Annual Field Crops Research Articles

Landscape-scale spatiotemporal dynamics of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) populations: implications for spatially-based pest management.

Brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), is an invasive and severe pest of specialty and row crops. A 2-year field study conducted in four Mid-Atlantic states in the USA characterized the spatial and temporal dynamics of BMSB populations and its association with landscape elements in commercial agriculture settings. In each state, two 1 km2 sites included typical landscape elements (i.e., tree fruit orchards, annual field and vegetable crops, woodlands, and human-made structures). Twenty-seven georeferenced pheromone traps were deployed per site and the number of BMSB adults and nymphs captured was counted throughout the growing season. Findings from spatial analysis by distance indices, along with time-series maps of BMSB distribution, showed that BMSB exhibited significant spatial aggregation, and that its distribution was spatially consistent between years. Analyses with geographic information systems (GIS) revealed that BMSB 'hot spots' occurred in different landscape elements throughout each season. Most patches (i.e., clusters of significantly higher trap captures) were found near woodlands early in the season, near tree fruit orchards in summer, and on the border of annual field crops in autumn. Buffer analysis with GIS indicated that more BMSB adults were captured closer to woodlands compared with other landscape elements. Understanding the spatial and temporal movement and distribution of BMSB is critical to predicting their potential impact and ultimately devising strategies to mitigate this risk to vulnerable crops. The results of this study can be used to design streamlined, spatially-based areawide management of BMSB in heterogeneous and complex agricultural landscapes. © 2023 Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Climate Change Impact on Horticultural Crops: A Review

Our civilization is fundamentally based on agriculture, which provides resources and food to an expanding population. But because of rising temperatures, altered rainfall patterns, and a rise in the frequency and severity of extreme weather events, climate change is endangering this industry. Our study aims to fill a significant gap in the existing literature by focusing on the effects of climate change on vegetable crops. It also highlights the need to address climate change in a differentiated manner, taking into account the unique characteristics of each agricultural sector. By using the Web of Science and Scopus databases, 219 publications were carefully examined to see which ones fully addressed how climate change is affecting vegetable crops. Only 53 of the 219 publications that were reviewed were solely concerned with how climate change is affecting vegetable crops. This suggests that more specialised research is needed in this field, especially considering the complex issues that climate change raises regarding yield, non-trivial quality, and food safety. Future research in this area is therefore encouraged. Crop-based adaptation techniques are required, taking into account the crop's characteristics, degree of sensitivity, and agro-ecological zone. In addition, monitoring the ability of various horticulture crops to absorb carbon dioxide in comparison to annual field crops can help create a blueprint for addressing climate change-related problems.

Intercropping Perennial Fruit Trees and Annual Field Crops with Aromatic and Medicinal Plants (MAPs) in the Mediterranean Basin

The Mediterranean basin (MB), a “climate hotspot”, is experiencing faster than average increases in global temperature and water deficit, as well as soil degradation, with detrimental impacts on food crop yield and pest/pathogen incidence. Hence, there is an urgent requisite for sustainable crop diversification strategies to promote crop resilience, soil quality conservation and pest/pathogen control. Intercropping is a strategy that has yet to be widely adopted. Presently, cereal–legume combinations represent the most common intercrops. Of relevance, a large number of medicinal and aromatic plants (MAPs), native to the MB, serve as potentially profitable indigenous resources for intercropping with food crops. Environmentally sustainable benefits of MB MAP intercropping with food crops have ironically been reported largely from research outside the MB. The present study aims to review the published literature from 2003 to 2023 on MAP intercropping with perennial nut/fruit crops and annual field crops in the MB. Published research is scarce but shows a promising upward trend, with 70% and 47% of intercropping studies with perennials and annual field crops, respectively, dated between 2020 and 2023. MAP intercropping shows potential in augmenting yield, pest/pathogen and weed control, soil health and cash crop quality, warranting further research with more widespread adoption in the MB.

Modelling direct field nitrogen emissions using a semi-mechanistic leaching model newly implemented in Indigo-N v3

Nitrogen plays a major role in agroecosystems as the key nutrient in agricultural production as well as a source of different emissions, which exceed currently planetary boundaries. N losses, conditioned by both pedoclimatic conditions and agricultural strategies (e.g. rotations, fertilisation), predominantly take the form of ammonia (NH3) volatilisation, nitrate (NO3) leaching, nitrification-driven nitric oxide (NOx) emission to air, and denitrification-driven nitrous oxide (NOx and N2O) emissions to air. The multiplication of initiatives and studies on nitrogen modelling resulted in a broad offer of complex simulation models (Tier 3) on one extreme of the gradient between feasibility and integration of processes. On the other side, a multiplication of initiatives has led to a broad offer of causal indicators in the form of proxies and considering one or a few input variables (Tier 1). A relevant compromise between those extremes lies in the development of operational models using a restricted number of parameters and input variables (Tier 2). Here, we propose a new semi-mechanistic operational model for the estimation of direct field N emissions (NH3, NO3, NOx and N2O) from contrasting agricultural situations: the Indigo-N v3 (I-N3) model. The gaseous emissions are based on Tier 1 (NOx) and Tier 2 (NH3, N2O) methods taken from the literature, with some enhancements, while we developed a totally new semi-mechanistic approach for nitrate leaching. A comparison of I-N3 outputs was performed with measurements of nitrate leaching in three countries (15 arable fields in France, 3 sugar cane fields at Reunion Inland, and 5 cropped fields in Kenya) and showed a reasonable predictive quality for temperate arable fields, and for some of the tropical fields (1 in Reunion and 3 in Kenya). It also performed better than the previous version of Indigo-N (IN-2) and the SALCA/SQCB models. In comparison with previous Tier 2 models, the newly developed Indigo-N v3 presents an original position on the gradient between integration of processes and feasibility of the simulation of processes. Another novelty of I-N3 lies in its broad scope, designed to be valid for temperate and non-temperate crops, including annual field crops, short-cycle vegetables, temporary grasslands and perennial grasses (such as sugarcane, miscanthus or switchgrass). Parameterisation and validation should be continued for further crops, such as associations and short cycle vegetables.

Introducing State-of-the-Art Deep Learning Technique for Gap-Filling of Eddy Covariance Crop Evapotranspiration Data

Gaps often occur in eddy covariance flux measurements, leading to data loss and necessitating accurate gap-filling. Furthermore, gaps in evapotranspiration (ET) measurements of annual field crops are particularly challenging to fill because crops undergo rapid change over a short season. In this study, an innovative deep learning (DL) gap-filling method was tested on a database comprising six datasets from different crops (cotton, tomato, and wheat). For various gap scenarios, the performance of the method was compared with the common gap-filling technique, marginal distribution sampling (MDS), which is based on lookup tables. Furthermore, a predictor importance analysis was performed to evaluate the importance of the different meteorological inputs in estimating ET. On the half-hourly time scale, the deep learning method showed a significant 13.5% decrease in nRMSE (normalized root mean square error) throughout all datasets and gap durations. A substantially smaller standard deviation of mean nRMSE, compared with marginal distribution sampling, was also observed. On the whole-gap time scale (half a day to six days), average nMBE (normalized mean bias error) was similar to that of MDS, whereas standard deviation was improved. Using only air temperature and relative humidity as input variables provided an RMSE that was significantly smaller than that resulting from the MDS method. These results suggest that the deep learning method developed here is reliable and more consistent than the standard gap-filling method and thereby demonstrates the potential of advanced deep learning techniques for improving dynamic time series modeling.

Determination of nitrogen dilution curves of corn, canola, and spring wheat in Canada using classical and Bayesian approaches

Determining the dynamics of crop nitrogen (N) uptake is essential to optimize N management and increase the sustainability of crop production. The concept of critical N concentration helps to achieve this goal by defining the minimum shoot N concentration required to produce the maximum aerial biomass at a given time during the crop cycle. The objective of this study was to determine new critical N dilution curves of the main annual field crops used in Canada (spring wheat, canola and corn) using a classical approach well established and a new Bayesian approach and compare these curves with the curves previously published. A total of 557 data for the three crops were used, covering a wide range of pedoclimatic conditions, crop management and cultivars across Canada. These data were processed following a classical statistical approach involving two steps to determine critical points used to calculate the parameters of the critical N dilution curve and then validate these curves against N limiting and non-limiting points. Data were also processed with a new one step Bayesian approach which allows estimating the 95% credibility intervals of the calculated critical curves. For spring wheat, our analysis confirmed the results of a previous study showing that the critical N curve established for winter wheat was not adequate for spring wheat. The critical N dilution curve determined with the classical approach (Nc = 4.14 W−0.51) performed well in separating the N limiting to the N non-limiting data of the validation dataset. The use of a larger dataset than in the previous study conducted for spring wheat in eastern Canada allowed us to demonstrate that new critical, minimum and maximum N dilution curves for spring wheat has a larger domain of validity than suggested by results of previous studies. Our study shows the strong interaction between plant N and water status, and that N dilution concept allowed us to reveal the occurrence of interaction between water and N stresses for crops in Western Canada, explaining the lower efficiency of N fertilizer in western than in eastern regions.For corn, the refined critical N dilution curve was very close to the critical N dilution curve determined in France and in eastern Canada, but the Bayesian approach allowed to propose a specific critical N curve for Canada (Nc = 3.07 W−0.40). In addition, minimum and maximum N dilution curves for corn were determined in Canada’s pedoclimatic conditions. For canola, the new critical (Nc = 4.26 W−0.26), minimum and maximum curves determined in this study were close to the curves found in previous studies during the vegetative stages. In addition, a new critical N curve valid after the flowering stage was determined.

Generating cropping schemes from FADN data at the farm and territorial scale

The paper presents an innovative approach to cropping scheme classification based on fad n data with two main goals. First, the identification at the regional level (NUTS 2) of land use patterns common to similar farms defined ‘group cropping scheme'. Second, the farm-level construction of farm cropping schemes, which expand the observed crop mix and identify suitable variation ranges considering the farm production context. The schemes are based on the observed behaviour of homogeneous farms and capture their common structural characteristics regarding land use.The schemes can be used at the territorial scale to analyse landuse trends and patterns over time. At the farm level, the method is designed to analyse short-term adaptations and is suitable to be used, together with other data, in mathematical programming models to run policy analysis exercises. At this latter scale, crop substitution within a scheme allows the set of eligible crops to be expanded while remaining linked to the observed behaviour on a spatial basis.The paper applies the methodology to identify and quantify the cropping schemes using FADN data on Italian farms specialising in annual field crops. An algorithm implemented in gams automates the process. Results confirm the validity of the method and open a field of research for future applications.

The effects of trapping effort and sources of variability on the estimation of activity-density and diversity of carabids in annual field crops by pitfall trapping; a meta-analysis

The effects of trapping effort and sources of variability on the estimation of activity-density and diversity of carabids in annual field crops by pitfall trapping; a meta-analysis

The Evaluation of Radiation Use Efficiency and Leaf Area Index Development for the Estimation of Biomass Accumulation in Short Rotation Poplar and Annual Field Crops

We evaluated the long-term pattern of leaf area index (LAI) dynamics and radiation use efficiency (RUE) in short rotation poplar in uncoppice (single stem) and coppice (multi-stem) plantations, and compared them to annual field crops (AFCs) as an alternative for bioenergy production while being more sensitive to weather fluctuation and climate change. The aim of this study was to evaluate the potential of LAI and RUE as indicators for bioenergy production and indicators of response to changing environmental conditions. For this study, we selected poplar clone J-105 (Populus nigra L. × P. maximowiczii A. Henry) and AFCs such as barley (Hordeum vulgare L.), wheat (Triticum aestivum L.), maize (Zea mays L.), and oilseed rape (Brassica napus L.), and compared their aboveground dry mass (AGDM) production in relation to their LAI development and RUE. The results of the study showed the long-term maximum LAI (LAImax) to be 9.5 in coppice poplar when compared to AFCs, where LAImax did not exceed the value 6. The RUE varied between 1.02 and 1.48 g MJ−1 in short rotation poplar and between 0.72 and 2.06 g MJ−1 in AFCs. We found both LAI and RUE contributed to AGDM production in short rotation poplar and RUE only contributed in AFCs. The study confirms that RUE may be considered an AGDM predictor of short rotation poplar and AFCs. This may be utilized for empirical estimates of yields and also contribute to improve the models of short rotation poplar and AFCs for the precise prediction of biomass accumulation in different environmental conditions.

Horticultural crops and climate change: A review

If agriculture is the main stay towards the emission of greenhouse gases induced climate change, horticultural crops have a much bigger role to play in countering the negative consequences of climate change by providing a better carbon trade and carbon sink. One of the most ominous physiological responses that accrue in response to climate change is the shortened growing period, causing distinctive reduction in production of fruits and vegetables. These responses will leave negative impact on growth and development of horticultural crops due to terminal heat stress and deprived soil water availability. Interventions seeking climate-smart horticulture are, therefore, felt an unwarranted necessity integrating location-specific and knowledge-intensive premise for improving production under such challenging environment. Crop-based adaptation strategies are needed keeping in view the nature of crop, its sensitivity level and the agro-ecological region. Simultaneously, keeping an eye on carbon sink potential of different horticultural crops vis-à-vis annual field crops will further aid in developing a blue print for redressal of climate change related issues.

HOW TO USE CROP GROWTH MODEL WOFOST FOR FORECASTING GROWTH AND YIELD OF A CROP

WOFOST version 7.1.3 is a computer model that simulates the growth and production of annual field crops. All the run options are operational through a graphical user interface named WOFOST Control Center version 1.8 (WCC). WCC facilitates selecting the production level, and input data sets on crop, soil, weather, crop calendar, hydrological field conditions, soil fertility parameters and the output options. The files with crop, soil and weather data are explained, as well as the run files and the output files. A general overview is given of the development and the applications of the model. Its underlying concepts are discussed briefly.

Impact of Continuous Cropping on the Diurnal Range of Dew Point Temperature during the Foliar Expansion Period of Annual Crops on the Canadian Prairies

It is important to increase our knowledge of the role of land use in changing the regional climate. This study asked, “Has the increase in continuous cropping over the past 50 years on the Canadian Prairies influenced the daily mean and range of morning dew point temperatures(Td)during the foliar expansion period (from mid-June to mid-July) of annual field crops?” We found that there has been a general increase in the decadal average of mean dailyTdand in the range of morningTdfrom the 1960s to the 2000s. The increase in the observed range ofTdbetween the daily minimum value, which typically occurs near sunrise, and the late morning peak was found to be related to the increase in annual crop acreage and consequent decrease in summerfallow area. The relationship was more significant in the subhumid climatic zone than in the semiarid climatic zone, and it was influenced by whether the region was experiencing either wet, normal, or dry conditions.

Focus Issue Articles on Emerging and Re-Emerging Plant Diseases

The history of plant pathology is closely tied to plant diseases that have changed the course of human history. The Irish potato famine, caused by late blight of potato, resulted in the starvation and death of millions of people and one of the most influential human migrations in history. Other plant diseases have impacted quality of life in myriad ways. The advent of fungicides, clean seeds, host resistance, and the development of a plethora of other techniques, has diminished the impact of plant diseases. However, impressive advances in modes of rapid transport have not only increased global trade and human migration, but also augmented the risk for anthropogenic invasions of plant pathogens. As a consequence, and possibly aggravated by climate change, many historical and contemporary diseases are emerging as threats to modern agriculture and food security. These emerging diseases are not only important in global crop production, but also pose severe risks on a local level, especially on small farms in developing countries. This Focus Issue of Phytopathology contains a collection of peer-reviewed research articles, invited reviews and perspective articles on an assortment of emerging and re-emerging diseases caused by bacterial (3 papers), fungal (6 papers), oomycete (5 papers), and viral plant pathogens (3 papers). These diseases cover a range of crops including annual field crops and perennial tree crops, and vegetables, across five continents.

EFSA Guidance Document for predicting environmental concentrations of active substances of plant protection products and transformation products of these active substances in soil

This EFSA guidance document provides guidance for the exposure assessment of soil organisms to plant protection products (PPPs) and their transformation products in accordance with Regulation (EC) No 1107/2009 of the European Parliament and the Council. This guidance was produced by EFSA in response to a question posed by the European Commission according to Art. 31 of Regulation (EC) No 178/2002 of the European Parliament and of the Council. Guidance is provided for all types of concentrations that are potentially needed for assessing ecotoxicological effects, i.e. the concentration in total soil and the concentration in pore water, both averaged over various depths and time windows. The current guidance is restricted to annual field crops under conventional and reduced tillage. The recommended exposure assessment procedure consists of five tiers. To facilitate efficient use of the tiered approach in regulatory practice, user-friendly software tools have been developed. In higher tiers of the exposure assessment, crop interception and subsequent dissipation at the crop canopy may be included. The models that simulate these processes were harmonised. In addition, an easy-to-use table for the fraction of the dose reaching the soil has been developed, which should be used at higher tiers in combination with the simple analytical model. With respect to substance-specific model inputs, this guidance generally follows earlier documents; however, new guidance is included for some specific substance parameters.

Application of Two-spotted Spider Mite <em>Tetranychus urticae</em> for Plant-pest Interaction Studies

The two-spotted spider mite, Tetranychus urticae, is a ubiquitous polyphagous arthropod herbivore that feeds on a remarkably broad array of species, with more than 150 of economic value. It is a major pest of greenhouse crops, especially in Solanaceae and Cucurbitaceae (e.g., tomatoes, eggplants, peppers, cucumbers, zucchini) and greenhouse ornamentals (e.g., roses, chrysanthemum, carnations), annual field crops (such as maize, cotton, soybean, and sugar beet), and in perennial cultures (alfalfa, strawberries, grapes, citruses, and plums)1,2. In addition to the extreme polyphagy that makes it an important agricultural pest, T. urticae has a tendency to develop resistance to a wide array of insecticides and acaricides that are used for its control3-7. T. urticae is an excellent experimental organism, as it has a rapid life cycle (7 days at 27 °C) and can be easily maintained at high density in the laboratory. Methods to assay gene expression (including in situ hybridization and antibody staining) and to inactivate expression of spider mite endogenous genes using RNA interference have been developed8-10. Recently, the whole genome sequence of T. urticae has been reported, creating an opportunity to develop this pest herbivore as a model organism with equivalent genomic resources that already exist in some of its host plants (Arabidopsis thaliana and the tomato Solanum lycopersicum)11. Together, these model organisms could provide insights into molecular bases of plant-pest interactions. Here, an efficient method for quick and easy collection of a large number of adult female mites, their application on an experimental plant host, and the assessment of the plant damage due to spider mite feeding are described. The presented protocol enables fast and efficient collection of hundreds of individuals at any developmental stage (eggs, larvae, nymphs, adult males, and females) that can be used for subsequent experimental application.

Characterization of Phytoplasmas Related to Aster Yellows Group Infecting Annual Plants in Iran, Based on the Studies of 16S rRNA and RP Genes

Abstract Several annual field crops, vegetables, ornamentals, oilseed crops, and weeds showing phytoplasma diseases symptoms were collected to detect phytoplasmas related to ‘Candidatus Phytoplasma asteris’. The collecting was done in the central regions of Iran. For general detection of phytoplasmas, 16S rRNA gene fragments were amplified using phytoplasma universal primer pair P1/P7 in polymerase chain reaction (PCR) followed by primer pair R16F2n/R16R2 in nested PCR. Then, for finer detection of phytoplasmas related to ‘Ca. P. asteris’, DNA samples were used to extend the rp and tuf gene fragments by PCR using aster yellows group specific primer pairs rp(I)F1A/rp(I)R1A and fTufAy/rTufAy, respectively. Restriction fragment lenght polymorphism (RFLP) analysis of rp gene fragments using digestion with AluI, MseI, and Tsp509I restriction enzymes indicated that aster yellows group related phytoplasmas in these Iranian regions, belong to rpI-B subgroups. Sequence analysis of partial 16S rRNA and rp genes from representative phytoplasma isolates confirmed the RFLP results. This research is the first report of annual plants infected with phytoplasmas related to subgroup rpI-B in Iran.

Root-length densities of various annual crops following crops with contrasting root systems

The aim of this study was to evaluate how soil structure and root-length densities of annual crops can be influenced by preceding crops. Three different annual field crops (spring wheat, Triticum aestivum L., winter barley, Hordeum vulgare L. and winter oilseed rape, Brassica napus L.) were cultivated either after two continuous years of chicory, Cichorium intybus L., a perennial taprooted fodder crop or after annual crops with fibrous root systems (oats, Avena sativa L. and tall fescue, Festuca arundinacea Schreb). Biopores of two diameter classes (2–5mm and >5mm) were quantified per unit surface area by visual classification in 45–145cm soil depth. Root-length density was estimated by using the profile wall method or by image analysis of roots washed from monolith samples. After chicory, the number of large sized biopores per unit surface area in the subsoil was greater than after annual crops with fibrous root systems. When grown after chicory, the root-length densities of annual winter crops below 115cm soil depth were greater than after fibrous precrops. It is concluded that cultivation of taprooted crops with the ability to create larger sized biopores allows subsequent crops to establish more roots in deep soil layers, with potentially greater access to nutrients and water from the subsoil.

Agroforestry Practices in Arid and Semi - Arid Regions of India: Challenges and Opportunities

The review indicates the potential of Agroforestry Practices to meet out the requirements of food, fodder, fuelwood and other tree products as well as resource conservation in the arid and semi-arid regions of the country. However, it is recommended that there is an urgent need of integration of forestry with agriculture at the same place. Based upon various studies conducted on Agroforestry Practices such as planting methods, fertilization, spacing and pruning schedules for raising some of the promising forest and fruit trees in association with annual and perennial field crops have been developed and standardized for management of land degradation. Successful efforts have been made to stabilize the yields of selected crops under tree canopies through agronomic manipulations and by tree canopy management practices. Supplement income can be obtained without reducing productivity and quality of natural grasslands through the introduction of promising leguminous trees on dry degraded lands. These lands which were producing only 2-3 t/ ha/ year biomass earlier are now producing 8-10 t/ha/year high quality biomass. Soil-root interface studies in terms of sharing of space, water, nutrients and light has been workout. The lands which belong to Classes IV/V-VII can be brought under protective measures through plantation of forest trees are considered very important for Agroforestry System. Fodder trees leaves are valuable feed stuffs to animals during lean period. These can be obtained from the top feed species by lopping management. Besides, these are good source of protein and supply of high energy diet during dry season of the year. Moreover, pods and fruits from planted tree species in Agroforestry System are highly palatable and can substitute in the concentrate feed. Some trees pods can also be used as a human and cattle feed. In general, pods are more nutritious than leaf. Under Agroforestry Systems agricultural crops can be grown successfully when the tree are lopped. The negative effects of Agroforestry trees can be narrowed down by lopping management. The plantation of trees as field boundary serves as shelterbelts and windbreaks to protect the field crops from biotic and abiotic stresses. Short rotation tree species are planted in high density and managed by regular pruning, thinning, felling, copping farming to ensure high productivity and conservation on degraded lands. The degraded lands could be rehabilitated by the use of silvi-pastoral system for continuous supply of fodder, fuelwood and other associated products. The yield of cultivated crops had decreased under trees because of competitions for natural resources like soil, water, light and nutrients. But reduction of fuel, fodder and soil nutrients can compensate this loss. Under horti-pastoral system, fruit trees can be planted very well and seeds of perennial legumes and grasses can be grown in between the rows of fruit trees. Hedgerows intercropping between bushes/ trees and agricultural crops primarily as an alternate land use system for enhancing productivity of whole system. Besides, it also fulfills the demand of fodder, firewood, and control of soil erosion. Alternate strip cropping of grasses and perennial legumes on sloppy degraded lands yielded high dry matter production when vegetative barriers were also used. Thus, in nutshell holistic approaches of Agroforestry Systems in dry fringe in India can be served as a multi purposes. This paper focused especially on the Agroforestry Practices recently conducted in dry parts of the country.

Mite pests in plant crops: Current issues, inovative approaches and possibilities for controlling them

In the middle of the last century, mites moved into the focus of attention as pests relevant to agriculture, forestry and landscape horticulture, presumably in direct reaction to the 'green revolution' that involved plant cultivation in large-plot monocropping systems, improved methods of cultivation, selection of high-yielding cultivars and intensified use of pesticides and mineral fertilizers. Agroecosystems in which phytophagous mites have become harmful organisms are primarily orchards, vineyards, greenhouses, urban greeneries, plant nurseries and stored plant products, as well as annual field crops to a somewhat lesser degree. Phytophagous mite species belong to a variety of spider mites (Tetranychidae), false spider mites (Tenuipalpidae), gall and rust mites (Eriophyoidae), tarsonemid mites (Tarsonemidae) and acarid mites (Acaridae). Most of these harmful species are widespread, some of them having more economic impact than others and being more detrimental as depending on various specificities of each outdoor agroecosystem in any particular climatic region. The first segment of this overview focuses on the most significant mite pests of agroecosystems and urban horticultural areas in European countries, our own region and in Serbia today, primarily on species that have caused problems in recent years regarding plant production, and it also discusses various molecular methods available for investigating different aspects of the biology of phytophagous mites. Also, acaricides are discussed as a method of controlling mite pests in the light of the current situation and trends on pesticide markets in Serbia and the European Union member-countries.

The effects of East African low level jet on food security in horn of Africa: A case study of coastal region of Kenya

Literature on rainfall variability in Eastern Africa has suggested a significant influence from local factors that control rainfall amounts and distribution in contrast to the global wind circulation systems in oceanic atmospheres. All oceans are associated with unique wind systems that reflect temperature and other physical attributes of the water masses. However, the influence of such systems on Eastern Africa has not been investigated in conjunction with unique climatic phenomena, including the June winds in the coastal region of Kenya. This study involved a review of literature and the analyses of secondary data from studies conducted in the region, including 39 years of meteorological data. The results indicated that only two months in a year, namely April and May, experience a positive net moisture regime. In all other months, predicted evaporation exceeds received precipitation. The results also suggest that the annual June winds create a cyclic depression in rainfall amounts during the long rains season, resulting in decreased soil moisture and therefore adverse effects on annual field crops. The June winds, at critical stages of maize growth, results in depressed crop yields that threaten food supply and food security. Maize yields in the region are associated over time with amounts of rain received during the long rains season. Cyclic patterns indicated that a year of higher rainfall alternates with a year of lower rainfall amounts. The study reveals that June winds causes over 95% in yield loses and suggests that the region can feed itself and export excess grains if only appropriate technologies to counter June winds effects are adopted. Since the occurrence of June winds is strongly linked to the La Niña climaticphenomenon the study suggests development of a maize yield prediction model for seasonal forecasting based on the onset of June winds during the long rains season.