November, 1909,1 



432 



Plant Sanitation. 



soned with a mixture of arsenic and 

 sugar, would be an attractive bait both 

 for this pest and for bandicoots. 



That Bandicoot 

 rats can be a 

 serious pest, can 

 be seen from the 

 accompa nyin g 

 figure, which re- 

 presents the base 

 of a yoaug Hevea 

 tree that has 

 been g n aw e d 

 completely 

 through by these 

 animals. The 

 characteristic 

 marks of the chi- 

 sel-like teeth are 

 very clearly 

 shown in the 

 illustration. My 

 co r r e s pondent 

 gives me the fol- 

 lowing account of 

 the ' modus oper- 

 andi' of this 

 pest :— "T h e 

 bandicoot always 

 scoops out a hole 

 at one side of the 

 rubber plant and 

 gnaws away the 

 tendei' root as 

 deeply as possi- 

 ble, that is — as 

 far down the root 

 as he can get, and 

 he invariably 

 gnaws the woody 

 part of the root. 

 The plant then 

 falls to the 

 ground and he 

 can get at the 

 tender bark 

 a b o v e." From 

 this account, it appears that the animal 

 deliberately fells the tree in order to 

 feed upon the tender bark that would 

 otherwise be out of its reach. My corre- 

 spondent informs me that a trial of 

 Danysz Virus produced no appreciable 

 result, and that the offer of a reward 

 of 50 cts. per rat met with no response. 

 He tells me that the Sinhalese plant a 

 poisonous species of yam which the rats 

 are said to eat with fatal results. I 

 think that baiting with artificially 

 poisoned yams— as suggested above — 

 would be equally if not more effective. 

 The rats are most destructive where 

 ' cheddy ' has been allowed to grow up 

 amongst the rubber. The removal of 

 this cover will do much to drive away 

 the pest. 



Base of Rubber Stem Gnawed 

 by Bandicoot Rats. 



I have recently examined a number 

 of diseased branches of Albizzia moluc- 

 cana which had become infested by 

 various small boring beetles. A study 

 of the material showed clearly that the 

 death of the branches was due to a 

 fungus which the Government Myco- 

 logist recognizes as a species of Nectria, 

 and the beetles had subsequently invaded 

 the diseased wood. I extracted seven 

 distinct species of Scolytidce from these 

 branches, and amongst them was one 

 which I am quite unable to distinguish 

 from the notorious shot-hole borer of 

 the tea plant (Xyleborus fomicatus). I 

 have— before now— noticed attempts at 

 infection of young Albizzias growing 

 amongst shot-hole-infected tea ; but, in 

 such cases, the insect had invariably 

 failed to establish itself, owing to exu- 

 dation of gum into its galleries. 

 I have an interesting specimen, in my 

 collection, showing one of the little 

 beetles entombed in a hardened drop 

 of gum, like a fly in amber. In the 

 present case, the Xyleborus had — in 

 every instance — attacked the branch in 

 a narrow zone just at the dividing line 

 between the dead and the living tissues. 

 It appeared to find the conditions— at 

 this spot— favourable, for the galleries 

 contained insects in all stages of 

 development. Curiously enough, ' shot- 

 hole borer' has never been found in 

 the tea on this estate. Under these 

 circumstances, the immediate destruc- 

 tion of the Albizzias was recommended. 



Many of the young sprouting stems of 

 the Giant Bamboos ( Dendrocalamus 

 giganteus) in these Gardens spring up to 

 a height of one or two feet, and then 

 cease to grow. A closer examination 

 shows that they are dead and decayed. 

 If one of these diseased sprouts is 

 broken open, it will be found to be full 

 of white maggots, which eventually 

 develop into a curious fly with banded 

 wings. This fly, which proved to be 

 a new species, has been named by Prof. 

 Froggatt Ceratitis striata. An allied spe- 

 cies (Ceratitis capitata) is the notorious 

 fruit fly that is so destructive to oranges 

 throughout southern Europe ; and all 

 other species — (at least those of which 

 the life-history is known) — are fruit 

 pests, It is curious that our Ceylonese 

 species should have adopted so different 

 a habit. It lays its eggs beneath the 

 imbricating sheaths of the young bam- 

 boo sprouts ; the maggots eat into the 

 soft heart of the stem and set up decay 

 which effectually stops all further 

 growth. The adult flies may often be 

 observed sunning themselves on the 

 older stems of the Giant Bamboo. To 

 check this pest, it will be necessary to 



