Zucchini Crops Research Articles

Application management of Codasal Plus 2000 on Italian Zucchini irrigated with saline water

Zucchini (Cucurbita pepo L.) is one of the main economically important vegetables in Brazil, but its production is limited in semi-arid regions due to its water requirement. This study evaluated the effect of Codasal Plus 2000 in different application management on zucchini crops irrigated with saline water. The experiment was carried out at the Federal Rural University of Semi-Árido, Mossoró-RN. A randomized block design was adopted with two salinity levels of irrigation water (S1 - 0.5 dS m-1; S2 - 5.0 dS m-1) and six application managements of Codasal Plus 2000 ((M1 - Absence (H2O); M2 - every 7 days (2 L ha-1); M3 - every 7 days (4 L ha-1); M4 - every 14 days (4 L ha-1); M5 - every 14 days (8 L ha-1); M6 - every 14 days (6 L ha-1)). Growth and production variables were evaluated. Regardless of application management, the dry mass of the vegetative part, dry mass of the fruits and total dry mass reduced by an average of 34.16%, 49.29% and 21.78. %, respectively, at the highest salinity. In fruits, the number, fresh mass and productivity were reduced by 67.75%, 21.77% and 72.48%, respectively, at the highest salinity level. Codasal Plus 2000 was unable to mitigate the negative effects of saline water.

A Hive Entrance System That Directs Honey Bees Inside or Outside a Greenhouse Reduced Colony Decline While Effectively Pollinating Zucchini Squash

Honey bee colonies rapidly decline when confined to greenhouses, increasing pollination rental costs as they need to be replaced frequently. We tested a hive system with entrances that can be manipulated to direct bees inside or outside greenhouses containing a zucchini crop. In one greenhouse, the bees could only forage inside for 15 days; in another, bees were directed to the inside from 5 to 9 a.m., after which they only foraged outside. This procedure was repeated two more times in each greenhouse with new hives. Data were collected on how the number of bee flower visits affected fruit production, the frequency of flower visits, and the amount of bee brood and food in the hives. Flowers visited by bees four times or more set more and larger fruit. The frequency of flower visits by bees from the hives confined to the greenhouse was reduced after eight days; it was not reduced in the greenhouse with bees that could forage outside. The bee brood area was reduced in the colonies that were confined to the greenhouse, while it was maintained in the semi-confined hives. The hives with controllable entrances proved effective for pollination, while causing less damage to the bees.

Cultivo de abobrinha sob estresse salino e aplicação exógena de paclobutrazol

ABSTRACT Salinity is considered an obstacle to the production system that limits the growth and yield of crops around the world. Therefore, it is essential to develop strategies to minimize the effects of salinity and increase yield, especially in the semi-arid region of the Northeast, which has limited water resources of good quality for irrigation. The objective was to evaluate the effects of applying paclobutrazol on zucchini crop under salt stress. The experiment was conducted in a greenhouse, in a randomized block experimental design, in a 2 × 5 factorial scheme, with two salinity levels of irrigation water (0.6 and 4.0 dS m-1) and five concentrations of paclobutrazol - PBZ (0; 2; 4; 6 and 8 g L-1), and with four repetitions. Application of 8 mg L-1 PBZ increases stem diameter in zucchini under irrigation of 4.0 dS m-1. Chlorophyll b and total chlorophyll contents increase with PBZ concentration of 4 mg L-1 and irrigation of 0.6 dS m-1. PBZ concentration of 4 mg L-1 increases the relative water content while reducing electrolyte leakage in zucchini under salinities of 4.0 and 0.6 dS m-1 respectively. Root, stem and leaf dry mass of zucchini increases when plants are irrigated with water of 0.6 dS m-1 and subjected to PBZ concentration of 8 mg L-1. PBZ concentrations do not attenuate the effects of salinity on leaf area, crown volume and diameter, vegetative vigor index, chlorophyll a and carotenoids.

Living mulches reduce natural enemies when combined with frequent pesticide applications

Agricultural intensification with frequent pesticide applications often diminishes biological control services delivered by beneficial insects. However, re-integrating diverse and structurally complex non-crop habitat may mitigate negative effects by providing refugia to natural enemies, enabling rapid recolonization of pesticide-treated crops. This study examines the compatibility of chemical control with non-crop habitat management by manipulating pesticide treatments and living mulches between rows of zucchini crops in four replicated experiments across the Southeastern United States. The hypothesis was that living mulches and pesticide applications would each negatively impact pests and have interactive effects on predatory insects, with negative pesticide effects being attenuated in plots with untreated living mulches serving as refugia for predators between crop rows. Instead, combining living mulches with pesticide applications reduced natural enemy densities, relative to bare plots. Pesticide applications had no effect on spotted and striped cucumber beetle pests, while living mulches directly reduced them by 25%. Conversely, pesticide applications reduced squash bug pressure by 50%, while living mulches had no effect. Although crops were grown in plastic mulch to protect them from competition, living mulches reduced zucchini yields by 54% at sites where living mulches were less-managed. Alternatively, living mulches had more neutral effects on yields at sites where mulches were mowed monthly, suggesting that living mulches require management to minimize competition with crops. These results suggest that the grass-dominated living mulches tested in this study did little to harmonize chemical and biological control. While non-crop plant diversity has clear benefits for natural pest suppression in many systems, these benefits cannot be generalized across all plant and insect taxa. Future efforts to fine-tune management of non-crop habitat within fields will be strengthened by consideration of traits of key pests and their specific responses to both pesticide applications and plant diversity.

Long-term monitoring of aphid-transmitted viruses in melon and zucchini crops: genetic diversity and population structure of cucurbit aphid-borne yellows virus and watermelon mosaic virus.

Understanding the emergence and prevalence of viral diseases in crops requires the systematic epidemiological monitoring of viruses, as well as the analysis of how ecological and evolutionary processes combine to shape viral population dynamics. Here, we extensively monitored the occurrence of six aphid-transmitted viruses in melon and zucchini crops in Spain for 10 consecutive cropping seasons between 2011 and 2020. The most prevalent viruses were cucurbit aphid-borne yellows virus (CABYV) and watermelon mosaic virus (WMV), found in 31 and 26% of samples with yellowing and mosaic symptoms. Other viruses, such as zucchini yellow mosaic virus (ZYMV), cucumber mosaic virus (CMV), Moroccan watermelon mosaic virus (MWMV), and papaya ring spot virus (PRSV) were detected less frequently (< 3%) and mostly in mixed infections. Notably, our statistical analysis showed a significant association between CABYV and WMV in melon and zucchini hosts, suggesting that mixed infections might be influencing the evolutionary epidemiology of these viral diseases. We then carried out a comprehensive genetic characterization of the full-length genome sequences of CABYV and WMV isolates by using the PacBio single-molecule real-time high-throughput technology, in order to assess the genetic variation and structure of their populations. Our results showed that most isolates clustered in the Mediterranean clade, with a fine-scale temporal structure, which was in part explained by the level of the variance between isolates from single and mixed infections. In contrast, the WMV population genetic analysis showed that most of the isolates grouped into the Emergent clade, with no genetic differentiation.

First report of Watermelon crinkle leaf‐associated virus 1 (WCLaV‐1) on Cucurbita pepo in the United States

Zucchini (Cucurbita pepo) is widely grown in Florida and contributes to the US$35 million value production of all types of squash in the state (United States Department of Agriculture/ National Agricultural Statistics Service, 2021). In August 2022, zucchini (cv. Renegade) in a commercial field in North Florida, USA, showed pronounced chlorosis and mild crinkle on leaves in scattered areas (Fig. 1). The disease incidence was approximately 35%. One diseased leaf from each of six zucchini plants were collected randomly for diagnosis; three from 21-day-old plants (noted as Z272), and three from 28-day-old plants (noted as Z273). All samples tested negative for Cucumber mosaic virus, Squash mosaic virus and Zucchini yellow mosaic virus using ImmunoStrips (Agdia, USA). Subsequently, total plant RNA was extracted using a Quick-RNA MiniPrep kit (Zymo Research, USA). A conventional one-step RT-PCR (New England Biolabs, USA) was used to test the samples using primer pairs for Cucurbit chlorotic yellows virus (CCYV; Jailani et al., 2022), Watermelon crinkle leaf-associated virus 1 and 2 (WCLaV-1 and WCLaV-2; genus Coguvirus) (Hernandez et al., 2021) and Watermelon mosaic virus 2 (WMV-2; 5′-AAAGCTCCATACATAGCTGAGAC-3′/ 5′-CGGCCTTCATTTGTGCTATTG-3′). The samples were negative for CCYV, WMV-2 and WCLaV-2, but positive for WCLaV-1 using specific primers for the RNA-dependent RNA polymerase (RdRP) region on RNA-1 (Table 1). To confirm the detection of WCLaV-1, specific RNA-2 primers, targeting the coding regions of movement protein (MP) and nucleocapsid protein (NP), respectively, were used in an RT-PCR assay (Table 1, Hernandez et al., 2021). The sequences of the RdRP amplicon (881 bp) (GenBank Accession No. OP484885) had 99% nucleotide identity with WCLaV-1 isolates from China (KY781184) and the USA (OL469153 and OL469154). The sequences of the MP amplicon (538 bp) (OP484884) shared 99% nt identity with Australian WCLaV-1 isolate S6 (ON934517) and American isolates “Turner” and “Wilcox-02” (OM751929 and OM751928). The NP amplicon sequences (786 bp) (OP484883) shared 99% nt identity with Chinese isolate KF-1 (KY781186) and American isolate Wig-WM-D10 (MW559081). Both the samples (Z272 and Z273) had similar results, therefore only sequences from sample Z272 were submitted to GenBank. The results were further confirmed by SYBR®-based real-time RT-PCR using the WCLaV-1 MP gene-specific primer pairs (WCLaV-1FP/WCLaV-1RP) (Adeleke et al., 2022). WCLaV-1 and WCLaV-2 were first reported in watermelon in China (Xin et al., 2017), followed by America (Hernandez et al., 2021), Brazil (Maeda et al., 2022) and Australia (Mulholland et al., 2023). To our knowledge, this is the first report of WCLaV-1 on zucchini in America and globally. The mode of transmission of the virus in currently unknown. Studies to understand the potential of vector and seed transmission should be conducted to aid the development of best management practices. In the meantime, growers will have to rely on keeping pests of zucchini crop under control, practicing tillage of plant residues, and removing weeds routinely as general good practices.

Sweet as She Can Be

Sweet as She Can Be

Strip cropping in organically managed vegetable systems: agronomic and environmental effects

Abstract This study evaluated the agro-environmental and economic effectiveness of strips introduced in a diversified organic vegetable system. Two experiments of three experimental years (2018, 2019, 2020) were carried out within the 4-year rotation of MOnsampolo VEgetable organic Long-Term Experiment (MOVE LTE) in Central Italy to test strip cropping vs pure stand. The crop combinations in the two experiments were faba bean (Vicia faba L.)–tomato (Solanum Lycopersicum L.) and common wheat (Triticum aestivum)–zucchini (Cucurbita pepo L.). We determined the productive and economic performances, disease and weed control, nutritional differences and effectiveness in returning carbon to the soil. The two strip cropping systems allowed a better use of resources, enhancing plant biomass and crop residues, particularly for tomato (+24%) and zucchini (+63%). However, the greater plant biomass did not always result in an increase in crop yields. For example, while the wheat–zucchini strip system showed a land equivalent ratio &gt;1 in all three experimental years with a high yield performance in zucchini (+54% of yield), the faba bean–tomato system was more productive in strips only in 2018. On the contrary, this latter system contributed a carbon return &gt;1 in all three experimental years. No significant differences between strip and pure stand systems were observed for fusarium (Fusarium oxysporum f. sp. lycopersici) and oidium (Oidium spp.) diseases on tomato and zucchini crops, respectively, and for weed control. Lastly, greater labor costs associated in both experiments did not affect their profitability (+21% and +319% in faba bean–tomato and wheat–zucchini experiments, respectively). Overall, our findings pointed out that farmers could increase sustainability of their cropping systems with the introduction of a well-designed strip cropping system, which can lead to the reduction of economic risks, greater potential soil carbon and more efficient use of resources on the same land.

Desalinated and Brackish Water Conjunctive use in Irrigation Strengthening Adaptation and Resilience in Water-Scarce Regions Santiago Island - Cape Verde

The scarcity of water resources remains a global challenge. Finding alternatives to increase water availability is an imperative for adaptation and resilience in Cabo Verde. The research developed consisted in evaluating the use of desalinated, blended1 and brackish water in a light textured soil and its impacts on the productivity of tomato (Solanum lycopersicum), sweet potato (Ipomoea batatas) and zucchini (Cucurbita pepo) crops. The yield of tomato crop, irrigated with blended water (T2 with 2.5 dS/m), was 23.38 ton/ha; followed by irrigation with blended water (T3 with 3.5 dS/m) with a yield of 16.56 ton/ha, and irrigation with brackish water (T4 with 5.75 dS/m) whose yield was16.93 ton/ha. The lowest yield recorded (4.8 ton/ha) was with the treatment T1, irrigation with desalinated water. Regarding fruit quality, no significant variations were observed in tomato quality parameters, however, the variety Savana F1 is sensitive to apical rot. The average weight of the fruits differed according to the treatments: T1 (33.3g), T2 (39.7 g), T3 (32.4 g) and T4 (26.9 g). In terms of yield decrease (Qy) the following values were recorded: T1 (Qy =79.5%), T3 (Qy =29.2%) and T4 (Qy =27.6%) compared to the best treatment, T2 (23.38 ton/ha). The zucchini crop despite being moderately sensitive to salinity, did not adapt to the environmental conditions of the trial. The yield of sweet potato crop, irrigated with T1, was 14.6 ton/ha, followed by T2 with 11.08 ton/ha and T3 with 9.15 ton/ha. The lowest value verified (5.87 ton/ha) was with T4, brackish water. Regarding tubers quality, no significant variations were observed, but the average weight was better with the T1 treatment (199.4 g) followed by T2 (181.5g) and T3 (141.4g) and lastly T4 (126.3g). In terms of Qy, T2 (Qy =24.1%), T3 (Qy =37.3%) and T4 (Qy =60%) were the best compared to T1 (14.6 ton/ha). The results show that irrigation with blended water (desalinated and brackish) in adequate doses is a solution for increasing water availability and strengthening the resilience of agricultural systems in Cabo Verde (SID).

Biofumigation effects of brassicaceous cover crops on soil health in cucurbit agroecosystems in Hawaii, USA

Brassicaceous cover crops, such as brown mustard (Brassica juncea) and oil radish (Raphanus sativus), are commonly used for biofumigation, a process that utilizes isothiocyanates (ITCs) generated from the hydrolysis of glucosinolates in Brassica plants to suppress soil-borne pathogens, including plant-parasitic nematodes. Given the biocidal nature of ITCs, limited information is available on the non-target effects of biofumigation on free-living nematodes, which are reliable soil health indicators. The objectives of this study were to determine if biofumigation methods effective against plant-parasitic nematodes would have non-target effects on free-living nematodes, and to examine the relationships between biofumigation indicators and nematode communities. Three field trials were conducted to examine whether different biofumigation methods would affect free-living nematodes. Tissue maceration of biofumigant crops, soil tillage, and black plastic mulching were adopted singly or in combination to generate different regimes of biofumigation efficacy. Termination of biofumigant crops by tissue maceration and soil tillage followed by black plastic mulching for one week was most effective in suppressing plant-parasitic nematodes and enhancing bacterial decomposition. However, these effects did not last through the subsequent zucchini (Cucurbita pepo) crop cycle. When comparing changes in soil glucose and sulfate concentrations as indicators of biofumigation efficacy, we found that soil sulfate was a better indicator of biofumigation efficacy than soil glucose, owing to the more stable state of sulfate in soil. Canonical correspondence analysis between soil sulfate as a biofumigation indicator and nematode soil health indicators revealed strong positive correlations of sulfate level with the abundances of bacterivorous and carnivorous nematodes, enrichment index, brown mustard biomass, and soil temperature. However, biofumigation did not affect the nematode community structure. This study demonstrated that biofumigation can suppress plant-parasitic nematodes without compromising soil health.

Tomato Leaf Curl New Delhi Virus in Zucchini crops in Iran

During a survey in 2020, in Hormozgan province, the following symptoms were observed in zucchini crops growing in the field: leaf curling, yellow mosaic, swelling of veins of young leaves, and shortening of internodes. Because of the importance of the Tomato Leaf Curl New Delhi Virus (ToLCNDV) in other crops in Iran, the presence of this virus in the plants was evaluated by PCR amplification of the coat protein gene. Sequence analysis confirmed ToLCNDV infection of the symptomatic plants. This is the first report of ToLCNDV in zucchini plants in Iran.

Host Species-Dependent Transmission of Tomato Leaf Curl New Delhi Virus-ES by Bemisia tabaci.

The tomato leaf curl New Delhi virus (ToLCNDV) is a bipartite, single-stranded begomovirus that was first identified in India in 1995 affecting solanaceous crops. A different strain, named ToLCNDV-ES, was introduced in Spain in 2012 and causes severe symptoms in zucchini crops. Virus transmission experiments with the whitefly Bemisia tabaci, were used to compare the transmission parameters in zucchini and tomato plants. The minimum acquisition access period and inoculation access period of ToLCNDV-ES transmission was similar in zucchini and tomato. However, the transmission efficiency was significantly higher in zucchini (96%) compared to tomato (2%). The maximum retention of the virus in the vector was 16 days. B. tabaci feeding on, or recently emerged from infected zucchini plants, accumulated more virus than those from infected tomato, as determined by real-time PCR. A total of 20% of B. tabaci that were recently emerged from infected zucchini, and none from infected tomato, were able to transmit the virus to virus-free zucchini. The results may explain the different incidences of ToLCNDV-ES in zucchini and tomato crops in Spain. But they are also relevant for ToLCNDV-ES management of crops and the role of the trade and transport of infected plant material, when small-sized immature stages of B. tabaci could be a source of infection.

Isolation and Diagnosis of Pathogenic Fungi Associated With Zucchini Cucurbita Pepo Roots and Their Bio-Control

This study aimed to isolate and diagnose the main pathogens of zucchini root rot, test their pathogenicity, and evaluate their control with some biological agents under laboratory conditions. The results of diagnostic isolation from the roots of the zucchini crop that showed symptoms of the disease showed the presence and dominance of two isolates of Fusarium oxysporum (FO1, FO2), three isolates of Fusarium solani (FS1, FS2, FS3) and three isolates of Rhizoctonia solani (RS1, RS2, RS3) and two isolates of Pythium spp (PY1, PY2), which was present in a ratio of 65-25% in most of the samples collected from the fields of the Faculty of Agriculture/University of Karbala. F. solani had the highest frequency, at 60.00%, and had the highest occurrence in sample 3, which was 65.00%, followed by R. solani and F. oxysporum with 48.33 and 40.00% occurrence, respectively. The pathogenicity test of fungal isolates on red radish seeds showed that all isolates significantly reduced radish seeds germination under laboratory conditions. The results showed the effect of pathogenic fungal isolates on germination and growth of zucchini plants in protected cultivation, which led to a significant reduction in germination percentage, fresh weight of the plant, plant height and a high rate of disease severity. FS1 and RS1 isolates completely prevented seed germination, followed by FS2 and FO2 isolates with equal germination rate of 22.22%, compared to control treatment with 100% germination rate. FS2 isolate had the highest infection severity rate of 97%, followed by FO2 isolation with 94% compared to no infection in control treatment. The minimum plant length was 0.267 cm in the FS2 isolation treatment, followed by the FS3 isolate, with a plant length of 0.567 cm, compared to 2.553 cm in the control treatment. FO1 isolation led to the highest reduction in plant fresh weight by 81%, followed by isolate FS2 with 78% compared to control treatment. The test of the inhibitory ability of the biological control agents showed the presence of high antagonism of Trichoderma harzianum, Chaetomium sp and Sordaria sp against pathogenic fungal isolates. T. harzianum was the highest antagonistic against all the pathogenic fungal isolates, recording grade 1 antagonism according to Bell et al. (1982) after seven days of dual culture. Also, Chaetomium sp and Sordaria sp showed antagonistic ability of 1 and 2 degrees against pathogenic fungal isolates under study.

Effects of fluopyram and azadirachtin integration with sunn hemp on nematode communities in zucchini, tomato and sweet potato in Hawaii.

Fluopyram (Velum® One) is a synthetic nematicide and azadirachtin (Molt-X®) is a biological nematicide. Both have shown promise against plant-parasitic nematodes on several agriculturally important crops. There is a lack of information on integration of pre-plant sunn hemp (Crotalaria juncea) cover crop with these post-plant nematicides, aiming to improve plant-parasitic nematodes management and mitigate any detrimental effects on free-living nematodes. Three field trials were conducted to investigate the effects of fluopyram alone or in combination with pre-plant sunn hemp cover crop, and azadirachtin combined with pre-plant sunn hemp on Rotylenchulus reniformis and Meloidogyne spp., and free-living nematodes. Zucchini (Cucurbita pepo) and tomato (Solanum lycopersicum) were grown in Trials I and II, and sweet potato (Ipomoea batatas) only was grown in Trial III. In all three trials, early applications of fluopyram at crop planting were effective in suppressing the abundance of Meloidogyne spp. (M. incognita and M. javanica) but it was not effective in reducing R. reniformis in the soil. Combining sunn hemp with fluopyram was suppressive to R. reniformis on short-term zucchini crop, but not on longer term tomato and sweet potato crops. In addition, application of fluopyram at transplanting was the key to successful suppression of Meloidogyne spp. as later fluopyram chemigation (at 2 weeks after planting in Trial II or 1 month after planting in Trial III) had no effect against Meloidogyne spp. On the other hand, planting of sunn hemp followed by monthly post-plant azadirachtin application consistently suppressed R. reniformis, but this treatment did not suppress Meloidogyne spp. Integrating sunn hemp with fluopyram increased zucchini yield by >2.3 folds and that with azadirachtin increased the zucchini yield by >1.7 folds. Although no yield improvement was observed on tomato in Trial II, integrating sunn hemp with azadirachtin and fluopyram increased tomato yield by 0.23 and 1.12 folds, respectively, in Trial I. Marketable yield of sweet potato was increased by 4.5–6.4 folds in all the fluopyram treatments but was only increased 61.5% by sunn hemp plus azadirachtin treatment. While fluopyram alone often reduced the abundance of free-living nematodes, integrating with sunn hemp mitigated the negative impacts of fluopyram on soil health.

Saline-water irrigation and plant growth regulator application on zucchini fruit yield and quality

ABSTRACT The objective of this study was to evaluate the effect of a plant growth regulator (PGR; Stimulate®) on the yield and quality of zucchini fruits from plants of the cultivar Caserta-Italiana grown under different salinity levels of the irrigation water (SLIW). A randomized block design was used, in a 2 × 6 factorial arrangement consisted of two SLIW (0.5 and 5.0 dS m-1) and six PGR application modes: imbibition of seeds for 8 h in distilled water (PGR-T1; Control); imbibition of seeds for 8 h in PGR at 10 mL L-1 (PGR-T2); imbibition of seeds for 8 h in PGR at 10 mL L-1 plus foliar application at 10 mL L-1 at the flowering stage (PGR-T3); imbibition of seeds for 8 h in PGR at 10 mL L-1 plus two foliar applications at the flowering stage and at 20 and 30 days after sowing (PGR-T4); foliar application at 10 mL L-1 at the flowering stage (PGR-T5); and two foliar applications at 10 mL L-1 at 20 and 30 days after sowing (PGR-T6). The SLIW affected differently the variables of the zucchini crops evaluated. The PGR application to plants under no salt stress (0.5 dS m-1) increased the solid soluble concentration and biomass accumulation of zucchini fruits. The PGR application as seed treatment and foliar application at the flowering stage increased the fruit yield of zucchini plants irrigated with saline water.

On-farm fertilizing materials in organic horticulture: agronomic performance, energy use and GHG emission evaluation

ABSTRACT Anaerobic digestate (AD), a sub-product of cattle manure treatment to produce biogas, could be used for agricultural purposes after co-composting. The aim of this research was to evaluate in organic horticulture the co-composted AD, obtained using two different aerobic stabilization processes (not aerated and aerated composting), by assessing (i) the energy requirements and the GHG emissions of on-farm co-composting; (ii) the agronomic performance of the co-composted AD, compared to a commercial organic (CF) fertilizer, on fennel, tomato and zucchini crops; (iii) the environmental sustainability of the different analyzed systems, through the energy and the carbon footprint analyses. The AD co-composting was a feasible way to valorize organic wastes by producing organic fertilizers. These fertilizers could substitute the CF, leading to similar production capacity, energetic and carbon efficiencies. In particular, despite the greater carbon stocks generated by CF, the carbon efficiency was higher in co-composted AD than CF for both fennel and tomato cultivation systems. The GHG emission analysis for the agricultural operations indicated that CF treatment determined the highest CO2 emissions. Therefore, an appropriate management of the fertilization strategies could allow reducing the GHG emissions.

Effect of Distribution Uniformity and Fertigation Volume on the Bio-Productivity of the Greenhouse Zucchini Crop

Greenhouse horticultural crops are characterized by high levels of efficiency and productivity of irrigation water and nutrients applied. However, these indices may be affected by poor distribution uniformity of fertigation (DU). Different previous prospective studies show that there is a significant percentage of facilities with a low level of DU. However, there is no precise relationship between DU and the efficiency and productivity of water and fertilizers. This relationship may be affected by different factors, especially by the irrigation dose. The objective of this work was to determine the effect of the distribution uniformity of fertigation and the fertigation volume (FV) on the bio productive parameters and efficiency of water and nutrient use of the zucchini crop. The trial was developed in a greenhouse located in La Mojonera (Almería), on sanded soil. The greenhouse was equipped with an automated fertigation installation. The experimental design was randomized complete blocks with six treatments and three repetitions. The established treatment was a combination of two factors: distribution uniformity and fertigation volume. Three levels of DU were established: 100%, 75% and 50% approximately and two levels of fertigation volume: FV100% and FV70%. Volume of water and nutrients applied, soil matric potential (SMP), yield, biomass and efficiency in the water and nutrients use were determined. The maximum efficiency in the use of water and nutrients was obtained with a DU of 100% or 75% and a fertigation volume of FV70%, but this fertigation volume reduced the bio-productive parameters of the crop such as yield. The maximum yield and biomass were obtained with the volume of fertigation of 100% (FV100%), and with a DU of 100% or 75%. DU50% level reduced all bio-productive parameters, reducing yield by 45%, as well as the water use efficiency (WUE) and nutrient efficiency with any level of fertigation.

Identification, molecular characterization and prevalence of a novel cytorhabdovirus infecting zucchini crops in Greece

A new cytorhabdovirus was identified in zucchini (Cucurbita pepo) in Greece with the aid of high-throughput sequencing technology. The negative-sense, single-stranded genomic RNA of the new virus was determined and includes seven open reading frames in the order 3’-N-P-P3-P4-M-G-L-5’ in the antigenomic orientation. Typical rhabdovirus-like particles were observed in infected leaf material. Comparative sequence analysis and phylogenetic reconstructions suggested that the described virus is a new member of the genus Cytorhabdovirus, and it was tentatively named cucurbit cytorhabdovirus 1 (CuCV1). To our knowledge CuCV1 is the first cytorhabdovirus infecting cucurbits in nature. Our surveys indicated that it occurs in a percentage of 36.7 % in zucchini crops in Greece.

Characterization of Thyme and Tansy Extracts Used as Basic Substances in Zucchini Crop Protection

Bio-sourced substances used for crop protection in natural and organic farming have a positive impact both on human and environment health: plant extracts are effective to stimulate plant defense against pests and diseases, with no toxic effect and they could be classified as basic substances. The chemical characterization of thyme and tansy extracts were carried out with ICP and NMR techniques for the analysis of elemental content and organic components. Antioxidant activity was evaluated by DPPH method. Phytostimulant effects of extracts were evaluated on zucchini crop in a preliminary field test. Vegetative plant conditions were assessed by measuring the chlorophyll content. The 1% extracts were chosen for field trial because of their maximum antioxidant activity (over 80%) and their cheapness compared to 2% concentration. NMR showed that the spectrum of tansy highlighted the phenolic fraction in 6-9 ppm region and, in particular, at 5.9 ppm the signals of thymol, a peculiar antioxidant compound; while the spectrum of thyme is less significant. The field trial results showed a higher fruit yield and a positive effect on plant growth in treated plants respect to control ones, due to the composition and antioxidant activity of both plant extracts. In fact, thyme extract treated plants showed a yield equal to 6,4 kg per plant, higher than no treated ones, 5,1 kg per plant; also tansy extract induced a higher yield respect to control plant, respectively 5,6 and 3,9 kg per plant. The results obtained indicate the role of the extracts investigated as basic substances.

Mulching materials and wetted soil percentages on zucchini cultivation

ABSTRACT Polyethylene mulch can cause serious problems in the environment. A promising alternative to polyethylene mulch is biodegradable mulch. Therefore, a two-year experiment was carried out with zucchini (Cucurbita pepo L.) during the cropping seasons of 2017 and 2018 in Southeast Brazil to investigate the effects of four soil mulching treatments (white polyethylene mulch: WP, black polyethylene mulch: BP, biodegradable mulch of brown recycled paper: RP and nonmulched: NM) and two wetted soil percentages (50 and 70% of the soil surface) using a randomized block design with five repetitions. The average water consumption of the zucchini was 157 mm in the WP treatment, 155 mm in the BP treatment, 155 mm in the WP treatment and 215 mm in the NM treatment. The yield was higher in the WP (78.1 ton ha-1) and BP (69.1 ton ha-1) treatments than in the RP (66.6 ton ha-1) or NM (52.4 ton ha-1) treatments. The daily thermal amplitude was lowest in the RP treatment (3.6-6.0 °C) and highest in the BP treatment (7.3-9.0 °C). The lower wetted soil percentage (50%) reduced water consumption (by 5-7%) and improved water-use efficiency (by 11%). Weeds, including Cyperus roduntus, were more efficiently controlled in the RP treatment than in the WP and BP treatments. In general, compared to the nonmulched treatment, mulches were effective in reducing weed infestation (95%), increasing yield (36%) and improving water-use efficiency (94%). RP, as an alternative to polyethylene mulch, can save water and control weeds in zucchini crops. These results represent useful information that extends the mulching options for technicians and farmers.