110 TB IN ID AD AND TOBAGO BULLETIN. \XIX. 5, 



H. ? seedlings gave stools of an average weight of only 40 to 501b., 

 but the juice from seven of them contained over 2 lb. of sucrose per 

 gallon and in one case practically 2^^ lb. per gallon. A. good typo of 

 seedling has been obtained from B. 6835 ; stools of cane weighing from 

 70 to 80 lb. were by no means unconnnon and in six instances the juice 

 contained more than 2 lb. of sucrose per gallon, A. fair number of 

 promising seedlings were also raised from L. 511. The canes from the 

 majority of the stools weighing over 70 lb. and in seven cases the juice 

 contained more than 2 lb. of sugar per gallon. 



During 1919 several thousand seedlings were again obtained and 

 2,400 of the most vigorous were planted out last year. Those showing 

 good field characters will be submitted to analytical tests from next 

 week, as they are now 13 months old and those that show a high 

 sucrose content will be propagated by cuttings about October or 

 November. 



Another batch of seedlings was raised last year and nearly 4,000 

 plants have been planted out. Their growth has been quite good for 

 this time of the year as the weather has been most favourable. 



Altogether 9,643 new seedlings have been grown and planted out 

 during the past four years. After a first selection, 210 of those raised 

 in 1917 and 1918 have been planted out in plots and of these 141 ai'e 

 showing promising growth. Plot results from 44 of the seedlings raised 

 in 1917 have been obtained and will be reported on later. 



.J. DE Y. 



The Mango Midge, 



The young shoots and flower stalks of mangos are attacked by a 

 small midge, the larvie of which destroy young flowers and leaves. 

 Occasionally this insect causes considerable injury ; as a rule it is kept 

 under control by natural enemies. 



The female midge la^s her eggs in the youngest flower and leaf 

 buds ; the young larvse or maggots bore into the tissues and form small 

 swellings in the centre of which the,y live by consuming the sap and; 

 eventually caiising the young leaves and flowers to dry up and die ; the 

 stalks of the flowers are also affected and the injury manifests itself by 

 small decayed spots through which injurious fungi can invade the plant. 

 Development of the larvse is rapid and in from 10 to 14 days they work 

 their way out of the mango shoots and fall to the ground, which they 

 enter and construct small cocoons of silk and particles of earth. Adults 

 appear about a week later. The total cj cle takes about 21 to 30 days. 

 When the maggots are parasitized they cannot leave the shoots and the 

 adult parasites issue from the swellings in the leaves and shoots. 



As the adult flies are only one-sixteenth of an inch in length they 

 are not easy to see ; the habits of the larva; in attacking the youngest 

 shoots and feeding internally make the application of insecticidal or 

 repellant sprays almost ineft'ective ; the control that is indicated would 

 be to prevent the larva? entering the soil by covering the ground under 

 the trees with white lime. The last " wet " dry season seemed 

 favourable for the development of this pest. Investigations are still 

 in progress. 



r.w.u. 



