ISl FROGHOPPER BLIGHT OF SUGAR-CANE. 



Tho first flight of adults is at the end of June or during July, about 

 seven weeks from the date of the first rains. The second brood is about 

 two months later, usually in September, and the third may appear after 

 a similar interval. Very occasionally a fourth brood appears about 

 December. The later broods are usually less distinct in tlieir limits 

 than the earlier. During the dry season nearly all the froghoppers are 

 in the egg stage, but occasional unexplained records are known of adults 

 persisting through the dry season, (p. 62). 



Four other froghoppers of the genus Tomaspis are known in Trinidad. 

 T. rubra feeds on the Christmas Bush (Eupatorium). T. pubescens 

 feeds on grass, chiefly in moist spots along river banks, and is an 

 alternative host of some of the parasites of the sugar-cane frog- 

 hopper. T. guppyi also feeds on grass but is very rare and local. An 

 unidentified species is known only from two nymphs found on a creeper 

 on a forest tree in the mountains. There are also species of the genus 

 Clastoptera on Casuarina and Hibiscus, and Cephisus sj). feeding 

 possibly on Immortelle, (p. 63). 



THE ENEMIES OF THE FROGHOPPER. 



The chief enemy of the eggs is the Vermilion Egg-parasite (Oligosita 

 giraulti), a minute red Chalcid. Its life cycle is about thirty days and 

 it can breed during most of the dr3' season when the froghopper itself is 

 inactive. It is almost certainly native to Trinidad and is not likely to 

 increase much above its present limits. It probably has some other 

 host in Trinidad. Abroad it is known from British Guiana to Costa Rica 

 on various species of froghoppers. (p. 65). 



The Trash -Coloured Egg-Parasite {Paraphelinus tomaspidis) was 

 recorded in 1913 as destroying froghopper eggs, but this habit has never 

 been confirmed and it is doubtful if it is of any value as a control, (p. 65). 



In Panama a new egg-parasite of the genus Anagrus was found.. 

 (p. 66). 



Thrips of the genus Haplothrips and ants are known to destroy the 

 eggs, and eggs are sometimes found filled with a fungus which may have 

 killed them. (p. 66). 



The nj'mph is eaten by some birds but the frothy covering seems to 

 render them unpalatable to most. They have been found in the 

 stomachs of the Boat-tail {Quisqualus lugiibris), the Gulden-head 

 {Agelaius icteroceplialus) and the Manicou-Bird (GeofJtylpis acquinocti- 

 alis). (p. 66). 



The Syrphid fly is the most important enemy of the nymph. It lays 

 its eggs in the froth of the froghopper, and the maggot, which hatches 

 in about two days, destroys the nymphs by piercing their skin and 

 sucking out the juices. One maggot may destroy 30-40 nymphs. The 

 larval stage lasts nine or ten days and the pupa about the same time. 

 The complete cycle takes about three weeks. In the moister parts of the 

 island the fly breeds throughout the year, but in the cane fields it is not 

 found in the dry season and is seldom common before the second or 

 third brood of froghoppers. It ranges outside Trinidad from Mexico to 

 Brazil on various species of froghoppers. (p. 67). 



An attempt was made by Kershaw and Guppy in 1914 to breed large 

 numbers of this fly through the dry season so that they could be 

 liberated to destroy the first brood in the following year. Owing to the 

 difficulty of obtaining, during the dry season, enough nymphs for the; 

 syrphid maggots to feed on, the work had to be abandoned, (p. 69). 



