Vulnerability Of Crops Research Articles

Crop damage by Asian elephant (Elephas maximus) in Ekgaloya and Dewalahinda areas in Ampara District, Eastern province, Sri Lanka

Crop damage by Asian elephant (Elephas maximus) in Ekgaloya and Dewalahinda areas in Ampara District, Eastern province, Sri Lanka

Field Evaluation of Different Attractants for Detecting and Monitoring Drosophila suzukii

Drosophila suzukii, more commonly known as the spotted-wing drosophila (SWD), is an invasive pest of soft, thin-skinned fruit responsible for significant economic losses for growers worldwide. To detect and monitor this pest, several host attractants have been developed for use in trapping SWD; however, they lack selectivity. Therefore, there is a significant need for more selective monitoring devices to enable growers to make timely pest management decisions to properly protect vulnerable crops. Previous studies identified a quinary blend (QB), based on fermenting apple juice odors, which offers significantly higher selectivity by reducing non-target captures compared with the standard apple cider vinegar bait commonly used by growers in the orchards. In this study, the selectivity and efficacy of a home-made QB dispenser was compared to an industry formulated version of the QB components (ChemTica) and two commercially available (Scentry and Trécé) SWD dispensers across blueberry and raspberry fields in Maryland, West Virginia, and New Jersey in different seasons. Controlled-release dispensers of the QB (home-made and ChemTica) consistently had higher selectivity within the blueberry and raspberry field sites compared with the two commercial dispensers; although efficacy was compromised such that total SWD captures per trap tended to be lower. The selectivity ratio range of SWD to non-targets (all non-SWD) for a QB-based (ChemTica) dispenser averaged from 15 to 57% compared with other commercial dispensers that ranged from 1 to 30% based on location and year. Due to high selectivity of the controlled-release dispenser of the QB, the potential for this dispenser to be utilized by growers as a SWD detection and monitoring tool is high.

Redesigning irrigated almond and pistachio cultivation: implications of a shift towards sustainable intensification

The global warming is increasing the variability of rainfall and temperature, peculiarly, in arid and semiarid environments worlwide. Alterations in precipitation patterns and evapotranspiration in these areas will provoke an augmentation in the water requirements for crops, therefore, a collapse in the water resources systems is contemplated. This work presents the deficit irrigation as an adaptation tool for water shortage in reducing the vulnerability of woody-fruit crops in the Mediteraean area. In this context, almond (Prunus dulcis Mill.) and pistachio (Pistacia vera L.) are traditional Mediterranean crops well-adapted to rainfed conditions with highly producer potential under irrigation, therefore, both fruit crops are convenient alternative due to its congenital response to water-stress. In general, moderate deficit irrigation technique enables to save about 30% of irrigation water at yield reductions below 20%. That is, the application of deficit irrigation could be recommended especially in those areas where the full water requeriments for crops are not available due to environmental constrains. In addition, the success of deficit irrigation is based on relevant knowledge of crop phenological development and its physiological reaction to water stress. Thus, the implementation of properly redesign of irrigated fruit plantations under climate change is vital, in order to mitigate the impact on yield, increase water-use efficiency, and preserve or improve the production quality.

Population size and human-grivet monkeys (Chlorocebus aethiops) conflict in Zegie peninsula, Bahir Dar, Ethiopia

BackgroundHuman-monkey conflict exists in different forms all over the world and is experienced more in developing countries. The conflict between human and grivet monkey (Chlorocebus aethiops) ranks among the main threats to biodiversity conservation and has become frequent and severe in different parts of Africa. A study on population size and human-grivet monkey conflict in Zegie Peninsula was carried out from August 2019 to March 2020; the study comprised both the wet and dry seasons. The line transect method was used to collect data on the population size of grivet monkeys. Questionnaires and focus group discussions were used to study the human-grivet monkey conflict and its conservation status.ResultsThe estimated population of grivets in the study area was 5046. Population structure of grivets indicated that there were 637 adult males, 1246 adult females, 1839 juveniles, and 1324 infants. The number of grivets in different habitat was; 1925 grivets in agricultural area, 1568 in lakeshore, 988 in forest and 565 grivets in shrub. Grivet population estimate between the wet and dry seasons did not show significant differences (χ2 = 0.941, df = 1, p > 0.05). But there was a significant difference in the population estimate of grivets among the different habitats (χ2 = 239.135, df = 3, p < 0.05 and among their age/sex (χ2 = 504.102, df = 3, p < 0.05.Based on the questionnaire result the most problematic crop pests in the area were grivet monkeys (96.4%), bush pigs (52.3%), porcupine (46.3%) and squirrels cover (33.2%). The result of discussions held with focus groups and questionnaires in the study area showed that grivet monkeys damage crops (98.4%), chicken depredation (49.5%), steal and snatch human food (32%), disturbing communities (11.3%) in the area. Most (62%) of the respondents noted that guava is the most vulnerable crop followed by papaya, mango, avocado to be damaged by grivet monkeys.ConclusionThe total number of grivet monkey in the study area is 5046. The number of grivet monkeys varies based on their sex/age and their habitat type. There is no significant difference in their number according to season since the movement of grivets is restricted to the area (there is no migration in the area). The increasing population number leads the occurrence of human grivet monkey conflict in the area and this inversely affects grivet monkeys. There was a human-grivet monkey conflict in the Peninsula and grivets damaged crops, not only crops but also predating poultry, stealing eggs, and human food. Consequently, grivets were killed in response to the damage they caused to crops. Grivet’s habitat in the Peninsula is highly disturbed because the local people cut trees for sale to support their livelihood. Awareness creation of the residents about wildlife and their habitat is necessary, and people should understand the impact of deforestation, illegal hunting, and the role of grivets in the ecosystem at large. Hence there is a need to protect the forest in order to ensure sustainable conservation of biodiversity in general and grivet monkeys in particular.

Is wetter better? Exploring agriculturally-relevant rainfall characteristics over four decades in the Sahel

The semi-arid Sahel is a global hotspot for poverty and malnutrition. Rainfed agriculture is the main source of food and income, making the well-being of rural population highly sensitive to rainfall variability. Studies have reported an upward trend in annual precipitation in the Sahel since the drought of the 1970s and early ‘80s, yet farmers have questioned improvements in conditions for agriculture, suggesting that intraseasonal dynamics play a crucial role. Using high-resolution daily precipitation data spanning 1981–2017 and focusing on agriculturally-relevant areas of the Sahel, we re-examined the extent of rainfall increase and investigated whether the increases have been accompanied by changes in two aspects of intraseasonal variability that have relevance for agriculture: rainy season duration and occurrence of prolonged dry spells during vulnerable crop growth stages. We found that annual rainfall increased across 56% of the region, but remained largely the same elsewhere. Rainy season duration increased almost exclusively in areas with upward trends in annual precipitation (23% of them). Association between annual rain and dry spell occurrence was less clear: increasing and decreasing frequencies of false starts (dry spells after first rains) and post-floral dry spells (towards the end of the season) were found to almost equal extent both in areas with positive and those with no significant trend in annual precipitation. Overall, improvements in at least two of the three intraseasonal variables (and no declines in any) were found in 10% of the region, while over a half of the area experienced declines in at least one intraseasonal variable, or no improvement in any. We conclude that rainfall conditions for agriculture have improved overall only in scattered areas across the Sahel since the 1980s, and increased annual rainfall is only weakly, if at all, associated with changes in the agriculturally-relevant intraseasonal rainfall characteristics.

Postharvest losses and mitigating technologies: evidence from Upper East Region of Ghana

Abstract Post-harvest losses (PHL) have been identified as a crucial challenge to achieving food and nutrition security in sub-Saharan Africa. Access to reliable data and standardized methods of estimating PHL are a twin barrier to developing long term mitigation options and policies to reduce PHL. This study assessed PHL in 6 districts of the Upper East Region of Ghana to facilitate planning and dissemination of mitigating strategies. The second part involved participatory evaluation of improved storage technologies to reduce PHL in two vulnerable crops (maize and cowpea). Overall, farmers’ declared PHL were higher across the crops compared to laboratory measurement. Crops recording higher PHL were in order of cowpea (17.3%), Bambara nut (11.5%), groundnut (8.9%) and maize (8.2%). By disseminating appropriate technologies to farmers, PHL were reduced to 3.1% from 36.7% in maize and 6.4% from 77.8% in cowpea during 12 months of storage. In spite of the high PHL, the respondents showed low technical and resource capabilities to minimize losses. Other factors contributing to PHL were the small-scale nature of production, and high cost of improved techniques tailored for same smallholders. Although the improved storage methods were associated with high variable costs, all the treatments showed positive stream of discounted net benefits .

New challenges for sunflower ideotyping in changing environments and more ecological cropping systems

As a rainfed spring-sown crop, sunflower (Helianthus annuus L.) is increasingly exposed to negative impacts of climate change, especially to high temperatures and drought stress. Incremental, systemic and transformative adaptations have been suggested for reducing the crop vulnerability to these stressful conditions. In addition, innovative cropping systems based on low-input management, organic farming, soil and water conservation practices, intercropping, double-cropping, and/or agroforestry are undergoing marked in agriculture. Because of its plasticity and low-input requirements (nitrogen, water, pesticides), sunflower crop is likely to take part to these new agroecological systems. Aside from current production outputs (yield, oil and cake), ecosystem services (e.g. bee feeding, soil phytoremediation…), and non-food industrial uses are now expected externalities for the crop. The combination of climatic and societal contexts could deeply modify the characteristics of genotypes to be cultivated in the main production areas (either traditional or adoptive). After reviewing these changes, we identify how innovative cropping systems and new environments could modify the traits classically considered up to now, especially in relation to expected ecosystem services. Finally, we consider how research could provide methods to help identifying traits of interest and design ideotypes.

Characterizations of Growth, Yield and Water Use Efficiency of Adzuki Bean as Affected by Drought Stress

Accurate and optimal water supply to crop is critical in growing stalks and producing maximum yields. Adzuki bean is one of the representative legume crops and known as a vulnerable crop to water stress. This study investigated drought effect on adzuki bean at various growth stages and water use efficiency (WUE) with different soil moisture contents in order to evaluate response of adzuki bean to drought. The experiment was performed at National Institute of Crop Science in Miryang. Adzuki beans were planted in a Wagner pot filled with 50% of silt loam soil and 50% of bed soil. Drought treatment was applied at six growth stages: V1, V3, V5, R1, R3, R5. Another pot experiment was performed in a stainless steel pot with an automated irrigation system in order to maintain targeted soil moisture content (40, 60 and 80% of field capacity). Growth and yield characteristics of adzuki bean were measured from all pots. Crop susceptibility (CS) was calculated from the Wagner pots to quantify drought effect at each growth stage and WUE was measured from the stainless pots to determine the least water requirement to prevent drought damage. Drought effect was the greatest in growth reduction at V1 and yield reduction at R3. CS value was the smallest value at V3 and the greatest at R3. Growth, yield and WUE data of adzuki bean were not different between soil moisture 60% of field capacity and 80%, while ones from 40% soil moisture content were smaller than others. Adzuki bean exhibited great vulnerability to drought stress at reproductive stage and it required at least soil moisture 60% of field capacity to prevent drought damage. These results will be useful to water management of adzuki bean and prevent drought damage in adzuki bean cultivation. Results of daily water used from adzuki bean cultivated with different soil moisture content (40, 60, 80% of filed capacity). DAP represents days after planting.

The alarming vulnerability of Coffea canephora varieties and germplasm to a virulent strain of Pseudomonas syringae pv. garcae, the cause of bacterial halo blight of coffee in Brazil

Bacterial halo blight caused by Pseudomonas syringae pv. garcae is a limiting disease to the coffee crop due to difficulty and low efficiency of the chemical control on field conditions. The simultaneous use of windbreaks and resistant cultivars seem to be the most appropriate measure of disease management. Although the bacterial halo blight resistance has been extensively studied in Coffea arabica, information about the reaction of C. canephora germplasm is not available. Thus, the objective of this study was to identify resistance sources to the bacterial halo blight in C. canephora germplasm, for use in breeding programs. Several commercial cultivars, botanical varieties, clones and hybrids of C. canephora were tested against a highly virulent P. syringae pv. garcae strain through artificial inoculations in greenhouse conditions. Only 1.4% of 2.421 evaluated plants were considered resistant to the disease. Our results showed the alarming vulnerability of Coffea canephora crop and germplasm to the bacterial halo blight from Brazil and the need to select resistant cultivars.

Fatty Acid Profile as an Indicator of Larval Host for Adult Drosophila suzukii.

Simple SummarySpotted-wing drosophila, Drosophila suzukii, is an invasive pest of soft-skinned fruits. Adult female flies oviposit, or lay eggs, into fruits where the larvae develop, making infested fruit unmarketable. The flies rely on alternative hosts, both cultivated and wild, to survive and maintain populations throughout the year. Better understanding of how the flies migrate between different hosts could be beneficial to improving management of the pest in crops. This study demonstrates potential to discriminate larval host of adult flies by analysis of fatty acids carried from the larvae to the adult stage in the body using a machine learning algorithm as an alternative to linear discriminant methods. Our study shows that fatty acids in adult flies can be used to determine larval host and that the machine learning algorithm can perform the discriminant analysis without making any assumptions about the data.Drosophila suzukii is a severe economic invasive pest of soft-skinned fruit crops. Management typically requires killing gravid adult female flies with insecticides to prevent damage resulting from oviposition and larval development. Fruits from cultivated and uncultivated host plants are used by the flies for reproduction at different times of the year, and knowledge of D. suzukii seasonal host plant use and movement patterns could be better exploited to protect vulnerable crops. Rearing and various marking methodologies for tracking movement patterns of D. suzukii across different landscapes have been used to better understand host use and movement of the pest. In this study, we report on potential to determine larval host for adult D. suzukii using their fatty acid profile or signature, and to use larval diet as an internal marker for adult flies in release-recapture experiments. Fatty acids can pass efficiently through trophic levels unmodified, and insects are constrained in the ability to synthesize fatty acids and may acquire them through diet. In many holometabolous insects, lipids acquired in the larval stage carry over to the adult stage. We tested the ability of a machine learning algorithm to discriminate adult D. suzukii reared from susceptible small fruit crops (blueberry, strawberry, blackberry and raspberry) and laboratory diet based on the fatty acid profile of adult flies. We found that fatty acid components in adult flies were significantly different when flies were reared on different hosts, and the machine learning algorithm was highly successful in correctly classifying flies according to their larval host based on fatty acid profile.

GIS-Based Land Suitability and Crop Vulnerability Assessment under Climate Change in Chtouka Ait Baha, Morocco

Agriculture plays a crucial role in the economic development in Morocco, contributing to 14% of the national gross domestic product. However, this sector is facing various challenges, including climate change. This study aims to assess relevant indicators that may affect land suitability, water demand, and crop growing season duration under climate change. Further, it may be used as a decision support tool in the Chtouka area known for its irrigated agriculture. The approach proposed, the spatial distribution of land based on suitability, is founded on the multiple-criteria decision-making method of four parameters; soil texture, temperature, land use, and slope. The duration of the length of crop season was simulated using the concept of growing degree days. The projection of land suitability for 2031–2050 indicated an important decrease of 12.11% of “highly suitable” agricultural land under the RCP4.5 emission scenario and a significant increase of 4.68% of “highly unsuitable” land, according to the RCP8.5 emission scenario compared to the baseline (1985–2005). The projected growing degree days in 2031–2050 showed a strong shortening in the growing period length compared to the baseline 1985–2006, mainly under the RCP8.5 emission scenario, with a reduction from 8% to 21% depending on crops. Moreover, crop water productivity indicated that berries were over 50% less water productive than other vegetable crops for almost the same amount of applied irrigation water. These findings highlight the vulnerability of agriculture to climate change, which requires important political and management efforts to sustain agricultural activity.

Nutritional niches reveal fundamental domestication trade-offs in fungus-farming ants

During crop domestication, human farmers traded greater productivity for higher crop vulnerability outside specialized cultivation conditions. We found a similar domestication tradeoff across the major co-evolutionary transitions in farming systems of attine ants. First, the fundamental nutritional niches (FNNs) of cultivars narrowed during ~ 60 million years of naturally selected domestication, and laboratory experiments showed that ant farmers representing subsequent domestication stages strictly regulate protein harvest relative to cultivar FNNs. Second, ants with different farming systems differed in their abilities to harvest the resources that best matched the nutritional needs of their fungal cultivars. This was assessed by quantifying realized nutritional niches (RNNs) from analyses of items collected from the mandibles of laden ant foragers in the field. Third, extensive field collections suggest that among-colony genetic diversity of cultivars in small-scale farms may offer population-wide resilience benefits that species with large-scale farming colonies achieve by more elaborate and demanding cultivation practices of less diverse crops. Our results underscore that naturally selected farming systems have potential to shed light on nutritional tradeoffs that shaped the course of culturally evolved human farming.

Effect of Climate Variables in Rice Yield in Nueva Ecija, Philippines

Climate variability is one of the factors that directly and greatly affect cropping system and plant yield. It is therefore very important to obtain a good understanding about climate variability or changes in the climate and the effect of these changes to clearly understand the vulnerability of food crops as well as its agronomic impacts for us to create and implement adaptive strategies to mitigate its negative effects. This study assessed the effect of climate in rice crop yield in both irrigated and rainfed ecotype farming system in Nueva Ecija Province in the Philippines using semi-annual yield data and the different climate variables such as seasonal rainfall, mean temperature, minimum temperature, and relative humidity by using empirical/statistical method through time series analysis, and correlation analysis. Results indicated that rice yield for irrigated and rainfed ecosystem type of farming in Nueva Ecija show an overall increasing trend from year 1991-2018, although there are observed decline and fluctuations in some years. The different climate variables (i.e., rainfall, temperature, and humidity) show fluctuating trends and irregularities spanning from the year 1991-2018. But it showed overall decreasing trends for relative humidity and increasing trends for rainfall, minimum temperature, and mean temperature. There are significant correlations between rice yield the all the climate variables in both irrigated and rainfed farming ecosystem types.

Consistency in Vulnerability Assessments of Wheat to Climate Change—A District-Level Analysis in India

In India, a reduction in wheat crop yield would lead to a widespread impact on food security. In particular, the most vulnerable people are severely exposed to food insecurity. This study estimates the climate change vulnerability of wheat crops with respect to heterogeneities in time, space, and weighting methods. The study uses the Intergovernmental Panel on Climate Change (IPCC) framework of vulnerability while using composite indices of 27 indicators to explain exposure, sensitivity, and adaptive capacity. We used climate projections under current (1975–2005) conditions and two future (2021–2050) Representation Concentration Pathways (RCPs), 4.5 and 8.5, to estimate exposure to climatic risks. Consistency across three weighting methods (Analytical Hierarchy Process (AHP), Principal Component Analysis (PCA), and Equal Weights (EWs)) was evaluated. Results of the vulnerability profile suggest high vulnerability of the wheat crop in northern and central India. In particular, the districts Unnao, Sirsa, Hardoi, and Bathinda show high vulnerability and high consistency across current and future climate scenarios. In total, 84% of the districts show more than 75% consistency in the current climate, and 83% and 68% of the districts show more than 75% consistency for RCP 4.5 and RCP 8.5 climate scenario for the three weighting methods, respectively. By using different weighting methods, it was possible to quantify “method uncertainty” in vulnerability assessment and enhance robustness in identifying most vulnerable regions. Finally, we emphasize the importance of communicating uncertainties, both in data and methods in vulnerability research, to effectively guide adaptation planning. The results of this study would serve as the basis for designing climate impacts adjusted adaptation measures for policy interventions.

ВЛИЯНИЕ ПРЕДШЕСТВЕННИКОВ И СРОКОВ ПОСЕВА НА ПЕРЕЗИМОВКУ И УРОЖАЙНОСТЬ ОЗИМОЙ ПШЕНИЦЫ В ИЗМЕНЯЮЩИХСЯ УСЛОВИЯХ РЕГИОНАЛЬНОГО КЛИМАТА

The research was carried out in order to determine the optimal time for sowing winter wheat according to various predecessors in the changing climate of Volga forest-steppe. The work was carried out in 2013–2019 in Ulyanovsk region on heavy loamy leached chernozem using conventional techniques. The experimental scheme provided for the study of two predecessors (peas and pure fallow) of winter soft wheat of Marafon variety, sown at 6 sowing dates with an interval of 10 days (from August 20 to October 10). The seeding rate for pure fallow is 5.0 million viable seeds per hectare, for peas - 5.5 million viable seeds per hectare. Average annual air temperature for 1961–2018 increased by 1.8°С. Its most significant increase was noted in the last twenty-five year period of time in the winter months. The increase in the frequency of extremely warm winters and temperature variability in the winter period significantly changed the conditions for overwintering winter crops. The danger of the development of wintering weeds, damping diseases, and soaking of winter crops has increased, and the conditions for overwintering pests have improved. It is possible to mitigate the danger of the natural and climatic vulnerability of crops during the wintering period by observing the optimal sowing dates, which should be postponed to a later period (7 ... 12 days), compared with the previously recommended ones. The optimal sowing period for winter wheat in Ulyanovsk region is from August 30 to September 10. Earlier crops are more intensively affected by diseases (powdery mildew and brown rust), and later crops, which have left in the winter in the germination phase, form a low density, form a small ear and provide low productivity or completely die

Ontogeny in the European earwig (Forficula auricularia) and grain crops interact to exacerbate feeding damage risk

AbstractThe preference of herbivores for different host plants can be modulated by plant ontogeny. In agricultural pest management, this has implications for sowing dates and pest monitoring. In the last 20 years, the European earwig (Forficula auricularia), a cosmopolitan pest, has been increasingly implicated in damage to grain crops in Australia. Among these, rapeseed, Brassica napus, appears especially at risk, but little information on F. auricularia as a grain pest is available. We tested the susceptibility of seven grain crops commonly grown in Australia to infestation by F. auricularia using closed microcosm experiments, exposing plant seedlings at two early growth stages to four different life stages of F. auricularia. Lucerne and rapeseed were shown to be the most vulnerable crops, and younger seedlings experienced significantly more damage than older seedlings across all crop types. Fourth instar F. auricularia were found to cause greater feeding damage than younger or older earwigs, while adults collected in winter generally caused more damage than those collected in summer. Surprisingly, even second instar F. auricularia caused greater damage than summer adults. This variation could reflect the ontogenetically dynamic nutritional needs of earwigs. Recent studies of F. auricularia's life cycle in southern Australia indicate that these damaging life stages have some overlap with sowing dates of the crops tested here, exposing their vulnerable seedling stage to infestation. The phenology of F. auricularia in southern Australia therefore partly drives its ability to act as a pest. Future monitoring will likely need to track the distribution of F. auricularia life stages in order to effectively mitigate risks to vulnerable crops.

Identification and Expression Analysis of Salinity-induced Genes in Rangpur lime (Citrus limonia)

Among the economically important horticultural crops, citrus is one of the most vulnerable crops to soil salinity. Rangpur lime is more tolerant to high soil salinity than other commonly used citrus rootstocks. However, the molecular mechanism involved in salinity tolerance has not been explored in Rangpur lime. In this study, a cDNA library was constructed from leaves of Rangpur lime watered for 30 days with 100 mmol · L−1 NaCl in tap water or tap water using suppression subtractive hybridization (SSH). Two hundred cDNA clones randomly selected from this library were sequenced, and an average of 569 bp was obtained from the majority of clones. Fifty-six salinity-induced genes, showing 2- to 6-fold increases in their expression levels, were identified by macroarray hybridizations. Salinity-induced genes were associated with transcription (5.36%), stress response and signaling (21.43%), metabolism (16.07%), transport facilitation (10.71%), photosynthesis (10.71%), protein synthesis and fate (19.64%) and cellular biogenesis (3.57%). Stress response- and signaling-related genes constituted the largest functional group, associated with the production of compatible solutes, regulation of stomatal movement, lipid modification, oxidative stress, antioxidant defense, and stress signaling. Expression levels of 13 identified genes were induced 1.8- to 3.1-fold, which were validated in salt-treated and untreated Rangpur lime. The functions of salinity-induced, stress-related genes and their potential roles in salinity tolerance in Rangpur lime were discussed.

Effects of Root-Knot Nematode Inoculums Densities on Morphological and Phytochemical Analysis of Selected Horse Gram Germplasm

Root-knot nematodes (Meloidogyne incognita; RKN) are important constraints on agricultural crops worldwide. Horse gram is a vulnerable pulse crop from the agriculture revolution exceptionally in southern India. This study intended to assess the resistance of four Horse gram accessions IC-1536, IC-1572, IC-1451 and IC-1115 selected from 100 accessions based on the morphological and biochemical scrutiny. Individual seedlings were transferred in the clay pots packed with sterile soil and inoculated with three doses (25, 50 and 100) of second stage juveniles of M. incognita. All nematode inoculums densities influenced the shoot length of plants, flowering and yield. The level of amino acid, proline, protein, total phenol and flavonoids contents were increased while carbohydrate and starch contents were decreased in all the varieties compared to the 15th day after inoculation. It is pointed out that M. incognita has not only impaired the plant growth but also biochemical parameters such as chlorophyll pigments, primary and secondary metabolites.

Effect of deltamethrin‐incorporated nets on mobility and survivorship of Halyomorpha halys (Hemiptera: Pentatomidae) adults and nymphs in the laboratory

AbstractThe brown marmorated stink bug, Halyomorpha halys Stål (Hemiptera: Pentatomidae), is an invasive pest that attacks specialty and row crops in North America and Europe. There has been a concerted effort to reduce frequent broad‐spectrum insecticide applications made on vulnerable crops. One tool that has emerged recently is the use of long‐lasting insecticide‐treated nets (LLINs) as a killing agent. Here, we conducted bioassays to evaluate the effect of direct contact on deltamethrin‐impregnated LLINs on the behaviour and survivorship of H. halys nymphs and adults in the laboratory. Following exposure at three different durations (1.25, 4.25 or 7.25 min), vertical and horizontal mobility of adults and nymphs and the flight capacity of adults were recorded and compared with individuals that were not exposed (control). Exposure to LLINs reduced the horizontal distance and velocity and increased the angular velocity of adults only but reduced vertical mobility of adults and nymphs. Adult flights were not significantly affected by LLIN exposure. Mortality of adults and nymphs at 7‐day post‐exposure ranged from 73% to 77% regardless of exposure time. We discuss our findings within the context of the potential for and limitations of deploying LLINs in vulnerable crops to manage H. halys populations.

Typhoon Type Index: A New Index for Understanding the Rain or Wind Characteristics of Typhoons and Its Application to Agricultural Losses and Crop Vulnerability

AbstractHeavy rainfall and strong wind are the two main sources of disasters that are caused by tropical cyclones (TCs), and typhoons with different characteristics may induce different agricultural losses. Traditionally, the classification of typhoon intensity has not considered the amount of rainfall. Here, we propose a novel approach to calculate the typhoon type index (TTI). A positive TTI represents a “wind type” typhoon, where the overall damage in a certain area from TCs is dominated by strong wind. On the other hand, a negative TTI represents a “rain type” typhoon, where the overall damage in a certain area from TCs is dominated by heavy rainfall. From the TTI, the vulnerability of crop losses from different types of typhoons can be compared and explored. For example, Typhoon Kalmaegi (2008) was classified as a rain-type typhoon (TTI = −1.22). The most affected crops were oriental melons and leafy vegetables. On the contrary, Typhoon Soudelor (2015) was classified as a significant wind-type typhoon in most of Taiwan (TTI = 1.83), and the damaged crops were mainly bananas, bamboo shoots, pomelos, and other crops that are easily blown off by strong winds. Through the method that is proposed in this study, we can understand the characteristics of each typhoon that deviate from the general situation and explore the damages that are mainly caused by strong winds or heavy rainfall at different locations. This approach can provide very useful information that is important for the disaster analysis of different agricultural products.