground are more successful than if placed two to four feet up. 

 Other insects are destroyed by the lamps, Lmt on the whole more are 

 injurious than useful. The light traps may be used for the spread of the 

 green muscardine fungus, but the method suffers from the limitations 

 due to the effect of weather on the spread of infection (p. 148). 



The adult froghoppers can be caught in very large numbers by the 

 use of nets ' in the late evening and early morning when the adults are 

 sitting on the grass and cane leaves. Nets have been designed drawn 

 by njules in order to cover the ground rapidly in the limited time 

 available. Experiments are being continued on this line (p. 146). 



Natural Enemies can be encouraged to a limited extent by providing 

 trees for birds to nest in, and by stopping all unnecessary burning. At 

 the same time the froghopper is a native insect and its enemies are 

 probably on the average as efficient as they are ever likely to be (p. 147). 



If the search for new enemies in other countries is again carried out 

 it must be recollected that it is a long and uncertain process. New 

 enemies are more likely to be found outside Central America, and Africa 

 is suggested as a likely place. At least two men should be engaged in 

 such a search, as results will be obtained sooner and there is less likeli- 

 hood of failure (p. 147). 



Several possible tyjDes of new enemies are indicated (p. 149). 



