**About the Editor**

**Elazar Fallik** is a Senior Research Scientist at the Agricultural Research Organization (ARO), Volcani Center, Rishon LeZiyyon, Israel, in the Department of Postharvest Science, assuming this role in 1990. He was the Head of the Department of Postharvest Science between 2004 and 2007 and the Head of the Institute of Postharvest and Food Sciences between 2007 and 2013. Currently, he is the Scientific Coordinator of the 8 AgriculturalR&D Centers in Israel. He received his B.Sc. (1979), M.Sc. (1981) and Ph.D. (1988) from the Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot, Israel. Between 1981 and 1984, he was a research associate at Biotechnology General (Israel) Ltd., Rehovot, Israel. He spent two years (1988–1990) as a postdoctoral fellow in the Department of Biochemistry, University of Georgia, Athens, Georgia. In 1996/7, he was on sabbatical leave at the University of Kentucky, Department of Horticulture and Landscaping Architecture, Lexington, Kentucky. His research is focused on the physiology, pathology and biochemistry aspects of fresh fruits and vegetables. His current research interests are the use of non-chemical treatment for disease control, fresh produce resistance by physical treatments, sensory (smell and taste), postharvest water loss, the use of 1-MCP in fresh produce, postharvest quality of grafted vegetables and development of quarantine treatments for fresh harvested produce. He has developed a unique technology which cleans and disinfects fresh harvested produce by a hot water rinsing and brushing machine. For this development, he received several awards from the Israeli government. In 2015, he received the 2014 Life Achievement Award from the ARO Volcani Center for his scientific and innovative contribution in the field of postharvest. He is an Adjunct Professor at the Hebrew University of Jerusalem and teaches at the Faculty of Agriculture, Rehovot, Israel. He coordinates and teaches international courses in postharvest research and development in Israel and around the world.

## **Preface to "Postharvest Disease Development"**

Postharvest losses of fresh produce have always been an obstacle in agriculture. About one third of global fresh fruits and vegetables are lost because their quality has dropped below an acceptance limit. Losses include any change and/or damage in quantity and quality of produce from the moment of harvest until consumption. Once produce is harvested, postharvest handling practices do not improve the quality attained in the field; they can only slow the rate at which deterioration occurs. The postharvest quality and shelf life of fresh produce are determined before harvest. Factors that include weather, soil preparation and cultivation, soil type, cultivar, fertigation, pest and disease control, and crop loads affect the quality and flavor properties of harvested fresh produce. However, postharvest practices such as temperature management, controlled and modified atmosphere, coatings, physical treatments, biocontrol, and more can affect fresh produce marketing and shelf life. This Special Issue on "Postharvest Disease Development: Pre and/or Postharvest Practices" gathers nine papers; two are reviews and seven are research papers. One review is focused on the use of nonpolluting chemicals classified as food preservatives or generally recognized as safe (GRAS) to control disease development after harvest. The other review is focused on the characterization of stem-end rot (SER) pathogens, the stem-end microbiome, and different preharvest and postharvest practices that could control fruit SER. Three research papers focused on postharvest treatments to reduce rot development. The first one evaluated different types of SO2 generator pads in order to prevent the incidence of gray mold of seedless grape, as well to avoid other grape injuries during cold storage. The second elucidated the best storage temperature for acorn squash and evaluated hot water rinsing and brushing (HWRB) technology to maintain fruit quality for several months. The third paper was focused on the effects of electron beam irradiation using a new Electronic Cold-PasteurizationTM (ECPTM) technology on fruit quality, microbial safety, and postharvest disease development in two highbush blueberries. Two research papers covered physiological and pathological aspects, such as ripening of harvested fresh produce and pathogen colonization on fruit treated with ethylene and plant growth regulators. One paper examined the effect of air and ethylene on the growth of fungi isolated from climacteric and non-climacteric fruits. One paper was focused on the use of different concentrations of carnauba wax and chitosan edible coatings for commercial quality preservation of carrots after harvest. In addition, one paper examined residual levels of preharvest applications of several fungicides on mandarin fruits after prolonged cold storage.

> **Elazar Fallik** *Editor*

*Article*

## **Dissipation of Pre-Harvest Pesticides on 'Clementine' Mandarins after Open Field Application, and Their Persistence When Stored under Conventional Postharvest Conditions**

**Natalia Besil 1, Verónica Cesio 2, Eleana Luque 3, Pedro Pintos 3, Fernando Rivas 3 and Horacio Heinzen 2,\***


Received: 13 October 2018; Accepted: 12 December 2018; Published: 18 December 2018

**Abstract:** The dissipation of field-applied difenoconazole, imidacloprid, pyraclostrobin and spinosad on Clementine mandarins (*Citrus clementina* Hort. ex Tan.) under controlled conditions throughout the citrus production chain was assessed. At harvest, 42 days after application, the dissipation of these pesticides were 80, 92, and 48% for difenoconazole, imidacloprid, pyraclostrobin, respectively, and spinosad was below the level of detectability. At day 28 after application, spinosad was no longer detected. The model equations that best describe the dissipation curves of these pesticides on Clementine mandarins showed different patterns. Their half-life on Clementine, calculated by the best-fitted experimental data, were 19.2 day (1st-order model) for difenoconazole, 4.1 day (Root Factor (RF) 1st-order model) for imidacloprid, 39.8 day (2nd-order model) for pyraclostrobin and 5.8 day (1st-order model) for spinosad. These results are the first record of pyraclostrobin persistence on mandarins, showing a longer half-life in this matrix than those reported for any other fruit. The treated fruit were harvested and submitted to the usual postharvest treatments: first, a hypochlorite drenching was performed; as a second step, imazalil and wax were applied, and then the mandarins were stored at 4 ◦C. After 32 days, cold storage caused no significant effects on the residue levels of the four pesticides compared with those determined on freshly harvested mandarins. All residues were below their Codex and European Union (EU) maximum residue limit (MRL) for mandarin since the spray application day.

**Keywords:** pesticide residues; degradation dynamic; citrus; LC-MS/MS
