The efficacy of applying biocontrol agents, chemical fungicide and nematicide as protective treatments against the soilborne parasites, Fusarium spp. (Fusaria) and citrus nematode Tylenchulus semipenetrans Cobb was evaluated. The experiment took place under field conditions in a citrus orchard cultivated with 16-year-old sweet orange (Citrus sinensis L.) osbech cv. Valencia trees grafted on sour orange (C. aurantium L.) rootstock during the growing season November 2006/ October 2007. This orchard is located at Bader district, Behera governorate, Egypt. The populations of soil fauna and flora under trees canopy were examined just before treatment, and 1, 3, 6, 9 and 12 months after the treatment application. A visual inspection for the appearance of symptoms related to Fusarium or nematode infection on treated and untreated citrus trees was carried out periodically every two weeks throughout the experimental period.
Plant growth regulators (PGRs) are a tool used to manipulate vegetative and reproductive growth, flowering, and fruit growth and development. PGRs have been successfully used in agriculture for decades to amend plant growth characteristics and maximize yield and thus grower profit. Foliar-applied PGRs are routinely used in various fruit crops for flower and fruit thinning, improving fruit set, growth and development, controlling vegetative growth, and reducing fruit drop. Citrus is no exception to the use of PGRs, which can provide significant economic advantages to citrus growers when used appropriately.
According to the Florida state legislature, PGRs are defined “as any substance or mixture of substances intended, through physiological action, for accelerating or retarding the rate of growth or maturation or for otherwise altering the behavior of ornamental or crop plants or the produce thereof, but not including substances intended as plant nutrients, trace elements, nutritional chemicals, plant inoculants, or soil amendments.”
Recent reports show that orange yield and fruit quality is on the decline in Kenya’s coastal lowlands hence need for an efficient and sustainable production system. A field study was conducted in Vitengeni, Ganda and Matuga locations within the coastal lowland of Kenya from May 2012 to April 2015 to evaluate the effect of three legume cover crops on orange fruit weight and brix. The treatments included mucuna (Mucuna pruriens), dolichos (Lablab purpureus), cowpea (Vigna unguiculata) cover crops and fallow of natural vegetation as the control.
University of California finds substance capable of controlling devastating citrus disease
Scientists at the University of California, Riverside (UCR) have found the first substance capable of controlling Citrus Greening Disease, which has devastated citrus farms in Florida and also threatens California.
The University of Florida has also been working towards a solution, as reported in March 2020.
Citrus is one of the most important fruit crops in the world, and they are particularly susceptible to postharvest damage before they reach the market for fresh consumption after storage. Green mold caused by Penicillium digitatum is considered to be the main postharvest pathogen of citrus fruit with up to 60–80% decay under suitable environment conditions.
As of July 1, the suspension of Argentinian fresh lemon exports to Europe came into force following several detections of black spot in some shipments upon arrival at European ports.
“In the last two weeks, the number of black spot detections has skyrocketed, so we believe that this has been a correct and necessary measure. As a sector, we have to find where the problem is in order to solve it. We are concerned about what has taken place this campaign, but we are even more concerned about what is to come. That is why I think Argentina should soon review the lemon export protocol for Europe. It is clear that this situation will bring changes and adjustments for future campaigns,” says Francisco Rotella, commercial director of the Argentinian lemon producer and marketer Citrusvil.
Current market trends of higher income group consumers include a desire for information related to the products they buy, such as its origin, safety, and social responsibility of the producer. Organically grown fruits seem to be favoured over conventionally produced fruit. Organic production requirements affect all practices related to fruit production including type of fertilisers used, pest and disease control as well as post-harvest chemicals used.
Liquid organic fertilizers for sustainable agriculture: Nutrient uptake of organic versus mineral fertilizers in citrus trees.
The main objective of this study was to compare the performance of two liquid organic fertilizers, an animal and a plant-based fertilizer, with mineral fertilization on citrus trees. The source of the fertilizer (mineral or organic) had significant effect in the nutritional status of the organic and conventionally managed mandarins. Nutrient uptake, vegetative growth, carbohydrate synthesis and soil characteristics were analyzed. Results showed that plants fertilized with animal based liquid fertilizers exhibited higher total biomass with a more profuse development of new developing organs (leaves and fibrous roots).
Citrus trees infected with Huanglongbing (HLB) bacteria become weak and develop dieback, resulting in lost production. These trees eventually decline to a production level that is not economical to maintain in a citrus operation. Sixteen-year-old ‘Valencia’ (Citrus sinensis Macf.) orange trees on Swingle citrumelo rootstock [C. paradisi × Poncirus trifoliata (L.) Raf.], 100% infected with HLB, in decline and losing production, were severely pruned (buckhorned) to stimulate regrowth and the new flush treated with foliar nutritional sprays. Nutritional sprays included the “Boyd cocktail” and two other nutrient treatments that contained phosphites plus nickel and cobalt. Heavily pruned trees and unpruned standard control trees were compared for shoot growth and canopy development.
Citrus is the main fruit tree crop in the world and therefore has a tremendous economical, social and cultural impact in our society. In recent years, our knowledge on plant reproductive biology has increased considerably mostly because of the work developed in model plants. However, the information generated in these species cannot always be applied to citrus, predominantly because citrus is a perennial tree crop that exhibits a very peculiar and unusual reproductive biology.