Zucchini Plants Research Articles

Effect of cow manure biochar on heavy metals uptake and translocation by zucchini (Cucurbita pepo L)

Little is known about the efficiency of biochar in the safety of food production in arid and semiarid contaminated soils. A field experiment in the semiarid region of Upper Egypt was conducted to explore heavy metals uptake by zucchini (Cucurbita pepo L) plants as affected by the application of cow manure biochar (CMB). Three rates of CMB were added, i. e., 0, 4, and 8 tonnes ha−1. The roots and shoots of zucchini plants stored 75 and 78% of Zn and Cu, respectively, while 25 and 22% were transported to the edible portions. On the other hand, the roots and shoots of zucchini plants stored more than 99% of Pb and Cd, while less than 1% was transported to the edible portions. Cow manure biochar (CMB) minimized the values of bioaccumulation factor (BAC) for Zn, Cd, and Ni by 5.6, 21.9, and 27.9%, respectively, while these reductions in the case of translocation factor (TF) were 4.9, 7.5, 23, and 5.9%. Cow manure biochar at a rate of 4 tonnes ha−1 reduced the availability of Zn, Cu, Pb, Cd, and Ni by 13.3, 8.3, 13.8, 9.1, and 3.6%, respectively, compared to the control treatment. Cow manure biochar at a rate of 8 tonnes minimized Zn, Cu, Pb, Cd, and Ni concentrations in the edible parts of zucchini plants by 10, 17, 66, 20, and 26%, respectively, in comparison with the untreated soil. Biochar reduced the heavy metals bioavailability, moreover; biochar minimized the soil-root transfer and the root-shoot of toxic metals. It is recommended to add cow manure biochar to zucchini plants to reduce the accumulating of hazard metals in the edible tissues.

Isolation and identification of PAH degrading bacteria from Jamaican Soil, Landfill Leachate, Kingston Harbour: Water and sediment samples

Hydrophobic pollutants have become widely distributed across the world. From an agricultural perspective, their accumulation in crops from contaminated soil threatens food security and quality, leading to many diseases in humans. The Cucurbitaceae family can accumulate high concentrations of hydrophobic pollutants in their aerial parts. The Cucurbitaceae family contains major latex-like proteins (MLPs) as transporting factors for hydrophobic pollutants. MLP genes are expressed in the roots in which the MLPs bind hydrophobic pollutants. MLPs transport these hydrophobic pollutants to the aerial parts of the plant through the xylem vessels. As a result, hydrophobic pollutant contamination occurs in the Cucurbitaceae family. In this study, we suppressed the expression of MLP genes in the roots and reduced the amounts of MLPs with pesticide treatments. First, the fungicides Benlate and Daconil that deceased the hydrophobic pollutant, perylene, concentration in the xylem sap of zucchini plants were selected. Daconil suppressed the transcription activity of MLP in the roots. In the Daconil treatment, the amount of MLPs in the roots and xylem sap of zucchini plants was decreased, and the concentrations of the hydrophobic pollutants, pyrene and dieldrin, were significantly decreased. Our research contributes to the production of safer crops.

De Novo Transcriptome Assembly of Cucurbita Pepo L. Leaf Tissue Infested by Aphis Gossypii

Zucchini (Cucurbita pepo L.), extensively cultivated in temperate areas, belongs to the Cucurbitaceae family and it is a species with great economic value. One major threat related to zucchini cultivation is the damage imposed by the cotton/melon aphid Aphis gossypii Glover (Homoptera: Aphididae). We performed RNA-sequencing on cultivar “San Pasquale” leaves, uninfested and infested by A. gossypii, that were collected at three time points (24, 48, and 96 h post infestation). Then, we combined all high-quality reads for de novo assembly of the transcriptome. This resource was primarily established to be used as a reference for gene expression studies in order to investigate the transcriptome reprogramming of zucchini plants following aphid infestation. In addition, raw reads will be valuable for new experiments based on the latest bioinformatic tools and analytical approaches. The assembled transcripts will serve as an important reference for sequence-based studies and for primer design. Both datasets can be used to support/improve the prediction of protein-coding genes in the zucchini genome, which has been recently released into the public domain.

First Report of Moroccan Watermelon Mosaic Virus in Zucchini in Iran.

Cucurbits are among the most important vegetable crops in Iran, growing both in open fields and in greenhouses. They are ranked first in economic value, second in yield, and third in acreage and are susceptible to a number of viruses (Bananej and Vahdat 2008). Whitefly-transmitted viruses, namely, cucurbit chlorotic yellows virus (CCYV) and cucumber yellows stunting disorder virus (CYSDV), and the aphid-borne watermelon mosaic virus (WMV), zucchini yellow mosaic virus (ZYMV), papaya ringspot virus (PRSV), and cucurbit aphid-borne yellows virus (CABYV), have all previously been reported from Iran (Bananej and Vahdat 2008; Bananej et al. 2013). During November 2017, 12 samples were collected from cucumber (Cucumis sativus) and 14 from zucchini (Cucurbita pepo) plants grown in open fields that showed virus-like symptoms such as leaf mosaic, mottling, deformation, and yellowing symptoms in Kerman province in the south of Iran. The majority of both plant species were heavily infested by Bemisia tabaci, whereas no aphid colonies were observed. Leaf samples collected from symptomatic plants were subjected to total RNA extraction (Chatzinasiou et al. 2010). Reverse transcription PCR assays used for the detection of CCYV, CYSDV, and CABYV (Orfanidou et al. 2014) showed that all samples were infected with CABYV (26/26), whereas three cucumber samples were infected with CCYV and four with CYSDV. Moreover, double antibody sandwich ELISA was used for detection of WMV, ZYMV, PRSV, and Moroccan watermelon mosaic virus (MWMV) using polyclonal antisera kindly provided by H. Lecoq (INRA, France). None of the samples (0/26) was found to be infected with WMV, ZYMV, or PRSV; however, 9 out of 14 zucchini samples were positive for MWMV infection, whereas none of the 12 cucumber plants were positive for MWMV infection. For further confirmation, the specific primers MoDetF/MoDetR (5′-AARGAYGTTGATGTTGGRAC-3′, 5′-CCATARTCAYTCTTGACYCCATC-3′) were used to amplify a 211-bp product of the capsid protein gene of MWMV. These results confirmed the presence of the virus in the nine zucchini plants. Two isolates were further characterized by sequencing the amplicon, and the BLASTn analysis of the obtained sequences (accession nos. LT985986 and LT985987) showed 100% nucleotide identity with MWMV isolates from Tunisia and Greece (accession nos. EF579955 and LN810061). To our knowledge, this is the first report of MWMV infecting zucchini in Iran. After the detection of the virus in several countries of the Mediterranean region, this report further extends the information on its geographical distribution in the Middle East. The high sequence similarity of the Iranian MWMV isolate with those from the other Mediterranean countries, but not sub-Saharan Africa, indicates their recent rapid spread in the Mediterranean region (Yakoubi et al. 2008). Further surveys should concentrate on the spread, incidence, and epidemiology of this virus in Iran.

Lipid-based bio-fungicides for control of powdery mildew in cucurbits

Powdery mildew (PM) infection of cucurbits is a major problem facing commercial New Zealand growers. Resistance to demethylation inhibitor fungicides is widespread so, there is a demand for new-generation bio-fungicides that can provide durable control alternatives in both conventional and organic systems. A wide range of milk products, plant and animal fats/oils, and natural plant elicitors were tested for their ability to control PM on squash and zucchini plants in a series of four glasshouse trials. The most promising product tested was anhydrous milk fat (AMF), in formulation with an emulsifier (Alanate 191™ or Panodan® AL10), an antioxidant (Grindox 122™) and/or other products (Synertrol Horti oil). These treatments were as effective as commercial fungicides in controlling PM, but there were significant issues with plant health. Future work will focus on reducing concentrations of the active ingredient to produce an effective formulation that is not detrimental to plant health. Soybean oil, coconut fat and olive oil formulations with Panodan® AL10 and Grindox 122™ also gave effective PM control with minimal effect on plant health.

NMR-Based Metabolomics Approach To Study the Influence of Different Conditions of Water Irrigation and Greenhouse Ventilation on Zucchini Crops.

This study describes the approach of 1H NMR metabolomic profiling for the differentiation of zucchini produced under different conditions of water irrigation (desalinated seawater -0.397 dS/m, 0.52 €/m3 vs groundwater -2.36 dS/m, 0.29 €/m3) and ventilation (surface area of the vent openings/greenhouse area was 15.0% for one sector and 9.8% for the other). Overall, 72 extracts of zucchini ( Cucubirta pepo L. cv Victoria) under four different conditions were regularly analyzed during the spring-summer cycle from April to July 2017. We have found that zucchini plants irrigated with desalinated seawater increased the zucchini production yield, presented fruits with higher concentration of glucose, fructose, and vitamin B3, and displayed an increased antioxidant activity. On the contrary, plant groundwater irrigation produced the increment of sucrose level that could rise the sweetness perception of the fruits. Finally, the ventilation variable produced a higher concentration of trigonelline, histidine, and phenylalanine but only on those zucchinis irrigated with groundwater.

Evaluation of Total Phenol and Flavonoid Content in a Wide Range of Local and imported Plants

Introduction: Today, due to the toxicity and carcinogenicity of synthetic compounds, the application of medicinal plants to treat chronic diseases has attracted the attention of many researchers. According to nutritionists claims, the inclusion of fruits and vegetables in the food basket, due to the presence of phenolic compounds and antioxidant substances in the plant as well as regarding the role of antioxidants in the treatment and prevention of chronic diseases such as cancer, the aim of this study was to evaluate the total phenol and flavonoid content of a wide range of local and imported plants of cucurbitaceae, rhamnaceae and citrus family. Materials & Methods: In this study, a wide range of Cucurbits family such as cucumbers and squash, Rhamnaceae and citrus fruits such as tangerine, orange, lemon, etc. from southern Iranian areas of Jiroft, Rodan, Jask and Minab and some seed sellers were evaluated, based on total fenol and flavonoid contents. Folin–Ciocalteu method was used to measure the amount of total phenolic content and the aluminum chloride method was applied to assess the flavonoid content. The data was analyzed by NTsys pc2.02, SAS 9.1 and student statistics 9 software. Findings: The results showed that Cucurbitaceous genotypes had the highest rates of total phenolic and flavonoid followed by zucchini and Citrus respectively. Spain Cucumber hybrid of tunnel Hilton Genotypes showed the highest rates of total phenolic (25.372 mg/gDW), while pumpkin hybrid stewed uni-flower genotypes indicated the highest rates of flavonoid (235.53 mg/gDW). Our findings also demonstrated that the environment did not prove as significant on anti-oxidant citrus products of Jiroft and Rodan. Furthermore, culsteral analysis segregated all the genotypes into three groups, allowing for their botanical properties. Discussion&Conclusion: As concluded by our investigation, the amount of total phenolic of the imported plants was more than that of the local ones, but the amount of flavonoid in local plants was more than the imported ones. Geographical conditions did not affect the amount of phenol and flavonoid compounds. Due to the high levels of antioxidant substances in Cucurbitaceae family and zucchini plants, and also to the risks of cancer from chemicals and synthetic drugs, this plant is suggested to be used as a rich source of antioxidant in food and pharmaceutical industry.

Antiviral activity of prickly pear (Opuntia ficus-indica (L.) Miller) extract: Opuntin B, a second antiviral protein

We previously showed that aqueous extract of prickly pear (Opuntia ficus-indica) cladode has significant antiviral activity against Cucumber mosaic virus (CMV: family Bromoviridae). Antiviral activity of the extract was retained for a period of 9 days on treated faba bean leaves. This activity was considerably decreased at concentrations lower than 30 mg mL−1, and by washing the treated leaves of faba bean plants 2 h after application of cactus extract, and was ineffective when applied 24 h after virus inoculation. No inhibitory effect was found against agro-inoculated strain of Beet curly top virus (BCTV: family Geminiviridae) on faba bean plants. Prickly pear extract reduced the efficiency of CMV transmission by Aphis gossypii on treated cucumber seedlings. An antiviral protein designated Opuntin B was isolated from the extract by heat treatment and differential centrifugation, and bulk protein precipitation by ammonium sulfate followed by cation and anion exchange chromatography. SDS-PAGE analysis in the presence of 2-ME revealed that Opuntin B is made of four protein components, in the molecular weight (Mr) range of 29–32 kDa, while in the absence of 2-ME, only two bands in the range of 26–28 kDa were visible. Native PAGE of the protein also showed 2 bands. Purified Opuntin B completely inhibited CMV on faba bean and zucchini plants at concentration of 40 μg mL−1 and had an IC50 of 0.75 μg mL−1 for inhibition of the virus on faba bean leaves. The isolated antiviral protein exhibited inhibitory activity against Zucchini yellow mosaic virus (ZYMV: family Potyviridae) Squash mosaic virus (SqMV: family Secouviridae) and Tobacco mosaic virus, (TMV: family Virgaviridae), as well.

Plant response to feeding aphids promotes aphid dispersal

AbstractPlant responses against biotic stress agents are affected by a number of environmental conditions, including the presence of other pests and pathogens. Moreover, the impact of infestation on subsequent plant colonization by conspecifics can vary, reflecting the high diversity in the co‐evolutionary processes shaping host‐plant interactions. Here, we address this issue by studying how aphid–plant interplay can influence the subsequent colonization of zucchini plants (Cucurbita pepo L., Cucurbitaceae) by conspecific Aphis gossypii Glover (Hemiptera: Aphididae, Aphidini). Previous infestation does not impact development time, longevity, and fertility of aphids. However, a previous infestation affects the distribution of the newly produced nymphs on the plant – they actively disperse on the plant, rather than starting their feeding activity where they were originally deposited, as observed in controls. Interestingly, this altered dispersal behaviour is reproduced by saliva application, suggesting the occurrence of an elicitor triggering a plant response affecting the strategy of host‐plant colonization by A. gossypii. The hypothesis that salicylic acid (SA) induction can trigger the observed behavioural response in a secondary infestation, was confirmed by exposure to methyl salicylate, a volatile product of the SA pathway. This evidence was further corroborated by analysis of gene expression profiles. Aphid infestation showed a transcriptional up‐regulation of genes underlying the biosynthesis of SA and of genes modulating the SA‐mediated defence response. Collectively, the experimental data consistently indicate regulation of aphid behaviour, mediated by plant metabolic changes following aphid infestation.

Survey of the distribution of Bemisia tabaci (Hemiptera: Aleyrodidae) in Lazio region (Central Italy): a threat for the northward expansion of Tomato leaf curl New Delhi virus (Begomovirus: Geminiviridae) infection

Bemisia tabaci (Hemiptera: Aleyrodidae) is responsible for severe damage to horticultural and ornamental crops worldwide, mainly for its role as virus vector. In Italy, the B. tabaci Mediterranean (MED) and Middle East–Asia Minor 1 (MEAM1) cryptic species are widespread in the Southern regions as well as in Sicily and Sardinia. During the last two decades, MED populations progressively increased, in those areas where intensive farming is applied. The recent introduction of the begomovirus Tomato leaf curl New Delhi virus (ToLCNDV) prompted extensive surveys of both vector and symptomatic plants. In 2016 and 2017, monitoring activities were carried out in Lazio region (Central Italy) where begomovirus epidemics had never occurred before and the presence of B. tabaci was thought to be only occasional. ToLCNDV-infected zucchini plants were found in Southern Lazio together with whitefly populations belonging only to the MED cryptic species. The MED-Q2 haplotype was the most abundant, likely favored by high temperatures and intensive agricultural practices. Single and mixed populations of MED and MEAM1 were found in Central and Northern Lazio, suggesting that agro-ecological factors still limit MED outbreaks in these areas. This preliminary survey indicates that B. tabaci is well established in Lazio, making ToLCNDV potentially able to spread to the rest of the region as well as to the nearby regions of Central Italy that have similar climatic and cultural conditions. The northward spread of B. tabaci is a critical issue for viral disease epidemiology and the management of whitefly-transmitted viruses in Central Italy, and must be kept under strict surveillance.

Markers for Rapid Evaluation of Virus Resistance for TYLCV in Tomato, ZYMV and PRSV-W in Zucchini and LMV in Lettuce and Hybrid Seeds in Pumpkin

Screening for the source of virus resistance in horticultural plants or specific characterization as hybridization, through symptoms, requires time and depends on the weather and knowledge of plant characteristics. So, it is important to develop specific gene markers to allow rapid diagnosis by PCR. Markers were developed based on sequences homology comparison of susceptible and resistant plants provided by HORTEC SEEDS in tomato for Tomato yellow leaf curl virus (TYLCV) by the resistance gene Ty-1, in zucchini for Zucchini yellow mosaic virus (ZYMV) and Papaya ringspot virus estirpe watermelon (PRSV-W), and in lettuce for Lettuce mosaic virus (LMV). Fragments of 249 bp were amplified only by resistant plants to TYLCV as the hybrids 2648 and Aguamiel, and not for varieties as Santa Cruz or Carina. It were observed for ZYMV the amplification of 791 bp by the resistant hybrid Px7051 and not for the susceptible cultivar La Belle; for PRSV-W using the same zucchini plants the amplification of 650 bp for susceptible and 750 bp for resistant; for LMV the 421 bp amplification only for the resistant cultivar Brasil 303 and not for susceptible Baba de Verao. Finally, it was observed that primers PK47F/R were able to check the Cabotia seed hybrids of pumpkin Jabras.

Doses of Crotalaria juncea: Residual effect on zucchini and maize crop in sequence to broccoli

ABSTRACT Amounts of N from green manures not absorbed in the first cycle can be absorbed by the subsequent crops. Therefore, it is important to quantify and monitor the residual effects of green manure to increase the agronomic benefits of its use in cropping systems. Our purpose was to study the residual effect of doses of the Crotalaria juncea green manure applied in broccoli crop in the zucchini-maize succession. This study was carried out in a crop succession system organized in three crops, with seven treatments and four major doses of green manure as 0, 3, 6, and 9 t ha-1. The control treatments consisted of a mineral fertilization, a treatment with 25 t ha-1 compost, and another as absolute control without organic compost or mineral fertilizer. The experimental plot consisted of five rows spaced 0.8 m with 3 m in length. The experimental design was a completely randomized block with four replications in a split-plot scheme in time for growth with variables of adjustment of statistical models by the response surface methodology. With the highest dose of green manure, the yield of zucchini plants was greater than the yield with 25 t ha-1 compost control and similar with mineral fertilizer. As for the maize yield in the dose of 9 t ha-1 green manure, the yield was superior only to absolute control. There was a residual effect of C. juncea mass, which was applied in broccoli crop for growth and yield of zucchini and maize grown in succession. The residual effect is dependent on the amount of weight of C. juncea applied, with the greatest effects in larger doses.

Biochar effects on nitrogen and phosphorus use efficiencies of zucchini plants grown in a calcareous sandy soil

Biochar effects on nitrogen and phosphorus use efficiencies of zucchini plants grown in a calcareous sandy soil

Absolute Quantification of Tomato leaf curl New Delhi virus Spain strain, ToLCNDV-ES: Virus Accumulation in a Host-Specific Manner.

Tomato leaf curl New Delhi virus (ToLCNDV) (family Geminiviridae, genus Begomovirus) has recently been introduced in western Mediterranean countries. Isolates in Spain constitute a new strain, denominated ToLCNDV-ES, that is causing losses in commercial zucchini and melon crops; however, it is also, although less often, detected in commercial tomato crops. We developed a tissue-print hybridization test to detect the two genomic components of the virus and a TaqMan quantitative polymerase chain reaction (qPCR) test to estimate the number of genome copies in plants. qPCR was approximately 104 to 106 times more sensitive than tissue-print hybridization to detect viral genomic DNA-A and DNA-B, respectively. It also detected the virus in more experimentally and naturally ToLCNDV-ES-infected zucchini squash and tomato plants. ToLCNDV-ES DNA-A titers were significantly lower in tomato than in zucchini plants, often falling below the detection limits in the hybridization test. In addition, the DNA-B accumulation was impaired in tomato when compared with zucchini. According to the data obtained in this study, the differences in viral titers of both plant species contribute to explain the dissimilarities in symptom expression, capability of detection, and transmission of the virus.

DDTs-induced antioxidant responses in plants and their influence on phytoremediation process

Phytoremediation is a low cost technology based on the use of plants to remove a wide range of pollutants from the environment, including the insecticide DDT. However, some pollutants are known to enhance generation of reactive oxygen species (ROS), which can generate toxic effects on plants affecting the phytoremediation efficiency. This study aims to analyze the potential use of antioxidant responses as a measure of tolerance to select plants for phytoremediation purposes. Tomato and zucchini plants were grown for 15 days in soils contaminated with DDTs (DDT + DDE + DDD). Protein content, glutathione-S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx) and catalase (CAT) activities were measured in plant tissues. Exposure to DDTs did not affect protein content or CAT activity in any of the species. GST, GR and GPx activity showed different responses in exposed and control tomato plants. After DDTs exposure, tomato showed increased GR and GPX activity in stems and leaves, respectively, and a decrease in the GST activity in roots. As no effects were observed in zucchini, results suggest different susceptibility and/or defense mechanisms involved after pesticide exposure. Finally, both species differed also in terms of DDTs uptake and translocation. The knowledge about antioxidant responses induced by pesticides exposure could be helpful for planning phytoremediation strategies and for the selection of tolerant species according to particular scenarios.

Control of Tomato leaf curl New Delhi virus in zucchini using the predatory mite Amblyseius swirskii

The tobacco whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), is a serious pest of vegetables in many horticulture systems. It vectors the Tomato leaf curl New Delhi virus (ToLCNDV) which causes considerable damage in zucchini crops. Both pest and the disease are well established in field and greenhouse crops in the southeast of Spain, the largest vegetable growing area in Europe. The predatory mite Amblyseius swirskii Athias-Henriot (Arachnida: Phytoseiidae) is known to effectively manage B. tabaci populations in crops such as sweet pepper and cucumber, feeding on eggs and crawlers of this pest. However, there are no reports on the effectiveness of predatory mites against tobacco whitefly in zucchini crops. The potential to reduce whitefly populations as well as the spread of ToLCNDV in zucchini was evaluated by the pre-installation of A. swirskii in seedlings. Results showed that the number of adult whiteflies and deposited eggs on zucchini plants were significantly lower on plants with the phytoseiid predator, showing a significant negative impact of A. swirskii on B. tabaci colonization and reproduction but not on the primary infection with ToLCNDV. However, the pre-release of the predatory mites resulted in a strong decrease in eggs and subsequently emerging adults of whiteflies relative to plants without predators, and a significant reduction in secondary spread of the virus.

Epiphytic Curtobacterium flaccumfaciens strains isolated from symptomless solanaceous vegetables are pathogenic on leguminous but not on solanaceous plants

In Iran, during 2013–16, 16 Gram‐positive corynebacteria‐like strains were recovered from the epiphytic parts of solanaceous vegetables including eggplant, pepper and tomato. The strains were recovered accidentally as a result of monitoring for other bacterial pathogens in solanaceous fields. The strains were phenotypically different from Clavibacter michiganensis strains. Although none of the strains were pathogenic on their host of isolation or on any other solanaceous plants, 12 out of 16 strains were pathogenic on common bean, cowpea, mung bean and soybean. Colonization by strains was observed on maize, zucchini, faba bean, honeydew melon, rapeseed, sugar beet and sunflower plants under greenhouse conditions. In PCR tests, the primer pair CffFOR2/CffREV4, specific for Curtobacterium flaccumfaciens pv. flaccumfaciens, enabled the amplification of the appropriately sized fragment in 12 out of 16 strains, and all 12 strains were pathogenic on dry beans. Phylogenetic analysis, using the gyrB and recA genes, showed all 16 bacterial strains clustered within several pathovars of C. flaccumfaciens. A nonpathogenic yellow‐pigmented strain (Xeu15) was clustered with the type strains of C. flaccumfaciens pv. betae and C. flaccumfaciens pv. oortii. Bacteriocin profiling assays revealed no significant differences among the pathogenic and nonpathogenic strains. Host range and population dynamics of four representative strains on 17 plant species showed population build‐up of the strains only on common bean, cowpea, wheat and red nightshade plants. The results provide important insights into the possible role of nonhost plants as reservoirs of plant pathogenic bacteria, which has important implications in plant disease epidemiology and management.

Compatibility of Beauveria bassiana with fungicides in vitro and on zucchini plants infested with Trialeurodes vaporariorum

The effect of fungicides on the entomopathogenic fungus Beauveria bassiana strain ATCC 74040 (Naturalis®) was evaluated in vitro and in vivo. The formulated fungicides Cantus® (boscalid), Frupica (mepanipyrim), Galben (benalaxyl), Melody® Compact (iprovalicarb+Cu oxychloride), Oracle™ (fenamidone+Cu), Prosper® 300 CS (spiroxamine), Signum® (boscalid+pyraclostrobin), Switch® (cyprodinil+fludioxonil) and Talendo® (proquinazid) were tested on fungal colony growth from 10 field dose (10FD) to 10−4FD. Each product mixed with Naturalis at FD was also tested against Trialeurodes vaporariorum on zucchini plants. Fungal colony growth was not affected by Cantus, Galben, Melody Compact, Oracle and Talendo at FD, while Frupica and Prosper 300 CS reduced colony growth by 9.7% and 6.9%, respectively. All these products did not inhibit the activity of B. bassiana on whiteflies at FD. On the contrary, Signum and Switch significantly inhibited colony growth at all doses and reduced the entomopathogenic activity on whiteflies when applied in mixture with B. bassiana. The toxic effect of both fungicides on B. bassiana persisted for 10days after treatments, with a 91.2% reduction in nymph mortality in comparison to control for Signum and 87.4% for Switch. The mode of action of their active ingredients, boscalid, pyraclostrobin, cyprodinil and fludioxonil, individually and in mixture (boscalid+pyraclostrobin and cyprodinil+fludioxonil), was studied on fungal colony growth, spore germination, germ tube elongation and spore survival from 10FD to 10−2FD. All these parameters were reduced by the four active ingredients at all doses, pyraclostrobin and fludioxonil completely inhibited spore germination, fludioxonil alone and in mixture with cyprodinil also inhibited completely spore survival.

Survival of Fusarium solani f. sp. cucurbitae and Fungicide Application, Soil Solarization, and Biosolarization for Control of Crown and Foot Rot of Zucchini Squash.

Fusarium crown and foot rot of zucchini squash (Cucurbita pepo L.) caused by Fusarium solani f. sp. cucurbitae is one of the major diseases affecting zucchini squash production in Almería, Spain. Experiments were conducted to determine the pathogen's ability to survive in infested bags of perlite and to test several control methods under greenhouse conditions. The pathogen survived in the bags for at least 20 months with enough inoculum at that time to produce disease symptoms in zucchini plants, although disease severity was significantly reduced after 14 months. A total of 14 zucchini cultivars were inoculated with F. solani f. sp. cucurbitae, and all were highly susceptible to the disease. Eight fungicides and two microbial products, Trichoderma harzianum and Rhizophagus irregularis, were tested to determine their efficacy for the control of this disease. Prochloraz, carbendazim, and thiophanate-methyl, which are not labeled for use in zucchini in Spain, were highly effective for the control of the disease, while the other products were ineffective. Two soil solarization and biosolarization experiments were conducted in a greenhouse for 45-day periods during the summer. Inocula in the soil samples decreased by more than 99%, indicating the efficacy of completely closing the greenhouse windows, solarization, and biosolarization in reducing inoculum. Fungicide applications, crop rotation for at least two years, and soil solarization or biosolarization are promising control methods for this disease.

Influence of agro-ecological service crop termination and synthetic biodegradable film covering on Aphis gossypii Glover (Rhynchota: Aphididae) infestation and natural enemy dynamics

AbstractAgro-ecological service crops (ASC) can increase the vegetation complexity of agroecosystems leading to a positive impact on natural enemies of arthropod pests and on weed control. In this study, two ASC terminations (green manure and roller crimper) and a Mater-Bi-mulched control (MB) were compared in order to describe the effects on pests and beneficial dynamics in an organic vegetable system. The trials were conducted over two consecutive growing seasons in 2014 and 2015. Zucchini were grown as cash crop and barley as ASC. Pests and natural enemies were monitored fortnightly by visual samplings along the whole zucchini-growing season. Zucchini plants showed a faster vegetative growth in MB treatment than in ASC terminations. In both years, MB plots were characterized by higher soil temperature and higher leaf nitrogen concentration resulting in plants more susceptible to Aphis gossypii infestations. In all the experimental plots, natural enemies controlled aphid infestations and no insecticide and sprays were necessary. In conclusion, the tested ASC techniques have been suggested as a tool to mitigate aphid infestation.