26 Jun 2019
Agriculture Technologies

Precision Agriculture Technologies in Citrus

Yiannis Ampatzidis

Citrus growers face issues from an increasing number of pests and diseases. Rapid and accurate tools for early pest and disease detection are needed to improve precision and timely management.

Almost all agrochemicals (e.g., pesticides) applied in specialty crop production are made uniformly with conventional spraying equipment, despite the fact that pathogen distribution is typically patchy. Uniform applications result in the use of agrochemicals where no diseases, weeds or pests occur. This unnecessary use of agrochemicals leads to increased costs, risk of crop damage, environmental pollution and contamination of the edible products.


22 Jun 2019
Asian citrus psyllid

Being Vigilant: HLB and South Africa

Hein Gerber and Christine Spreeth
First Fruits Consulting

Citrus greening disease takes two forms: Huanglongbing (HLB), the devastating Asiatic strain of citrus greening disease caused by the bacterium Candidatus leberibacter asiaticus and African greening disease, caused by the bacterium Candidatus lebiribacter africanus. Both forms can be spread by infected plant material or by citrus psyllid vectors, namely Diaphorina citri (Asiatic greening) and Trioza erytreae (African greening) (Gottwald et al., 2007). When a vector is carrying the bacteria, it is called a ‘hot vector’ (Jansen, 2019). The psyllid vectors transfer the disease-causing pathogens when they feed on plant sap from citrus leaves (Grafton-Cardwell et al., 2006).


12 Jun 2019
GDP Growth

SA’s economy is shrinking at an alarming rate – and only oranges and interest rates are offering hope.

Helena Wasserman
Business Insider SA

SA’s economy shrank by an appalling 3.2% in the first quarter of this year compared to the last quarter – the worst performance in a decade.

Weak levels of investment and more than 270 hours of loadshedding wreaked havoc across the economy, while a gold mining strike and a weak grape harvest added to the pain.

The latest numbers from the Statistics SA show that the economy was exactly the same size in the first quarter of 2019 than it had been in the same quarter of 2018.


22 May 2019
Citrus Picking

Agri growth helps SA out of recession

Sabrina Dean
Farmers Weekly

Positive performance in the agriculture sector in the third quarter (Q3) of 2018 has helped lift South Africa’s economy out of a technical recession.Stats SA said in its Q3 GDP release that South Africa’s economy grew 2,2% quarter-on-quarter (q/q), bringing to an end the country’s second recession since 1994.A number of sectors apart from agriculture had contributed to the growth; these included manufacturing (the main driver with growth of 7,5%), transport and finance and business services.


21 May 2019
Biostimulant activity

Biostimulant activity of phosphite in horticulture

Fernando C. Gómez-Merinoa
Colegio de Postgraduados Campus Córdoba, Veracruz
Libia I. Trejo-Téllezb
Colegio de Postgraduados Campus Montecillo, Mexico

Phosphite (Phi), a reduced form of phosphate (Pi), is emerging as a novel biostimulator in horticulture. Though there is still no consensus on its physiological function as a P-source for plant nutrition, experimental evidence has shown that Phi can act as a biocide and affect plant production and productivity. Positive effects of Phi on plant metabolism are more evident when applied to the roots in hydroponic systems or to the leaves in the form of foliar sprays in the presence of sufficient Pi. Published research conclusively indicates that Phi functions as an effective pesticide against various species of pathogenic bacteria and Oomycetes. Nonetheless, the use of Phi as a sole P-source for plant nutrition is still at issue.


30 Apr 2019
Aluminum toxicity

Aluminum Toxicity and Tolerance in Plants

Emmanuel Delhaize and Peter R. Ryan
Division of Plant Industry, Commonwealth Scientific and Industrial Research Organization, Australia

The most easily recognized symptom of Al toxicity is the inhibition of root growth, and this has become a widely accepted measure of A1 stress in plants. In simple nutrient solutions micromolar concentrations of Al can begin to inhibit root growth within 60 min. However, the inhibition of growth per se offers little information about the causes of stress that will either precede or coincide with changes in growth. To understand the mechanisms of Al toxicity, it is essential to identify the primary sites involved, both anatomical and metabolic, being mindful that A1 could have diverse effects and act differently in different species.


30 Apr 2019
Aluminum toxicity

How do Citrus Crops Cope with Aluminum Toxicity

KKIU Arunakumara
Department of Crop Science, Faculty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya, Sri Lanka
Buddhi Charana Walpola1,  Min-Ho Yoon
Department of Bio-Environmental Chemistry, College of Agriculture and Life Sciences, Chungnam National University, Daejeon, 305-764, Korea

World Agriculture faces daunting challenges in feeding the growing population today. Reduction in arable land extent due to numerous reasons threatens achievement of food and nutritional security. Under this back ground, agricultural use of acidic soils, which account for approximately 40 % of the world arable lands is of utmost important. However, due to aluminum (Al) toxicity and low available phosphorous (P) content, crop production in cidic soils is restricted. Citrus, in this context, gains worldwide recognition as a crop adapted to harsh environments. The present paper reviewed Al toxicity and possible toxicity alleviation tactics in citrus.


30 Apr 2019
Aluminium in Acid Soils

Aluminium in Acid Soils

Dragana Krstic, Dragoslav Nikezic
University of Kragujevac, Faculty of Science
Ivica Djalovic
Institute of Field and Vegetable Crops
Dragana Bjelic
University of Kragujevac, Faculty of Agronomy

Soil acidity is a limiting factor affecting the growth and yield of many crops all over the world. The basic problems concerning chemical properties of more acid soils are, besides acidity itself, the presence of toxic compounds and elements, such as soluble forms of Al, Fe and Mn, nitrites and various toxic organic acids. Aluminium (Al) toxicity is one of the major constraints on crop productivity on acid soils, which occur on up to 40% of the arable lands of the world.


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).


31 Mar 2019
SA Flag

SA’s agri exports


Agricultural exports represented 10.8% of total South African exports in 2017, and came to R127.69-billion. The report counts South Africa among the top exporters of a number of products.

South Africa is the second largest exporter of citrus fruit (fresh or dried) in the world, even though it is ranked 14th in citrus production. Citrus exports amounted to R18.6-billion. Ranking 21st in the world in wool production, South African is remarkably the world’s third-biggest exporter, bringing in R4.7-billion.