scholarly journals ‘Ray Ruby’ Grapefruit Affected by Huanglongbing I. Planting Density and Soil Nutrient Management

HortScience ◽  
2020 ◽  
Vol 55 (9) ◽  
pp. 1411-1419
Author(s):  
Dinesh Phuyal ◽  
Thiago Assis Rodrigues Nogueira ◽  
Arun D. Jani ◽  
Davie M. Kadyampakeni ◽  
Kelly T. Morgan ◽  
...  

Huanglongbing (HLB), or citrus greening disease, affects practically all fruit-bearing trees in commercial citrus orchards in Florida with no cure identified yet. High-density plantings and enhanced nutritional programs such as application of controlled-release fertilizer (CRF) with higher micronutrient levels can mitigate disease symptoms and extend the tree life span of sweet oranges (Citrus sinensis). The objective of this study was to evaluate the effects of tree planting density and application of CRF blends differing in N to K ratio and micronutrient content on grapefruit (Citrus paradisi) plant health, canopy volume, fruit yield, and fruit quality in an HLB-affected orchard. A study was conducted in Florida for two growing seasons (2017–18 and 2018–19) to evaluate the response of ‘Ray Ruby’ grapefruit on Kuharske citrange (Citrus sinensis × Poncirus trifoliata) to three planting densities (300, 440, and 975 trees per ha) and two CRF blends [12 nitrogen (N)–1.31 phosphorus (P)–7.47 potassium (K) and 16N–1.31P–16.6K] with different nutrient sources and composition. According to quantitative real-time polymerase chain reaction testing, all sampled trees tested positive for Candidatus Liberibacter asiaticus, the pathogen associated with HLB. Trees planted at 975 trees per ha had 33% lower canopy volume per tree but 160% greater fruit yield per hectare and 190% higher yield of solids compared with 300 trees per ha. Fruit produced in high-density planting (975 trees per ha) was 18% more acidic with higher soluble solid compared with low-density planting (300 trees per ha). The use of a CRF blend with higher amounts of micronutrients along with lower K increased canopy volume in both seasons and resulted in 24% and 29% reduction in fruit yield per hectare and yield of solids, respectively, in 2017–18. Our results indicate that high-density plantings increase fruit yield per area, and regardless of the N to K ratio, the use of CRF blends supplemented with micronutrients may not increase fruit yield in HLB-affected grapefruit.

HortScience ◽  
2020 ◽  
Vol 55 (9) ◽  
pp. 1420-1432
Author(s):  
Dinesh Phuyal ◽  
Thiago Assis Rodrigues Nogueira ◽  
Arun D. Jani ◽  
Davie M. Kadyampakeni ◽  
Kelly T. Morgan ◽  
...  

Since the arrival of Huanglongbing (HLB) disease in Florida, several management approaches, including modification of orchard architecture design and nutritional therapy, have been explored. High-density plantings anticipate early economic returns from HLB-affected orchards. With no cure available for HLB, balanced nutrient application through soil and foliar spraying can mitigate the disease. A 2-year study was conducted to investigate the effects of three grapefruit (Citrus paradisi) planting densities [single-row (300 and 440 trees per ha), and double-row high-density (975 trees per ha)], two controlled-release fertilizer (CRF) blends, and foliar-applied micronutrients (FAM) (a blend of B, Mn, and Zn at 0, 1.5, 3, and 6 times the recommended rates) on grapefruit growth and fruit yield, physiological parameters, and foliar nutrient concentrations in an HLB-affected orchard. All the trees tested positive for HLB based on real-time quantitative polymerase chain reaction (qPCR) test. The highest planting density resulted in the lowest trunk diameter and canopy volume. Despite lower yield per tree in 2019–20, 975 trees per ha planting induced the greatest fruit and solid yields per ha. Also, the fruit produced from 975 trees per ha planting tended to be acidic with the deposition of more soluble solids. Use of CRF with higher micronutrients increased canopy volume with the expense of reduced fruit number in 2019–20. FAM did not affect cycle threshold (Ct) value and tree growth parameters. Fruit yield, photosynthesis rate, and stomatal conductance (gS) decreased, and all leaf nutrient concentrations except B increased in 2019–20 with all FAM rates tested. In conclusion, our study showed that high-density planting optimizes yield under HLB-endemic conditions. In addition, supplemental soil and foliar micronutrient application do not enhance yield of HLB-affected trees over a 2-year timeframe, warranting further research for confirmation of results.


HortScience ◽  
2021 ◽  
pp. 1-10
Author(s):  
Eduardo Esteves ◽  
Gabriel Maltais-Landry ◽  
Flavia Zambon ◽  
Rhuanito Soranz Ferrarezi ◽  
Davie M. Kadyampakeni

The bacterial disease Huanglongbing (HLB) has drastically reduced citrus production in Florida. Nutrients play an important role in plant defense mechanisms and new approaches to manage the disease with balanced nutrition are emerging. Nutrients like nitrogen (N), calcium (Ca), and magnesium (Mg) could extend the productive life of affected trees, although interactions among these nutrients in HLB-affected citrus trees are still unclear. A 2-year study was established in Florida to determine the response of HLB-affected trees to applications of N, Ca, and Mg. The study was conducted with ‘Valencia’ trees (Citrus sinensis L. Osbeck) on Swingle citrumelo (Citrus paradisi Macf. × Poncirus trifoliata L. Raf.) rootstock on a Candler sand. Applications of N at 168, 224 (recommended rate), and 280 kg⋅ha−1 N were used as the main plots. Split-plots consisted of a grower standard treatment receiving only basal Ca (51 kg⋅ha−1) and Mg (56 kg⋅ha−1); supplemental Ca (total Ca inputs: 96 kg⋅ha−1) only; supplemental Mg (total Mg inputs: 101 kg⋅ha−1) only; and supplemental Ca (total Ca inputs: 73.5 kg⋅ha−1) and Mg (total Mg inputs: 78.5 kg⋅ha−1). The following variables were measured: tree size, fruit yield, and juice quality. Although some differences in tree growth among treatments were statistically significant (e.g., greater canopy volume with Mg fertilization at 168 kg⋅ha−1 N), there was no clear and consistent effect of plant nutrition on these variables. Fruit yield was higher with Ca and Mg relative to the grower standard at the lowest N rate in 2020, and there were no other statistically significant differences among treatments. Juice acidity was significantly higher with Mg fertilization relative to other treatments in 2019. As N rates had no significant effect in this study, unlike secondary macronutrients, N rates could potentially be reduced to 168 kg N⋅ha−1 in HLB-affected citrus without affecting vegetative growth, fruit yield, and juice quality. However, this will require optimizing the supply of secondary macronutrients and all other nutrients to develop a balanced nutritional program. Ultimately, the effects of N, Ca, and Mg obtained in this 2-year study should be confirmed with longer-term studies conducted at multiple sites.


Horticulturae ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 50
Author(s):  
Rhuanito S. Ferrarezi ◽  
Thiago A. R. Nogueira ◽  
Arun D. Jani ◽  
Alan L. Wright ◽  
Mark A. Ritenour ◽  
...  

Conventionally managed citrus orchards can be modified to incorporate advanced horticultural practices such as higher plant density and efficient water and fertilizer application known as open hydroponics system (OHS) to increase productivity under Huanglongbing (HLB) endemic conditions. A field study was conducted from 2013 to 2018 to evaluate the effect of an OHS on “Ray Ruby” grapefruit (RR) production under HLB-endemic conditions. We tested a combination of different rootstocks [Sour orange (RR/SO) and US-897 (RR/897)], tree planting densities [standard (STD, 358 trees per ha) and high density staggered (HDS, 953 trees per ha)], fertilization methods (dry granular—dry and fertigation—fert), and irrigation systems (double driplines—DD and microsprinkler—MS), arranged in five treatments: RR/SO_STD_dry_MS, RR/SO_HDS_fert_DD, RR/897_HDS_fert_MS, RR/897_HDS_fert_DD, and RR/SO_HDS_fert_MS. All trees were infected by Candidatus Liberibacter asiaticus five years after planting. Trunk diameter and canopy volume increased over time and were higher under RR/SO_STD_dry_MS compared to other treatments. Total fruit number increased in 2016/17 compared to other seasons; however, 65% of fruit were classified as small (<100 mm). Fruit produced under RR/897_HDS_fert_DD had the highest amount (79%) of adequate size fruit (100–117 mm) compared to other treatments. Fruit yield was similar for both rootstocks planted at HDS using DD and MS fertigation, and 67% higher than the standard treatment (RR/SO_STD_dry_MS). Soluble solid contents (SSC), titratable acidity, and SSC-to-titratable acidity ratio were not affected by the treatments. HDS planting resulted in higher fruit yield, irrespective of rootstock and irrigation system, representing an important advance in grapefruit production. Overall, our results demonstrated that production of grapefruit in high-density using OHS can be used by citrus growers who aim to make the best water and fertilizer management under HLB-endemic conditions.


2007 ◽  
Vol 42 (5) ◽  
pp. 679-687 ◽  
Author(s):  
Eduardo Augusto Girardi ◽  
Francisco de Assis Alves Mourão Filho ◽  
Sônia Maria de Stefano Piedade

O objetivo deste trabalho foi avaliar o desenvolvimento vegetativo e estimar o custo de produção de 11 porta-enxertos de citros para fins de subenxertia, em diferentes recipientes. Avaliaram-se limão 'Cravo' clone Limeira (Citrus limonia Osbeck); citrumelo 'Swingle' (Poncirus trifoliata (L.) Raf. x Citrus paradisi Macf.); tangerina 'Cleópatra' (Citrus reshni Hort. ex Tanaka); tangerina 'Sunki' (Citrus sunki Hort. ex Tanaka); limão 'Volkameriano' clone Catânia 2 (Citrus volkameriana Pasquale); laranja 'Caipira' clone DAC (Citrus sinensis L. Osbeck); limão 'Rugoso da África' clone Mazoe (Citrus jambhiri Lush.); Poncirus trifoliata 'Davis A'; tangerina 'Sun Shu Sha Kat' (Citrus sunki Hort. ex Tanaka); tangerina 'Sunki' clone 2506 ou Fruto Grande (Citrus sunki Hort. ex Tanaka) e Poncirus trifoliata 'Barnes'. Foram utilizados tubetes de 290 mL, sacolas de 1,7 L, e porta-enxertos transplantados de tubetes de 75 mL para sacolas de polietileno de 1,7 e 4,5 L. Porta-enxertos produzidos diretamente em sacolas de 1,7 L atingem ponto ideal de subenxertia em menor tempo, de 100 a 150 dias após a semeadura, e permitem a obtenção de plantas maiores e com sistema radicular adequado, porém com custo de produção superior ao sistema de produção em tubetes de 290 mL.


2010 ◽  
Vol 32 (3) ◽  
pp. 855-864 ◽  
Author(s):  
Eduardo Augusto Girardi ◽  
Francisco de Assis Alves Mourão Filho ◽  
André Siqueira Rodrigues Alves

O manejo da adubação é uma das principais práticas culturais para a produção de mudas cítricas em cultivo protegido. Avaliou-se o efeito de seis tipos de manejo das adubações comercialmente recomendadas na produção de mudas de laranjeira 'Valência' [Citrus sinensis (L.) Osbeck] enxertada sobre os porta-enxertos limoeiro 'Cravo' (Citrus limonia Osbeck) e citrumeleiro 'Swingle' [Citrus paradisi Macf. x Poncirus trifoliata (L.) Raf.]. As avaliações foram conduzidas a partir da transplantação dos porta-enxertos até 180 dias após a enxertia, em viveiro empresarial, em Conchal-SP. Os manejos corresponderam a duas soluções de fertilizantes solúveis aplicadas isoladamente, soluções de fertilizante solúveis associadas a fertilizante de liberação controlada e aplicação exclusiva de fertilizante de liberação controlada. O delineamento experimental adotado foi o fatorial 2 x 6 (porta-enxerto x manejo da adubação), em blocos casualizados, com três repetições e 12 mudas na parcela. O limoeiro 'Cravo' induziu maior crescimento ao enxerto. O crescimento vegetativo das mudas foi similar após o uso de fertilizantes solúveis ou de liberação controlada, apesar da grande variação de quantidades totais de nutrientes fornecidas às plantas. Desta forma, o viveirista poderá optar pelo manejo mais econômico ou prático, conforme as condições locais.


2017 ◽  
Vol 66 (3) ◽  
pp. 397-402
Author(s):  
Hans Chaparro ◽  
David Ricardo Hernández ◽  
Diana Mayerly Mateus ◽  
Javier Orlando Orduz Rodriguez

‘Cleopatra’ tangerine (Citrus reshni hort. ex Tanaka) is a commonly used rootstock in the piedmont of Meta department, Colombia for establishing of commercial citrus orchards. Have allowed a late production entrance rootstock and produced big plants when grafted with tangelo ‘Minneola’ (C. reticulata Blanco x C. paradise Macf), decreasing the productive efficiency in plants and hard crop practices. The evaluated performance were as follows:  tree size, productive efficiency and fruit quality of tangelo ‘Minneola’ grafted in six rootstocks. It found that the cumulated production of 11 years was better with Citrumelo ‘Swingle’ (Citrus paradisi Macf. × Poncirus trifoliata (L.) Raf) with 1388.3 kg tree-1, followed by ‘Cleopatra’ (Citrus reshni hort. ex Tanaka) with 893.2 kg.tree-1, in last place was ‘Carrizo’ (Citrus sinensis Osb. × Poncirustrifoliata (L.) Raf) with 182.9 kg tree-1. The other rootstocks, had a medium production. The greatest height and canopy value, was found with ‘Cleopatra’ without significant differences with Citrumelo ‘Swingle’. In fruit quality no significant differences occurred.


2019 ◽  
Vol 11 (2) ◽  
pp. 440-444
Author(s):  
Mushtaq ◽  
A. R. Kurubar  ◽  
M. R. Umesh ◽  
Shekharagouda Patil ◽  
Ashok Hugar

Nutrient requirement for guava under high density planting is much higher than normal planting. Combined application of organic manures and chemical fertilizers will enhance nutrient use efficiency. The field experiment was carried out at Raichur, Karnataka, India during 2017 to standardize rate of fertilizers and organic manures for Guava (Psidium guajava L.)  cv. Allahabad safeda under high density planting. Treatments consists of application of fertilizers for normal planting compared with 100:40:75 g NPK/plant as recommended dose of fertilizers (RDF), 75% and 50% of high density planting (HDP) along with 25 kg farmyard manure, organic manure alone and foliar application of urea @ 1 % at 2,3 and 4 months after pruning. Results indicated that application of NPK@ 235: 118: 120 g per plant as per the RDF for HDP along with 25 kg FYM has resulted in taller plants, plant spread E-W as well as N-S directions, canopy volume and leaf area index. Higher fruits/plant, average fruit weight, fruit diameter, fruit length, fruit yield per plant and fruit yield (48.58 t ha-1) was recorded by application of NPK@ 235: 118: 120 g per plant same as that of HDP along with 25 kg FYM. Application of 50 % of HDP recommendation along with foliar application of urea @ 1% at 2, 3 and 4 months after pruning and 25 kg FYM was also found effective in achieving higher fruit yield of guava.


2006 ◽  
Vol 63 (1) ◽  
pp. 5-10 ◽  
Author(s):  
Eduardo Augusto Girardi ◽  
Francisco de Assis Alves Mourão Filho

Incompatibility among certain citrus scion and rootstock cultivars can be avoided through interstocking. 'Pera' sweet orange (Citrus sinensis L. Osbeck) nursery tree production was evaluated on 'Swingle' citrumelo (Poncirus trifoliata (L.) Raf x Citrus paradisi Macf) and 'Volkamer' lemon (Citrus volkameriana Pasquale) incompatible rootstocks, using 'Valencia' and 'Hamlin' sweet oranges (Citrus sinensis L. Osbeck), 'Sunki' mandarin (Citrus sunki Hort. ex Tanaka), and 'Cleopatra' mandarin (Citrus reshni Hort. ex Tanaka) as interstocks. Citrus nursery trees interstocked with 'Pera' sweet orange on both rootstocks were used as control. 'Swingle' citrumelo led to the highest interstock bud take percentage, the greatest interstock height and rootstock diameter, as well as the highest scion and root system dry weight. Percentage of 'Pera' sweet orange dormant bud eye was greater for plants budded on 'Sunki' mandarin than those budded on 'Valencia' sweet orange. No symptoms of incompatibility were observed among any combinations of rootstocks, interstocks and scion. Production cycle can take up to 17 months with higher plant discard.


2003 ◽  
Vol 60 (1) ◽  
pp. 155-160 ◽  
Author(s):  
Dirceu Mattos Jr. ◽  
José Antônio Quaggio ◽  
Heitor Cantarella ◽  
Ashok Kumar Alva

The knowledge of the nutrient distribution in trees is important to establish sound nutrient management programs for citrus production. Six-year-old Hamlin orange trees [Citrus sinensis (L.) Osb.] on Swingle citrumelo [Poncirus trifoliata (L.) Raf. x Citrus paradisi Macfad.] rootstock, grown on a sandy Entisol in Florida were harvested to investigate the macro and micronutrient distributions of biomass components. The biomass of aboveground components of the tree represented the largest proportion of the total. The distribution of the total tree dry weight was: fruit = 30.3%, leaf = 9.7%, twig = 26.1%, trunk = 6.3%, and root = 27.8%. Nutrient concentrations of recent mature leaves were in the adequate to optimal range as suggested by interpretation of leaf analysis in Florida. Concentrations of Ca in older leaves and woody tissues were much greater than those in the other parts of the tree. Concentrations of micronutrients were markedly greater in fibrous root as compared to woody roots. Calcium made up the greatest amount of nutrient in the citrus tree (273.8 g per tree), followed by N and K (234.7 and 181.5 g per tree, respectively). Other macronutrients comprised about 11% of the total nutrient content of trees. The contents of various nutrients in fruits were: N = 1.20, K = 1.54, P = 0.18, Ca = 0.57, Mg = 0.12, S = 0.09, B = 1.63 x 10-3, Cu = 0.39 x 10-3, Fe = 2.1 x 10-3, Mn = 0.38 10-3, and Zn = 0.40 10-3 (kg ton-1). Total contents of N, K, and P in the orchard corresponded to 66.5, 52.0, and 8.3 kg ha-1, respectively, which were equivalent to the amounts applied annually by fertilization.


2001 ◽  
Vol 26 (1) ◽  
pp. 95-98
Author(s):  
SERGIO A. CARVALHO ◽  
GERD W. MÜLLER ◽  
JORGINO POMPEU JR ◽  
JAIRO LOPES DE CASTRO

Seedlings of 41 different citrus species and varieties were massively colonized with the citrus brown aphid Toxoptera citricidus, obtained from Pêra sweet orange (Citrus sinensis) trees, presenting symptoms of the "Capão Bonito" complex of the Citrus tristeza virus (CTV). The objective was to evaluate resistance or tolerance of the varieties to that virus complex, but even after eight months of inoculation no stem pitting was observed in the plants. Otherwise, the presence of galls similar to those induced by the vein enation-woody gall disease was observed in 73% of the plants of Volkamer Palermo (Citrus volkameriana), 60% of the Volkamer Catania 2, 2% of the Rangpur Lime D.22.30 (Citrus limonia), 13% of the Volkamer Australian Red, the Rangpur Lime hybrid, the Orlando tangelo (Citrus reticulata x Citrus paradisi) and the Florida Rough lemon (C. jambhiri), and 7% of the Carrizo citrange (Poncirus trifoliata x Citrus sinensis). The highest incidence and the largest gall size were observed in the Palermo Volkamer showing that this clone would be the most suitable to be used as an indicator plant in biological indexing tests for the disease. There are no previous reports in the literature about the occurrence of woody galls in Orlando tangelo and Carrizo citrange.


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