Plant Sanitation. 



122 



[February, 1910. 



were tieated with green manure, before 

 sowing, and had produced a very. rank 

 dark green growth in marked contrast 

 to the golden green of the rice plants 

 in the remainder of the field. The 

 caterpillar is of a leaf-green colour, 

 and of the normal form of such leaf- 

 rolling larvae. Its modus operandi is 

 to turn up the edges of the leaves and 

 stitch them together with bands of 

 white silk, at intervals of about half 

 an inch, along the greater part of their 

 length, forming a long tubular retreat 

 within which it feeds upon the tissues 

 of the upper surface, leaving only the 

 lower cuticle intact. This lower cuticle 

 dies and bleaches to a dead white. It 

 finally transforms itself into a small 

 reddish pupa, in a covering of white 

 silk, within the folded leaf. The moth 

 is extremely abundant in grass ravines 

 and probably feeds upon various grasses. 

 It seems possible that the cuticle of 

 the rice plant is normally too hard for 

 its purpose, but that the rank growth 

 induced by fertilizers has altered the 

 texture of the foliage. 



In the Tropical Agriculturist of 

 November, 1909, I reported a ease in 

 which 'Shot-hole Borer' had been 

 discovered in cankered branches of 

 Albizzia moluccana. I have now to 

 record a case in which otherwise 

 healthy branches of the same tree have 

 been riddled by the borer. I have 

 hitherto found that Albizzia s — in good 

 health — have been able to resist infection. 

 But I can find no signs of disease in 

 the branches now sent to me. The bark 

 is of a healthy green colour and is 

 full of sap, showing that the trees 

 must have been in vigorous growth, 

 yet they are riddled from end to end. 

 The galleries of the insect contain lar- 

 vae and pupae in all stages of de- 

 velopment. On the estate in question, 

 the tea is infested with ' shot-hole' and 

 the prunings are being systematically 

 burnt. The Albizzias are growing 

 amongst the tea and are being lopped 

 to supply a green manure. It is in 

 these lopped branches that the borer 

 has been discovered. The Superinten- 

 dent writes : — " All the expense incurred 

 in burning prunings and manuring 

 again before its time bids fair to be 

 of no avail, I fancy, after my pruning 

 and burning, the few surviving borers 

 must have taken refuge in the Albizzias 

 and, being apparently prolific, are well 

 on their way to infect this field again 

 seriously. I am burning the stripped 

 Albizzia branches now, instead of laying 

 them in the rows." This is a serious 

 matter and — if of common occurrence — 

 will render Albizzia moluccana an un- 



suitable tree for such cultivation, at 

 any rate, in 'shot-hole' infested dis- 

 tricts. 



The same tree is subject to attack 

 by a boring caterpillar (Arbela quadri- 

 notata), A report from an estate in the 

 Ruanwella district states that these 

 caterpillars (the 'Brown Borer') were 

 attacking Albizzia trees in hundreds, and 

 were found in the very heart of the 

 trees, many of which bad died out. 

 This is an unusual sequence of events. 

 The borer feeds upon the outer bark only 

 of the tree, and usually makes a tunnel — 

 down some knot-hole— merely as a re- 

 treat. It is possible that the death of 

 the trees may have been due to some 

 other cause. 



Two pests affecting Albizzia seedlings 

 have been reported. A nui'sery in the 

 Ratnapura district has been extensively 

 defoliated by caterpillars of the Noctuid 

 moth (Polydesma inangulata). The 

 second case is of more importance- It 

 was observed that the young plants 

 hung back unaccountably, Exami- 

 nation of the roots showed that they 

 were badly infested by the Root Gall- 

 worm ( Heterodera radicicola). This 

 necessitated the complete destruction of 

 the nursery. 



' Dadap ' (Erythrina Utho&perma) trees 

 are subject to the attacks of a small 

 boring caterpillarCTerasii'a meticulosalis) 

 that tunnels in the ends of the green 

 shoots. The pest may seriously check 

 the growth of young plants and- in 

 such cases — the affected shoots should 

 be cut off and destroyed. But in older 

 plants the injury is of little importance. 

 The borer confines its work to the sappy 

 ends of the branches, and the tunnels do 

 not penetrate very far. Where Dadaps 

 are grown for manurial purposes, the 

 presence of the insect may even be ad- 

 vantageous as — by stopping back the 

 ends of the branches— it induces them to 

 bush out along the sides. 



Eucalyptus trees, at Bandarawella, 

 have been attacked by a minute Chry- 

 somelid beetle— one of the hopping 

 species (Flea-beetles). The insects feed 

 upon the undersurlace of the young 

 leaves and cause considerable disfigure- 

 ment of the foliage. 



A correspondent of the "Times of 

 Ceylon " wrote, under date November 

 18th, to warn planters against encourag- 

 ing Passiflora foetida on estates, and asks 

 "if estate managers are aware that 

 snakes feed on the fruits of the passi- 

 flora." He is consequently afraid that 

 the cultivation of this plant " would in- 

 crease the number of poisonous snakes,' 



