730 



unbarked until the next April. The emergence of the adults of the 

 first broods occurs in late March or early April. If the material remains 

 unbarked until the end of May, the second generation can develop. 

 This generation attacks living trees adjoining the breeding centres. 

 Maturity is reached in July ; if the conditions are favourable, a third 

 generation is produced, which extends the infested area. The adults 

 of the third brood appear at the end of September and in October 

 and either migi'ate or found the hibernating generation. The genera- 

 tions show considerable overlapping, hence there is a more or less 

 constant emergence of adults. 



The remedial measures carried out in Jaunsar indicate that the 

 pest can be controlled, at any stage in the attack, but that it is simpler 

 to adopt preventive measures. Methods of control are based on the 

 principle that felling operations should be completed, and felling-areas 

 cleared, before the beginning of April. In cases where this is impossible, 

 the following rules should be observed : — (1) All trees felled and not 

 removed by 1st April should be barked and the bark and small branches 

 should be burned ; (2) all trees felled during April or subsequently, 

 and not removed within one month of felling, should be barked ; 

 (3) refuse remaining on the felling-area after April should be burned. 

 Remedial measures should include the removal and burning of all 

 dead, dying and freshly- attacked trees. Fresh attacks are indicated 

 by small heaps of red bark dust in the bark crevices or at the base of 

 the tree ; the removal of a strip of bark will reveal the egg-laying 

 aduJts in their galleries. The boundaries of groups of attacked trees 

 should be accurately ascertained. 



De Charmoy (D. D'E). Report of the Division of Entomology.— 



Ann. Rept. Dept. Agric, Colony of Mauriiius, for 1914. [Received 

 18th October 1915.] 



Virgin sugar-canes grown in damp localities have suffered from 

 attack by Sesamia vuteria {nonagrioides), the pink borer ; the planting 

 of maize as a trap has given excellent results. The Chalcid, Prophanurus 

 {Cera])hron) beneficiens, has been found to parasitise the eggs ; this 

 parasite has not previously been recorded in the island. As the eggs, 

 which are laid on maize, are very conspicuous, it is easy to coUect them 

 and save those which are parasitised. The spotted borer, Diatraea 

 striatalis, has been reported as seriously attacking young virgin canes 

 at Moka ; elsewhere it is limited to cane-stalks. In 1913-14, 17,500 

 canes were examined to determine the actual loss caused and the 

 average infection was 21 and 12 "8 per cent, and r2'6 and 13'4 per cent, 

 at Moka and Pamplemousses respectively. The white borer, 

 Argyroploce schistaceana, has spread all over the island and is very 

 abundant in some localities. The life-history of this moth has been 

 studied, but more data are required before control measures can be 

 advised. In one small area, a species of Lachnosterna associated with 

 Oryctes tarandvs, caused very serious damage to full grown canes. 

 Young plantations of mahogany trees at Mahebourg were severely 

 attacked by a P}Talid moth. Illipe trees at "La Ferme " suffered 

 much from a Longicorn beetle {Philematium femornle) and Bois noir 

 {Alhizzia lehhek) was again reported as having been badly affected by 

 another Longicorn, Batocera rubus. 



