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'the Supplement to the Tropical Agriculturist. 



this may cause exudation of latex when the 

 cells become turgid once more. But the re- 

 appearance of the latex will itself be the best 

 cure, and will almost certainly kill the intrud- 

 ing insects. 



(4) Bark-eating Beetles (M vchoytpa verruci- 

 colhs, GahaVi). — This beetle has the reputation 

 of damaging the stems of young Hevea trees by 

 eating away the bark. Specimens of the injured 

 stems showed irregular patches of the (still 

 green) bark destroyed, in some cases completely 

 ringing the tree. The beetles themselves have 

 been captured at work. It was noticeable, how- 

 ever, that no latex had exuded from the wounds, 

 and where the whole plant was submitted for 

 examination the roots were found to be attacked 

 by a fungus {Botryodiplodia elaaticm.) The pro- 

 bability therefore was that the attacked plants 

 were diseased, and had ceased to produce latex 

 before the advent of the beetles. To put the 

 matter to the test, 1 obtained numerous living 

 specimens of the beetles and confined them in a 

 cage, together with a living healthy young tree. 

 1 watched one individual climb up the stem and 

 fix its jaws in the tender bark. The first punc- 

 ture resulted in a bead of latex, which adhered 

 to the mouth parts of the beetle, and evidently 

 proved very distasteful to it. The insect 

 immediately abandoned the attack and wandered 

 oft', doing its best to remove the sticky fluid. 

 Other individuals made similar attempts to 

 feed, but were promptly refused in the 

 same way, nor could they be induced to repeat 

 the experiment. After a week's confinement 

 without other food, they still refused to touch 

 the living bark ; but when removed to another 

 cage containing fresh branches of Cassia, they 

 greedily fed upon the bark. They were also 

 tried with tea branches, but this was not alto- 

 gether to their taste. They fed only sparingly 

 upon the outer layers of the bark. 



This insect is one of the Longicorn (or long- 

 horned) Beetles. It measures an inch in length, 

 and is of proportionately stout build. The 

 colour ranges from olive brown to pinkish, 

 variegated with darker markings. Another 

 smaller species of Longicorn (Niphona, sp.) has 

 been accused of similar injury, but it is prob- 

 ably as innocent of the priginalattack. As 

 both these beetles may possibly be destructive 

 to the bark of less well-protectod plants, it 

 will be advisable to treat them as potential 

 enemies, and to collect and destroy them when 

 found congregated on the stems of the trees. 



(5) Click Beetle Alaus speciosus, Linn.).— Speci- 

 mens of this handsome species have been re- 

 ceived with the report that they were found 

 clinging to the stem of a Hevea tree, upon the 

 bark of which they were supposed to have been 

 feeding. Some of the living beetles were im- 

 prisoned with several healthy sections of rubber 

 stem, but after three weeks' confinement no at- 

 tempt had been made to attack the bark, and 

 in the meantime one of the insects had died of 

 starvation. 



(6) Porcupines, rats, hares, &c., are sometimes 

 very troublesome in rubber clearings. Porcu- 

 pines in particular can be extremely destructive, 

 tearing oft* and devouring the juicy bark at the 

 base of the trees. It is noticeable that many 

 mammals seem to relish and to be capable of 



digesting the rubber latex. Several mixtures 

 have been put upon the market designed as 

 deterrents to such attacks. They are all rather 

 dangerous to young plants while the bark is 

 still green, but can be safely applied on older 

 bark. Bat the only sure method to prevent 

 attack is to enclose each individual stem in 

 a cylinder of wire netting until they are old 

 enough to take care of themselves. The syste- 

 matic trapping and poisoning of porcupines 

 will greatly lessen the evil. 



III. — Bkakche.s and Green Stems. 



(1) "Cut Worm " (Agrotis segetis, Schiff.). — 

 A few instances of damage to young plants 

 by " cut worms ■' have been reported. But 

 this insect does not appear to be nearly so 

 troublesome with rubber as with the seedlings 

 of many other plants. If necessary, injury 

 could be prevented by mixing a small quan- 

 tity of " vaporite " with the soil (ljoz. to the 

 square yard) before putting in the seed. 



(2) Locusts (various species of Acridiidce). — 

 I have received specimens of young rubber 

 plants said to have been killed by small 

 locusts. The bark was gnarled and completely 

 eaten off in parts. The insect (an apterous 

 species) were found clinging on to the damaged 

 stems. The insects disappeared with the advent 

 of heavy rains. The usual treatment is to dis- 

 tribute poisoned baits amongst the plants to be 

 protected. The best of these is compounded 

 of 1 part Paris green, 2 parts salt and 40 

 parts of fresh horsedung, with sufficient water 

 to make the mixture soft without being sloppy. 



(3) Shot-hole Borers {Scolytidrc, various spp.). 

 — I have never yet seen a vigorous plant, with 

 its laticiferous system in working order, 

 that has been injured by these insects. But 

 there is no doubt that there is a critical period 

 after transplanting, especially in the case of 

 plants transported from considerable distances, 

 when they are specially liable to attack. The 

 nender bark has become partially dry, and yields 

 to latex when wounded. If unmolested such 

 plants might recover, but they are not suffi- 

 ciently vigorous at the time to withstand the 

 attack of these borers. 



Some "vaporite'' dusted on the surface of the 

 soil around each plant (leaving a clear space of 

 a couple of inches from the stem) might deter 

 the attack, as it gives off an unpleasant odour of 

 gaslime. But the best safeguard is to ensure 

 the vigorous condition of the plants at the time 

 of planting. If plants have to travel for any 

 distance, the roots and lower parts of the stems 

 should be dipped into a thick mixture of cow- 

 dung and water immediately after removal 

 from the nursery. 



(4) Pith Bom s. —The ends of stumped plants 

 are very frequently tunnelled by various small 

 bees and wasps, which habitually choose such 

 situations for the construction of their nests. 

 Various species of Ceratina till these tunnels 

 with cells containing a mixture of pollen and 

 honey. But the wasps store their cells with 

 paralysed insects destined for the nourishment 

 of their young Trypoxylon intrudens provides 

 small spiders, and Stiguius niger employs aphi- 

 des for the purpose. 



