MITES IN RUBBER NURSERIES. 



My attention has lately been attracted to several cases whi re 

 the seedlings of the ''Para" rubber tree presented a somewhat 

 unhealthy appearance, and on more than one occasion I have 

 been assured that this was there natural appearance during, or 

 immediately after, a spell of dry weather. It is evident, however, 

 that all is not as it should be, and if the growing point or the 

 very young leaves are closely examined, a minute insect will 

 generally be observed moving rapidly about, chiefly on the under 

 side of the leaf. 



This is not a true insect, but one of the Mites (A carina) 

 and allied to the pests that infest and produce the galls and leaf 

 blister on plants. One of the best known of these Mites is that 

 commonly referred to as "Red Spider " (Tetranychus telarius), 

 which is very common in hot houses in Europe, being especially 

 abundant on various species of Acalypha plants of the same 

 order as the " Para " rubber tree; other Mites are parasitic on 

 animals, while the itching Mite is parasitic on man, causing 

 the disease known as itch; the sensation which gives the name 

 to the disease being due to the Mites burrowing in the skin. 



In the particular case under note, the very young leaves fall 

 from the plant before they are developed — in this respect the result 

 is much the same as though the plants had been attacked by 

 "Red Spider" — while those leaves which mature, present a 

 crinkled appearance and are generally of a yellowish green colour, 

 and will be found upon examination to be perforated by numerous 

 holes, due to the punctures of the Mites when the leaves were 

 young. Saprophytic fungi are also present, but the disease is 

 primarily due to the depredations of these minute parasites. 



Being so small, these Mites are apt to be overlooked, and the 

 cause of the disease attributed to other causes; they can be 

 detected by the naked eye by anyone possessed with keen 

 eyesight, though a good lens or a microscope is indispensable 

 to enable us to obtain a correct idea of their structure. 



The particular Mite causing the disease alluded to above, is 

 probably a species of Tarsonymus. but I am unable, with the 

 literature at my disposal, to determine the species. This, however, 

 is not of much consequence to the planter, as the cause and 

 effect is much the same in the various members of this family. 

 Mites are produced from eggs, and. as a rule, the young are 

 provided with three pairs of legs : they thrive best in a warm dry 

 atmosphere. When they occur on plants having smooth leaves, 

 they can be kept in check by syringing with clean water, or with 

 a solution of soft soap and quassia chips. Dusting the affected 

 parts with tobacco dust will also be found very effective and 

 perhaps more expedient : this should be done in the evening so as 

 to reduce the risk of it being blown off. or washed off by heavy 

 rain. 



