Hormonivalmisteiden vaikutuksesta rikkaruohoihin ja hyötykasveihin

In the research carried out observations have been made as to the effect of plant hormone products upon weeds and several cultured crops. In the tests have been used hormone dusts Agroxone and Bayer 2,4 D, also hormone sprays Bayer 2,4 D, Hormotox II, 2—4 Dow Weed Killer and Weedone. The tests or field experiments have been made in Tuusula, 40 km from Helsinki, on the school farm of Järvenpää and also on the farm of Kyrölä. Part of tests was placed in cereal crop cultures, the other parts on potato and beet crops, grasslands, stubble fields, flax cultures, gardens, small woods and free places. The effect of the above named hormone products was different. The most sensitive weeds in the trials were Brassica campestris, Raphanus raphanistrum and Equisetum arvense. Medium sensitive were a great number of weeds as Erysimum cheiranthoides, Thlaspi arvense, Capsella bursa pastoris, Sonchus arvensis, S. oleraceus, Cirsium arvense, Urtica dioica, Potentilla anserina, Gnaphalium uliginosum, Chenopodium album and Ranunculus repens. More durable weeds than the above mentioned species were Galeopsis speciosa, G. tetrahit, Stellana media, Spergula arvensis, Viola tricolor, Polygonum lapathifolium, P. convolvulus, Lamium purpureum, Rumex acetosa, R. acetosella, Matricaria inodora, Achillea millefolium, Anthriscus silvestris, Aegopodium podagraria, Taraxacum vulgare, Leontodon autumnalis, Senecio vulgaris, Galium spurium, Chamamerium angustifolium, Artemisia vulgaris, Mentha arvensis and Stachys paluster. Perfect or were durable were Agropyrum repens, Linaria vulgaris, Centauren cyanus, Solidago virga-aurea, Myosotis arvensis, Plantago major, Pinnaria officinalis and Polygonum aviculare. Among the cultivated plants were Brassica campestris v. rapa, Br. napus v. napobrassica, Br. oleracea, v. capitata, Raphanus sativus v. radiculata, Beta vulgaris v. crassn (food beet), Beta vulgaris v. altissima (sugar beet), Beta vulgaris v. rapa, Daucus carota, Spinacia oleracea, Lactuca sutiva and Petroselinum hortense very sensitive for the hormone poison application. Considerably suffered also Trifolium spp, Pisum spp, Vida saliva, Phaseolus spp., Linum usitatissimum, Cichorium intybus and Ruhus idaeus and also a few decorative plants (Helianthus annuus and Calendula officinalis). The cereal crops (rye, winter wheat, summer wheat, oats and barley) are not damaged in the trials except for barley and summer wheat. The length-growth of barley weakened about 10 cm and m summer wheat appeared a small malformation of ears. The application with plant hormone products did not damage or damaged only a little Pirus malus, Ribes spp, Fragaria grandiflora, Solanum lycopersicum, S. tuberosum, Nicotiana rustica, Armoracia rusticana, Cucumis sativus, Allium spp. and Rheum rhaponticum. Among trees and bushes proved Alnus incarta very sensitive for the hormone applications. The other deciduous trees and bushes have been only a little damaged in the triale and the coniferous trees not at all. Among the hormone products experimented with in these trials were the sprays diluted according to directions for use more effective than the corresponding amounts of dusts (200—250 kg/hc). Greater quantities of dust (300--400 kg kg/hc), however, were as effective as the diluted sprays. Most effective were the strong sprays but they damaged also most culture plants. On sand soils was the effect of hormone products quicker and more perfect than on clay soils. The effect of hormone application turned to be quicker in the middle of the summer than in the later part of it. The effect of the hormone products was obviously better upon plants in the later stage of development, the test series having been organized in the middle and later part of the summer, the effect of hormone products was apparently worse than it might have been after treatments organized in the early part of the summer.