DISEASES OF PLANTS. oot 
Fruits, as plumbs, apples, pears, hazel-nuts, and 
the grain of corn and the like, often contain the 
larvee of insects, which destroy them. 
Except the destruction of the larva no remedies 
will resist these ravaging enemies. 
§ 324, 
Tabes, or the wasting of a plant, is frequently 2 
consequence of the already mentioned diseases, or 
those which we have still to explain. Its causes, 
however, are likewise, sterile or improper soil, un- 
favourable climate, clumsy planting, exhaustion of 
strength from too frequent flowering, insects, ul- 
ceration, and the like. ‘The whole plant gradually 
begins to decline, and dries up. As soon as this 
disease really appears, help is rarely possible. 
There is a kind of tabes in pine trees, which has 
been called Teredo pinorum. It attacks principally 
their alburnum and inner bark. The causes of this 
disease are, long continuing dry weather, or violent 
frost of long duration, especially after preceding 
mild or warm weather, and violent gales of wind. 
Its signs are, an unusual colour of the acerous 
leaves, as they are more of a reddish yellow hue. 
A. great number of small drops of resin in the mid- 
dle of the boughs, and a putrid, turpentine-like 
odour spreading in their neghbourhood ; lastly, the 
bark scaling off, and the alburnum presenting a 
blackish blue appearance. At the same time the 
tree is full of insects. This is an incurable disease, 
and in large forests nothing more can be done than 
strictly to prohibit, that the leaves or the moss round 
the 
