Abstract |
The influence of abiotic factors on the spreading and development of F. oxysporum f. sp. callistephi in agrobiocenosis
of C. chinensis (L.) Nees. under conditions of urban ecosystems of the Forest-steppe of Ukraine has been determined, namely
the optimal conditions of spreading and development are: average daily air temperature 16,4 ºC, ATS - 2838 ºC, ETS (> 5
0C) – 2108,8 ºC, precipitation amount – 239.8 mm, ARH – 65 %, HTC – 1,3. The spread of Fusarium root rot in phenophase:
germination - sprouts-forming system under the following conditions: daily average temperature of 13,9 ºC, ATS – 142,0
ºC, ETS (> 5 ºC) – 92,2 ºC, precipitation – 12,8 mm, HTC – 1,39, from t> 5 ºC – 6,7, t> 10 ºC – 11,7, t> 15 ºC – 22,7, t>
20 ºC – 27,1, t> 25 ºC – 22,8 days, dry period – 59,8 days; Fusarium wilt in phenophase: budding, flowering – the average
daily temperature of 21,7 ºC, ATS – 1369,7 ºC, ETS (> 5 ºC) – 1063,3 ºC, precipitation amount – 107,1 mm and the HTC –
1,3, within t> 15 ºC – 3,3, t> 20 ºC – 19,5, t> 25 ºC – 38,6 days, dry period – 43,6 days.
The first signs of the pathologies display caused by Fusarium species infestation were found during the second decade of
April - the third decade of May, with the following average hydrothermal figures: daily average temperature of 13,8 ºC, ATS
– 142,05 ºC, ETS (> 5 ºC) – 91,98 ºC, precipitation amount – 12,7 mm, ARH – 63,4 %, HTC – 1,4. The massive growth was
observed from the first decade of July to early August under the following conditions: daily average temperature of 23,7 ºC,
ATS – 249,4 ºC, ETS (> 5 ºC) – 198,9 ºC, precipitation amount – 5,9 mm, ARH – 62,87 %, HTS – 0,31.
The spread of Fusarium within 20 % occurred under the conditions of climate top: daily average temperature – 17,2 ºC;
SAT – 2947,9 ºC; ETS (> 5 ºC) – 2193,25 ºC; precipitation amount – 298,2 mm; ARH – 66,8 %; HTC – 1,7, period with
t> 5 ºC – 11,5, t> 10 ºC – 30,5, t> 15 ºC – 48,5, with t> 20 ºC – 56, with t> 25 ºC – 57,3 days, dry period – 122,8 days;
distribution in the range of 20 – 50 % - daily average temperature of 20 ºC; ATS – 2666 ºC; ETS (> 5 ºC) – 2016 ºC;
precipitation amount – 278,3 mm; ARH – 65 %; HTC – 2,3, within t> 5 ºC – 29, t> 10 ºC – 22, t> 15 ºC – 34, within t> 20 ºC – 56, t> 25 ºC – 77 days, dry period – 134 days; spreading over 50 % - the daily average temperature of 19,32 ºC;
ATS – 2749,06 ºC; ETS (> 5 ºC) – 2027,3 ºC; precipitation amount – 149,3 mm; ARH – 65,7 %; HTC – 0,69, period of t>
5 ºC – 17, t> 10 ºC – 24,4, t> 15 ºC – 45, t> 20 ºC – 62, 4, t> 25 ºC – 65,4 days, dry period 160,7 days. It is found out
that excessive (HTC > 1,5) or optimal humidification (HTC – 1,0–1,5) in spring and sufficient moisture (HTC – 1,0–1,5) or
low drought (HTC – 0,7–0,9) during the growing season result in weak and average intensity of Fusarium wilt spreading in C.
chinensis (L.) Nees., very high (HTC <1,5) or average (HTC – 0,5–0,6) spring drought and low drought (SCC – 0,7–0,9) – to
strong intensity of Fusarium wilt spreading in C. chinensis (L.) Nees.
The high positive correlation coefficients during the period of plants phenophase: germination - sprouts system forming
between the spreading and the duration of dry period (r = 0,73), duration of daily average temperatures > 25 ºC (r = 0,55)
and high negative - with precipitation (r = - 0,8), HTC (r = - 0,71); during the period of plants phenophase, budding and
flowering within Fusarium spreading and duration of daily average temperatures > 20 ºC (r = 0,55), dry days number (r =
0,60) and high negative - within precipitation amount (r = - 0,66), HTC (r = - 0,64). |