62 FltOOlIOPi'ER liMOIlT OF SUGAR-CANE. 



Cane is by far the most seriously damaged of these plants but reports 

 of damage to corn, rice and other pastures have been made. 



Rice. Damage has been reported once or twice on hill-rice or 

 upland rice and in one case investigated the nymphs and adults were 

 present on the rice in some numbers but the damage was almost 

 negligible. The lowland or wet rice is never likel_y to be seriously 

 damaged by froghoppers as the conditions at its roots are quite unsuited 

 to the nymph. 



Corn. Blight has been frequently reported on corn but in every_case 

 investigated the damage has been complicated by the presence of other 

 insects, particularly the small moth-borer {Diatroea s})}}.). On a few 

 occasions the froghopper has, however, been responsible for considerable 

 damage. 



Pasttires. In other countries (e.r/. Cuba, Colombia, etc.) pastures 

 seem to suffer nmch more than canes from the attacks of froghoppers. 

 In Trinidad the reverse is the case and on onl^' one occasion, was an> 

 considerable damage done to pastures. This was at Harmony Hail 

 Estate, in September 1918, on land that had recently been in cane and 

 had been thrown out owing to the continual damage by froghoppers. 



LIFE CYCLIC, 



The egg stage of the froghopper lasts from fourteen days upwards, 

 the nymph stages occupy five to seven weeks and the adult may live as 

 long as a month. Under normal wet season conditions a single complete 

 cycle takes slightly under two months. 



In the wetter parts of the country, in the mountains, forests and 

 cacao districts, breeding goes on throughout the year and nymphs and 

 adults may be found at any time. In the drier portions, in which the 

 sugar districts are situated, there is an almost complete standstill during 

 the four or five months of the dry season. 



With the coming of the wet season about May or June the eggs, which 

 have been held up by the dry weather, hatch out and the first nymphs 

 are usually reported in the sugar districts a week or two after the first 

 rains. These produce the first flight of adults at the end of June or 

 •during Jnly, about seven weeks from the date of the first rains {see p. 103.) 



Eggs from these produce a second flight of adults about two months 

 later, varj-ing in different years from the end of August to the beginning 

 of October, and from these again a third brood in October to December 

 and rarely a fourth in December or January. Each of these broods in 

 succession is less definite in its limits owing to the varying dates at 

 which eggs are laid by the females and individual variation in the leiagth 

 of the egg and nj-mph stages. At the same time the broods up to the 

 third are almost always quite distinct and recognizable. Figs. 5 and 6. 

 show these broods of adults in 1918 and 1919 as indicated by captures in 

 light traps. 



The fourth brood is very seldom of any considerable size even in 

 years when there is quite sufficient wet weather after the third brood for 

 it to develop, from which it must follow that many eggs laid by the 

 third brood, and possibly in some cases by the second brood also, fail to 

 hatch that year but hold over until the coming of the next wet season. 



There has been some disagreement as to the manner in which the 

 insect passes over the drj' season but most authorities are now convinced 

 that in Trinidad this is spent in the egg stage. At the same time there 

 is no doubt that in the moister spots in the dry sugar districts the 

 insect can continue to breed in small numbers, but these are never 

 sufficient to account for the enormous numbers of insects which some- 

 times appear in the first brood. 



