Plant Sanitation. 



194 



A case of infestation of the stem of a Hevea tree by the ' horned Termite ' 

 (Termed inanix) has been brought to my notice. This species of termite takes 

 advantage of any hollow in a tree for the construction of its nest, but does not 

 apparently feed upon the wood itself. My observations lead me to believe that it 

 subsists principally upon lichens growing upon the stems of trees and rocks. In 

 the present instance the tree is still alive, the termites occupying a large cavity in 

 the bole where the original stem had been broken off by the wind. I have recom- 

 mended the removal of as much of the nest as can be reached without further 

 damaging the tree. The more inaccessible portions can be treated with naphthaline 

 dissolved in petrol which will drive out the remainder of the insects. The cavity 

 should then be tightly plugged with dry earth. 



The grub of the large Cockchafer (Lepidiota pinguis) continues to give 

 trouble by feeding upon the roots of rubber plants. In some cases the tap 

 root has been eaten right through. Kainit, and nitrate of soda are the recognised 

 deterrents for this pest ; but they must be employed carefully and not allowed 

 to come into direct contact with the tender roots of the plants, or their caustic 

 properties will cause further injury. The best method of application is to mix 

 the substance with earth and spread it upon the surface round the plants. The 

 first shower of rain will dissolve the salts and carry them down into the soil. 

 For very young plants, one ounce of the nitrate or three ounces of the kainit will 

 be sufficient per plant. For larger plants from one and a half to twice this 

 dose may be safely employed. When the adult cockchafers are on the wing, 

 they may be trapped by placing small kerosene lamps, in trays containing water 

 and kerosene, in the field at night. During the daytime, the beetles may be 

 found resting upon the stems and branches of plants and should be collected 

 and destroyed. (For figures of the grub and adult beetle see T. A., Oct. 1905, p. 520.) 



I have made an interesting examination of samples of various shade trees 

 containing galleries of the ' shot-hole-borer ' (Xyleborux fornicatus). Young 

 branches of A Ibizzia moluccana had been tunnelled by the insect, but the galleries 

 were deserted and showed no signs of having produced a brood. The insect had 

 evidently found this wood unsuitable for breeding purposes. The galleries wer e 

 more or less filled by an exudation of gum. The same remarks apply to Grevillea 

 branches, in which only a single living beetle (evidently a recent arrival) was found. 

 Several dead beetles were found, enveloped in gum. Loquat branches had also 

 been tunnelled ; but here again there was no present occupation. A single dead 

 beetle was found in one of the galleries. Under these circumstances, it would 

 appear that though ' shot-hole-borer ' may attack and — to a certain extent — damage 

 these shade trees, it cannot successfully breed in them ; and that such trees are not 

 therefore of any real danger to the tea amongst which they may be growing. On 

 the other hand, a section (4 inches in diameter) of the stem of an old castor-oil plant, 

 from the same estate, was found to be badly infested by the borer. The numerous 

 galleries penetrated deep into the wood, and contained living insects in all stages 

 of development. It is evident that we have here a prolific breeding place of the 

 borer, and that such plants would constitute a source of infection to the surround- 

 ing tea. Young castor plants will not be so liable to attack. It is only when they 

 liave been allowed to grow old and woody that they harbour the pest to any 

 serious extent. 



A correspondent asks if tar, applied to the stems and branches of tea plants, 

 would prevent the invasion of 'Shot-hole Borer' (Xyleborux fornicatus) from 

 neighbouring infected estates. He writes, " I have shot-hole borer all round me, 

 but not— as far as I can see — actually on the estate." I have found a complete 

 coating of tar very injurious to the tea plant. It burns the bark badly and— in 



