Non-Chemical Approaches to Control Postharvest Gray Mold Disease in Bell Peppers

Bell pepper (Capsicum annuum) is a widely grown vegetable crop that is nutritious and flavorful and economically important for growers worldwide. A significant limiting factor in the postharvest storage and long-distance transport of peppers is gray mold caused by Botrytis cinerea. The pathogen is widespread in nature, highly aggressive, and able to cause disease at cool refrigerated temperatures during transport and storage. Fungicides have been relied on in the past to reduce bell pepper rots in storage; however, concern over residues on the fruit and environmental degradation have heightened the importance of natural and generally recognized as safe (GRAS) solutions that effectively limit disease. Essential oils, plant extracts, inorganic chemicals, biocontrols, defense activators, hot water treatments, and modified storage conditions have been tested to reduce losses from gray mold. Despite significant amounts of research on natural methods of control of B. cinerea postharvest, research specific to gray mold in peppers is limited. The objective of this review is to summarize the research conducted with environmentally friendly alternatives to chemical fungicides to control this important pathogen of peppers postharvest. To ensure a steady supply of healthy and nutritious produce, more research is needed on the development, use, and application of non-hazardous Botrytis control methods. Until an effective solution is found, using a combined approach including environmental controls, sanitation, and GRAS products remain paramount to limit Botrytis fruit rot of peppers postharvest.

Debaryomyces hansenii, Stenotrophomonas rhizophila, and Ulvan as Biocontrol Agents of Fruit Rot Disease in Muskmelon (Cucumis melo L.)

The indiscriminate use of synthetic fungicides has led to negative impact to human health and to the environment. Thus, we investigated the effects of postharvest biocontrol treatment with Debaryomyces hansenii, Stenotrophomonas rhizophila, and a polysaccharide ulvan on fruit rot disease, storability, and antioxidant enzyme activity in muskmelon (Cucumis melo L. var. reticulatus). Each fruit was treated with (1) 1 × 106 cells mL−1 of D. hansenii, (2) 1 × 108 CFU mL−1 of S. rhizophila, (3) 5 g L−1 of ulvan, (4) 1 × 106 cells mL−1 of D. hansenii + 1 × 108 CFU mL−1 of S. rhizophila, (5) 1 × 108 CFU mL−1 of S. rhizophila + 5 g L−1 of ulvan, (6) 1 × 106 cells mL−1 of D. hansenii + 1 × 108 CFU mL−1 of S. rhizophila + 5 g L−1 of ulvan, (7) 1000 ppm of benomyl or sterile water (control). The fruits were air-dried for 2 h, and stored at 27 °C ± 1 °C and 85–90% relative humidity. The fruit rot disease was determined by estimating the disease incidence (%) and lesion diameter (mm), and the adhesion capacity of the biocontrol agents was observed via electron microscopy. Phytopathogen inoculation time before and after adding biocontrol agents were also recorded. Furthermore, the storability quality, weight loss (%), firmness (N), total soluble solids (%), and pH were quantified. The antioxidant enzymes including catalase, peroxidase, superoxide dismutase, and phenylalanine ammonium lyase were determined. In conclusion, the mixed treatment containing D. hansenii, S. rhizophila, and ulvan delayed fruit rot disease, preserved fruit quality, and increased antioxidant activity. The combined treatment is a promising and effective biological control method to promote the shelf life of harvested muskmelon.

Molecular characterization and in vitro control measures of fruit rot disease of Sweet pepper

Fruit rot disease of sweet pepper is one of the main fungal diseases causing huge economic losses to the grower. An experiment was conducted to find out the fungal pathogen associated with fruit rot disease of sweet pepper, obtained from experimental fields of Jahangirnagar University, Bangladesh. Fruit rot disease-causing fungus was isolated from infected fruits and identified using morphological characterization based on colony features, mycelia, conidia as well as molecular characterization based on internal transcribe spacer (ITS) region of the fungus. ITS sequence of our studied fungus MH368146.1 was genetically 99-100% similar to sequences of Fusarium solani in NCBI database. Typical fruit rot symptoms were reproduced by artificial inoculations of the isolated fungus. The mycelial growth of this fungus was evaluated on ten different solid culture media i.e., Potato Dextrose Agar, Yeast Extract Agar, Honey Peptone Agar, Hansen’s Medium, Sabouraud’s Glucose Agar, Kauffman’s Agar, Potato Sucrose Agar, Richard’s Agar and Carrot Agar. Fungus grew well on all tested solid culture media. Several bio-control agents and two commercial fungicides were evaluated against isolated fungus under in vitro condition, in which the highest percent inhibition of radial growth of the fungus was determined as 64.75% due to Trichoderma reesei isolate 2, and 60.63% by Tilt 250 EC (500 ppm) at 7 days post-incubation. Therefore, T. reesei was found as the most suitable to control the growth of F. solani under laboratory conditions. However, further pot and field trials needed to be confirmed the bio-control potential of it. Int. J. Agril. Res. Innov. Tech. 11(2): 108-116, Dec 2021

First Report of Fruit Rot Caused by Fusarium luffae in Muskmelon in China

Muskmelon (Cucumis melo L.) is one of the most widely cultivated and economically important fruit crops in the world. However, many pathogens can cause decay of muskmelon fruit, including Fusarium spp.. Fusarium spp. are the most important pathogen, affecting muskmelon fruit yield and quality (Wang et al. 2011). In August 2020, fruit rot symptoms were observed on ripening muskmelons (cv. Tianbao) in several fields in Jiyang District, Jinan City of Shandong Province, China. The incidences of infected muskmelon ranged from 15% to 30% and caused an average 20% yield loss. Symptoms appeared as pale brown, water-soaked lesions that were irregular in shape, with the lesion sizes ranging from a small spot (1 to 2 cm) to decay of the entire fruit. The core and surface of infected fruit were colonized and covered with white mycelia. Two infected muskmelons were collected from two fields, 3.5 km apart. Tissues removed from inside the infected fruit were surface disinfected with 75% ethanol for 30 s, and cultured on potato dextrose agar (PDA) at 25°C in the dark for 5 days. Four purified cultures were obtained using the single spore method. On carnation leaf agar (CLA), 3 to 5 septate, falcate, with a pronounced dorsiventral curvature macroconidia with tapered apical cell, and foot-shaped basal cell, measuring 20 to 40 × 3.5 to 4.5 μm. Microconidia and chlamydospores were not observed. These morphological characteristics were consistent with the description of F. luffae (Wang et al., 2019). Because these isolates had similar morphology, two representative isolates (XP11 and XP12) were selected for multilocus phylogenetic analyses. DNA was extracted from the representative isolates using a CTAB method. Nucleotide sequences of the internal transcribed spacers (ITS) (White et al. 1990), calmodulin (CAM), RNA polymerase II second largest subunit (RPB2), translation elongation factor 1-α gene (TEF1) (Xia et al. 2019) were amplified using specific primers, sequenced, and deposited in GenBank (ITS: MW391509 and MW391510, CAM: MW392789 and MW392790, RPB2: MW392797 and MW392798, TEF1: MW392793 and MW392794). Alignments of a combined dataset of ITS, CAM, RPB2 and TEF1 were made using MAFFT v. 7, and phylogenetic analyses were conducted in MEGA v. 7.0 using the maximum likelihood method. The muskmelon isolates (XP11 and XP12) clustered together with the F. luffae reference strain LC12167 (99% bootstrap). To perform a pathogenicity test, 10 μl of conidial suspensions (1 × 106 conidia/ml) were injected into each muskmelon fruit using a syringe, and the control fruit was inoculated with 10 μl of sterile distilled water. There were ten replicated fruits for each treatment. The test was repeated three times. After 7 days at 25°C, the interior of the inoculated muskmelons begun to rot, and the rot lesion expanded from the core towards the surface of the fruit, then white mycelia were produced on the surface. Ten isolations were re-isolated from the infected tissues and confirmed to fulfill Koch’s postulates. No symptoms were observed on the control muskmelons. To our knowledge, this is the first report of fruit rot caused by F. luffae in muskmelon in China. Considering the economic value of the muskmelon crop, correct identification can help farmers select appropriate field management measures for control of this disease.

IDENTIFICATION OF CHILLI PLANTS PLANTING ORGANISMS IN TEKO VILLAGE, LOMBOK TIMUR

The main objective of this research is to identify and introduce various types of pests to farmers in Teko Village, Pringgebaya District. The method used is a survey method with a data collection approach in the form of direct observation on the expanse of chili plants and questionnaires as a guide for interviews with respondent farmers. Identification of pests on chili plants in Teko Village, namely: yellow virus, anthracnose fruit rot, fruit and leaf rot, whitefly, weeds (puzzle grass, spinach, and grass weeds).

First Report of Postharvest Fruit Rot Disease of Yellow Peach Caused by Diaporthe eres in China

The yellow peach (Amygdalus persica), is a fruit crop native to China with golden peel and pulp that is of particular interest in the fruit markets. In August of 2021, yellow peaches showing fruit rot symptoms were purchased from a commercial market in Linyi city, Shandong province, China. The symptoms included circular, tan to brown in color, rotten, necrotic lesions, and whitish mycelium mass in the center of the lesions. The infected fruit were surface disinfected with 1% NaClO for 30 s and rinsed with sterile distilled water three times. Diseased tissues from the infected fruits were cut into small segments, aseptically shifted onto potato dextrose agar media containing petri plates and incubated at 25℃ for 5 days. Eight isolates were obtained in total from two isolation experiments. Fungal colonies were initially white, aerial, fluffy at first, and gradually turned brown to gray, with black stromata at maturity. Alpha conidia were aseptate，hyaline，fusiform to ellipsoidal，and ranged in size from 4.16 to 7.76 µm × 1.95 to 3.14 µm (n=30). Beta conidia were aseptate, hyaline, filiform, curved to hamate, and 15.91 to 22.55 µm × 0.82 to 1.66 µm (n=30). The morphological characteristics were consistent with those of Diaporthe species (Gomes et al. 2013). For further identification, a multigene phylogenetic analysis was carried out. The internal transcribed spacer (ITS) region, translation elongation factor 1-α (TEF1-α), histone H3 (HIS), calmodulin (CAL), and β-tubulin (TUB) genes of two representative isolates were amplified by using primers ITS1/ITS4, EF1-728F/EF1-986R, CYLH3F/H3-1b，CAL228F/CAL737R, and Bt2a/Bt2b (Chaisiri et al. 2021), respectively. The sequences were deposited in GenBank (Accession No. OL375154 for ITS; OL406409 for TEF1-α; OL406410 for HIS; OL106407 for CAL; OL406408 for TUB). phylogenetic analyses were conducted using the concatenation of multiple sequences (ITS, TEF1-α, HIS, CAL, TUB) with Maximum Likelihood (ML) in IQtree v1.5.6 (Nguyen et al. 2015). Based on the morphological and phylogenetic characters, the isolates were identified as D. eres. A Pathogenicity test was performed by wound inoculation on harvested fruits of A. persica Variety ‘Jinxiu’. Mature and healthy yellow peaches purchased from Shandong, Anhui, and Hunan Provinces in China were surface sterilized with 1% NaClO solution for 1 minute, rinsed with sterile water and dried. Each fruit was wounded with a sterile scalpel creating a 2-3 mm incision on the peel. A 5 mm agar disc with mycelium grown on PDA at 28℃ for 7 days was placed on wound and sealed with parafilm. Sterile PDA plugs were used as controls. Ten fruit were used for each treatment and the assays were repeated three times. Inoculated fruit were placed in sterilized transparent plastic cans containing wet, sterile paper towels. After 5 days of incubation at 25℃, the same rot symptoms were observed on fruits inoculated with mycelium and the control remained symptomless. D. eres was re-isolated from the lesions of inoculated fruits and the pathogen identification was confirmed by molecular analysis, thus fulfilling complete Koch’s postulates. Although D. eres was previously reported on peach trees of causing shoot blight (Thomidis and Michailides 2009) and stem canker (Prencipe et al. 2017). To our knowledge, this is the first report of D. eres causing postharvest fruit rot of yellow peach in China and it may lead to considerable economic losses in the peach industry should post-harvest disease management practices not be implemented.

The effect of the crown shape on qualitative indicators of picking maturity and keeping capacity of apple fruits in the conditions of Crimea

В современных условиях развития интенсивного садоводства актуальной проблемой является подбор менее затратных и трудоемких систем формирования крон с соблюдением всех агротехнических мероприятий для получения высоких урожаев хорошего качества. Цель исследований направлена на изучение влияния разных способов формирования кроны на показатели съемной зрелости и лежкость плодов. Работа выполнялась в отделении «Крымская опытная станция садоводства» ФГБУН «НБС-ННЦ РАН» по методикам полевых исследований с плодовыми культурами. Объектами исследований являлись четыре формы кроны на подвое ЕМ-IХ (4 х 1 м, 2500 дер./га) и плоды сортов зимнего срока созревания: Джалита, Бреберн, Ренет Симиренко. Проведенные исследования позволили выявить наиболее эффективные формы кроны и достаточно устойчивые сорта для закладки интенсивных садов с высокой плотностью посадки, дающие высококачественную товарную продукцию, как в саду, так и в период хранения. Изменчивость показателей съемной зрелости в плодах зависит от сорта, погодных условий выращивания и формы кроны. Установлено, что плоды сортов Джалита, Бреберн (французская ось) и Ренет Симиренко (стройное веретено, безлидерная уплощенная, трехлидерная) в период хранения не имеют физиологических заболеваний. Дегустационная оценка вкуса составляет - 4,5-5,0 баллов, а естественная убыль не превышает 5,1%. Установлено также, что при хранении плоды сорта Джалита (стройное веретено, трехлидерная крона) повреждаются до 20% разными плодовыми гнилями, а плоды сорта Бреберн (стройное веретено) - подкожной пятнистостью - до 30%. Отмечено, что в период хранения происходит снижение плотности мякоти плодов в 1,4-2,2 раза, а также изменение вкуса в зависимости от сорта и формы кроны. In modern conditions of intensive gardening development, the actual problem is the selection of less costly and labor-intensive systems of crown shaping in compliance with all agrotechnical actions in order to obtain heavy yield of good quality. The goal of the research is aimed at studying the effect of different methods of crown shaping on the indicators of picking maturity and keeping capacity of fruits. The work was carried out in the department "Crimean experimental gardening station" of the FSBSI NBS-NSC RAS using methods of field research with fruit crops. The objects of research were four crown shapes on the EM-IX rootstock (4 x 1m, 2500 trees/ha) and the fruits of winter ripening varieties ‘Dzhalita’, ‘Brebern’, ‘Renet Simirenko’. The studies provided allow us to identify the most effective crown shapes and sufficiently resistant varieties for establishing intensive gardens with a high density of planting, giving high-quality marketable products, both in the garden and during storage. The variability of indicators of fruit picking maturity depends on the variety, weather conditions of growing and the crown shape. It was established that fruits of varieties ‘Dzhalita’, ‘Brebern’ (French axis) and ‘Renet Simirenko’ (slender spindle, leaderless flattened, three-leader) did not have physiological diseases during storage. Tasting assessment is 4.5-5.0 points, and the natural loss does not exceed 5.1%. It is also established that fruits of the ‘Dzalita’ variety (slender spindle, three-leader crown) during storage are subject to damage by various fruit rot up to 20%, and fruits of the ‘Brebern’ variety (slender spindle) by subcutaneous spotting - up to 30%. It is noted that during the storage period there is a decrease in the density of fruit pulp by 1.4 - 2.2 times, and a change in flavor depending on the variety and crown shape.