Root Feeding Research Articles

How to control nasty scarabs? Effectiveness of the generalist entomopathogenic fungus Metarhizium brunneum against garden chafer larvae

Several scarab beetles (Scarabaeidae) cause major damage in agriculture, horticulture, and forestry. Especially root feeding scarab larvae cause substantial economic losses on crops, forage plants and recreational areas. In Europe, the entomopathogenic fungi (EPF) Beauveria brongniartii and Metarhizium brunneum are applied against the most problematic, native scarabs, the common cockchafer (Melolontha melolontha) and the garden chafer (Phyllopertha horticola). While the control of cockchafer larvae with B. brongniartii is well-researched, conclusive results from field applications for the control of the garden chafer with M. brunneum remain elusive. We therefore assessed the performance of commercially available fungal strains of M. brunneum against garden chafer larvae in pot and large-scale field experiments.The application of M. brunneum significantly increased the abundance of fungal propagules in the soil by approximately a factor of ten, irrespective of high levels of naturally occurring Metarhizium spp. Furthermore, the applied strains infected and propagated on the larvae and the mortality of garden chafer larvae was slightly increased due to the fungal treatments. We found three other EPF species frequently infecting garden chafer larvae (mean infection rates: 13–25%), including B. brongniartii which is considered to be a specific pathogen of the cockchafer. Thus, the applied fungal strains were only part of a consortium of natural enemies which reduces garden chafer populations strongly as a whole. Hence, we suggest that the application of EPF may be advisable on areas with reduced natural enemies such as golf courses but is probably redundant on meadows harboring a diverse consortium of antagonists.

Rapid and Direct Detection of the Stubby Root Nematode, Paratrichodorus allius, from Soil DNA Extracts Using Recombinase Polymerase Amplification Assay.

The stubby root nematode, Paratrichodorus allius, is one of the most important plant-parasitic nematodes. Besides root feeding, P. allius also transmits the Tobacco rattle virus in potatoes, which causes corky ringspot disease. Rapid detection of P. allius is key for efficient management. This study was conducted to develop a real-time recombinase polymerase amplification (RPA) assay that is capable of detecting P. allius directly in DNA extracts from soil using a simple portable device in real time. A fluorophore-attached probe was designed to target the internal transcribed spacer (ITS)-rDNA of P. allius and was used along with primers designed previously. The real-time RPA assay had the ability to detect P. allius DNA extracted directly from infested soil with a sensitivity of one-sixteenth portion of a single nematode. This RPA assay was specific, as it did not produce positive signals from non-target nematodes tested. The real-time RPA was found to be rapid as it could even detect P. allius in as little as 7 min. Testing with 15 field soil samples validated the RPA assay developed in this study. This is the first report of P. allius detection directly from soil DNA using real-time RPA and is the fastest method for P. allius detection in soil to date.

A "love match" score to compare root exudate attraction and feeding of the plant growth-promoting rhizobacteria Bacillus subtilis, Pseudomonas fluorescens, and Azospirillum brasilense.

The rhizosphere is the zone of soil surrounding plant roots that is directly influenced by root exudates released by the plant, which select soil microorganisms. The resulting rhizosphere microbiota plays a key role in plant health and development by enhancing its nutrition or immune response and protecting it from biotic or abiotic stresses. In particular, plant growth-promoting rhizobacteria (PGPR) are beneficial members of this microbiota that represent a great hope for agroecology, since they could be used as bioinoculants for sustainable crop production. Therefore, it is necessary to decipher the molecular dialog between roots and PGPR in order to promote the establishment of bioinoculants in the rhizosphere, which is required for their beneficial functions. Here, the ability of root exudates from rapeseed (Brassica napus), pea (Pisum sativum), and ryegrass (Lolium perenne) to attract and feed three PGPR (Bacillus subtilis, Pseudomonas fluorescens, and Azospirillum brasilense) was measured and compared, as these responses are directly involved in the establishment of the rhizosphere microbiota. Our results showed that root exudates differentially attracted and fed the three PGPR. For all beneficial bacteria, rapeseed exudates were the most attractive and induced the fastest growth, while pea exudates allowed the highest biomass production. The performance of ryegrass exudates was generally lower, and variable responses were observed between bacteria. In addition, P. fluorescens and A. brasilense appeared to respond more efficiently to root exudates than B. subtilis. Finally, we proposed to evaluate the compatibility of each plant-PGPR couple by assigning them a "love match" score, which reflects the ability of root exudates to enhance bacterial rhizocompetence. Taken together, our results provide new insights into the specific selection of PGPR by the plant through their root exudates and may help to select the most effective exudates to promote bioinoculant establishment in the rhizosphere.

Evaluation the impact of silicon nanoparticle on growth and water use efficiency of greenhouse tomato in drought stress condition

This study focused on the effect of silicon nanoparticles (Si-Nps) use on growth and water use efficiency (WUE) of tomato in hydroponic cultivation under drought stress. Experimental treatments included full irrigation, supplying 85 and 70% of crop water requirement (I100, I85 and I70) and use of Si-Nps in three levels of 0, 50 and 100 ppm (N0, N50 and N100) which was performed in a completely randomized design with three replications. Si-Nps were applied in two ways: leaf feeding (L) and root feeding (R). Data analysis showed that different levels of irrigation, Si-Nps and the interaction effect of theirs had a significant effect on fruit weight, leaf fresh and dry weight, stem fresh weight and WUE at 1% level. Si-Nps had a significant effect on stem dry weight at 1% and fruit sugar at 5%. The interaction effect of irrigation and Si-Nps had a significant effect on stem dry weight and fruit sugar at 1%. The maximum fresh fruit weight was related to treatment I85LN100 and compared to the control treatment, it was 7.9% more. The maximum WUE was observed in I70RN50 treatment, which was 56.3% higher than control treatment. Generally, applying irrigation I70RN50 gives the best result for hydroponic tomato cultivation in greenhouse conditions.

Nematode community structure suggests perennial grain cropping cultivation as a nature‐based solution for resilient agriculture

AbstractIntroductionConventional agricultural land‐use may negatively impact biodiversity and the environment due to the increased disturbances to the soil ecosystem by tillage, for example. Cultivation of the perennial grain intermediate wheatgrass (Thinopyrum intermedium, IWG, Kernza®) is a nature‐based solution for sustainable agriculture, improving nutrient retention mainly through its extensive root system. Nematodes serve as sensitive bioindicators, detecting early changes in the soil food web, reflecting in changes in their community structure.Materials and MethodsIWG and annual wheat sites in South France, Belgium and South Sweden were investigated in April 2022 for two depths (5–15 cm; 25–35 cm) to evaluate the difference in nematode community structure among the cropping systems.ResultsSites with IWG cultivation held an accumulation of structure indicators (c‐p 3–5 nematodes) compared to sites with annual wheat cultivation. A generalised linear mixed model revealed significantly more root feeders, especially for the subsoil, under IWG as a result of the perennial cultivation. The maturity index, plant‐parasitic index, channel index and structure index were greater for IWG sites. The enrichment index was greater for annual wheat sites due to the dominance of bacterivores and enrichment indicators (c‐p 1 nematodes). The nematode community structure (weighted faunal profile analysis) indicates IWG sites as being a generally undisturbed system with efficient nutrient cycling and balanced distribution of feeding types, as well as higher metabolic footprint values for root feeders (including plant‐parasitic nematodes) and fungivores. Annual wheat sites, on the other hand, held indicators of a disturbed system with increased occurrence of opportunistic species and a more bacterial driven pathway. The topsoil had an increased occurrence of structure indicators in both cropping systems.ConclusionIWG creates favourable conditions for a diverse food web, including improved nutrient cycling and a heterogeneous resource environment, regardless of climatic conditions, establishing it as a stable and resilient agricultural management system.

Flavonoids mediate systemic defenses induced by root feeding in cotton

Flavonoids mediate systemic defenses induced by root feeding in cotton

Application of revitalize liquid biocomplex to increase adaptability of grapes at planting in open ground conditions

At present, the range of modern grape varieties suitable for cultivation in the conditions of the Non-Black Earth zone of the Russian Federation is represented by hybrids of different species origin derived from Vitis berlandieri Planch., Vitis Amurensis Rupr., Vitis riparia Michx., Vitis Labrusca L., which are characterized by low ability to vegetative propagation. Therefore, the development of techniques to improve the technology of accelerated propagation of these varieties, including the technology of clonal micropropagation is currently urgent. However, most studies in the field of in vitro propagation of grapes are devoted to laboratory experiments, but there is little information on the influence of the propagation method on the development indicators and vegetative productivity of grape mother plantations in protected and open ground conditions. Therefore, the purpose of this study was to develop methods of application of Revitalize liquid to increase the adaptability and stress resistance of ex vitro grape plants during summer transplanting into the open ground to create mother plantations. The research objectives are to reveal the effectiveness of feeding (root, foliar, combined) with Revitalize liquid during summer transplanting ex vitro grape plants of grape varieties Kishmish № 342, Moscow White and Kober 5BB rootstock into the open ground. The obtained results indicate that double combined treatments (root 500 ml: 500 ml H2O + foliar 25 ml:1000 ml H2O) are effective for pre-growing of ex vitro mother plants of Kishmish № 342 and Kober 5BB rootstock in open ground conditions, and double root feeding (at a concentration of 25 ml:1000 ml H2O) with Revitalize liquid is promising for Moscow White variety.

Sustaining the Yield of Maize, Blackgram, Greengram, Groundnut, Cotton, Sugarcane, and Coconut through the Application of Nutrients and Plant Growth Regulator Mixture.

The foliar application of nutrients and plant growth regulators (PGRs) at critical crop growth periods can improve the yield of field crops. Hence, the present study was conducted to quantify the effects of the combined application of nutrients and PGRs (crop-specific formulation) on maize, blackgram, greengram, groundnut, cotton, sugarcane, and coconut yield. In all the crops except coconut, the treatments included (i) a foliar spray of crop-specific nutrients and PGR combinations and (ii) an unsprayed control. In coconut, the treatments included (i) the root feeding of coconut-specific nutrients and PGR combinations and (ii) an untreated control. Crop-specific nutrient and PGR formulations were sprayed, namely, Tamil Nadu Agricultural University (TNAU) maize maxim 1.5% at the tassel initiation and grain-filling stages of maize, TNAU pulse wonder 1.0% at the peak flowering stage of green gram and black gram, TNAU groundnut-rich 1.0% at the flowering and pod-filling stages of groundnut, TNAU cotton plus 1.25% at the flowering and boll development stages of cotton, and TNAU sugarcane booster 0.5% at 45 days after planting (DAP), 0.75% at 60 DAP, and 1.0% at 75 DAP of sugarcane. The results showed that the foliar application of TNAU maize maxim, TNAU pulse wonder, TNAU groundnut-rich, TNAU cotton plus and TNAU sugarcane booster and the root feeding of TNAU coconut tonic increased the yield of maize, pulses, groundnut, cotton, sugarcane, and coconut, resulting in higher economic returns.

Salinity stress alters plant-mediated interactions between above- and below-ground herbivores

Below-ground herbivory impacts plant development and often induces systemic responses in plants that affect the performance and feeding behavior of above-ground herbivores. Meanwhile, pest-damaged root tissue can enhance a plant's susceptibility to abiotic stress such as salinity. Yet, the extent to which herbivore-induced plant defenses are modulated by such abiotic stress has rarely been studied. In this study, we examine whether root feeding by larvae of the turnip moth, Agrotis segetum (Lepidoptera: Noctuidae) affects the performance of the above-ground, sap-feeding aphid Aphis gossypii (Hemiptera: Aphididae) on cotton, and assess whether those interactions are modulated by salinity stress. In the absence of salinity stress, A. segetum root feeding does not affect A. gossypii development. On the other hand, under intense salinity stress (i.e., 600 mM NaCl), A. segetum root feeding decreases aphid development time by 16.1 % and enhances fecundity by 72.0 %. Transcriptome, metabolome and bioassay trials showed that root feeding and salinity stress jointly trigger the biosynthesis of amino acids in cotton leaves. Specifically, increased titers of valine in leaf tissue relate to an enhanced performance of A. gossypii. Taken together, salinity stress alters the interaction between above- and below-ground feeders by changing amino acid accumulation. Our findings advance our understanding of how plants cope with concurrent biotic and abiotic stressors, and may help tailor plant protection strategies to varying production contexts.

Evaluation of new generation fungicides against Ganoderma induced basal stem rot of oil palm

Basal stem rot (BSR), incited by Ganoderma spp. poses a significant challenge to the oil palm industry in India. A total of ten roots and basidocarps samples were taken from BSR-infected fields of Pedavegi, Andhra Pradesh, and identified as Ganoderma based on distinctive colony characters. To enhance identification accuracy, PCR with GB4 genus-specific primers, resulting in a 500 bp amplicon that confirmed the isolate affiliation with the Ganoderma genera. The efficacy of 13 fungicides against Ganoderma was evaluated through solid plate assay. Noteworthy inhibition of mycelial radial growth was observed with the eight fungicides at all tested doses, including Hexaconazole 5 per cent SC, Propiconazole 25 per cent EC, Tebuconazole 25.9 per cent EC, Tebuconazole 50% + Trifloxystrobin 25% w/w WG, Propiconazole 13.9% + Difenconazole 13.9%, Fluopyram 17.7% w/w + Tebuconazole 11.4% SC, Azoxystrobin 8.3% + Mancozeb 66.7% WDG and Pyraclostrobin 5% + Metiram 55% WG. Complete inhibition was achieved at 2000 and 4000 ppm with Triflumizole 42.14% SC and Azoxystrobin 18.2% + Difenoconazole 11.4% SC. Additionally, the liquid broth assay validated the efficacy of five fungicides in hindering mycelial dry weight. Furthermore, effective strategies against BSR, such as root feeding, stem injection and soil drenching, emerged as valuable insights for the integrated Ganoderma management in plantation crops.. KEYWORDS :Basal stem rot, fungicides, Ganoderma, management, oil palm

Insect root feeders incur negative density-dependent damage across plant species in an alpine meadow.

Although herbivores are well known to incur positive density-dependent damage and mortality, thereby likely shaping plant community assembly, the response of belowground root feeders to changes in plant density has seldom been addressed. Locally rare plant species (with lower plant biomass per area) are often smaller with shallower roots than common species (with higher plant biomass per area) in competition-intensive grasslands. Likewise, root feeders are often distributed in the upper soil layers. We hypothesized, therefore, that root feeders would incur negative density (biomass)-dependent damage across plant species. To test this hypothesis, we investigated the diversity and abundance of plant and root feeder species in an alpine meadow and determined the diet of the root feeders using metabarcoding. Across all species, root feeder load decreased with increasing aboveground plant biomass, root biomass, and total plant biomass per area, indicating a negative density dependence of damage across plant species. Aboveground plant biomass per area increased with increasing individual plant biomass and root depth per area across species, suggesting that rare plant species were smaller in size and had shallower root systems compared to common plant species. Both root biomass per area and root feeder biomass per area decreased with soil depth, but the root feeder biomass decreased disproportionately faster compared to root biomass with increasing root depth. Root feeder load decreased with increasing root depth but was not correlated with the feeding preference of root feeder species. Moreover, the prediction derived from a random process incorporating vertical distributions of root biomass and root feeder biomass significantly accounted for interspecific variation in root feeder load. In conclusion, the data indicate that root feeders incur negative density-dependent damage across plant species. On this basis, we suggest that manipulative experiments should be conducted to determine the effect of the negative density-dependent damage on plant community structure and that different types of plant-animal interactions should be concurrently examined to fully understand the effect of plant density on overall herbivore damage across plant species.

Mesozoic evolution of cicadas and their origins of vocalization and root feeding

Extant cicada (Hemiptera: Cicadoidea) includes widely distributed Cicadidae and relictual Tettigarctidae, with fossils ascribed to these two groups based on several distinct, minimally varying morphological differences that define their extant counterparts. However, directly assigning Mesozoic fossils to modern taxa may overlook the role of unique and transitional features provided by fossils in tracking their early evolutionary paths. Here, based on adult and nymphal fossils from mid-Cretaceous Kachin amber of Myanmar, we explore the phylogenetic relationships and morphological disparities of fossil and extant cicadoids. Our results suggest that Cicadidae and Tettigarctidae might have diverged at or by the Middle Jurassic, with morphological evolution possibly shaped by host plant changes. The discovery of tymbal structures and anatomical analysis of adult fossils indicate that mid-Cretaceous cicadas were silent as modern Tettigarctidae or could have produced faint tymbal-related sounds. The discovery of final-instar nymphal and exuviae cicadoid fossils with fossorial forelegs and piercing-sucking mouthparts indicates that they had most likely adopted a subterranean lifestyle by the mid-Cretaceous, occupying the ecological niche of underground feeding on root. Our study traces the morphological, behavioral, and ecological evolution of Cicadoidea from the Mesozoic, emphasizing their adaptive traits and interactions with their living environments.

Influence of biological fertilizers on the carrots cultivation and yield

Providing the country’s population with high-quality vegetables remains one of the priority areas for agricultural development. The task of agricultural science in solving this problem is to improve agrotechnological techniques and individual operations of soil cultivation, sowing and harvesting, as well as measures to protect against infections and pests. The purpose of this study was to determine the effectiveness of using biofertilizers when cultivating carrots on gray forest soils of medium loamy granulometric composition. Small-plot experiments to improve the technology for cultivating carrots of the Losinoostrovskaya variety were carried out on the basis of the experimental collection site of the Chuvash State Agrarian University during 2022–2023. To stimulate the processes of growth and accumulation of plant biomass, three-time root and leaf feeding of vegetative plants with biological preparations Microbionic and Gumat EM was used. In the course of monitoring the growth processes of carrots, the accumulation of tops and root crops biomass, the authors recorded positive changes in the reduction of the duration of phenophases and a positive trend in increasing carrot yields. The timing of the onset of bunching and trimming ripeness in carrots in plots using root and leaf fertilizing with biological products was shifted by 2–5 days, the total biomass of aboveground mass and root crops was increased to 36%, the yield and marketability of finished products was up to 43% compared with a control group.

The prolonged influence of stimulants on the growth of three-year-old Korean pine (Pinus koraiensis Siebold et Zucc.) seedlings

Relevance. Currently, one of the main tasks in forestry is to obtain high–quality planting material. Studies are being conducted on accelerated cultivation of coniferous and deciduous plants in forest nurseries with the use of growth stimulants that positively affect seed germination, the growth of biometric indicators, the safety and survival of plants. In this regard, the use of plant growth stimulants, which also include “Zircon” and “Ferovit”, is relevant.Methods. The effect of root feeding with Ferovit and Zircon preparations on morphometric parameters of three-year-old Korean cedar seedlings (Pinus koraiensis Siebold et Zucc.) was studied. Venue: nursery of the Mountain Taiga Station — branch of the Federal Research Center for Biodiversity of Terrestrial Biota of East Asia FEB RAS in 2019—2022. Parameters such as the height of seedlings, height gain, root neck diameter, root length and biomass were studied.Results. It was found that a significant effect is provided by a variant of root fertilization of seedlings with the use of “Zircon” and “Ferovit” at a concentration of 1.5 ml / 3 l of water solution. The indicators of the height of seedlings compared to the control increased by 126.1%, height increase — by 136.7%, root neck diameter — by 20%, root length — by 21.8%, biomass — by 252.1%.

Host search behaviors of specialist and generalist root feeding herbivores (Diabrotica spp.) on host and non-host plants

Western, northern, Mexican, and southern corn rootworms (WCR, NCR, MCR, and SCR) are serious corn pests. We evaluated host search behavior of these pests on six plant species using a video tracking system. After a 5-min exposure to plant roots, behavioral parameters were automatically recorded and used to quantify the search behavior. The search behavior was not observed for sorghum since no neonates survived after contacting sorghum roots. After exposures to corn roots, all neonates exhibited the localized search behaviors (i.e., shortening total distance traveled, lowering movement speed, increasing turn angle, moving farther from origin) which are used to stay in and search within root systems. When larvae contacted roots of wheat, barley, oats, soybean, or controls, they expanded the search area by extending the travel path, increasing velocity, and reducing turn angles and total distance moved. The intensity of the search expansion is highly associated with the host preferences known for the four rootworm species and subspecies. Neonates of each corn rootworm exhibited distinct search behaviors. In fact, NCR larvae had the highest speed, the greatest travel path, and the lowest turn angle, whereas MCR larvae had the highest turn angle and moved faster than WCR and SCR larvae.

Influence of growth stimulants on the biometric indicators of four-year-old Khingam fir (white-bark) (<i>Abies nephrolepis</i> (Trautv.) Maxim.) seedlings

Relevance. One of the main methods of reforestation is the use of growth stimulants, which are widely used in agriculture in Russia and abroad. In forestry, their use is carried out on an experimental basis. The increase in the sowing qualities of seeds, in the biometric indicators of seedlings is observed, their safety is activated. In this regard, the use of such growth stimulants as Zircon, HB-101, Root Super and Ferovit is relevant.Methods. The effect of root feeding with stimulants Zircon, HB-101, Root Super and Ferovit on the biometric parameters of four-year-old seedlings of Khingam fir (Abies nephrolepis (Trautv.) Maxim.) was studied. The experiments were carried out in the nursery of GTS — the branch of Federal Scientific Center of the East Asia Terrestrial Biodiversity FEB RAS. The growth of seedlings was studied in terms of stem height, height gain and root collar diameter.Results. It has been established that root fertilization with the stimulants Zircon and HB-101 has the greatest effect on the growth of fir seedlings. The increase in the height of seedlings is by 3.9–60.7%, in height gain — by 11.4–137.1%, as well as in the diameter of root collar — by 16.7-66.7% was noted. It was revealed that the use of the stimulator HB-101 in the solution concentration of 0,5 ml / 10 l has a more positive effect compared with the concentration of the drug solution of 0.5 ml / 5 l of water.

Effect of fertigation on nutrient dynamics of gray-brown soils and apple (Malus pumila) yields in intensive orchards of Kazakhstan

Over the past 13 years, drip irrigation in intensive orchards has gained popularity in southern Kazakhstan. However, its impact on soil has not been studied before. Our research group conducted experiments from 2019 to 2022 in intensive orchards to study the dynamics of fertigation, the application of fertilizers through irrigation water, on soil nutrient levels. Experiments were conducted in Southern Kazakhstan at "Kentau" LLP on intensive orchards with a planting scheme of 0.8*3.5m from 2019 to 2022 with the aim of determining the dynamics of the impact of fertigation on the content of available nutrient elements in the soil. The effectiveness of traditional root feeding method was compared with fertigation (drip application of mother liquor) on large areas of 136.5 hectares in laboratories at the Kazakh National Agrarian Research University and the Laboratory of TOO "KosAgroKommertz". Results showed that proper calculation of fertilizer doses for fertigation resulted in cyclic changes in soil nutrient levels (up to 23%), depending on the season and phenological phase of apple trees. The correlation between fruit quality and quantity was influenced by timing and assimilability of nutrients and method of application. Implementation of recommended fertilization methods resulted in increased yield, although the young age of some orchards may have contributed to the results. Under optimal nutrient management plans, nutrient levels in the soil showed noticeable fluctuations depending on the phenological phases of apple trees, which can be used to adjust fertigation practices. The study also revealed that fertigation can affect soil properties such as bulk density, soil density, and humus content, with potential long-term implications for soil health and fertility. In conclusion, fertigation significantly impacts soil nutrient levels in intensive orchards in southern Kazakhstan, and careful management of fertilizer doses and application timing is crucial for maximizing its effectiveness. Further research is needed to understand the long-term effects of fertigation on soil health and fertility, and its implications for sustainable agriculture practices. The findings contribute to knowledge on fertigation dynamics in Kazakhstan, serving as a basis for further studies and practical applications in agricultural management.

Justification of the parameters of the rotary vane device for the orientation of beetroot during their planting

The existing market of sugar beet seeds shows a significant dependence of Russian agricultural entities engaged in the cultivation of sugar beet on the supply of hybrids of foreign agricultural firms, mainly from the European Union. First of all, this is due to the fact that over the past decades, capital investments in the material and technical base of breeding and seed production on the part of the state were insignificant, which led to the aging of the seed technology used. As is known, the most labor-intensive operation of the technological process associated with the production of sugar and fodder beet seeds is their planting, which is least mechanized and requires a lot of human labor spent on the selection, orientation of root crops and supply them into the planted cones of planting machines with subsequent embedding in the soil with the sharp end down. Currently, a planting machine MV-2.8 is used for planting sugar beet root crops, which is serviced by four people. Consequently, research related to the mechanization of orientation and feeding of root crops into planting cones without the participation of planters is relevant. The article presents a 3D model of a rotary vane device of a planting machine for orienting conical root crops and feeding them into the planting cones of the planting apparatus. At the same time, with a vane length of 280 mm, its thickness will be 11.9 mm, and the greatest deflection is no more than 3 mm, which will ensure the orientation of root crops and their supply to the planting cones of the planting apparatus.

Dominant plants mediate effects of grazing on soil nematode traits in a wet meadow grassland

Grazing is an integral disturbance in grassland ecosystems, however, its effects on belowground ecosystems are poorly understood. As the extent and quality of grasslands continue to decline around the world, metrics are required to monitor the effects of grazing on the function of rangeland soils. Soil nematodes are an important group of soil biota used to understand soil function. However, traditional approaches that rely on indices based on life-history information of soil nematodes have been supplemented in recent literature with trait-based analyses. Here, we test how changes in the structure and composition of soil nematode communities relate to grazing. We collected and measured morphological and reproductive traits of dominant genera of soil nematodes in a wet meadow grassland in Manitoba, Canada, to test how grazing alters trait profiles of nematode communities. For ten genera of soil nematodes, representing 80 % of community abundance, we measured morphometric traits, including body length and mass and used published literature to collect data describing reproductive traits. Communities of free-living nematodes were dominated by bacteriovore and root feeding genera and grazing intensity decreased the richness, diversity, and evenness of soil nematode communities. However, we observed no significant differences in the feeding structure of nematode communities based on the timing or intensity of grazing and no effect of grazing on mean trait values of the most abundant genera of soil nematodes. In contrast, changes in the community weighted means of nematode traits were strongly related to the abundance of dominant vegetation. We discuss the potential effects of changes in soil nematode communities on the function of wet grassland soils. Results from our research indicate that sustainable management and restoration of wet meadow rangelands must consider the impacts of grazing intensity on soil function and that plants play a key role in structuring the soil nematode communities belowground.

Early detection and integrated disease management against coconut basal stem rot disease

Coconut (Cocos nucifera L.) is a multipurpose palm known as kalpavriksha due to its extensive use of all plant parts. Basal stem rot disease, caused by Ganoderma lucidum/Ganoderma aplanatum in coconut, may affect this palm. Under pot culture studies, Redgram (Cajanus cajan) and Bengal gram (Cicer arietinum) were identified as indicator plants for early detection of basal stem rot (Ganoderma wilt) disease in coconut. Furthermore, in 2014, the dosage, frequency, and method of application of effective biocontrol agents, Trichoderma reesei, Pseudomonas fluorescens, and neem cake (5 kg/palm/year), were standardised and compared to root feeding of Hexaconazole @3ml/100ml of water/palm/quarter and micronutrient application @1kg/palm/year at Patha gannavaram village of east godavari district of Andhra Pradesh. Soil application of a talc-based formulation containing 125 g of Trichoderma reesei and 125 g of Pseudomonas fluorescens + 5 kg of Neem cake/palm/year was found to be successful in lowering the disease index from 28.44 to 4.23 under field conditions over three years from 2014 to 2017.