Field spatial pattern of seedy fruit and techniques to improve yield on ‘Afourer’ mandarin

Otero, Álvaro; Rivas, Fernando

doi:10.1016/j.scienta.2017.06.067

Cited by 8 publications

(29 citation statements)

References 18 publications

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“…During winter, NPN reduced the foliar spray deposition of a medium-volume foliar spray on leaves and fruit at different canopy positions. The practice of using NPN in orchards is popular for short periods in citrus-producing countries such as Australia, Chile, and the United States (personal communication with Etienne Rabe, Wonderful Citrus, CA, and Tim Grout, Citrus Research International), because of its efficacy for excluding bees and producing seedless fruit (Gambetta et al, 2013;Otero and Rivas, 2017). Producers would not be able to grow seedless fruit without NPN, which is a method that is safe for the environment.…”

Section: Discussionmentioning

confidence: 99%

“…The trees in the experimental orchard were planted in sandy soil, for which it is standard practice to supply a proportion of certain mineral nutrients using low-volume foliar spray applications during spring and early summer (Lovatt, 2013), which is the period when the coverage of trees by NPN is recommended (Gambetta et al, 2013;Otero and Rivas, 2017). There were no differences in the concentrations of macronutrients in leaves of the trees subjected to control and NPN treatments.…”

Section: Discussionmentioning

confidence: 99%

“…In Citrus spp., nonpermanent netting (NPN) is used in certain production regions during a particular stage of the season to protect trees and fruit from damage that could be caused by hail (Wachsmann et al, 2014). It is also used for some citrus cultivars during flowering to exclude bees, thereby preventing crosspollination and unwanted seed development (Gambetta et al, 2013;Gravina et al, 2016;Otero and Rivas, 2017).…”

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confidence: 99%

“…'Nadorcott' mandarin is also sexually selfincompatible (Gambetta et al, 2013;Nadori, 2006), which means that its flowers are unable to produce seed on self-pollination (De Nettancourt, 1977). This trait is advantageous for commercial citrus production because when trees are isolated from certain potential crosspollinators, they can produce seedless fruit (Gambetta et al, 2013;Otero and Rivas, 2017), which are preferred by the market and sold at a premium (Barry, 2006).…”

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confidence: 99%

“…When flowers of 'Nadorcott' mandarin are exposed to pollen from a different compatible cultivar, the fruit are normally seeded (Nadori, 2006;Wright, 2007), thereby reducing the market value of the fruit (Barry, 2006). During commercial 'Nadorcott' mandarin production, for which the potential for cross-pollination is high and seed development likely, some growers cover the entire tree with NPN during flowering to exclude pollinators such as honeybees (Gravina et al, 2016;Otero and Rivas, 2017). This method is successful and environmentally safe.…”

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confidence: 99%

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Influence of Nonpermanent Netting on Foliar Spray Deposition, Insect Pest Prevalence, and Production of ‘Nadorcott’ Mandarin (Citrus reticulata)

Stander¹,

North²,

Niekerk³

et al. 2019

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Additional index words. False codling moth, fruit quality, fruit yield, leaf mineral nutrients, fruit fly, shade nettingAbstract. This study aimed to determine the effects of different types of nonpermanent netting (NPN) on foliar spray deposition, insect pest prevalence, and production and fruit quality of 'Nadorcott' mandarin (Citrus reticulata) trees in a commercial orchard at Citrusdal (lat. 32 32#31$S, long. 19 0#42$E), Western Cape, South Africa. The deposition quantity (FPC%) of foliar spray volumes of 3500, 7000, or 15,000 L · ha L1 was greater for leaves of control trees compared with leaves treated with NPN during summer (January) (8.8 vs. 6.1; P = 0.0055) and winter (June) (4.8 vs. 3.1; P = 0.0035). Deposition uniformity (CV%) was better for control leaves during summer (64.9 vs. 75.2; P = 0.0062) and winter (59.6 vs. 80.5; P = 0.0014), and deposition quality (ICD%) was better during winter (79.4 vs. 84.2; P = 0.0393). There were no differences in FPC%, CV%, and ICD% for fruit when foliar spray volumes of 3500 and 15,000 L · ha L1 were used for the control and NPN treatment groups during winter. However, with a foliar spray volume of 7500 L · ha L1 , fruit from the control treatment group had greater FPC% (19.3 vs. 6.1; P = 0.0262), CV% (70.3 vs. 50.9; P = 0.0484), and ICD% (57.1 vs. 79.9; P = 0.0157). There were no differences in macronutrient concentrations between the leaves of trees subjected to control and NPN treatments, but leaf zinc (<81%; P = 0.0317) and iron (<78%; P = 0.0041) concentrations were lower with the NPN treatment. During short NPN treatments, fruit yield was reduced by ' '37% compared with that after control treatment, and longer NPN treatments had no effect on fruit yield. The reduction in fruit yield with NPN was not related to the effects of NPN on foliar spray deposition or to lower leaf micronutrient concentrations. The lower fruit yield during short NPN treatments was most likely caused by fruit drop that was exacerbated by the removal of the NPN. In the long NPN treatment group, fruit damage caused by sunburn was reduced by 17%, but the outer canopy fruit experienced increased wind damage or scarring. Except for the lower titratable acidity content with the shortest NPN treatment and the higher Brix8:TA ratio with two NPN treatments, NPN did not impact other fruit quality attributes. The use of NPN excluded male wild false codling moths (Thaumatotibia leucotreta) (FCM) males; however, it was still possible to capture a very small amount of mass-released sterile FCM and wild fruit flies under the NPN.

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Section: Discussionmentioning

confidence: 99%