394 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



parts. Wlieii the apple is att.v.kcd late 

 the damage is eoiifiuej to spots which, 

 without preventing ripening, greatly injure 

 its appsarance ami depreciate its market 

 value. 



Galerdcv ok the Elm. Galeni-ca cal- 

 mariensis. — The larva of this insect is as 

 injurious as the perfect insect. The eggs 

 laid on the leaves hatch in May ; tiie larvae, 

 very voracious, reiluee the leaves to skeletons 

 up to till' tiini' thi\v iiymphose, siy up to 

 August, wli.M tli.'v .Irs. ,.11(1 the trunk to 

 bury tlnMiM-h,.. ii, ihr s.il. The paren- 

 chyma of till- lca\i-s liL-iuj; gnawed the veins 

 alone persist, and the leaves, reduced to a 

 .skeleton, soon fall. The tree then towards 

 the end of summer presents quite a winter 

 appearance. If their ravages occur two years 

 in succession they may kill the finest trees 

 on a promenade. 



Gall Mitks, see EniNosrs. 



Gangrene of the Stem of the Potato 

 (disease caused by the Bacillus ciuUvorus 

 which especially attacks plants from cut 

 potato seed). — The diseased stem is greatly 

 altered in its lower part. The disease ex- 

 tends from the surface of the soil to the 

 leaves, the infected plants soon die. 



Glceosi'Orium kuutigenum (bitter rot of 

 the apple). — This disease, prevalent in 

 America and in England, is characterized by 

 brown spots wiiich are produced on the 

 green apples and are covered by black dots, 

 the pycnides of the fungus. The spores do 

 not appear to attack the apples e.xcept at the 

 wounded spots. 



Glceosporiom Juglandis (disease of the 

 leaves of the walnut). — Fungus, which pro- 

 duces on the leaves of the walnut large red- 

 dish-brown or greyish spots on which black 

 pycnides are observed. 



Gl(EOsfoiuum NKRvrsEQUUM (plane (pla- 

 tanus) leaf scorch). — This fungus attacks 

 the veins of the leaves a little after their full 

 growth. Towards the middle of May great 

 witlici'.d s]j(its form on the leaves with veins. 

 'Vhr<,. l,.:u,., soon fall. 



Ci.'i I-,! iiitiUM RIBIS (currant leaf spot). 

 — The (iisi-ase jjroduces withered spots on 

 the leaves and causes them to fall in mid- 

 summer. A number of small spots are pro- 

 duced on the upijer surface of the leaves 

 attacked. These spots are produced by the 

 organs of fructification of the fungus and 

 are still covcreij by the brown epidermis of 

 the leaf, wIimIi l.ursts at a certain moment 



to let tllr S|,,r.s ,.s,;ipc. 



Gl(E(jsimiiulm vknetom (raspberry spot). 

 — This fungus produces grey spots bonlered 

 with red on the stem and leaves of tlie rasp- 

 berry. They so damage the plants tliat the 

 fruits do not ripen. 



Graphoutha Wceberiana (tinea of stone 

 fruit trees) ; Tortrix (Carpocapsa) Weber- 

 IANa. — The caterpillar of tliis niicrolepi- 

 doptera perforates the bark of plum-trees, 

 peach-trees, apricot-trees, and almond-trees, 

 penetrates into the alburnum and there 

 undergoes metamorphosis. It kills the bark 

 by the wounds it produces ; it causes canker 



and a How of gum. It prefers the peach and 

 the plum. 



Gryllotalpa vaLOARIs (mole cricket).— 

 The mole cricket lives abnost entirely on 

 insects and their larviB. To search for this. 

 un<lerground food it cuts all roots that hinder 

 it. It passes the winter in the earth at 

 depths varying with the temperature and 

 moisture, then in the sjjring it re-ascends 

 to within a few centimetres of the surface,, 

 where it excavates numerous runs, which 

 end in a vertical hole, which <;ives access to- 

 the burrow properly so called. The in- 

 vasions of the mole cricket are not spon- 

 taneous ; it takes about twelve years for the 

 number of these insects to increase so far as. 

 to render culture impossible. The existence 

 of e:fli iiisi-t is thriT vi-nr- : I lie female lays. 

 200 .---'N liut ill s,,it.- tit this uT,.at fecundity 

 multipliratinii is rdiupai'ativrh slow. Short 

 of food the lu'ilr .•ni.krts .-at rarji other. 



Gdm. r///,/////r,,s/,s (liaillary of the vine). 

 French terms : A'-.//«vV, f, ',•/,, ■»',■,', Auhei-nnr/f^ 

 MorcKjemfiit, <]<m.rtn<iHe, f)artrose, Mai 

 nern. —Hhi-i disease is due to the parasitism 

 of a bacteria. The damage of the tissues con- 

 .sists in a gumnay degeneration of the wooil. 

 It is believed that the disease enters through 

 the pruning wounds, for this dLsfase gains- 

 ground more especially from top to Ijottom. 

 At the same time as the dis.'ase propagates- 

 itself towards the roots the bark becomes- 

 hollow on the shoots, and big fissures are 

 formed on that year's branches. The dis- 

 ease<l stems languish, wither ; the branches- 

 become stunt 'd, the leaves tall ])rematurely,. 

 and iiuiiirniiis shoots sjirin^ IV. hu the foot of 

 thesto.k.s. Tl,,- Mnrscvriitiially die. 



GUMMosisoK SriiM-; Full I' Trees (cherry 

 leaf spot). — The fungus Cori/iieum Ikyer- 

 inckii is regarded as the chief cause of the 

 gum of stone fruit trees, known under the 

 name of spot of stone fruit trees. 



GVMNOSPORANGID.M Sabin.k (pear leaf 

 cluster cups). — This uredina is heteroic ; it 

 has its spermogonia and aecidium forms on 

 the pear-tree, its uredo and telculn fonus. 

 on the JuiiipiT Sabitins, oxi/fn/nr of 

 Virginia. Wlien the relation which exists 

 between these two forms of the same fungus; 

 was unknown, one was callc<l Itnrsli-lln raii- 

 cdldla, the other (i i/iniimpiirtUKjiiun Sahincv 

 et J'nscuM. The disease appears on the 

 pear-tree in the spring. It forms big 

 yellow spots on tin- surface of the leaves, 

 spots wliirli avc lics]ii'inkled with purple- 

 red s|i..ts, 111,. s|i,.iiii .-t>iiia. At the end of 

 the .\iMr ilh--f s|, ,ts iiiriu white excrescences 

 on til.- lowi-i- siiriai-c of the leaves, a sort of 

 irreuular ,i,m11s, which contain aecidio spores. 

 When thrsr sputs are numerous the growth 

 of the pear is greatly weakened, but the 

 parasite becomes especially dangerous to the 

 crop when it attacks the fruits. It then 

 forms irregular swellings. The fruits .sa 

 hypertrophied are .stopped in growth and 

 are absolutely valueless. The aecidium form 

 lives in the spring-time on the juniper. The 

 destruction of Junipers causes the disease to 

 disappear. 



