28 Nov 2025
Fruit Thinning

Economics of Fruit Thinning A Review Focusing on Apple and Citrus

Hundreds of fruit thinning experiments have been reported for various fruits including apple (Malus x domestica) and citrus (Citrus spp.). Unfortunately, very few of these reports attempt to evaluate the economic implications of thinning. Researchers routinely report significant cropload reduction accompanied by an increase in fruit size. Although these are crucial responses to thinning, they are not always associated with an increase in crop value, which is the commercial justification for thinning.

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29 Aug 2025
Fertilization

Effects of Fertilization Approaches on Plant Development and Fertilizer Use of Citrus

Fertilization is an important part of citrus crop management. However, limited details are available about the fertilization approach on citrus plant development. A pot experiment for the fertilization approaches and fertigation levels were conducted in this study. Four fertilization approaches, namely, drip fertigation (DF), broadcast fertilization (CK+), hole fertilization (HF) and pour fertilization (PF) were tested. The fertigation level treatment included 100% (DF-337.5), 80% (DF-270), 60% (DF-202.5) and 40% (DF-135) fertilizer supply with DF, and the 100% fertilizer supply with broadcast fertilization were served as control (CK). The results showed that DF not only increased the absorptions of nitrogen (N), phosphorus (P) and potassium (K) but also promoted citrus plant height, stem diameter and dry weight.

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25 Nov 2024

Fruit thinning chemical agents improves fruit size and quality in ‘kinnow’ Mandarin

‘Kinnow’ mandarin (Citrus reticulata Blanco) fruit needs to be thinned to increase the availability of photosynthates used to increase fruit size, fruit quality, profitability and can also help to overcome alternate bearing. This study evaluated ‘Kinnow’ fruit thinning using three chemical agents with different levels of concentration i.e. naphthalene acetic acid (NAA) @ 0.2, 0.3, 0.4, and 0.5 gL 1; 3,5,6 trichloro 2 pyridyloxyacetic acid (3,5,6 TPA) at TPA at 0.2, 0.5, and 0.7 gL 1, and ethephon @ at 0.4, 0.5, and 0.6 gL 1, in Pakistani orchards just after the June fruit drop for two growing seasons 2017 19. Fruit weight was increased due to chemical thinning application when compared with the respective controls.

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21 Oct 2024
Post harvest citrus

Alternative methods for the control of postharvest citrus diseases

The postharvest diseases of citrus fruit cause considerable losses during storage and transportation. These diseases are managed principally by the application of synthetic fungicides. However, the increasing concern for health hazards and environmental pollution due to chemical use has required the development of alternative strategies for the control of postharvest citrus diseases. Management of postharvest diseases using microbial antagonists, natural plant-derived products and Generally Recognized As Safe compounds has been demonstrated to be most suitable to replace the synthetic fungicides, which are either being banned or recommended for limited use.

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21 Oct 2024
Girdling

Influence of girdling on the seasonal leaf nutrition status and fruit size of Robinson Mandarin

This study was undertaken to investigate the effects of single and double girdling applications on the fruit yield, commercial size, quality, photosystem II (PSII), leaf chlorophyll and leaf nutrition content of 22-year-old Robinson mandarin (Citrus reticulata). Girdling treatments were performed at anthesis (when 60% of the flowers were opened) with approximately 5 mm trunk diameter in 2014. The fruit was harvested in 2014 at the optimum harvest time (in December) for fruit yield, properties and size. Evaluations of leaf mineral content, chlorophyll concentration and fluorescence measurements were performed at monthly intervals.

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25 Aug 2024
Leaf Analysis

Evaluation of the usefulness of early leaf analysis to improve nutrition management of citrus

The response of Citrus sinensis ‘Midknight’ (Nelspruit, Mpumalanga, South Africa) and Citrus paradisi ‘Orri’ (De Wet, Western Cape, South Africa) to excessive fertilisation (double the normal rate) with nitrogen (N), phosphorus (P), potassium (K) and magnesium (Mg) was investigated. The goal was to determine whether early-season leaf mineral compositions respond to fertilisation rates so that in-season adjustments of the fertilisation programme can be made.

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25 Jun 2024

Short-term effects of cover crops on soil properties and the abundance of N-cycling genes in citrus agroecosystems

Limited information is available on the influence of cover crops (CCs) on soil nutrient cycling and the abundance of bacterial and archaeal communities, nitrogen (N)-fixers, nitrifiers, and denitrifiers in tree crops. We examined the effect of replacing the traditional weedy inter-row middle of a commercial citrus orchard in Florida with two different mixtures of CCs: legumes and non-legumes (LG + NL) and non-legumes only (NL). A no-treatment/grower standard was used as a control (GSC). After one year of CCs, the use of NL and LG + NL CCs significantly increased soil carbon (C) availability in the row middles compared to GSC as shown by increases in permanganate oxidizable C, and to a lesser extent, soil organic matter. Treatment with LG + NL significantly increased soil ammonium content compared to the NL and GSC treatments. Improved C cycling in soils treated with CCs was related to increased abundance of bacteria and archaea. Changes in the size of the soil N pool were accompanied by increases in the abundance of N-fixation (nifH) and nitrification (amoA) genes in soils treated with LG + NL, likely due to greater N-mineralization and N-fixation by legumes.

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