AN ENCYCLOPEDIA OF HORTICULTURE. 



139 



Fittus 



circulation of air and light, such as prevails in badly- 

 tended shrubberies, will destroy or weaken shrubs and 

 trees, and that plants brought into an unhealthy condition 

 by any of these causes are rendered far more liable to 

 suffer harm from parasites. The larger Fungi, such as 



FIG. 168. RHIZOMORPHA FRAGILIS var. SUBCORTICALIS. Mycelium 

 of Agaricus melleus, in the form it assumes when growing 

 between the bark and the wood a, Form intermediate be- 

 tween fragilis and subcorticalis expanding into the latter on 

 the left ; 6, Portion where growth is slower ; c, Lobed Margin ; 

 d, d, Margin that has reached cut surface of Stump : , Wood 

 of Stump of Fir-tree. 



Polyporus, very often gain access to the stem or root 

 through wounds left by the fall of branches or by careless 

 pruning. Boot parasites spread through the soil from 

 diseased to healthy roots. Most of them can live for a 

 considerable time on the dead roots ; hence, young trees 



Fro. 169. AGARICUS MEI.LEUS. Pine-root attacked by Mycelium 

 (a) in the form known as JRhizomorpka fragilie. 



should not be planted at once in the place of diseased 

 ones that have been uprooted, however carefully the roots 

 have been removed ; and it is better, in any event, to let 

 some time elapse, when trees are cut down, before planting 

 others in their place. 



Remedies. Whatever can promote healthy growth, espe- 

 cially the removal of the unfavourable conditions noted 

 above, must be regarded as of the greatest importance 

 as a preventive of disease due to the attacks of parasites. 

 To prevent the spread of the root Fungi, Dr. Hartig 

 recommends that narrow trenches be dug round the in- 

 fected area, thus cutting the roots and preventing the 

 spread of mycelium. Polypori on stems and branches 

 usually denote that the wood is attacked for some distance 

 around the spots, and that the prospect of saving the 

 trees is not great ; though, in the case of choice trees, it 

 may be worth while to scoop away the di. eased part, and 

 to 11 up the cavity in such a way as to prevent water 

 lodging in it. Dead or dying trees should not be left 

 standing to spread disease. Dead branches should be 

 removed, and ragged stumps should be trimmed, and 

 coated with some compound to prevent water and Fungus 

 spores from getting into them. Branches attacked by 

 Peridermium Pini should be cut off and burned, and 

 Senecios should be uprooted from the neighbourhood of 

 Fir-trees, even though the connection of P. Pini with 

 Coleosporium Senecionis still demands investigation. 



Pinus continued. 



Hysterium Pinastri can, probably, best be combated by 

 the destruction of the Fungus in the needles ; and, with 

 this view, all fallen branches, bearing leaves and debris 

 from trees attacked by this Fungus, should be col- 

 lected, as far as possible, and burned. 



In crowded shrubberies and woods, and in shady situa- 

 tions, the needles of Conifers are apt to be overgrown 

 with Fungi of the group of Fumago, with an alga, Pleura- 

 coccus vulgaris, &c., which form a dark coat, like soot, 

 on the needles. This coat prevents the latter doing their 

 work for the welfare of the plant, and is thus hurtful, 

 even though the plants forming it do not directly absorb 

 food from the needles. The most effectual remedy is 

 thinning out the shrubberies, and allowing better access 

 of light and air. 



INSECTS. Pines, Scotch Firs, and other Conifers are 

 very subject, in forests, to the attacks of various kinds 

 of insects ; and they are liable to injury from the same 

 insects, though in a less degree, in pleasure-grounds and 

 gardens. The roots are sometimes injured by the 

 operations of Cockchafers and Mole Crickets ; and some 

 of the Bark Beetles live in them in the same way 

 as they live in the stems. The wood of the stems is 

 bored into, and seriously damaged, by the larvae of 

 certain species, of which may be mentioned Sirex, as fre- 

 quently present, the Goat Moth occasionally, and the 

 Pine Weevils. Sickly trees often have their death 

 hastened by the ravages of various species of small 

 beetles (see Fine Bark Beetles) chiefly belonging to the 

 family Scoly tides ; and the young branches, and the trees 

 themselves while young, are often killed by these beetles, 

 and by the larvae of certain small moths, all of which 

 bore into the branches and young stems, nearly or 

 quite to the pith, and tunnel up them towards the tips, 

 causing them to wither and fall. See Retinia. Several 

 beetles are very hurtful in the mature state, by gnawing 

 the bark off young twigs and young stems, or by 

 puncturing the bark (Pissodes Pini and P. notatus). 

 They thus cause an outflow of resin from each puncture. 

 The larvae of certain moths of the genus Retinia also 

 cause an outflow of resin, which by R. resinana is made 

 into a shelter that looks remarkably like a gall). The 

 buds also are injured by these insects. The thinner 

 branches of Scotch Firs are often swollen to twice their 

 natural thickness by Gall Mites of the genus Phytoptus 

 (see Mites), the effect of which is, frequently, the death 

 of the branches. These galls should be cut off and 

 destroyed, to prevent the disease spreading. The needles 

 or leaves are eaten by numerous insects, of which the 

 more injurious are Sawflies (see Fine Sawflies) and 

 Moths. Of the latter, we may specify the Pine Beauty, 



FIG. 170. PINE BEAUTY MOTH (Trachea piniperda). 



Trachea piniperda (see Fig. 170), a heavy-bodied insect, 

 with variegated wings of a reddish- brown colour, mottled 

 with orange, yellow, white, and sometimes green ; the 

 Bordered White (Fidonia piniaria), a Geometer in 

 which the male is white and black above, with 

 feathered antennae, and the female is dull orange-brown, 

 with slender antennas; and the Carpet Moths (Thera 

 firmata, &c.), similar in form to the last, but with the 

 sexes alike, the antennae slender, and the fore-wings 

 brown or chestnut, with a broad, darker cross-bar. 

 Several small species of the Tortricina live, as larvae, 

 between needles of Coniferce, spun loosely together, and 



