Vol. IX. No. 210. 



TffE AGRICULTURAL NEWS. 



159 



In the Agaricaceae, tlie fructification is of the type 

 usually known as a toadstool. On the under surface of the 

 umbrella-like expansion are long radiating gills, over the 

 surface of which is the hymeniuni. The fructifications 

 may or may not be stalked, and the stalk may be 

 central or lateral, but the gills are. a constant feature. 

 To this group belong Jlarasmius san-hnri, the fungus caus- 

 ing root disease of sugar-cane (Fig. 27); Jfarasmins semim- 

 tiis, causing disease of bar.anas; Si--hizophi//hi>ii romiiiiinc, which 

 .sometimes attacks cane stems; and all the numerous sapro- 

 phytic toadstools. 



In the Polyporaceae, the hymeniuni lines the cavities of 

 long or short densely packed tubes or shallow depressions 

 occurring in a sporo[phore that frequently /projects from trees, 

 like a bracket. Several of the genera, especially Puli/porus are 

 wound parasites on ditterent trees (Fig. 28). The sporophores 

 may .sometimes live for as long as fifty years. 



In the Hydnaeeae, the fructification again projects at 

 right angles to the tree bearing it, and produces from its 

 under side numerous acute spines, or warts, or folds, on 

 which the hymeniuni is borne. Some members of the genus 

 Jfydniiin are parasitic on trees. 



In the Thelephoraceae, the hymenium is smooth and 

 superficial, and the sporophore maj' have a central stalk, or 

 may lie flat on the subtratum. To this group belongs the 

 fungus causing i>ink disease of cacao {Corficiumlilaco-Jiiscum). 

 j\Iost of its members are saprophytes. 



The members of the Hymenomycetes, in general, contain 

 comparatively few species recognized as parasite.s, the majority 

 being saprophytes on decaying wood, or other vegetable 

 remains. 



The cAsTKRO.MVi ETKs. This group contains very few 

 parasitic forms, though numerous saprophytes of beautiful 

 colouring and shape belong to it. 



Two families may be shortly mentioned: — 

 Phalloidaceae. ' ■ 

 Lycoperdaceae. 



In the Phalloidaceae, the hymenium is borne on a recept- 

 acle that frequently takes the form of a fine net-work, or 

 a wrinkled swollen terminal portion hung on a central stalk; 

 the stalk and receptacle are at first enclosed in a definite skin, 

 and the fructification is spherical. Later, however, the skin 

 is broken by the elongation of the stalk, and the net-work, 

 when present, hangs free at its summit. It is covered 

 u.sually with drops of strongly smelling mucilage in which the 

 spore.s are contained. The mucilage attracts flies, which 

 assist in the dispersal of the spores. One species. Phallus 

 gracilis, also known as Ithi/phallus coralloides, and another 

 Clathrus trilo'/atiif, are responsible for root diseases of sugar- 

 cane in Hawaii. 



To the family Lycoperdaceae belong the puff bells, which 

 are closed, more or less spherical, white or yellowLsh fructifi- 

 cations, dehiscing Ijy a terminal pore when ripe, and setting 

 free a mass of dusty spores. In some ca.ses, there is a long 

 central stalk, as in the Phallaceae, surmounted by a cap 

 bearing the spores, the whole being enclosed within a definite 

 .skin until these are ripe. 



In the Aijrii-ultural News, Vol. VII, p. 227, there 

 appeared a paper by Mr. W. P. Ebbels, of Mapore, Mauritius, 

 on the u.se of molasses in increasing the fertility of sugar 

 cane lands. An abstract in the Experiment Station Record, 

 Vol. XXI, No. 2, of the I'nited States Department of Agri- 

 culture, shows that further work has confirmed the results 

 obtained at first. E,\periments in connexion with this matter 

 are being conducted in .-\ntigua. (See Pamphlet Xo. (!4.) 



LEAD CHROMATE AS AN INSECTICIDE. 

 The Agricultural Research Institute, Pusa, has 

 recent)}' published a pamphlet in which the use of 

 lead chromate in the place of arsenical insecticides, is 

 advocated. The contents of this are as follows : — 



There are grave disadvantages in India in the u.se of 

 arsenical poisons as insecticides, and for many reasons we 

 have endeavoured to find a reliable substitute. Formerly, 

 Paris green was used in India, as elsewhere, as a sUndard 

 application; in 1903, lead arseniate was introduced and 

 arrangements made for its manufacture and sale. We have 

 now abandoned lead arseniate in favour of a non-arsenical 

 preparation, one of many hundretls that have been tested at 

 Pusa during the last four years. This is lead chromate, 

 a compound that is poisonous to human beings and cattle, 

 but which has not the very grave disadvantages attaching to 

 arsenic. It is cheaper than lead arseniate, and arrange- 

 ments have been made for its sale at annas 13 (Is. \d.) per ft), 

 in paste or powder, the paste being .sold on its lead chromate 

 content, and not on its bulk weight. For ordinary uses, 

 lead chromate is most easily made by dissolving separately, 

 2 parts by weight of a lead salt, e.g., lead acetate or nitrate, 

 and 1 of potassium bichromate; the solutions are mixed 

 and 2 parts of lead chromate precipitated. In this way, 

 the substance is made in its best form for spraying. The 

 simplest procedure is to dissolve the lead salt in the spraying 

 machine, and to dissolve the bichromate separately in a tin 

 of water, and then to pour it into the spraying machine. 



Lead chromate is a heav}-, yellow substance, easily 

 visible upon the plant, which does not burn the foliage, 

 adheres extremely well in spite of wind and rain, and does 

 not decompose into compounds that burn the plant. It has 

 been used on a great variety of crops in the Pusa farm; 

 leaves sprayed heavily with it have retained it for six weeks 

 in spite of heavy rain, and the leaf has remained healthj'. 

 Plants can be sprayed with it until they are yellow, and no 

 harm is done. The substance is not as poisonous as lead 

 arseniate or Paris green, but is a first rate deterrent to plant- 

 feeding insects; sprayed plants will not be eaten by insects. 



We recommend a strength of 1 lb. in 64 gallons of water, 

 as an insecticide on crops that are being attacked, or 1 lb. in 

 100 gallons of water as a deterrent upon crops which it is 

 essential to protect from attack. 



Applied at these rates, no harm results to fodder crops, 

 which can be safely fed to cattle, and unless the spraying is 

 done very badly and all the lead chromate applied at one 

 spot, no poisoning efteot would follow upon any crop or plant 

 if eaten afterwards. 



For the Knapsack spraying machine, 1 oz of lead 

 acetate may be dissolved in the machine, i-oz. of potassium 

 bichromate, powdered, dissolved and added; or U oz. of paste, 

 or 1 oz. of dry chromate may be thoroughly rubbed up in 

 the machine. 



Careful trials would be required before it could be 

 determined if lead chronia^te is more suited to West 

 Indian conditions, as an insecticide, than Paris green. 



