ON ORCHIDS. 



(By permission of the Board of 

 Agriculture.) 



attack by any pests, animal or vegetable, which is seldom vouch- 

 safed to most popular plants, is certain. Of late years, however, 

 several formidable pests have threatened the Orchid-grower, and 

 in some collections much damage has actually been inflicted. 



The most destructive of insect pests 

 amongst the newcomers is a tropical 

 beetle, scientifically known as Xyle- 

 borus perforans. The genus is un- 

 represented in this country, but in 

 the sugar - cane districts this same 

 "^'^ \ beetle occasions the planter not a 



'r^ \ " ^^-^^^ rnt»SS little anxiety. The generic and 



specific names give sufficient clue to 

 its propensities, which are to tunnel. 

 Dendrobiiim PhalcEfiopsis are the 

 plants usually selected, and these are 

 Fig. 402. — Dendrobium Beetle, attacked by means of the pseudo- 

 AND Portion of Plant bulbs. Having gained access, the 

 SHOWING Perforations. ^^^^^^^ practically tunnel the stems, 



(Much magnined.) , 



causmg the plants to have a most 

 unhealthy appearance and not in- 

 frequently to die. The beetle (Fig. 



402) is about 2^mm. long, and chestnut-brown. The larva (Fig. 



403) is w^hite and footless, and is also capable of much mischief. 

 Dendrobiums, therefore, which show signs of decay without a cause 

 being readily assigned for it, should be carefully examined, and if 

 the small perforations are noticed in the growths (Fig. 402), the 

 portions must be cut away ; for it is better to risk the check that such 

 is sure to cause than the utter destruction of the plant attacked. 



In Cattleyas there is a species of fly {Isosoi?ia orchideai^um) 

 which occasions a lot of damage. This insect deposits its 

 eggs in the eye of the young growth when 

 the plant is in a dormant state. As a con- 

 sequence, the growth does not advance much 

 above lin., swells in the centre, and generally 

 exhibits a stunted appearance. If this growth 

 is cut off at the base and spht open, there 

 will be disclosed from three to seven yellowish 

 maggot-like creatures. After eating a large 

 hole in the young growth, they become pupae, 

 and eventually emerge as perfect flies. They 

 should be destroyed as soon as seen. Fumiga- 

 tion with a vaporising insecticide will effectually 

 settle them before they have time to deposit 

 their eggs. The roots, too, not infrequently. Fig. 403.— Grub of 

 are pierced bv the insects, and a warty growth Dendrobium 

 results. The grubs should be picked out Beetle. 

 with a stout needle. 



