MEANS OF PREVENTION AND CONTROL BACTERIAL AND FUNGOID DISEASES OF VARIOUS CROPS two other plants of the same genus in the Toulouse Botanical Gardens. This fungus is very near Peronospora Dipsaci Tul., which occurs on teazel (Dipsacus fullonum L.), but is quite distinct from it. 612 The Wetting Power of Fungicides (1). — FONZES-DIACON, H.: in Progrès agricole M. Fonzes-Dia con suggests a simple method by which vine growers may ascertain whether the cupric sprays used for the control of pernospora really possess "wetting power", which, according to M. Ravaz' definition, means that instead of running off the green parts they spread on them, thus covering them with an even coating of mixture, and at the same time reaching the interior of the most compact clusters of blossoms; these latter are hardly touched by ordinary "non-wetting" fungicides. For this it is only necessary to prepare the cupric mixture by dissolving the powder to be used in a quart of ordinary water; after stirring it, a vine leaf should be dipped into the mixture. If the latter has the wetting property, the leaf, on withdrawal, is found to be covered with a uniform uninterrupted film, both surfaces being alike wetted, which would not have been the case had the leaf been dipped into water or an ordinary "non-wetting" cupric mixture. Further, when the leaf has become completely dry in the air, it will be observed that the mixture has left a continuous coating of copper compounds on all the surfaces with which it has been in contact. Experiments made with bunches of grapes, at any stage of development, should give the same results. When the vine is not in leaf, the "wetting" property of the mixture can be tested on cherry-laurel or ivy leaves. MM. Vermorel and Dantony, on the other hand, contend that the property of the mixture can only be tested by applying it to the vegetative organs for which it is destined, and observing if these are covered with a uniform coating. To test the "wetting" property of a mixture still better, a little methylene blue may be added; then, if the leaf is immersed and dried, and subsequently placed in a letter copying-press, a clear and faithful impression is left of the vine-leaf, showing that the treatment has been wholly sucessful. 613 - Rotting of Tomatoes caused by Phytobacter lycopersicum sp. nov. GROENVEGE, F.: in Centralblatt für Bakteriologie, Parasitenkunde und Infektionskrankheiten, Part 2, Vol. 37, No. 1-3, pp. 16-31, I plate. Jena, March 8, 1913. In the course of the summer of 1911, the Phytopathological Institute of Wageningen (Holland) received several times tomatoes attacked by a rot, which showed itself in the form of brown patches, usually corresponding to the point of insertion of the style, but sometimes occurring also on other (1) See also No. 1236, B. Aug. 1912. (Ed.). parts of the fruit. The rot extended all round the portion first attacked and also affected the underlying tissues, in which microscopic examination revealed the presence of bacteria only. In the Netherlands, the disease was observed in 1904 for the first time; it was afterwards recorded in the annual reports of the Wageningen Phytopathological Station for 1906 and 1910. But at a still earlier date this disease was recorded as occurring in the North of France (1895) by Prillieux, who considered it of bacterial origin, in North America (1896) by Earle, and in England and Denmark by Rostrup. The writer was able to make practical reaserches in the West of Holland into the appearance, development and spread of the disease. Though not of a serious nature, it nevertheless was of frequent occurrence in the fields. He considers that there is a connection between the appearance of this disease and the prolonged cultivation of the tomato, which practice gives rise to a partial soil sickness (not to be wholly remedied by the use of fertilizers) and consequently to a decrease in the resistance of the plants to the disease. In a greenhouse in the neighbourhood of Wageningen, where tomatoes had been grown for a long time, the rot did much injury. On replacing the old soil to a depth of 10 or 12 inches by fresh earth, the tomatoes subsequently grown succeeded well. This shows, according to the writer, that the parasite generally occurs in the soil and that the presence of the tomato plants is favourable to its development. The latter is also assisted by the practice of leaving the diseased fruits on the ground. It is therefore recessary to collect and carefully destroy all tomatoes attacked by the disease and not to use them for manure. If the soil is renewed at sufficiently short intervals, the percentage of fruit attacked is considerably reduced. When possible, it is well to turn over the soil in such a manner as to substitute a completely fresh layer for the former surface soil. Another factor predisposing the plants to the disease is dampness; greenhouses used for tomato cultivation should therefore be suitably ventilated. Usually the fruits which are mearest the ground are the first attacked, and the disease is limited to them, which proves, in the writer's opinion, that the infection comes from the soil. Mr. Groenewege was able to isolate, from material sent to him from different parts of Holland, a bacterium, which he describes minutely under the name of Phytobacter lycopersicum sp. nov. Infection experiments showed this bacterium to be a wound parasite. Nevertheless, the writer is not in a position to assert whether this microorganism is the first cause of the disease, or whether, as Earle supposes, it finds way into the fruit through punctures made by small insects. He remarks that this opinion of Earle's is, at present, a mere hypothesis. 614 A Case of Specialized Parasitism in the Uredineae: Gymnosporangium tremelloides parasitic on the hybrid Sorbus confusa Gremli. GUINIER, PH.: in Comptes rendus hebdomaires des Séances de la Société de Biologie, Vol. LXXIV (1913), No. 11, pp. 648-649. Paris, March 21, 1913. In the neighbourhood of Annecy (Haute-Savoie), the following trees are found growing together in the same coppice: Juniperus communis L., Sorbus Aria Crantz, S. torminalis Crantz, as well as a large number of their hybrid S. confusa Gremli. In 1911-1912, the writer observed that S. Aria was severely attacked by Gymnosporangium tremelloides R. Hart., S. torminalis was completely immune; the hybrid, on the contrary, shared almost equally the immunity of S. torminalis and the susceptibility of S. Aria, as far as this fungus was concerned. S. confusa offered sufficient resistance to the parasite to limit its extension and, as at rule, to prevent the normal formation of aecidia, but not enough to arrest its development. Its resistance, however, varies as regards the individual fungi, which develop simultaneously on the same leaf. The fact that only some of these produce aecidia seams to point to the existence of races more, or less, capable of overcoming the relative immunity of S. confusa; in the opinion of the writer, we have here the beginnings of a specialised form. M. Guinier intends continuing his observations in this direction. PARASITIC AND OTHER INJURIOUS FLOWERING PLANTS PARASITIC AND OTHER INJURIOUS FLOWERING PLANTS. 615 - Hyoscyamus agrestis Kit. in Poppy Crops. MALZEFF, A. J.: in Anna len der Samenprüfungsanstalt am Kaiserlichen Botanischen Garten zu St. Petersburg, Vol. I, Part 7, 9 pp. St. Petersburg, 1912. M. Malzeff has identified seeds of Hyoscyamus agrestis Kit. (1) collected in Podolia, Volimia, Kherson, Jekaterinoslav, Kharkov, Vcroneshk and Kursk. It has been observed, both by himself and others, that H. agrestis infests the poppy crops of South and South-West Russia, as well as the fields of millet and flax in the Province of Voroneshk. GENERALITIES 616 INSECT PESTS. Injurious and Beneficial Insects of California. ESSIG, E. O.: The Monthly Bulletin of the State Commission of Horticulture, Vol. II, No. 1 2, pp. XXXI+ 351, 321 figs. Sacramento, California, January-February 1913. A concise and practical description, for the use of Inspectors of Fruit Culture and of Horticulture, of the insects and other invertebrates of known economical importance existing in California. The writer gives (1) According to the Index Kewensis, Hyoscyamus agrestis Kit. is a synonym of H niger L. (Ed.). a brief account of the general appearance of each species, its life-history, distribution, host plants, and the natural and artificial methods of its control. Hints follow on catching the insects, the use of collections, and the different remedies used. A list is given of the legislative enactments and administrative measures in force in California respecting the animal parasites of plants. 617 - Cocobacillus Erausquinii sp. nov. Parasitic on Romalea miles in 618 Parasites of Insects attacking Sugar Cane. PERKINS, R. C. L.: Reports of the Work of the Experiment Station of the Hawaiian Sugar Planters' Association, Entomological Series, Bulletin No. 10, 27 pp. Honolulu, Hawaii, 1912. This is a systematic description of different Chalcids, which are nearly all reared from the eggs of insects, parasitic on the sugar cane in America, Fiji, China and the Malay archipelago. The genera Neotetrasticus, Jassidophthora and Eomymar are new to science, as are also several species belonging to the genera Oetetrastichus, Closterocerus, Westwoodella, Pentarthron, Gonatocerus and Polynema. 619 The Caterpillars of Thaumetopoea (Cnethocampa) herculeana Injurious to Low-Growing Plants in the Neighbourhood of Tunis. COMTE, A. Chenilles nuisibles aux plantes basses. Revue Agricole et Viticole de l'Afrique du Nord (Algérie-Tunisie-Maroc), Vol. II, No. 44, pp. 33-34, I fig. Algiers, 1913. The writer records the presence, in the neighbourhood of Tunis, of an enormous rumber of the caterpillars of Thaumetopoea (Cnethocampa) herculeana. These, before pupating, migrate and devour every kind of lowgrowing plant, whether wild or cultivated: cereals, lucerne, clovers, thistles, mustards, lettuces, spurges, docks, etc. The writer recommends for the control of this pest, the burning of the nests of the caterpillars as soon as they are discovered, and the destruction, during winter, of weeds growing near crops. 620 · Phytalus smithi and other Insects injurious to Sugar Cane in Mauritius (2). D'EMMEREZ DE CHARMOY, D. Rapport sur Phytalus smithi (Arrow) et autres Scarabées s'attaquant à la Canne à sucre à l'ile Maurice, 35 pp., 8 plates, I map. Port Louis, 1912. In the first part of his report, the writer gives a detailed description of the development and habits of Phytalus smithi Arrow. This insect, (1) See No. 750, B. April 1912. (2) See No. 1587, B Nov. 1912, (Ed.). (Ed). MEANS OF PREVENTION AND CONTROL INSECTS INJURIOUS TO VARIOUS CROPS having been energetically controlled in 1911, thanks to the intervention of the Government, did not reappear in Mauritius the next year; nevertheless it is necessary to continue to keep a careful and systematic lookout in the district where it occurred. Amongst the natural enemies of Phytalus are a minute mite (Gamasus sp.), and some micro-organisms which have so far not been determined. Further researches are necessary as to their efficiency in the control of the pest. Amongst irsecticides should be mentioned especially petroleum emulsion with creolin or with carbolic acid. A list and description follows of the other Scarabeids which, like Phytalus, live at the expense of the sugar-cane roots. These are: Adoretus versutus, A. compressus, Serica sp., Oryctes tarandus, O. insularis, Oryctes sp., Gymnogaster buphthalma, Agrypnus fuscipes, Eutochia fullo, Opatrum crenatum, Cratopus punctum, Trocharocephalus strangulatus. In conclusion, the writer enumerates other insects attacking sugar cane in Mauritius: a) Lepidoptera - Cyllo leda, Leucania unipuncta, L. loreyi, Sesamia nonagriodes, Spodopteris mauritia, Diatraea striatalis, Grapholita schistaceana, Alucita sacchari; b) Hemiptera - Aphis sacchari, Tetraneura lucifuga, Dactylopius calceolariae, Sphaerococcus bambusae, Chionaspis tegalensis. 621 Icerya purchasi damaging Tangerines and Lemons in Sicily. DE STEFANI, PEREZ TEODOSIO: in Bollettino del Regio Orto botanico e Giardino coloniale di Palermo, Year XI, Part 1-2-3 (Jan.-Sept. 1912), pp. 81-82. Palermo, 1913. The orange scale, already known from the citrus groves about Messina and Catania, has recently been observed at Bagheria. Some tangerines are already dead, and a good many young lemons are in process of dying. 622 Notes on the Chief Insects affecting Forest Trees in Great Britain. — JEMMETT, C. W. South-Eastern Agricultural College, Wye (Department of Zoology and Entomology), 44 pp. figs. Ashford and London. A description, accompanied by plates, of the chief insects (Lepidoptera, Coleoptera, Hymenoptera, and Hemiptera) which are injurious to forest trees in Great Britain and of the best methods for their control. In the appendix, the means of preventing the damage done by these insects are briefly described. 623 - Chalcidids Injurious to Forest Tree Seeds. ROHWER, S. A.: in U. S. Department of Agriculture, Bureau of Entomology, Technical Series, No. 20, Part VI, pp. 157-163. Washington, 1913. The Chalcidids hitherto known to be injurious to the seeds of forest trees (Sorbus spp., Abies spp., Tsuga spp., Pseudotsuga sp.) are as follows: Syntomaspis druparum, Megastimus sp., M. brevicaudis, M. strobilobius, M. pinus, M. spermotrophus. The complete life-cycle is known only for the first-named, which is also destructive to the pips of apples. ALFREDO RUGGERI, gerente responsabile. |