Introduction The progressive withdrawal of soil insecticides has created an urgent need for sustainable alternatives against Agriotes wireworms. Here, we evaluated an attract-and-kill strategy based on entomopathogenic fungi (EPF) designed to overcome the spatial and behavioral constraints that limit biocontrol efficacy in soil. Methods Our approach integrated in vitro virulence screening, in vivo efficacy assays using starch-enriched alginate beads in sterilized soil microcosms, dual-choice olfactometer bioassays, and volatolomic profiling by thermal desorption gas chromatography coupled with mass spectrometry. Results Ophiocordyceps sp. MUCL 58550 exhibited the highest in vitro virulence, yet its efficacy declined in soil microcosms. Volatolomic and behavioral analyses suggest that this loss of performance resulted from poor larval attraction, as its profile blend was dominated by ubiquitous alkanes and carbonyl compounds. In contrast, Metarhizium anisopliae MUCL 58549 maintained high efficacy in vivo and elicited positive chemotaxis (65% choice). This response was associated with a distinctive volatile signature enriched in sesquiterpenes (e.g., aristolochene and eremophilene). The non-pathogenic strain Trichoderma harzianum MUCL 29707 induced the strongest attraction (70% choice), consistent with a volatile profile enriched in C8 oxylipins, including 1-octen-3-ol and 3-octanone. Discussion However, its inability to infect wireworms highlights the risk of creating pest “safe havens” if attraction is not coupled with lethality. Although the causal role of individual volatile compounds remains to be validated, these results demonstrate that effective biological control relies on a “dual-action” mechanism. Specifically, the integration of volatile-mediated host recruitment with targeted pathogenicity enables formulated EPFs to function as active lethal sinks, offering a viable framework for sustainable wireworm management, pending future field validation.
IntroductionConservation Agriculture (CA) is based on three core principles that, at farm scale, imply minimizing soil disturbance through tillage, maintaining a permanent soil cover with residues and diversifying the species in crop rotations. Precision Agriculture (PA) envisages a more efficient use of inputs by reducing the overlaps between machine passes. The combination of both contributes to a more sustainable agricultural system.MethodsA four-season study was carried out to assess the energy consumption and carbon balance of a combined CA and PA system. No-tillage (NT) with residue retention and tractor guidance assistance (GA) was compared with conventional tillage (CT) in three annual crops: wheat, sunflower and legumes. To analyse the data obtained, a simple methodological approach was developed to facilitate energy and carbon balance calculations.ResultsNo significant differences were found in yield between systems. NT with GA reduced fuel consumption by around 50%, and the energy parameters studied improved compared with CT. Across crops, energy efficiency relative to CT ranked as follows: sunflower > wheat > legumes. A similar pattern was observed for carbon use efficiency and carbon use productivity.ConclusionsThe results show the suitability of jointly using CA and PA techniques, such as tractor guidance under NT soil management.
The establishment of Theobroma cacao L. plantlets in the field is a critical stage in the cultivation process for ensuring successful crop development. Perennial crops such as cacao may benefit from biostimulants that enhance early establishment and support long-term growth and productivity. The objective of this study was to investigate the effects of algal-based biostimulant extracts derived from Acanthophora spicifera and Ulva sp. on the growth and physiological performance of T. cacao plantlets. A grafted CCN-51 plantlets from approximately 2 to 3 months old before acclimatation period for two weeks, were used for transplantation and later treatment initiation. The extracts of seaweeds were obtained using water, 25% of aqueous ethanol and 50% aqueous ethanol were applied at concentrations of 2.5%, 5% and 7.5% (V/V). The treatments were applied for eight consecutive weeks, where plants physiological traits were evaluated at 15-day intervals. Treatment effects depended on the algal species, extraction medium, and mainly application concentration. Selected Ulva sp. extracts, particularly the 50% ethanol extract applied at a low concentration (doses at 2.5%), increased the Chlorophyll Content Index compared with other treatments up to 43.1 ± 1.19 CCI. Leaf number also varied among treatments across assay, whereas plant height and leaf length were not significantly affected. These findings indicate that selected seaweed extracts can modulate the early physiological performance of cacao plantlets, although their effects are dose and time dependent.
IntroductionLate sowing constrains grain yield formation in wheat by shortening the duration of post-anthesis assimilate accumulation and limiting the effective utilization of source-derived assimilates during grain filling. Optimizing nitrogen nutrition and growth regulation could help maintain physiological activity, sink development and grain productivity under late-sown conditions.MethodsThis two-year field study evaluated the effects of nitrogen fertilization and mepiquat chloride application on physiological responses, assimilate partitioning and grain yield of late-sown wheat in north-western India. Nitrogen treatments comprised 100% (M1), 125% (M2) and 150% (M3) of the recommended dose of nitrogen (RDN), while growth regulation treatments included an untreated control (S1), mepiquat chloride at 750 ppm at maximum tillering (S2), flag leaf (S3) and both stages (S4), and 1000 ppm at maximum tillering (S5), flag leaf (S6) and both stages (S7).ResultsNitrogen fertilization significantly increased grain yield compared with 100% RDN (M1), while 125% RDN (M2) and 150% RDN (M3) produced statistically comparable grain yields during both years. Grain yield under M2 was 48.1 and 49.1 q ha-1, compared with 43.7 and 45.7 q ha-1 under M1, representing increases of 10.1 and 7.4%, respectively, whereas M3 recorded 50.4 and 51.9 q ha-1, corresponding to increases of 15.3 and 13.6%, respectively, over M1 during 2023–24 and 2024–25. Among growth regulation treatments, dual-stage application of mepiquat chloride at 750 ppm (S4) recorded grain yields of 50.2 and 51.8 q ha-1 during 2023-24 and 2024-25, respectively, and remained statistically comparable with the corresponding 1000 ppm treatment (S7). S4 also increased harvest index by 11.7-13.2% compared with the untreated control (S1), with values similar to S7 in both years.DiscussionHigher nitrogen supply and dual-stage mepiquat chloride application were associated with improved physiological activity, sink capacity and assimilate partitioning toward grains during grain filling. These findings indicate that appropriate nitrogen management and dual-stage mepiquat chloride application can help sustain wheat productivity under delayed sowing.
IntroductionIntercropping is a sustainable agricultural practice known to enhance farmland biodiversity and productivity. However, research on rhizosphere microbial communities in walnut-soybean intercropping systems remains limited.MethodsThis study investigated a 5-year-old orchard on the Loess Plateau. Rhizosphere soil characteristics and microbial communities were compared between walnut monoculture and walnut-soybean intercropping treatments, where soybean had been intercropped for three consecutive years.ResultsIntercropping significantly increased soil organic matter (SOM), microbial biomass carbon (MBC) and nitrogen (MBN), and the activities of carbon- and phosphorus-cycling enzymes (e.g., β-glucosidase), whereas it markedly reduced total nitrogen (TN) and total phosphorus (TP). Bacterial and fungal community composition and abundance differed significantly between intercropping and monoculture treatments, with Mortierellomycota and Proteobacteria enriched under intercropping. Mantel tests revealed that bacterial community composition was correlated solely with SOM, while fungal community composition was correlated with both TN and SOM. Bacterial co-occurrence networks exhibited higher connectivity than fungal networks. The mean soil multifunctionality (SMF) index was significantly higher under intercropping (0.54) than under monoculture (0.43, P < 0.01). Bacterial PC1 emerged as the dominant positive predictor of SMF (parameter estimate = +0.39, P < 0.05), and bacterial variables collectively explained 70.51% of the variation in SMF, further indicating that bacteria were the primary microbial drivers of soil multifunctionality in this intercropping system.ConclusionThis study suggests walnut-soybean intercropping may improve soil properties via regulating soil properties and microbial dynamics, providing preliminary guidance for sustainable walnut orchard management.
