The root-knot nematode, Meloidogyne javanica, is one of the most damaging plant-parasitic nematodes, affecting chickpea and causing substantial yield losses worldwide. The damage potential and population dynamics of this nematode in chickpea in Ethiopia have yet to be investigated. In this study, six chickpea cultivars were tested using 12 ranges of initial population densities (Pi) of M. javanica second-stage juveniles (J2): 0, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32, 64 and 128 J2 (g dry soil)-1 in a controlled glasshouse pot experiment. The Seinhorst yield loss and population dynamics models were fitted to describe population development and the effect on different measured growth variables. The tolerance limit (TTFW) for total fresh weight ranged from 0.05 to 1.22 J2 (g dry soil)-1, with corresponding yield losses ranging from 31 to 64%. The minimum yield for seed weight (mSW) ranged from 0.29 to 0.61, with estimated yield losses of 71 and 39%. The 'Haberu' and 'Geletu' cultivars were considered good hosts, with maximum population densities (M) of 16.27 and 5.64 J2 (g dry soil)-1 and maximum multiplication rate (a) values of 6.25 and 9.23, respectively. All other cultivars are moderate hosts for M. javanica; therefore, it is crucial to initiate chickpea-breeding strategies to manage the tropical root-knot nematode M. javanica in Ethiopia.
The horticultural crops, including spices and plantation crops, are known for their enormous benefits, contributing to the country's economy. However, Phytophthora, a genus of Oomycetes class, poses a threat to spice and plantation crops by infecting and damaging them, resulting in yield losses, economic hardship for farmers, and food security concerns, thereby threatening the sustainability of spice and plantation crops. Moreover, Phytophthora has greater adaptation sys tems in varying environmental conditions. Therefore, eradicating or controlling Phytophthora is a highly challenging process due to the longevity of its infective propagules in soil. Early detection and curative measures would be more effective in managing this destructive pathogen. Additionally, molecular detection using innovative methods such as polymerase chain reaction, reverse transcription polymerase chain reaction, recombinase polymerase amplification, and loop-mediated isothermal amplification would offer reliable and rapid detection. Furthermore, integrated disease management strategies, combining cultural, physical, chemical, and biological methods, would prove highly beneficial in managing Phytophthora infections in spices and plantation crops. This review provides a comprehensive overview of the diversity, symptomatology, pathogenicity, and impact of Phytophthora diseases on prominent spice and plantation crops. Finally, our review explores the current disease reduction strategies and suggests future research directions to address the threat posed by Phytophthora to spices and plantation crops.
Climate change and its impact on agricultural production due to the occurrence of extreme weather events appear to be more imminent and severe than ever, presenting a global challenge that necessitates collective efforts to mitigate its effects.There have been many practical and modelling studies so far to estimate the extent of climate change and possible damages on agricultural production, suggesting that water availability may decrease by 50% and agricultural productivity between 10 and 30% in the coming years ahead. Though there have been many studies to estimate the possible level of damage by the climate change on the production of many agricultural crops, no study has been conducted on the greenhouse tomato production. Therefore, this study was conducted to discover the effects of extreme high temperatures during the 2022-2023 growing season on the high-tech Turkish tomato greenhouse industry through a survey. The results showed that all greenhouses lost yield, ranging from 6 to 53%, with an average of 12.5%. Survey data revealed that irrigation and fog system water consumption increased by 29.32% and 31.42%, respectively, while fertilizer and electricity consumption rose by 23.66% and 19%. Some 76.5% of the growers declared difficulty in climate control, 11.7% reported tomato cluster losses with no information on yield loss, 9% experienced yield losses despite no cluster losses, and 61.7% observed a decline in tomato quality, leading to reduced sales prices. Considering these findings, it is recommended that greenhouses must adopt advanced climate control technologies, expand fog system capacities, and integrate renewable energy sources to enhance resilience against climate-induced challenges. Additionally, improving water-use efficiency, optimizing cooling strategies, using new and climate-resistant varieties and adjusting cropping seasons could help mitigate yield losses due to extreme temperatures. The study results offer extremely valuable insights into greenhouse production for researchers, technology developers, and policymakers for the mitigation of climate change effects and the development of more sustainable production systems.
Winter wheat (Triticum aestivum L.) is a crucial crop that guarantees food supply in the North China Plain (NCP). As the frequency of extreme cold events increases, it is necessary to explore the freezing resistance of different wheat varieties in order to clarify planting boundaries and help with risk assessment. In this study, 2-year controlled experiments were conducted to explore the effect of freezing temperatures (T air) and freezing durations on three winterness types. A set of indexes were used to characterize the subfreezing stress on wheat tiller, leaf, and final yield. Logistical regressions were used to quantify the temperature threshold for 10%, 30%, and 50% of freezing injury. The results showed that the lower temperature threshold of tiller (LT) varied from -9.6 to -15.9 degrees C, -10.7 to -19.1 degrees C and -11.4 to -21.2 degrees C for LT10, LT30, and LT50, respectively. The difference between LT and yield loss (YL) indexes reduced with decreased winterness types and was -0.1 to 3.4 degrees C, -0.7 to 2.1 degrees C, and 0.3 to 0.9 degrees C higher compared with YL thresholds for winterness, semi-winterness, and weak-winterness types, respectively. The average minimum soil temperature was 7.5, 4.8, and 4.2 degrees C higher than T-air for 1-, 2-, and 3-day treatment, respectively. Soil effective negative accumulated temperature hours (TSEh) ranged from 6.9 to 12.0, 48.4 to 6.9, and 84.7 to 106.9 degrees Ch for 10%, 30%, and 50% tiller mortality, respectively. Freezing treatment with T-air < -12, -9, and -8 degrees C obviously decreased leaf Fv/Fm for the three varieties and Fv/Fm declined obviously after 5 days of recovery under field conditions. Our results provided multiple indexes for quantifying subfreezing damage in practical wheat production and could shed light on future risk assessment.
Spodoptera frugiperda (J.E. Smith), fall armyworm (FAW), a polyphagous Noctuid pest, was first reported in Uganda in 2016. Farmers were trained to identify and manage the pest, but there was a lack of information on farmer knowledge, perceptions and practices deployed to control it. Therefore, we conducted a survey to assess maize farmers' knowledge, perceptions and management of the pest during the invasion. We interviewed 1,289 maize farmers from 10 maize-growing agro-ecological zones (AEZ) of Uganda using well-structured questionnaires. The data were analyzed using R version 4.2.3. The respondents faced many constraints, including pests, drought, poor soils and labor constraints. Among the pests, FAW was ranked by most (85%) of the respondents as the number one pest problem in maize, and some farmers reported having noticed it way back in 2014. By 2018, more than 90% of the farmers had seen or heard about FAW, and about 80% saw FAW in their fields. The most common FAW symptoms reported by maize farmers were windowing, near tunnel damage, and holes on the cobs. The developmental stages of FAW identified by farmers included eggs (10%), young larvae (78.7%), mature larvae (73.5%) and adult moths (6.7%). Insecticides were the major control tactic, although some farmers used plant extracts, hand-picking, sand, and ash. Farmers sourced information on FAW from various sources, including fellow farmers, radio/TV, extension agents, input dealers, print media, research and NGO extension. There is a need to package clear and uniform information for the farmers and to develop and promote a sustainable solution for FAW management, including harnessing biological control and cultural practices.
Plant parasitic nematodes (PPN) and fungi cause biotic stress and are responsible for considerable yield losses to different crops. PPN and fungi are very abundant microorganisms in soil and both interact with each other in multiple ways. PPN besides causing direct damage to plants, also possess capability to interact with fungi resulting into disease complexes. The PPN invasion in plant parts especially in root may enhance severity of fungal diseases in many instances. This review critically analyses the information on the combined nematode-fungus stress and economic losses caused by them. Combined PPN and fungal stress has been discussed which results into synergistic and additive interactions. Similarly, role of wounds created by nematode feeding, physiological changes in the host, modification in rhizosphere, breaking of host resistance and changes in the host plant due to combined interaction of PPN-fungus has been described. Role of PPN and fungus in antagonistic interaction has also been analysed. Role of microbial communities in the rhizosphere in influencing nematode-fungus interaction has also been discussed. Management of disease complexes using mixture of biocontrol agents and use of nanoparticles in integrated management has been suggested. Conclusion and future prospects have been discussed.