Reducing Chlorothalonil Use in Fungicide Spray Programs for Powdery Mildew, Anthracnose, and Gummy Stem Blight in Melons

Fungicides are applied to nearly 80% of U.S. melon acreage to manage the numerous foliar and fruit diseases that threaten yield. Chlorothalonil is the most widely used fungicide but has been associated with negative effects on human and bee health. We designed alternative fungicide programs to examine the impact of reducing chlorothalonil use (Bravo Weather Stik) on watermelon, cantaloupe, and honeydew melon in 2016, 2017, and 2018 in Maryland. Chlorothalonil was replaced in the tank mix of weekly sprays of targeted fungicides with either polyoxin D zinc salt (Oso) or an extract of Reynoutria sachalinensis (Regalia). Powdery mildew (PM; Podosphaera xanthii), gummy stem blight (GSB; Stagonosporopsis spp.), and anthracnose (Colletotrichum orbiculare) were the most prevalent diseases to occur in the 3 years. Replacing chlorothalonil with the biopesticides as the tank-mix component of the fungicide spray program was successful in reducing GSB and PM severity in cantaloupe, honeydew melon, and watermelon compared with the untreated control, with the exception of GSB in 2017 in cantaloupe, and similar to the program including chlorothalonil in all cases, except anthracnose in watermelon. Anthracnose disease severity was not significantly reduced compared with the untreated control when chlorothalonil was replaced with the biopesticides and yields were not improved over the chlorothalonil-alone treatment in any of the trials. Therefore, replacement of chlorothalonil may not fully address its loss as a fungicide resistance management tool but efficacy can be maintained when polyoxin D is alternated with R. sachalinensis as a tank mix with targeted fungicides to manage PM and GSB.

Physico-chemical Characteristics of Sokoto Locally grown Cucumis melo L (Honeydew Melon) Seed Oil

Introduction: Owing to increase demand for safer and health promoting vegetable oils, a number of potential sources are being explored by researchers. Materials and Methods: In this study, oil was extracted using Soxhlet from Sokoto locally grown Cucumis melo L (honeydew melon). Physical and chemical properties (colour, moisture, pH, specific gravity, refractive index, acid value, iodine value, saponification value and peroxide value) of the oil were determined using standard analytical methods by Association of Official Analytical Chemists (AOAC). Results: The results showed the percentage yield of the oil to be 27.46%. Physically, the oil was yellowish in colour, liquid at room temperature, with pH of 6.2 (0.01), specific gravity of 0.89 (0.32), and refractive index of 3.62 (1.0). The saponification, acid, iodine and peroxide values of the oil were 45.81 (5.19), 9.16 (0.21), 64.80 (4.31) and 10.50 (1.50) respectively. Conclusion: The results suggest that the oil has a potential for use as vegetable oil, in industries and, subject to further evaluation of the contents, health promoting purposes.

Anticancer Properties of Different Solvent Extracts of Cucumis melo L. Seeds and Whole Fruit and Their Metabolite Profiling Using HPLC and GC-MS

Honeydew melon (Cucumis melo L.) is an oval-shaped delicious fruit of one cultivar group of the muskmelon with immense nutritional importance and is extensively consumed by many tropical countries. The effect of various organic solvents on the recovery of phytochemicals from honeydew melon plant fruits and seeds was assessed. Further, High-Performance Liquid Chromatography (HPLC) was used to examine and assess the contents of phenolic acid (gallic acid) and flavonoid (rutin) compounds. The use of gas chromatography–mass spectrometry (GC-MS) analysis explained the presence of volatile phytocompounds in the extracts. The use of organic solvents had a substantial impact on the total dry weight and extract yield. In general, the solvent-extracted constituents remained in the order of methanol>chloroform>distilled water for both honeydew melon seeds and whole fruit. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) was used to assess the cytotoxicity effect against PC3, HCT116, HeLa, and Jurkat cell lines. The chloroform extract exhibited a good cytotoxic activity against all cell lines as compared to other solvent extracts. HPLC analysis revealed the occurrence of gallic acid content of 0.102±0.23 mg/10 mg of dry whole fruit extract, while 10 mg of dry seed extract contained only 0.022±0.12 mg of gallic acid content. Likewise, rutin content was observed to be 0.224±0.31 mg and 0.1916±0.82 mg/10 mg of dry whole fruit and seed extract, respectively. Further, GC-MS analysis revealed the presence of a total of 37 compounds in chloroform extract of whole fruit, while only 14 compounds were found in seed extract. Nevertheless, more examinations are needed to identify and characterize other metabolites from honeydew melon and evaluate their pharmacological importance.

Oscillating Magnetic Field (OMF) Based Supercooling Preservation of Fresh-Cut Honeydew Melon

An oscillating magnetic field (OMF) was used to extend the supercooled state in honeydew melon samples. The internal temperature of the samples under OMF treatment was kept at -5.5°C during a 21-day storage period without freezing. To inhibit ice crystal nucleation, the OMF treatment was controlled using a repeated sequence of on/off cycles with durations of 120/420 s. Quality factors of the supercooled samples were measured and compared with fresh, refrigerated, and frozen samples. Factors such as microbiological analysis, drip loss, pH, titratable acidity, and soluble solids contents indicated that the overall quality of the supercooled samples after 21 days was not significantly different (p > 0.05) from that of fresh samples. Although a few cells in the supercooled samples had undulated walls compared to fresh samples under microscopic analysis, the cells were closely bonded to each other, and distorted cells were not found. Keywords: Fresh-cut fruits, Honeydew melon, Oscillating magnetic fields, Quality assessment, Subzero preservation.

Papaya ringspot virus Populations From East Timorese and Northern Australian Cucurbit Crops: Biological and Molecular Properties, and Absence of Genetic Connectivity

To examine possible genetic connectivity between crop viruses found in Southeast Asia and Australia, Papaya ringspot virus biotype W (PRSV-W) isolates from cucurbits growing in East Timor and northern Australia were studied. East Timorese samples from cucumber (Cucumis sativus) or pumpkin (Cucurbita moschata and C. maxima) were sent to Australia on FTA cards. These samples and others of pumpkin, rockmelon, honeydew melon (Cucumis melo), or watermelon (Citrullus lanatus) growing in one location each in northwest, north, or northeast Australia were subjected to high throughput sequencing (HTS). When the 17 complete PRSV genomic sequences obtained by HTS were compared with 32 others from GenBank, the five from East Timor were in a different major phylogroup from the 12 Australian sequences. Moreover, the East Timorese and Australian sequences each formed their own minor phylogroups named VI and I, respectively. A Taiwanese sequence was closest to the East Timorese (89.6% nt dentity), and Mexican and Brazilian sequences were the closest to the Australian (92.3% nt identity). When coat protein gene (CP) sequences from the 17 new genomic sequences were compared with 126 others from GenBank, three Australian isolates sequenced more than 20 years ago grouped with the new Australian sequences, while the closest sequence to the East Timorese was from Thailand (93.1% nt identity). Recombination analysis revealed 13 recombination events among the 49 complete genomes. Two isolates from East Timor (TM50, TM32) and eight from GenBank were recombinants, but all 12 Australian isolates were non-recombinants. No evidence of genome connectivity between Australian and Southeast Asian PRSV populations was obtained. The strand-specific RNA library approach used optimized data collection for virus genome assembly. When an Australian PRSV isolate was inoculated to plants of zucchini (Cucurbita pepo), watermelon, rockmelon, and honeydew melon, they all developed systemic foliage symptoms characteristic of PRSV-W, but symptom severity varied among melon cultivars.

Role of Brushes and Peelers in Removal of Escherichia coli O157:H7 and Salmonella from Produce in Domestic Kitchens

Consumers are being advised to increase their consumption of fruits and vegetables to reduce their risk of chronic disease. However, to achieve that goal, consumers must be able to implement protocols in their kitchens to reduce their risk of consuming contaminated produce. To address this issue, a study was conducted to monitor the fate of Escherichia coli O157:H7 and Salmonella on produce (cantaloupe, honeydew melon, carrots, and celery) that were subjected to brushing or peeling using common kitchen utensils. Removal of similar levels of Salmonella from carrots was accomplished by peeling and by brushing, but significantly greater removal of E. coli O157:H7 from carrots was accomplished by peeling than by brushing under running water (P < 0.05). Brushing removed significantly fewer pathogens from contaminated cantaloupes than from other produce items (P < 0.05), suggesting that the netted rind provided sites where the pathogen cells could evade the brush bristles. A Sparta polyester brush was less effective than a scouring pad for removing Salmonella from carrots (P < 0.05). In all cases, brushing and peeling failed to eliminate the pathogens from the produce items, which may be the result of contamination of the utensil during use. High incidences of contamination (77 to 92%) were found among peelers used on carrots or celery, the Sparta brush used on carrots, and the scouring pad used on carrots and cantaloupe. Of the utensils investigated, the nylon brush had the lowest incidence of pathogen transference from contaminated produce (0 to 12%). Transfer of pathogens from a potentially contaminated Sparta brush or peeler to uncontaminated carrots did not occur or occurred only on the first of seven carrots processed with the utensil. Therefore, risk of cross-contamination from contaminated utensils to uncontaminated produce may be limited.