scholarly journals Effects of Low pH of Hydroponic Nutrient Solution on Plant Growth, Nutrient Uptake, and Root Rot Disease Incidence of Basil (Ocimum basilicum L.)

HortScience ◽  
2020 ◽  
Vol 55 (8) ◽  
pp. 1251-1258
Author(s):  
Daniel P. Gillespie ◽  
Chieri Kubota ◽  
Sally A. Miller

Rootzone pH affects nutrient availability for plants. Hydroponic leafy greens are grown in nutrient solutions with pH 5.5 to 6.5. Lower pH may inhibit plant growth, whereas pathogenic oomycete growth and reproduction may be mitigated. General understanding of pH effects on nutrient availability suggests likely toxicity and deficiency of specific micronutrients. We hypothesized that if adjustments are made to the micronutrient concentrations in solution, plants will grow in lower-than-conventional pH without nutrient disorders, while oomycete disease incidence and severity may be reduced. To develop a new nutrient solution management strategy, we examined pH of 4.0, 4.5, 5.0, and 5.5 with or without micronutrient adjustments for growing two cultivars of basil plants Dolce Fresca and Nufar in a greenhouse hydroponic deep-water culture (DWC) system. Micronutrient adjustments included reduced concentrations of copper, zinc, manganese, and boron by one-half and doubled molybdenum concentration. Plants harvested 20 to 28 days after transplanting did not show significant effects of pH or the micronutrient adjustment. Phosphorus, calcium, magnesium, sulfur, boron, manganese, and zinc concentrations in leaves significantly declined, while potassium and aluminum concentrations increased with decreasing pH. However, these changes and therefore micronutrient adjustments did not affect basil plant growth significantly. ‘Nufar’ basil plants were then grown in a growth chamber DWC system at pH 4.0 or a conventional 5.5 with and without inoculation of Pythium aphanidermatum zoospores. Fourteen days after inoculation, P. aphanidermatum oospore production was confirmed only for the inoculated plants in pH 5.5 solution, where a significant reduction of plant growth was observed. The results of the present study indicate that maintaining nutrient solution pH at 4.0 can effectively suppress the severity of root rot caused by P. aphanidermatum initiated by zoospore inoculation without influencing basil growth.

2020 ◽  
Vol 8 (4) ◽  
pp. 496
Author(s):  
Dilfuza Egamberdieva ◽  
Vyacheslav Shurigin ◽  
Burak Alaylar ◽  
Hua Ma ◽  
Marina E. H. Müller ◽  
...  

The effects of biochar on plant growth vary depending on the applied biochar type, study site environmental conditions, microbial species, and plant–microbial interactions. The objectives of the present study were therefore to assess 1) the response of growth parameters of lupin and root disease incidence to the application of three biochar types in a loamy sandy soil, and 2) the role of endophytic bacteria in biological control of root rot disease incidence in lupin after the amendment of soil with different biochar types. As biochar types we tested (i) hydrochar (HTC) from maize silage, (ii) pyrolysis char from maize (MBC), and (iii) pyrolysis char from wood (WBC) at three different concentrations (1%, 2%, and 3% of char as soil amendments). There were no significant effects in lupin shoot and root growth in soils amended with WBC at any of the concentrations. MBC did not affect plant growth except for root dry weight at 2% MBC. HTC char at 2% concentration, significantly increased the root dry weight of lupin by 54–75%, and shoot dry weight by 21–25%. Lupin plants grown in soil amended with 2% and 3% WBC and MBC chars showed 40–50% and 10–20% disease symptoms, respectively. Plants grown in soil without biochar and with HTC char were healthy, and no disease incidence occurred. Pseudomonas putida L2 and Stenotrophomonas pavanii L8 isolates demonstrated a disease reduction compared to un-inoculated plants under MBC and WBC amended soil that was infested with Fusarium solani.


2003 ◽  
Vol 2 (3) ◽  
pp. 215-219 ◽  
Author(s):  
Prommart Koohakan ◽  
Hideo Ikeda ◽  
Shin-ichi Kusakari ◽  
Takao Masuda ◽  
Kazuto Mano ◽  
...  

HortScience ◽  
1999 ◽  
Vol 34 (2) ◽  
pp. 287-291 ◽  
Author(s):  
B.K. Duffy ◽  
G. Défago

Host nutritional variables were evaluated for their effects on the severity of crown and root rot of tomato caused by Fusarium oxysporum f.sp. radicis-lycopersici. Tomato (Lycopersicon esculentum Mill.) seedlings (cv. Bonnie Best) were grown in a pathogen-infested, soilless rockwool system in the greenhouse and were fertilized with a nutrient solution that was amended with macro- and microelements at various rates. Disease was evaluated after 2 weeks using an index of 0 to 4, and plant fresh weight was measured. Regression analysis indicated that disease severity was significantly increased by ammonium-nitrogen [NH4Cl, (NH4)6Mo7O24, and (NH4)2SO4], NaH2PO4·H2O, Fe-EDDHA, MnSO4, MoO3, and ZnSO4·7H2O. Disease severity was reduced by nitrate-nitrogen [Ca(NO3)2·4H2O] and CuSO4·H2O. Low rates of NH4NO3 (39 to 79 mg·L-1 N) reduced disease, but rates above 100 mg·L-1 N increased it. Disease was not affected by MgSO4·7H2O. In all cases, plant growth was inversely related to disease severity. Mineral fertilizers had no effect on nutrient solution pH. This information sheds new light on environmental factors that influence plant-pathogen interactions, and may be applied to develop a management strategy for Fusarium crown and root rot based on host nutrition.


1970 ◽  
pp. 34
Author(s):  
J. Sherly, R. Renuka

Five wild Solanum species were screened against dry root rot disease in glass house condition with commonly cultivated brinjal as control. The disease was scored at different day’s interval on 30th, 45th and 60th days after planting (DAP). Among the wild species screened and evaluated the species S. torvum was observed without any disease incidence i.e (0). The least per cent of disease incidence was observed in S. incanum (38.60%) which was followed by S. xanthocarpum (42.80%), S. viarum (64.20%) and CO2 (78.50 %) susceptible check at 30 DAP. Secondary metabolites were analysed from both wild and control plants. Based on the per cent disease incidence values S. torvum was graded as ‘Resistant’ against M. phaseolina and can be recommended as a best rootstock for brinjal under varying climatic condition especially where the dry climate prevails.


Author(s):  
Mahfouz M. M. Abd-Elgawad ◽  
Ibrahim E. Elshahawy ◽  
Farid Abd-El-Kareem

Abstract Background Strawberry (Fragaria ananassa Duch.) is an economically important crop in Egypt. Yet complex black root rot disease of strawberry caused by Fusarium solani, Rhizoctonia solani, and Pythium sp. can cause considerable yield losses. Therefore, this study aimed at evaluating different aspects of soil solarization against this disease. Such an evaluation would better be viewed in the context of other beneficial effects of soil solarization on nematodes and weeds. Materials/methods Growth agar disks, growth suspension, and resting stages of strawberry black root rot fungi were evaluated at different temperatures and exposure times using digital hot water bath. Cloth bags artificially infested with single fungal species were buried into the soil before soil solarization at soil depths of 1–10, 11–20, and 21–30 cm at three spots of each plot for each of the abovementioned fungi for 3, 6, or 9 weeks. The disease incidence and severity in solarized and un-solarized soil was compared with the application of the fungicide Actamyl. Effects of soil solarization on nematodes and weeds were also consulted. Results The lethal temperature to F. solani, Pythium sp., and R. solani was 58, 58, and 56 °C, respectively when exposure time was 1 min. Chlamydospores were killed at 62 °C while sclerotia were killed at 58 °C in hot water for 1 min. Maximum soil temperature in solarized soil was raised by 15, 14, and 12 °C at depths of 1–10, 11–20, and 21–30 cm as compared with non-solarized soil. Solarization for 3, 6, and 9 weeks significantly reduced the disease incidence and severity and increased the strawberry yield. Complete reduction in total count of all tested fungi was obtained after 9 weeks at all tested depths. A review of collective soil pest and pathogen control via solarization documented its beneficial application. Conclusion The study may exploit hot months in Egypt for soil solarization against the serious root rot disease either singly or in an integrated pest management program.


2012 ◽  
Vol 40 (2) ◽  
pp. 113-129
Author(s):  
Maisa Abd El-Moneim ◽  
Manal Gad El-Mola ◽  
Samy Gaafer

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