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Soil factors affecting tree growth and root development in a citrus orchard
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: D.J. Nel --- , A. T.P. Bennie --- ,Tree- and root-growth parameters correlated well with a number of soil properties Useful relationships were established between unconfined penetrometer resistance, air capacity (at FWC), tree growth and root development. -
In situ field comparisons of Citrus jambhiri leaf water potential using hygrometric and pressure chamber methods
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: M.J. Savage --- Department of Soil Science and Agrometeorology, A. Cass --- Department of Soil Science and Agrometeorology, H.H. Wiebe --- Biology Department, U.S.A.In an experiment conducted outdoors, using Citrus jambhiri plants, we obtained comparative in situ dew point hygrometer, Psychrometer and pressure chamber water potential measurements. Partial abrasion of the leaf cuticle was effected prior to sealing thermocouple hygrometers against leaf surfaces... -
Die invloed van voedingsoplossingkonsentrasie op groei van growweskilsuurlemoen en Troyer citrange saailinge
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: J. G.K. Coetzee --- Outspan Laboratoriums, Republiek van Suid-Afrika L.C. Holtzhausen --- Departement Tuinboukunde, Republiek van Suid-Afrika R.O. Barnard --- Departement Grondkunde en Plantvoeding, Republiek van Suid-AfrikaIn sitruskwekerye word vegetatiewe groei gestimuleer deur die konsentrasie van voedingstowwe in die groeimedium so hoog moontlik te handhaaf. Dit kan egter te hoë konsentrasie teweegbring. In die ondersoek is gevind dat growwe- skilsuurlemoensaailinge (GS) optimaal groei waar sproeibemes was... -
Gentisic acid concentration in healthy and greening infected fruit albedo and leaves of citrus species and cultivars
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: L.J. van Lelyveld --- , Republic of South Africa S.P. van Vuuren --- , Republic of South Africa G. Visser --- , Republic of South AfricaGentisic acid was shown to be present in citrus leaves and fruit albedo irrespective of tolerance or susceptibility of different cultivars and species to greening disease. There was no linearity between gentisic acid concentration and observed tolerance or susceptibility. An... -
Measurement of water potential in the trunks of citrus trees using screen-caged thermocouple Psychrometers
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: D.M. Oosterhuis --- Department of Agronomy, U.S.A. M.J. Savage --- Department of Soil Science and Agrometeorology, Republic of South Africa H.H. Wiebe --- Biology Department, U.S.A.Screen-caged thermocouple Psychrometers were used to non-destructively measure the water potential (ψ) in the trunks of mature citrus trees (Citrus sinensis L. Osbeck), and the values compared with the ψ of covered, exposed, and shaded leaves of the same tree... -
Effect of paclobutrazol on vegetative growth in citrus nursery trees
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.P. Hadlow --- Department of Horticultural Science, Republic of South Africa P. Allan --- Department of Horticultural Science, Republic of South AfricaTwo foliar sprays of paclobutrazol applied at four different concentrations, viz. 50,100, 200 and 500 mg a.i. l−1 on Citrus volkameriana (Ten. & Parq.) under greenhouse conditions, showed that concentrations of 100 mg l−1and above are suitable for reducing undesirable... -
Rootstock-dependent soil respiration in a citrus orchard
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: N. Keutgen --- Department of Horticultural Science, Republic of South Africa M. Huysamer --- Department of Horticultural Science, Republic of South AfricaSoil respiration is a major contributor to the carbon flux in apple orchards, but very little data exist for citrus. Daytime soil respiration, grass respiration, and grass photosynthesis were recorded in a ‘Nules’ clementine (Citrus reticulata Blanco) orchard on ‘Carrizo’... -
Effects of early winter gibberellic acid and mineral oil applications on flowering of young non-bearing clementine (Citrus reticulata Blanco.) and satsuma (Citrus unshiu Marc.) trees
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: M.J. Mudzunga --- Department of Horticultural Science, South Africa K.I. Theron --- Department of Horticultural Science, South Africa E. Rabe --- Department of Horticultural Science, South AfricaGibberellic acid (GA3) and heavy mineral oil (Bac-oil) treatments, either individually or in combination, applied during the flower initiation period in early winter (April to July) were evaluated as a means to reduce flowering levels in young non-bearing citrus trees... -
Rind texture and juice acid content of Citrus spp. as affected by foliar sprays of mono-potassium phosphate (MKP), urea ammonium phosphate (UAP) and mono-ammonium phosphate (MAP)
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: F.N. Mudau --- Department of Plant Production, Republic of South Africa K.I. Theron --- Department of Horticultural Science, Republic of South Africa E. Rabe --- Department of Horticultural Science, Republic of South AfricaRind coarseness of fruit of Citrus spp. is a general problem in the Citrusdal region of South Africa (Western Cape Province), often limiting the percentage of exportable fruit. Acid content of the juice of Citrus fruit is an important determinant... -
Citrus tristeza virus cross-protection of ‘Palmer’ navel orange in the Eastern Cape Province of South Africa
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: S.P. van Vuuren --- , J.G.J. Maritz --- , N. Combrink --- ,Citrus tristeza virus (CTV) is endemic in southern Africa due to the abundance of the citrus brown aphid, To x -optera citricida Kirk., the main insect vector. Virus-free propagation material in the Southern African Citrus Improvement Scheme is pre-inoculated with... -
Effect of production site, storage duration, and hot water and molybdenum dips on bioactive compounds with antioxidant properties in lemon flavedo during cold storage
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Nhlanhla Mathaba --- School of Agricultural, Earth and Environmental Sciences, South Africa John P Bower --- School of Agricultural, Earth and Environmental Sciences, South Africa Isa Bertling --- School of Agricultural, Earth and Environmental Sciences, South AfricaCertain bioactive compounds, such as vitamin E (α-tocopherol), vitamin C (ascorbic acid), β-carotene, polyphenols (e.g. flavonoids and flavonones, viz. hesperidin and naringin) have antioxidant properties and their presence in the citrus flavedo plays a significant role in mitigating oxidative stress,... -
An allele-specific PCR assay for detection of mutations that confer benzimidazole resistance and zoxamide sensitivity in Phyllosticta citricarpa
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Beatrix Coetzee --- Stellenbosch University, South Africa Elma Carstens --- Citrus Research International (Pty) Ltd, South Africa Gerhardus C Schutte --- Avima (Pty) Ltd, South Africa Elaine Basson --- Citrus Research International (Pty) Ltd, South Africa Mia J Groeneveld --- Stellenbosch University, South Africa Tankiso Mpholo --- Land Reform and Rural Development, South Africa Providence Moyo --- Citrus Research International (Pty) Ltd, South Africa Jessica C Winn --- Stellenbosch University, South Africa Paul H Fourie --- Citrus Research International (Pty) Ltd, South Africa Aletta E Bester van der Merwe --- Stellenbosch University, South AfricaPhyllosticta citricarpa is the causative agent of citrus black spot (CBS), a cosmetic fungal disease that has been reported in most of the citrus-growing regions of the world. The occurrence of CBS in orchards is predominantly controlled by the application... -
Parasitoid guild of the citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) in Tunisian citrus orchards and a new report of Cirrospilus ingenuus Gahan (Hymenoptera: Eulophidae)
Item type: Journal Article • Journal: African Zoology • Authors: Dorra Mansour --- University of Sousse, Regional Research Centre on Horticulture and Organic Agriculture at Chott Meriem, Institut Supérieur Agronomique de Chott-Mariem, Tunisia Mohamed Braham --- University of Sousse, Regional Research Centre on Horticulture and Organic Agriculture at Chott Meriem, Institut Supérieur Agronomique de Chott-Mariem, TunisiaA survey of the parasitoid species of the citrus leafminer (CLM), Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), a cosmopolitan pest of citrus, was carried out in 2019 and 2020 in the major citrus production area of Tunisia. Four different Eulophidae species...