Patho-physiologic studies on the damping-off of cultivated plants

The seed-borne fungi of cabbage, swede, turnip, rape, turnip rape, radish and black radish and their importance in seedling raising have been examined in this study. The seed lots used in the study were on sale at seed merchants in Finland during the period 1968 —1976. Alternaria brassicicola (Schw.) Wiltshire was the most common pathogen, being more common on cabbage than on any of the other plant species. 91 % of the white cabbage and red cabbage seed lots were infected. The mean A. brassicicola contents of the infected seed lots were 29.5 % and 30.6 %. Plenodomus lingam (Tode ex Fr.) Höhnel occurred in 10 % of the white cabbage and 27 % of the red cabbage seed lots, the fungus content varying from 0.5 % to 14 %. The fungus was also found on cauliflower, swede and radish. Alternaria brassicae (Berk.) Sacc. was found in 4 % of the cabbage and in 31 % of the rape seed lots at fungus contents of 0.5—6.5 %. Alternaria raphani Groves & Skolko was found in 30 % of the radish and black radish seed lots at fungus contents of 0.5—8 %. The following fungi were also found on the seeds of Cruciferous plants: Pleospora herbarum (Pers.) Rabenh., Whetzelinia sclerotiorum (Lib) Korf & Dumont, Botrytis cinerea Pers., Ulocladium concortiale (Thum.) Simmons, Fusarium spp. and Rhizoctonia solani Kühn as well as 18 fungus genera and species either saprophytic or pathogenic to other plants. When the Alternaria brassicicola content of the seeds was 20 % it caused 10 % damping-off damage on the sand substrate. A similar level of damage occurred on the peat substrate when the fungus content reached 70 %. In addition to causing damping off and damaging the seedlings, the fungus also slowed-down seedling growth without apparently damaging them. When the seedlings were grown at a lower temperature the amount of damage caused by A. brassicicola was much less than that which occurred when a higher temperature was used. Plenodomus lingam caused as much damping-off as there were seeds infected with the fungi. Other seed-borne fungi had no importance in seedling raising. Sphagnum fuscum peat, which is used in Finland as a growth substrate, reduced the amount of damping-off caused by seed-borne fungi in comparison to disinfected substrates and prevented the spread of A. brassicicola and P. lingam from diseased to healthy seeds. Dressing the seeds with thiram proved to be very effective against A. brassicicola.

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Additional notes to the checklist of Cuban cultivated plants (2)

Feddes Repertorium ◽

10.1002/fedr.4921030124 ◽

1992 ◽

Vol 103 (1-2) ◽

pp. 143-150

Author(s):

K. Hammer ◽

H. Knüpffer ◽

M. Esquivel ◽

V. Fuentes ◽

J. Menéndez

Keyword(s):

Cultivated Plants

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Ukrainian Chernozem Fertility Reproduction under Soil Conservation Agriculture

Agrobìologìâ ◽

10.33245/2310-9270-2020-157-1-67-79 ◽

2020 ◽

pp. 67-79

Author(s):

Yu. Kravchenko

Keyword(s):

Soil Conservation ◽

Agricultural Land ◽

Crop Yields ◽

Conservation Agriculture ◽

Instructional Materials ◽

Cultivated Plants ◽

Forest Steppe ◽

Typical Chernozem ◽

Degradation Processes ◽

Biological Potential

In Ukraine 57.5 % of agricultural land is subjected to erosion with 10–24 million tons of humus, 0.3–0.96 million tons of nitrogen, 0.7–0.9 million tons of phosphorus and 6–12 million tons of potassium lost annually. Degradation processes are also common on chernozems, which cover about 60 % of the Ukrainian territory. The aim of the research is to defi ne the most eff ective soil conservation practices and legislative decisions aimed to conservation/recovering the Ukrainian chernozem fertility. The experimental data of the agrochemical certifi cation of Ukrainian lands, data from scientifi c papers, stock and instructional materials as well as our own fi eld and laboratory studies were used. It has been established that the long-term use of deep subsurface tillage on typical chernozem increases, compared with plowing, the content of 10–0.25 mm of air-dry and water-resistant aggregates, the bulk density, soil water storages, water infi ltration rates, the content of mobile phosphorus and exchangeable potassium, pHH2O, CaCO3 stocks, the contents of humic and fulvic acids, molecular weights of humic acids – by 5.5 and 3.06 %; 0.05 g/cm3; 25.5 mm; 22.6 mm/h; 0.1 and 3 mg/100 g of soil; 0.03 pHH2O; 18 t/ha, 0.02 and 0.04 %, 91195 kDa, respectively. Fertilizers may contribute to the crop yields increase from by 60% in the Polissya, by 40 % – in the Forest Steppe, by 15 % – in the Wet Steppe, by 10 % – in the Dry Steppe and by 40 % – in the Irrigated Steppe areas. In soil-conservation rotations, the crop placement and alternation are advisable to combine with strips or hills sowing, taking into account the local relief features; soil alkalinization, applying anti-erosion structures. Ukrainian agriculture will receive additional 10–12 million tons of forage units or 20–22 % from all fodder in a fi eld agriculture under increasing 8–10 % of arable lands for intercrops. It is advisable to mulch the eroded chernozems of Ukraine depending on their texture composition: 1.3 t/ha of mulch for sandy and loamy soils, 1.9 t/ha – for sandy and 1.1 t/ha – for loamy soils. The implementation of soil conservation agriculture can minimize some soil degradation processes and improve eff ective soil properties required to realize the biological potential of cultivated plants. Key words: chernozem, degradation, fertility, soil conservation technologies, agriculture policy.

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VAVILOV, N. I. Origin and geography of cultivated plants. (Translated by Doris Löve). Cambridge University Press, Cambridge: 1992. Pp xxxiv, 498; illustrated. Price: UK £ 75.00. ISBN: 0-521-40427-4.

Archives of Natural History ◽

10.3366/anh.1994.21.1.142a ◽

1994 ◽

Vol 21 (1) ◽

pp. 142-142

Author(s):

F. VRUGTMAN

Keyword(s):

Cultivated Plants ◽

Cambridge University

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Daniel Chambers Macreight FRCP, FLS (1799–1856), a little-known, innovative Irish botanist

Archives of Natural History ◽

10.3366/e0260954108000594 ◽

2009 ◽

Vol 36 (1) ◽

pp. 26-36

Author(s):

E. CHARLES NELSON

Keyword(s):

Cultivated Plants ◽

Channel Islands ◽

Biographical Information

Biographical information is provided for Daniel Chambers Macreight. He worked in Augustin-Pyramus de Candolle's herbarium at Geneva during the early 1830s, and later in the decade was prominent in medico-botanical circles in London. Macreight retired in 1840, due to ill-health, and moved to Jersey in the Channel Islands where he died. In 1837, he published an innovative Manual of the British flora which covered both native and cultivated plants. This flora contained two novel features: dichotomous keys were provided to assist students to identify plants, and the category subspecies was employed for taxa within the genera Rosa, Rubus and Salix.

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Damping-off of sugar beet in Finland: II. Disease control

Agricultural and Food Science ◽

10.23986/afsci.72140 ◽

1983 ◽

Vol 55 (5) ◽

pp. 431-450

Author(s):

Mauritz Vestberg ◽

Risto Tahvonen ◽

Kyösti Raininko

Keyword(s):

Sugar Beet ◽

Disease Control ◽

Field Experiments ◽

Damping Off ◽

Good Protection ◽

Great Damage

In pot and field experiments carried out in 1979-1981, the systemic funqicide hymexazol prevented satisfactorily soil borne damping-off of sugar beet caused mainly by the fungus Pythium debaryanum auct. non Hesse. The results with the combination hymexazol + thiram were still better. This treatment gave very good protection against the disease up to about two to three weeks after emergence, increased the yield on the average by 5-10 % and produced considerably thicker and denser stands. Thereafter a large number of beets may have become infected, but no great damage was caused as only few died. Band spraying at emergence using hymexazol with a large amount of water as well as spraying into the seed furrow prevented the outbreak of the disease almost completely. Liming had little effect on damping-off.

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