31 Mar 2019
Citrus Juice

Modulation in yield and juice quality characteristics of citrus fruit from trees supplied with zinc and potassium foliarly

M. Yasin Ashraf, F. Hussain, J. Akhter
Nuclear Institute for Agriculture and Biology (NIAB), Jhang Road, Faisalabad, Pakistan
M. Ashraf
Department of Botany, University of Agriculture, Faisalabad, Pakistan
Department of Botany and Microbiology, King Saud University, Riyadh, Saudi Arabia
G. Ebert
Agricultural Advisory Department, K+S KALI GmbH, Kassel, Germany

Citrus is the largest fruit crop grown in Pakistan and Kinnow is the major planted species. About 94% of the total citrus is produced in the Punjab province (Sharif et al., 2005). Macro- and micro-nutrient deficiencies have been reported in citrus orchards of Punjab (Rashid et al., 1994). These deficiencies are usually recognized by distinctive symptoms that appear on the leaves and sometimes on fruits, branches or general growth of the tree (Ibrahim et al., 2007).

READ MORE

28 Feb 2019
Citrus Rootstock

The effect of chloride on four different citrus rootstocks

N. J.J. Combrink, N. Labuschagne, R. O. Barnard & J. M. Kotzé
South African Journal of Plant and Soil

Most of the world’s citrus is irrigated (Furr & Ream, 1969) and salt accumulation often results from use of poor quality irrigation water and inadequate soil drainage (Bernstein, 1975; Backlund & Hoppes, 1984). Citrus is generally considered to be a salt sensitive plant (Bernstein, 1969; Furr & Ream, 1969; Kirkpatrick & Bitters, 1969) although a wide range of salt . tolerance exists among citrus rootstocks (Cooper, 1961; Embleton, Labanauskas & Bitters, 1962; Peynado & Roger, 1962). Most rootstocks are adversely affected by salinity levels at which conductivity of the satl.l,rated soil extract (ECe) is about 250 – 300 mS m-I (Bernstein, 1975),. ‘It has been reported that heavy losses in production can occur even in the absence of visible toxicity symptoms such as leaf burn (Harding, Pratt & Jones, 1958; Pearson & Huberty, 1959; Peynado & Roger, 1962; Shalhevet, Yaron & Horowicz, 1974).

READ MORE

28 Feb 2019
Chloride-stressed Citrus

Polyamines in Chloride-stressed Citrus Plants: Alleviation of Stress by Nitrate Supplementation via Irrigation Water

Yoel Bar, Akiva Apelbaum, Uzi Kafkafi, and Raphael Goren
The Kennedy–Leigh Centre for Horticultural Research
The Hebrew University of Jerusalem, Rehovot 76100, Israel

A study was conducted to elucidate the effects of chloride in the irrigation water on growth and development of two citrus rootstocks. ‘Cleopatra’ mandarin (Citrus reshni Hort. ex Tan) is salt tolerant and ‘Troyer’ citrange (Poncirus´Citrus sinensis) is salt sensitive. Increasing chloride from 2 to 48 mM in the irrigation water resulted in increased leaf chloride levels, more severe damage of the leaves, and reduced branch growth. High chloride in the irrigation water also caused increased putrescine (PUT) and decreased spermine (SPM) contents of the leaves.

READ MORE

28 Feb 2019
Boron and Chlorine for Citrus Trees

Boron (B) and Chlorine (Cl) for Citrus Trees

Mongi Zekri and Tom Obreza
IFAS Extension, University of Florida

To maintain a viable citrus industry, Florida growers must consistently and economically produce large, high-quality fruit crops year after year. Efficiently producing maximum yields of high-quality fruit is difficult without understanding soil and nutrient requirements of bearing citrus trees.

READ MORE

25 Jan 2019
Mandarin

Plant nutrition status, yield and quality of satsuma mandarin (Citrus unshiu Marc.) under soil application of Fe-EDDHA and combination with zinc and manganese in calcareous soil

Ying Zhang, Cheng-Xiao Hu∗, Qi-Ling Tan, Cang-Song Zheng, Hui-Ping Gui, Wei-Nan Zeng, Xue-Cheng Sun, Xiao-Hu Zhao
College of Resources and Environment/Micro-element Research Center, Huazhong Agricultural University, Wuhan, Hubei Province 430070, PR China

The purpose of this study was to investigate citrus tissue’s response to varying applications of Fe-EDDHA, zinc (Zn) and manganese (Mn) combinations and the resulting effects on citrus fruit yield and quality in calcareous soil. A field experiment was conducted for three years with satsuma mandarin trees planted in calcareous soil. Four treatments were conducted: (i) control; (ii) soil Fe application; (iii) soil Fe + Zn application; and (iv) soil Fe + Zn + Mn application. Soil available Fe and Zn concentrations were raised through the application of Fe-EDDHA and Zn, whereas the soil available Mn concentration was not increased through the application of Mn. Applying Fe-EDDHA raised the leaf active Fe content significantly without influencing the leaf and fruit Fe concentrations. The Zn concentrations in leaf and fruit decreased when Fe-EDDHA was applied exclusively, but increased when Fe + Zn and Fe + Zn + Mn were applied in the third year. There was no significant difference in leaf and fruit Mn concentrations among all treatments between 2010 and 2012.

READ MORE

25 Nov 2018
Botrytis cinerea

Rind distortion of lemon caused by Botrytis cinerea Pers

R. A. Fullerton, F. M. Harris & I. C. Hallett
(1999) Rind distortion of lemon caused by Botrytis cinerea Pers, New Zealand Journal of Crop and Horticultural Science.

The infection process by Botrytis cinerea Pers on lemon fruits (Citrus Union (L.) Burm.), and development of rind distortion are described. Infections occur on juvenile fruitlets soon after petal fall from hyphae growing over the surface of the fruit from adjacent colonised flower debris. The hyphae form compact infection cushions at their tips. There is a collapse of epidermal cells and several layers of underlying cells in the vicinity of the infection cushion, leading to the formation of small necrotic pits on the surface of the fruit. As the fruitlets grow, there is generalised hyperplasia in a zone up to 20 cell layers deep in the region of the necrotic pits, leading to conspicuous outgrowths on the fruit surface.

READ MORE

25 Nov 2018
Lemons and Limes

South Africa sold 33% more lemons in Europe this year – and we can thank Argentina

Bombi Mavundza
Business Insider SA

Severe weather conditions have had a big impact on Argentina’s lemon and lime production, while ongoing political and economic woes cut into its ability to export.

And that has been great news for South African exporters.

Argentina’s output shortfall created unmet demand in Europe – and that in turn saw a 33% increase in lemon exports to Europe for this production year, according to figures from Exsa Europe, the Dutch-based importer with growers around the world.

READ MORE

23 Nov 2018
Non-compliance regarding FCM

South Africa under pressure to get it right on FCM and CBS

Carolize Jansen
https://www.freshplaza.com

DAFF proposes new recommendations to deal with loopholes and non-compliance regarding FCM

On 24 October, officials from the National Plant Protection Organisation of South Africa (NPPOZA) of the Department of Agriculture, Forestry and Fisheries and the Citrus Growers’ Association gave growers, packhouses, forwarding agents, exporters and traders, an overview of the past season during the annual citrus coordinating meeting. It kicked off with an overview of the season in the European Union.READ MORE