Tomato Fields Research Articles

A regional-scale study of the contribution of local, management and climate factors to the infestation of processing tomato fields with Amaranthus species

Determining the various factors affecting weed infestation in arable fields is complicated by the considerable spatiotemporal variability of agricultural systems. A possible solution lies in regional-scale studies of weeds in commercial fields to provide insights into the influence of field properties, climate, and weed management practices on the efficacy of weed management. The current study focused on Amaranthus species – noxious weeds infesting many crops worldwide – in processing tomato fields in Northern Israel, a geographical region characterized by a significant climate gradient. This gradient provides an ideal opportunity to study the effect of climate on weed infestation and management. The objective of this study was to investigate the associations between Amaranthus infestations and local (field properties), climate, and management factors in processing tomato fields. A survey of 103 commercial tomato fields was carried out in 2018 and 2019 throughout the four major tomato-growing areas in Northern Israel. The spatiotemporal change in infestation for fields surveyed both pre- and post-weed control was evaluated relative to management and climate variables. A bootstrapped model selection for beta regression models with varying dispersion was performed to determine factors associated with weed infestation before and after weed management. The analysis showed that the application of sulfosulfuron pre-planting, could potentially reduce Amaranthus infestation depending on environmental and local conditions of the field; management comprising of more intense control measures reduced infestation; and precipitation led to an increase in mean infestation when occurring before planting, but a decrease when occurring after weed management. In addition, the onset timing of weed control was found to be negatively correlated with precipitation occurring post-treatment. Our findings show that management actions are key factors in controlling Amaranthus infestation but that these actions are affected by the local climate conditions. Therefore, this work indicates the need for a regional-scale perspective when making weed management decisions.

Abundance and Population Dynamics of the Key Insect Pests and Agronomic Traits of Tomato (Solanum lycopersicon L.) Varieties under Different Planting Densities as a Sustainable Pest Control Method

In Saudi Arabia, the tomato is susceptible to a wide range of insect pests that could destroy this valuable vegetable crop, cause yield losses, and affect fruit quality and quantity. Insecticides are widely applied to protect tomatoes and control pests that develop a resistance to pesticides, but these affect human health and have a negative impact on the environment. The application of Good Agriculture Practices (GAP) is a worthwhile sustainable alternative for controlling insect pests in tomato fields. To investigate the population dynamics of the major pests affecting tomato growth and yield, two commercial varieties (Areenez F1 and Tala F1) were cultivated at three plant spacings (30 × 50 cm, 60 × 50 cm, and 90 × 50 cm) under the conditions of the desert climate. The experiments were conducted in the field in 2020 and 2021 and were laid out in a Randomized Complete Block Design (RCBD) with each treatment repeated for 4 times. A total of 14 major insect pests including Empoasca fabae, Bemisia tabaci, Orosius orientalis, Acheta domesticus, and Lasius niger were recorded on a weekly basis. The results showed that the mean abundances of E. fabae, O. orientalis, and B. tabaci were higher in the 30 × 50 cm plant spacing, whereas the 90 × 50 cm plant spacing resulted in a higher abundance of A. domesticus and L. niger. The measured agronomic traits, plant height (cm), plant dry mass (g), and total yield/ha (ton) of both the tomato varieties were significantly increased when the plants were spaced at 60 cm between plants and 50 cm between rows. We recommend that growing tomato plants at 60 cm between plants and 50 cm between rows may reduce the need to apply pesticides given that this plant spacing significantly reduced the abundance of some key insect pests and enhanced the tomato fruit yield.

Seed germination responses of broomrape species (Phelipanche ramosa and Phelipanche aegyptiaca) to various sanitation chemicals

AbstractBranched broomrape, an obligate root parasitic weed, has recently re-emerged in tomato fields in several California counties. California produces more tomato than any other state, and the outbreak of this noxious weed could potentially wreak havoc on the industry’s economy. Preventive measures must be taken to stop or reduce the spread of branched broomrape seeds to other areas. Branched broomrape can produce thousands of tiny seeds, which can easily spread with farm machinery over short and long distances. To prevent branched broomrape seed dispersal, sanitation and disinfection of farm equipment are necessary before entering a new farm. We tested the effectiveness of various ammonium compounds, including didecyl dimethyl ammonium chloride (DDAC), alkyl dimethyl benzyl ammonium chloride (ADBC), didecyl dimethyl ammonium bromide (DDAB), ammonium bromide (AB), and ammonium chloride (AC) on prevention of branched broomrape seed germination. Dose-response analysis showed that three chemical products, ADBC, DDAB, and DDAC, could completely inhibit branched broomrape seeds (potentially making them nonviable) at 1%, 1%, and 10% wt/vol concentrations, respectively. These three compounds were further tested in an exposure duration experiment that additionally included Egyptian broomrape. Only 10 min of exposure to these compounds was needed to prevent germination of both branched and Egyptian broomrape seeds at 1% (ADBC, DDAB) and 10% wt/vol (DDAC). Lower concentrations can provide similar inhibition effects when combined with longer exposure times. Egyptian broomrape seeds were more sensitive than branched broomrape seeds. Findings suggest that quaternary ammonium compounds could be used as potential sanitation agents to disinfect agriculture machinery from branched and Egyptian broomrape seeds.

Optimization of irrigation and N fertilization management profoundly increases soil N retention potential in a greenhouse tomato production agroecosystem of Northeast China

Soil nitrogen (N) retention capacity can influence crop production, soil health, and environmental quality, especially in greenhouse agroecosystem with multiple cropping and high N application rate. However, the key N components and indices for predicting greenhouse soil N retention potential and the underlying driving mechanism of soil N retention under different agricultural management practices remain elusive. Here, a three-year tomato field experiment with mulch-film drip irrigation was conducted to investigate the effects of different irrigation and N fertilization regimes on soil organic N fractions and soil-retained N pools in a greenhouse agroecosystem of Northeast China. Three irrigation levels (W1, high, 25 kPa; W2, moderate, 35 kPa; W3, low, 45 kPa) and three N application rates (N1, low, 75 kg N ha−1; N2, moderate, 300 kg N ha−1; N3, high, 525 kg N ha−1) were considered. The results showed irrigation, N fertilization, and their interactions profoundly influenced soil properties, organic N fractions, and soil-retained N pools at 0–30 cm greenhouse vegetable soil layers. The dominant forms of greenhouse soil organic N fractions and soil-retained N pools were acidolysable amino acid N (AAN) and fixed ammonium (FA), respectively. Structural equation modeling and redundancy analysis indicated that there were significant direct effects of soil properties (SOC, Ntotal, and C/N) on FA, acidolysable ammonium N (AN), and AAN; additionally, soil microbial biomass N (SMBN) also exerted a significant direct effect on AN. Our results suggest that soil organic N fractions are closely correlated with soil-retained N pools and soil properties under different irrigation and N fertilization regimes. Furthermore, AAN and FA could be the appropriate indicators for predicting greenhouse soil N retention potential, and the optimization of irrigation and N fertilization application schedule (W3N2 treatment: 45 kPa – 300 kg N ha−1) is conducive to improve soil N retention potential in greenhouse tomato production of Northeast China.

Density and seasonal dynamics of Bemisia tabaci and its predators in different agricultural landscapes in South China.

Bemisia tabaci is the main pest of agriculture in many regions of the world. The resistance of whitefly to pesticides has increased as a consequence of the continuous irrational use of wide-spectrum pesticides. Thus, pesticides are no longer always effective as a long-term control method. The agricultural landscape can affect the occurrence of an insect population. The objective of this study was to clarify the occurrence of whitefly and its predators in tomato fields in different agricultural landscapes. Different landscapes are classified into urban, flower, water, and mountain landscapes by the principal component analysis method. In 2018–2019, whitefly had the longest main activity period and the lowest density in the flower landscape. The water landscape helped to maintain the highest densities of whitefly during the main activity period. Nine species of predators were sampled, and Nesidiocoris tenuis, Chrysoperla sinica, Menochilus sexmaculata, and Harmonia axyridis were the dominant species throughout the sampling season in both years. During the main activity period, N. tenuis had the highest density in all sampled landscapes. The density of the dominant predators was the highest in the flower landscape, and each natural predator had the largest temporal niche width in the 2-year sampling period. Bemisia tabaci, N. tenuis, and M. sexmaculata were highly synchronized temporally. The flower landscape showed satisfactory results in suppressing whitefly. Increasing the proportion of flowering plants and increasing the diversity of plant crops in the agricultural landscape can effectively reduce the densities of whitefly during an outbreak.

Development of a Multi-Scale Tomato Yield Prediction Model in Azerbaijan Using Spectral Indices from Sentinel-2 Imagery

This paper presents the development and update of a multi-scale yield prediction model for processing tomatoes. The study was carried out under the EU-funded programme “Support to Development of a Rural Business Information System (RBIS)”, and the performance of the updated crop-specific yield prediction models and their generated predictions at regional and national levels are presented. The model was built using Sentinel-2 satellite imagery to obtain cumulative values of six (6) selected vegetation indices (VIs). The data were collected on five (5) different dates for processing tomato fields in the Khachmaz region of Azerbaijan during summer 2021 (June to August) at 10- to 13-day intervals. In addition, a targeted field sampling campaign was conducted on selected Khachmaz pilot fields towards the end of the growing season to assess the potential of Sentinel-2 data to determine yield variability in tomato fields. Finally, actual recorded yields were collected at the field level to build the yield prediction regression model and evaluate its performance at different spatial scales, ranging from single field to national level, as well as under different data availability scenarios (number of consecutive Sentinel-2 images used). The results showed a high degree of correlation between all implemented VIs and processing tomato yield, with a coefficient of determination of up to 0.89 for the NDVI, providing valuable information for future estimates of tomato production across multiple spatial scales. The developed prediction model could also be used in the agri-food sector for national yield estimates to support policy and regulatory decisions at the national level.

Modeling water and nitrogen dynamics from processing tomatoes under different management scenarios in the San Joaquin Valley of California

Study regionThe Southern San Joaquin Valley (SSJV), California. Four representative soil types were evaluated. Study focusEvaluation of regional scale hydrology and nitrogen (N) fate and transport requires a robust modeling framework that considers critical local scale environmental conditions and crop root zone physical processes. Two widely used yet conceptually and mechanistically different models, HYDRUS(2D/3D) and SWAT (Soil and Water Assessment Tool), were used to investigate water and N dynamics in processing tomato fields across a range of soil types and management scenarios over a 30-year period in the SSJV. New hydrological insights for the regionThis study implements a framework to evaluate a regional scale model against a field scale model and provides a framework for assessing percolation and N transport results from regional scale simulations in the absence of extensive field observations. Field scale models developed in HYDRUS (2D/3D) produced similar results to a regional-scale SWAT model in four specific soils in terms of responses to percolation and N losses as a function of varying N fertilizer and irrigation management practices. This model-to-model agreement at the local scale provides confidence in region-scale hydrological and N fate and transport findings, particularly in the absence of extensive field observations. Both models suggest that promoting conservation practices targeting the optimization of irrigation and fertilizer-N management would have a large impact in protecting regional groundwater quality.

Environmental Assessment of an Innovative High-Performance Experimental Agriculture Field

To increase food availability, optimizing production systems and reducing burdens related to human activities is essential in a scenario of population growth and limited natural resources. In this context, the life cycle methodology can represent a valuable asset for assessing the environmental performance of agricultural products and services. This study sought to investigate and characterize potential impacts of an experimental tomato field at the University of Perugia and evaluate if the production increment obtained using high-reflective mulching compensated for the emissions caused by this extra component. The first-year crop campaign was the baseline reference to measure the system’s efficiency. A CML baseline method applied demonstrated that the covered field (F1) was associated with more than 23 kg CO2 eq emissions (25% attributed to the mulch) in comparison to about 18 kg CO2 eq of the non-covered sector (F2). In addition, electronic components and drainage systems were linked with most toxicity indicators. However, the F1 field’s higher productivity compensated for the mulch impact, resulting in 9% lower CO2 equivalent emissions per kg yield in the first year and 18% lower each year for 30 years. The results encourage application of this approach in urban contexts with several benefits.

Factors Affecting Tomato Productivity in Western Oromia, Ethiopia: Evidence from Smallholder Farmers

Tomato is one of the most important fruit vegetable crops in Ethiopia supporting the livelihood and improving the economic life of many farmers. However, the productivity of the crop is low due to poor production management practices, limitations in the availability of pesticides and fungicides, limitations to access information, market fluctuation, and shelf life of the crop. The study was undertaken in western Oromia to understand major factors affecting the tomato productivity of smallholder farmers. It was based on the cross-sectional data collected from 135 randomly selected farmers during the 2019/20 cropping season. The data were analyzed using descriptive statistics and an econometric model. The result depicted that the productivity of tomatoes was significantly affected by inputs like labor, oxen power, fertilizer, and pesticides. From the OLS result, gender, education, family size, off/non-farm activities, farm experience, livestock holding, extension access, credit access, and market/traders information positively affected tomato productivity, while age and field distance was affected negatively. The variety and biotic factors affected the tomato productivity of smallholder farmers positively and negatively, respectively. The findings will be helpful for tomato producers, private companies, and other sectors that participated in crop production by solving the above important variables.

The Differential Effects of Tuta absoluta Infestations on the Physiological Processes and Growth of Tomato, Potato, and Eggplant.

Simple SummaryOur study aimed to assess how Tuta absoluta affects different Solanaceae plant species. It was observed that susceptible plants experience diminished growth and reproduction rates, which may be a result of a physiological malfunction. Infestation by T. absoluta caused 100% crop loss to tomato plants, whereas significant yield reduction was observed for potato plants, and no significant feeding effect was observed for eggplant. The affected plants also experienced physiological impairments. This study is essential in that it demonstrates the differential risk of T. absoluta infestations on the production of the tested Solanaceae plant species.Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) is a destructive insect pest toward crops and belongs to the Solanaceae family. Since it was first recorded in South Africa in 2016, the pest has spread extensively and caused tremendous damage to field and tunnel-grown tomato crops. This study aimed to investigate how T. absoluta affects the growth and physiology of three Solanaceae plant species: tomato, potato, and eggplant. These three crops were infested with L1 instar larvae, and their growth and physiology were assessed during insect feeding. The damage to the infested tomato host plant was severe, with T. absoluta destroying 100% of the plants. The tomato plants were distorted 15 days after infestation, that is, before the fruit set. For potato, the defoliation was moderate, but the infested plants produced fewer tubers compared to the uninfested host plants. Eggplant had fewer visible signs of feeding, resulting in no significant difference between the infested and uninfested host plants in terms of growth and physiological functions. Infested tomato and potato plants had stagnant growth, fewer and damaged leaves, a reduced chlorophyll content, a reduced photosynthesis rate, a poor transpiration rate, poor water conductance, and poor intercellular carbon dioxide concentrations. This study closes the knowledge gap on the morphological (growth) and physiological responses of different Solanaceae species to T. absoluta infestation, and it also demonstrates the differential risk of T. absoluta infestations in the production of tomato, potato, and eggplant.

Intelligent yield estimation for tomato crop using SegNet with VGG19 architecture

Yield estimation (YE) of the crop is one of the main tasks in fruit management and marketing. Based on the results of YE, the farmers can make a better decision on the harvesting period, prevention strategies for crop disease, subsequent follow-up for cultivation practice, etc. In the current scenario, crop YE is performed manually, which has many limitations such as the requirement of experts for the bigger fields, subjective decisions and a more time-consuming process. To overcome these issues, an intelligent YE system was proposed which detects, localizes and counts the number of tomatoes in the field using SegNet with VGG19 (a deep learning-based semantic segmentation architecture). The dataset of 672 images was given as an input to the SegNet with VGG19 architecture for training. It extracts features corresponding to the tomato in each layer and detection was performed based on the feature score. The results were compared against the other semantic segmentation architectures such as U-Net and SegNet with VGG16. The proposed method performed better and unveiled reasonable results. For testing the trained model, a case study was conducted in the real tomato field at Manapparai village, Trichy, India. The proposed method portrayed the test precision, recall and F1-score values of 89.7%, 72.55% and 80.22%, respectively along with reasonable localization capability for tomatoes.

Potency of two Trichoderma harzianum isolates in liquid and solid organic formula for controlling bacterial wilt on tomato in the field

This research aimed to determine the potency of two Trichoderma harzianum isolates in solid and liquid organic formulas to control bacterial wilt and on growth and yield of tomato in the field. This research was carried out at the Laboratory of Plant Protection and the tomato field at Banteran Village, Sumbang Sub-District, Banyumas Regency at altitude of 600 m above sea level for four months. A randomized block design was used with five replicates. The treatments were control, T. harzianum T10, T. harzianum T215, combination of T. harzianum T10 + T. harzianum T215, and bactericide (a.i. 20% streptomycin sulfate). Variables observed were pathosystem components (incubation period, infection rate, disease intensity, and late populations of the antagonists), growth components (plant height, plant fresh and dry weight, and root fresh and dry weight), yield components (number of fruits, fruit weight), and phenolic compounds analysis qualitatively. The results showed that T. harzianum T10 + T. harzianum T215 was effective to suppress the disease as 58.61%. The treatment of T. harzianum T10 + T. harzianum T215 was effective to increase crop height, fresh weight of plants, dry weight of plants, fresh weight of roots, dry weight of roots, number of fruits and fruit weight as 38.86, 35.37, 51.67, 24.78, 37.41, 40.61, and 53.22%, respectively. All treatments could increase phenolic compound content qualitatively.

The hunt for beneficial fungi for tomato crop improvement – Advantages and perspectives

Beneficial fungi with antagonistic and entomopathogenic properties have shown promising effect in the biological control of diseases and pests in a variety of commercially significant crops, including tomato, in recent years. Despite the fact that such treatments are environmentally safe, their risk on non-target species in tomato fields remains unknown. Beneficial fungi that have been commercialised for field use have had little effects on the population of arthropod pests and the incidence of diseases in tomato fields due to various reasons. The use of fungal antagonists and entomopathogenic fungi-based products for the management of diseases and pests of tomato crop has been done all over the world. The investigated reports, however, are scattered throughout the research papers, so they need to be compiled and discussed. Therefore, efficiency of antagonistic and entomopathogenic fungi against important pests and pathogens of tomato crop, as well as their practical use as biofungicides and bioinsecticides to reduce the use of synthetic pesticides, are discussed in this review paper. Besides, plant growth promotion activity of beneficial fungi, their appropriateness as an alternative of synthetic pesticides, and future prospects are also discussed.

Flowering agricultural landscapes enhance parasitoid biological control to Bemisia tabaci on tomato in south China.

Agricultural landscape pattern may enhance biocontrol services by supporting parasitoid populations, including parasitoids of Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). In this study, we selected four landscape types in Yunnan province, in south China, which were characterized by flower fields, mountain, river, and urban areas as their main elements. We then carried out systematic surveys in tomato fields found within each landscape type, to determine the diversity, occurrence, and parasitism rate of parasitoids. We found that parasitoids from the genus Encarsia and Eretmocerus were the main natural enemies present, and the most abundant species were recorded in the flower and the mountain landscapes. Also, Encarsia formosa (Hymenoptera: Chalcidoidea) formed the highest relative abundance regardless of the landscape type. We also found that the population density of B. tabaci in flower landscapes was the lowest than that in other landscape types. During the main activity period of B. tabaci, the parasitism rate in the flower landscape was higher than that in other landscape types. Our findings showed that the occurrence of B. tabaci was relatively mild in the flower landscapes. The landscape type was also beneficial to parasitoids as it enhanced their parasitism rate. Therefore, agriculture environmental schemes should consider increasing the size of flower fields in the surrounding landscape to enhance the sustainable control of B. tabaci by the natural agricultural ecosystem.

Effects of soil treated fungicide fluopimomide on tomato (Solanum lycopersicum L.) disease control and plant growth.

Fluopimomide is a novel acid amide fungicide registered for the control of many plant pathogens. In the present study, the effects of soil-treated fluopimomide on soil micro biomass, disease incidence, plant growth, soil enzyme activity, and marketable yield of tomato (Solanum lycopersicum L.) were investigated via field trial. In addition, the application prospect in China was also evaluated. In the experiment, five treatments with three replications and a randomized complete block design were followed. The treatments were: furrow application of fluopimomide (25% suspension concentrate, SC) at the dosage of 375, 750, and 1,500 g ha−1, which was recommended, double recommended, and quadruple recommended dosages, respectively. Besides, common control fungicide fluopicolide (5% SC) furrow was applied at recommended application dosages of 750 mL ha−1, and a non-treated control was also undertaken. Results indicated that fluopimomide exhibited no effects on the amount of soil bacteria and actinomycetes, and its inhibition effect on fungi amount could be recovered at 60 days after treatment (DAT). With the recommended application dosage, fluopimomide could efficiently reduce the number of plant pathogens in soil by 79.56–85.80%, significantly reduce the disease incidences in tomato plants by 80.00–88.24%, and improve plant height by 13.25–24.05% and marketable yield by 16.88%. Furthermore, soil enzymes exhibited a complex response to fluopimomide, and AOB and nifH gene copy numbers were increased by the double and quadruple recommended dosage of fluopimomide. Based on the above results, fluopimomide could be recommended as an efficient fungicide for the tomato field.

Isolation and Characterization of Novel Lytic Bacteriophage vB_RsoP_BMB50 infecting Ralstonia solanacearum.

Ralstonia solanacearum is a soil-borne phytopathogen, and it can cause bacterial wilt disease in a variety of key crops around the world, thus resulting in enormous financial losses. However, there is a lack of effective, green, and safe prevention and control measures against increasingly devastating bacterial wilt disease. Bacteriophages (phages) are considered as potential biocontrol agents against bacterial wilt disease. Although many phages infecting R. solanacearum have been isolated, so far, these Ralstonia phages are still insufficient to deal with the diversity of the bacteria of R. solanacearum. In this study, a novel lytic bacteriophage vB_RsoP_BMB50 infecting multiple R. solanacearum was isolated from tomato fields in Dalian, China. Transmission electron microscopy and genomics analysis indicated that vB_RsoP_BMB50 belonged to the subfamily Okabevirinae, Autographiviridae family, and order Caudovirales, and it comprised a double-stranded DNA with a full length of 43,665bp and a mean G+C content of 61.79%, containing 53 open reading frames (ORFs). This novel phage exhibited a large burst size, high temperature stability (4-50 °C), and strong pH tolerance (pH 5-10). Comparative analyses and phylogenetic analyses revealed that vB_RsoP_BMB50 represented a novel Ralstonia phage genus since it exhibited a low sequence similarity to other phages in the GenBank database. Due to its broad lytic spectrum, high thermal stability, and strong pH tolerance, vB_RsoP_BMB50 is considered as an effective candidate biocontrol agent against bacterial wilt disease caused by R. solanacearum.

Spatial and Temporal Changes of Soil Microbial Communities in Field Tomato Production as Affected by Anaerobic Soil Disinfestation

Anaerobic soil disinfestation (ASD) has been demonstrated as an effective alternative to pre-plant chemical soil fumigation (CSF) commonly used to control soilborne pathogens. However, the ASD effects on spatial and temporal changes in soil microbial communities remain poorly understood in production systems with low soilborne disease pressure. The objective of this study was to assess the influence of ASD treatments on soil microbial community composition at different soil depths during the spring tomato production season in Florida. Soil treatments included ASD using 6.9 m3 ha−1 of molasses with 11 Mg ha−1 of composted poultry litter (CPL) (ASD0.5), ASD with 13.9 m3 ha−1 of molasses and 22 Mg ha−1 CPL (ASD1.0), and chemical soil fumigation (CSF) using a mixture of 1,3-dichloropropene and chloropicrin. Soil microbial community composition was measured at soil depths of 0–15 and 15–30 cm using phospholipid fatty acid (PLFA) analysis at 0, 36, 76, and 99 days after transplanting (DAT). Fatty acid methyl esters were categorized into biomarker groups including total microbial biomass (TMB), G+ bacteria (G+), G− bacteria (G−), actinomycetes (Actino), arbuscular mycorrhizal fungi (AMF), protozoa, and general fungi (F). Soil concentrations of G+, Actino, F, AMF, and the ratio of F:bacteria (B) were significantly impacted by a soil treatment × soil depth × sampling time three-way interaction. All the microbial biomarkers were significantly affected by soil treatment × sampling depth two-way interactions except for protozoa and F:B ratio. Concentrations of TMB, Actino, AMF, F, G+, and G− bacteria were significantly increased in ASD treated soils at both 0–15 and 15–30 cm soil depths across different sampling times compared with CSF. In addition, the concentrations of G+ and G− bacteria, AMF, F, and TMB were higher at 0–15 vs. 15–30 cm soil depth under ASD treatments, whereas no soil depth differences were observed in CSF. Discriminant analysis further confirmed that soil microbial community composition was distinctly different in CSF compared with ASD treatments. The soil microbial profile was well-differentiated between the two soil depths under ASD treatments but not in CSF, while the enhancement of PLFA biomarkers by ASD decreased with increasing soil depth.

In Vitro Evaluation of Wood Vinegar (Pyroligneous Acid) VOCs Inhibitory Effect against a Fungus-like Microorganism Ovatisporangium (Phytopythium) Isolate Recovered from Tomato Fields in Iran

Crop diseases and agricultural pests and pathogens are causing huge economic losses. The actual means for dealing with them involve the use of damaging chemical pesticides that harm the environment, threaten biodiversity, and undermine human health. This research was aimed at developing an environmentally friendly means to cope with emerging oomycete disease from tomato fields in the province of East-Azerbaijan. The oomycete disease causal agent was isolated and identified as Ovatisporangium sp. using a combination of morphological features and molecular methods. Six wood vinegars (pyroligneous acid) belonging to pine, pomegranate, pistachio, almond, walnut, and cypress were produced during this study and examined against Ovatisporangium sp. Their inhibition of volatile metabolites (VOCs) using different dilutions (1, 1/2, 1/4, 1/8, and 1/10) was assessed against the mycelial growth of Ovatisporangium sp. In vitro analysis demonstrated that pistachio, cypress, and almond dilution 1 (D 1) wood vinegar VOCs had the ability to stop the mycelial growth of Ovatisporangium sp. All other treatments including pine, walnut, and pomegranate with relevant dilutions significantly reduced the mycelial growth of Ovatisporangium sp. compared with the control (p ≤ 0.05). Wood vinegar is therefore a potent means to cope with pathogenic infections and allows plant protection against oomycete diseases.

Approaches to conservation of Nesidiocoris tenuis for biological control of pests in field-grown tomato in Senegal

Conservation biological control is a promising approach to natural pest control in both open field and protected crops. In sub-Saharan Africa, tomato crops are commonly damaged by several arthropod pests but can also host the predatory mirid bug, Nesidiocoris tenuis. Unfortunately, farmers do not currently take full advantage of this zoophytophagous and generalist biocontrol agent. We conducted field investigations in the Niayes area of Senegal, combined with laboratory experiments, to determine how to enhance natural regulation services provided by this natural enemy. We found that strong full-plant watering and insecticidal sprays, both conventionally applied in the Niayes area, had a detrimental effect on N. tenuis. We identified Sesamum radiatum (false or black sesame) as a promising insectarium plant that could also serve as a leaf vegetable and medicinal plant. This plant supports good N. tenuis development and reproduction, even without alternative food sources. Y-tube olfactometry indicated no attraction to odors of Sesamum radiatum, suggesting that N. tenuis would not abandon tomato plants for this insectarium plants when present in tomato fields. Our results suggest potential approaches to improve conservation of N. tenuis for biological control of Tuta absoluta and other tomato pests in Africa.

Micronutrient Status and their Deficiency Diagnosed through DRIS in Tomato Growing Areas

The nutritional imbalances in tomato plants determined on the basis of soil and plant tests with interpretations on the critical nutrient level are less well correlated with the corresponding crop yields. Nutrient imbalance in tomatoes yield was assessed using Diagnosis and Recommendation Integrated System (DRIS) approach was more efficient. The study objectives were to evaluate micronutrient status in tomato growing areas and determine the nutrient(s) limiting tomato yield and establish DRIS norms for micronutrients for tomato crop. Twenty-six tomato fields from Chatter plain (Khyber Pakhtunkhwa), and Sheikupura (Punjab) were collected with soil, accompanying leaf index tissue and tomato yield was recorded. Tomato yield data were recorded and divided into high- (≥3.90 kg per 10 plants) and low- yield (3.95 kg per 10 plants) populations. DRIS analysis identified a deficiency of iron in the tomato production areas. Norms established through DRIS can be used for potential tomato yield.