Plant Sanitation. 



431 



[November, 1909. 



is that which Nature has provided it, viz., 

 its bark. But when accident has pro- 

 duced a flaw in the armour the most 

 efficient substitute is coal tar." Bailey, 

 in his Pruning Book, describes a series 

 of experiments with different sub- 

 stances, in which the wound covered 

 with coal tar healed quickest, but he 

 points out, what is generally overlooked, 

 that rapidity of healing is governed 

 more by the position of the wound than 

 by the preservative used ; he expresses 

 a preference for white lead paint, and 

 many orchardists agree with him on this 

 point. Watt and Mann state that 

 vegetable tar, not coal tar, should be 

 used, but they do not give any evidence 

 in favour of their preference. It must 

 be remembered that a book on Tea or 

 Rubber or Cacao must be a compilation, 

 and the compiler cannot be supposed to 

 test every statement. He usually accepts 

 the current tradition; and the traditiou 

 brought out from Europe thirty years 

 ago would undoubtedly have been in 

 favour of Stockholm tar. It would 

 seem that the recommendation is an 

 extension of the old doctrine of signa- 

 tures, — that Stockholm tar, being a vege- 

 table tar, must therefore be most suit- 

 able for plants. 



ENTOMOLOGICAL NOTES. 



By E. Ernest Green, 

 Government Entomologist. 



In the July and August numbers of 

 this journal, I described a case of tea 

 seedlings attacked by the "Root Gall- 

 worm " (Heterodera radicicola). The 

 accompanying plate gives a good idea of 

 the appearance of tea roots attacked 

 by this pest. 



The ' Red Borer ' (Zeuzera coffem) ap- 

 pears to : be unusually prevalent just 

 now. Within the last month numerous 

 specimens have been received from tea 

 estates in various localities. In one case, 

 the borers were found in nursery 

 plants. I have also recorded an addi- 

 tional food plant for this pest, which 

 has occurred in young teak trees in the 

 Matale district. 



Specimens of the large Cockchafer 

 grub (Lepidiota pinguis) have been 

 received from several localities, where 

 they have been destructive in tea 

 nurseries, feeding on the roots of the 

 young plants. 'Vaporite' will be found 

 an efficient remedy for this pest. It 

 dibbled into the soil (between the rows 

 of plants) it gives off a gas which quickly 



brings the grubs to the surface, when 

 they fall a prey to ants, birds, and 

 numerous other natural enemies. 



' Red Slug '—the caterpillar of the 

 moth Heterusia cingala — has attracted 

 attention in several tea districts. This 

 is one of our ever-recurrent tea pests. 

 If noticed in time— when the first brood 

 is confined to a few bushes — the cater- 

 pillars may be collected by hand and 

 further trouble prevented. 



A limited outbreak of the ' Small 

 Tussock Caterpillar ' (Orgyia postica) 

 upon tea, has been reported. 



Further information concerning the 

 slug pest of Hevea rubber has been ob- 

 tained, and the name of the slug has 

 been determined. It proves to be 

 Mariaelia dussumieri, Gray. 



My correspondent writes: — "A rubber 

 tree which has a:ot to the branching 

 stage does not suffer so very much from 

 their depredations. It is the single- 

 stemmed ' wintering ' tree — which has 

 lost its foliage — that suffers so badly. 

 The slugs will not permit it to get into 

 leaf again, as they nibble away every 

 growing-point and— in addition to this 

 — ' tap ' the green Jbark of the latest 

 formed portions of the stems. The 

 latex can be sometimes seen running 

 down the stem, where these pests have 

 been operating overnight. The supplies 

 also cannot get a start, as the slugs eat 

 off the growing-point close to the stem." 



I have seen specimens of some of these 

 afflicted trees. It is evident that the 

 plants have made repeated efforts to 

 throw out fresh shoots, and that each 

 attempt has been promptly 'nipped in 

 the bud .' The top of the plant shows a 

 cushion of these aborted buds. 



Some of the slugs were observed to be 

 feeding upon the renewing bark in a 

 wound. It may be mentioned that it 

 was this same species that attracted 

 notice — four years ago— by lapping up 

 the remains of the latex left in the 

 wounds after tapping, with the result 

 that little ' scrap rubber ' was forth- 

 coming. (See " T. A." July, 1905, p. 408.) 



Several ways of circumventing this 

 pest suggest themselves. Cylinders of 

 freshly tarrod brown-paper might be tied 

 loosely round the base of each stem. 

 ' Vaporite ' strewn over the surface of 

 the ground round each tree would bar 

 the passage of the slugs. This would 

 be more effective than lime, as its action 

 would not be completely destroyed by 

 rain. Fowls, and especially ducks, will 

 devour the slugs with avidity ; but it 

 would be difficult to turn the whole of a 

 rubber plantation into a fowl-run, or to 

 stock it sufficiently. Sliced yams, poi- 



