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Essential oils (EOs) and their components have toxic effects on insects and mites. In the present study, we evaluated the effects of the EOs of mexican oregano, grapefruit, albahaca and sour orange at 0.2% (v/v) on the mortality and population density of Bemisia tabaci and Tetranychus urticae in a greenhouse. All EOs caused significant mortality (70–90%) of eggs and nymphs of B. tabaci, with the highest by the mexican oregano EO. This EO also produced the highest mortality (50–55%) of adults and nymphs of T. urticae. All EOs caused a significant decrease in the population density of T. urticae, but no effect was observed on the population of B. tabaci. Gas chromatography-mass spectrometry analysis showed that the major constituent in mexican oregano EO was carvacrol, in grapefruit and sour orange EOs was d-limonene, and in albahaca EO was eucalyptol. [ABSTRACT FROM AUTHOR]

The evaluation of biorrational products to control the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is of primary importance in the agriculture sector. In this study, we evaluated the effects of commercial botanical acaricides (BAs) on T. urticae and its predatory mite Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae). In the laboratory, T. urticae was exposed to acaricide-immersed leaves and A. swirskii to acaricide-coated glass vials. In the greenhouse, potted eggplants infested with mites were sprayed with different BAs. In the laboratory, Zea mays oil-based and Glycine max oil-based BAs caused more than 95% and 80% mortality of adults after 48 h of application and caused also 100% mortality of eggs. Residual exposure of A. swirskii adults to the BAs caused 45–60% mortality. In the greenhouse, these BAs caused more than 50% decrease in the population of T. urticae for 21 d. [ABSTRACT FROM AUTHOR]

This work was carried out to evaluate the insecticidal effect of mono, bi and trimetallic nanoparticles (NPs) from leaf extract of habanero pepper (Capsicum chinense Jacq.) on the red flour beetle (Tribolium castaneum herbst.) and cotton mealybug (Phenacoccus solenopsis Tinsley). The results showed that Cu NPs, Cu/Mn NPs and Zn/Cu NPs had high insecticidal effect against T. castaneum (63%-80% mortality after 96 h). The Cu NPs and Zn/Cu NPs showed also insecticidal effect against P. solenopsis, but to a lesser extent (20%-28% after 96 h). With regards to the physicochemical characterization, Cu NPs had a zeta potential of 21.1 mV, whereas Cu/Mn NPs and Zn/Cu NPs exhibited zeta potentials of 200 mV. The polydispersity index (PDI) values for Cu NPs, Cu/Mn NPs, and Zn/Cu NPs were 10.1, 29.16, and 14.34, respectively. The TF-IR spectra of the NPs varied from 600 to 4000 cm-1. The EDX weight percentages showed the presence of Cu (0.29%-2.4%), Mn (1.4%), and Zn (2.6%) in Cu/Mn NPs and Zn/Cu NPs, respectively. [ABSTRACT FROM AUTHOR]

Intercropping is extensively used to increase land productivity and agricultural benefits. In developing countries, intercropping has historically been one of the most widely used cropping systems. Crop models have been used to assess risk productivity over time and space, particularly in monocropping systems. Crop models, such as the Decision Support System for Agrotechnology Transfer (DSSAT), have been widely used to improve crop growth, development, and yield predictions; however, this model has some limitations when assessing interspecific competition in intercropping systems (e.g., it does not have a subroutine capable of running two crops simultaneously). Therefore, in this study, we developed a new approach to allow DSSAT to run two crop species in intercropping systems. A light interception algorithm and modified source code were integrated into the DSSAT to simulate the relay-strip intercropping system. The intercrop model developed in this study is the first intercrop model for DSSAT. This model is generic and can be employed to build other cereal–legume intercrop models for DSSAT Version 4.8. Regarding risk assessment of crop production, the model can evaluate long-term cereal–legume intercrop yields in low-input cropping systems. Therefore, before officially launching the new model in DSSAT, more field trials are recommended to rigorously evaluate and improve the model with data from different environments. The intercrop model developed in this study is simple, so this modeling approach can be employed to develop other cereal–noncereal intercrop models. [ABSTRACT FROM AUTHOR]

Herein, we describe the synthesis and characterization of fused pyrroles in cholestane and norcholestane side chains derived from kryptogenin and diosgenin, respectively. Both conventional and microwave heating techniques were used to synthesize the steroidal pyrroles from primary amines, with the microwave method producing the highest yields. In particular, the norcholestane pyrroles were tested as acaricides against the two-spotted spider mite (Tetranychus urticae Koch) under laboratory conditions and as plant growth promoters on habanero pepper (Capsicum chinense Jacq) under greenhouse conditions. [ABSTRACT FROM AUTHOR]

Simple Summary: In the neotropics, stingless bees co-exist with plant pests in agroecosystems. The use of chemical insecticides used to control sap-sucking insects may pose a risk to the communities of stingless bees. To gain insight into the potential risk of insecticides commonly used for farmers in horticultural crops, we evaluated under laboratory conditions the effects of oral exposure to five insecticides on the survival of two species of stingless bees, Nannotrigona perilampoides and Frieseomelitta nigra. The results showed that some insecticides have a significant negative impact on the survival of stingless bees under laboratory conditions. These results suggest that stingless bees may be negatively affected when foraging flowers of crops that have been treated with insecticides. Insecticides used in agricultural pest management pose survival risks to the stingless bees that forage on crops in tropical and subtropical regions. In the present study, we evaluated, under laboratory conditions, the acute oral toxicity of five selected insecticides (dinotefuran, imidacloprid, flupyradifurone, spirotetramat, and cyantraniliprole) to two species of neotropical stingless bees: Nannotrigona perilampoides and Frieseomelitta nigra. At field recommended doses, dinotefuran, imidacloprid, and flupyradifurone caused the highest mortality in both bee species. These insecticides also caused the largest decrease in the survival rate when exposed to a 10-fold dilution of the field recommended doses. Notably, dinotefuran exerted a high effect even at 100-fold dilution (100% mortality). In contrast, cyantraniliprole had a low effect and spirotetramat was virtually nontoxic. These results suggest that some insecticides used to control sap-sucking insects may have a significant negative impact on the communities of stingless bees. [ABSTRACT FROM AUTHOR]

In developing countries, intercropping is commonly used to boost land productivity and agricultural benefits. However, in the Yucatan region of Mexico, maize (Zea mays L.) yields remain low, despite consistent fertilizer and pesticide inputs in traditional intercropping systems. Furthermore, little is known about the photosynthetic mechanisms that occur when maize plants interact with legumes, and there is a lack of understanding of how intercropping systems affect other organisms in the system, such as beneficial and insect pest population dynamics. A field experiment was carried out on the Yucatan Peninsula in 2021 to assess the impact of maize–legume intercropping systems on maize yield, physiological characteristics as evaluated by gas exchange measurements, and the abundance of beneficial insects in traditional and novel maize intercropping systems. The experiment was carried out with a randomized complete block design with three replicates. Treatments included maize intercropped with a novel legume, crotalaria (Crotalaria juncea L.), maize intercropped with a traditional legume, cowpea (Vigna unguiculata (L.) Walp.), and sole maize as a control. Significant differences in plant height were shown at growth stages V12 (45 days after sowing) and VT (60 days after sowing). No differences were observed in stem diameter, leaf area index, or chlorophyll content. The maize/cowpea intercrop increased the photosynthesis rate by 12.9% and 9.84% in the maize/crotalaria and sole maize, respectively (p < 0.001), and transpiration rate by 6.5% and 8.5% in the maize intercropped with crotalaria and sole maize treatments, respectively (p < 0.001), of maize plants. No significant effects on stomatal conductance or water use efficiency were observed, but the carbon intercellular rate was reduced by 9.74% and 9.15 when compared to the maize/crotalaria and the sole maize treatments, respectively. Overall, intercropping treatments attracted more beneficial insects than sole maize. For predators, the families that stood out were Coccinelidae, Formicidae, Araneidae, Thomisidae, Syrphidae, Chrysomelidae, Oxypidae, Vespidae, Reduviidae, Carabidae, Asilidae, Salthicidae, Dolichopodidae, while among parasitoids, the most frequent families were Eurytomydae, Braconidae, Tachinidae, Pteromalidae, Scelionidae, and Figitidae. In comparison to the maize/cowpea and maize/crotalaria treatments, the sole maize treatment resulted in a grain yield increase of 24.5% and 32%, respectively. However, sole maize was not statistically different to that of maize/cowpea intercropping. In conclusion, our findings suggest that maize/cowpea intercropping could be a viable alternative to sole maize cropping systems for enhancing maize yield and the abundance of beneficial insects, without increasing interspecific competition with the maize crop. Therefore, the maize/cowpea intercropping system represents a sustainable planting alternative for promoting maize grain yield and also promoting edible legume production within the system. Furthermore, the outcomes of this study can serve as a theoretical framework for increasing maize–legume intercropping profitability under growing conditions on the Yucatan Peninsula. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the concentration and distribution of a number of macro- and micronutrients in response to imbibition in habanero pepper seeds extracted from fruits with different stages of maturity and postharvest storage times, as well as in their seedlings. Fruits were harvested unripe, half-ripe, and ripe, and were subjected to storage for 0 (control), 7, and 14 days postharvest prior to seed extraction. An X-ray microfluorescence analysis was carried out on seeds pre- and post-imbibition, as well as on seedlings at 10 and 14 days after sowing. K, Ca, Fe, P, Mg, and Mn were detected by elemental analysis. The results indicated that the elements had a higher concentration and distribution in seeds extracted from half-ripe fruits and ripe unstored fruits, as well as in seeds extracted from fruits stored for 7 and 14 days postharvest. K and Ca were the elements with the highest distributions and concentrations in seeds and seedlings pre- and post-imbibition compared to the other elements. At all maturity stages, postharvest storage increased the concentration and distribution of mineral nutrients in seeds and seedlings before and after imbibition. Storage translocated mineral elements to the radicle before germination, increased meristem growth in emerged seedlings, decreased electrical conductivity, and increased germination. Fourteen days of postharvest storage increased the distribution of macro- and micronutrients in immature seeds, decreasing electrical conductivity, potentiating germination, and improving mineral element distribution in seedlings. [ABSTRACT FROM AUTHOR]

The silverleaf whitefly (Bemisia tabaci) is the most harmful pest for vegetables in tropical zones. One alternative for its ecological management is the use of repellent aromatic plants. The hypothesis of this study is that the aromatic plants that diminish the attraction of B. tabaci to tomato have the capacity to prevent the infestation of this pest in the tomato crop when an intercropping system of tomato-aromatic plant is established. The objective of this study was to evaluate by means of the technique of olfactometry, the response of B. tabaci to the volatiles emitted by the crushed leaves of tomato and by the combination tomato + aromatic plant. The aromatic plants with highest activity in the olfactometry tests were intercropped in a tomato crop in the field. In the bioassays of olfactometry, a significant decrease was observed in the attraction of B. tabaci to crushed leaves of tomato + some aromatic plants compared with the attraction to tomato alone. The repellence indices (IR) showed that the aromatics Lavandula angustifolia Mill. (IR, 0.1), Petiveria alliacea L. (IR, 0.48), Petroselinum crispum Mill. (IR, 0.28) and Thymus vulgaris (IR, 0.5) had the greatest effect as repellent of adults. By integrating these aromatic species through intercropping in the tomato field crop, no significant difference was observed in the population density of eggs and adults of B. tabaci in the tomato foliage in regard to what was observed in the control (only tomato). The incidence and severity of viral symptoms did not decrease from the presence of the aromatic species intercropped in the tomato crop. [ABSTRACT FROM AUTHOR]

In this study, three commercial botanical acaricides (BA) were evaluated on two species of phytophagous mites, the red palm mite (Raiella indica) and the papaya mite (Oligonychus sp.). The toxicity of the BA on the predatory mites Neoseiulus californicus and Phytoseiulus persimilis was also assessed. For R. indica, CinnAcar and EPA-90 caused more than 90% decrease in the population density in the laboratory. In field trial, CinnAcar was the most effective in suppressing the mite population density. For Oligonychus sp., CinnAcar and EPA-90 caused up to 88.5 and 95.2% mortality in the laboratory. In greenhouse trial, EPA-90 caused more than 90% decrease in the population density of motile stages. Residual exposure showed that EPA-90 had moderate toxicity to the phytoseiid predators, causing 48% mortality in N. californicus and 55% mortality in P. persimilis, whereas CinnAcar and NeemAcar produced 22 to 32% mortality. [ABSTRACT FROM AUTHOR]

Solubilization of inorganic P-sources and production of siderophores and indole-3-acetic acid (IAA) by Beauveria brongniartii were quantified and then, the effects of biofertilization using B. brongniartii on the plant growth, fruit yield and quality of Capsicum chinense were evaluated. Beauveria brongniartii solubilized more P from Ca3(PO4)2 (158.95 mg L−1) than FePO4 (31.7 mg L−1) and produced siderophores (59.8% of Fe3+-Chrome azurol-S degradation) and IAA (31.2 mg L−1). Plants fertilised at 100% of the recommended dosage (120N-150P-150K) had the tallest height at 30 (37.56 cm, P = 0.0494), 45 (57.56 cm, P = 0.0510) and 60 (67.87 cm, P = 0.0461) days after transplanting (dat) compared to plants inoculated and fertilised at 75% (90N-112.5P-112.5K) during the same period (30 dat = 30.68 cm, 45 dat = 45.81 and 60 dat = 55.75 cm). Inoculated plants with B. brongniartii had a higher foliar N content (3.53%, P = 0.0532) than non-inoculated plants (3.31%). The fruit weight (FW = 6.767 g, P = 0.00001), longitudinal fruit diameter (LFD = 37.82 mm, P = 0.0001) and equatorial fruit diameter (EFD = 25.59 mm, P = 0.0003) were also higher in inoculated versus non-inoculated plants (FW = 5.632 g, LFD = 33.98 mm and EFD = 24.10 mm). The P-solubilizing ability and siderophore and IAA production of B. brongniartii played an important role in the plant growth, foliar nutrient content and fruit quality of C. chinense plants. [ABSTRACT FROM AUTHOR]

This study was performed to assess the impact of inclusion of biorational insecticides for pest management in tomato and tomatillo. The pest population densities, pest damage and the abundance of flower visiting bees were periodically evaluated. In tomato, overall the population of Bemisia tabaci, the final incidence and severity of viral sysmptoms showed no difference (P > 0.05) among treatments. In tomatillo, the biorational treatments had sligtly lower effects (P < 0.05) than the conventional treatment on Liriomyza trifolii and Epitrix cucumeris. Marketable fruit yield in both crop species was not significanlty different (P > 0.05) among pest mamagement treatments. The abundance of flower visiting bees showed no difference (P > 0.05) among treatments in tomato. But in tomatillo higher abundance (P < 0.05) of Apis mellifera and lower abundnace (P < 0.05) of Trigona nigra were observed in plants treated with Bio-1 relative to those treated with Bio-2. [ABSTRACT FROM AUTHOR]

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The bioprospection for antagonistic bacteria, as biological control agents to manage plant pathogenic fungi, is a preponderant activity to reduce the use of chemical fungicides. The bacterium Bacillus subtilis has shown an excellent capacity to inhibit the growth and sporulation of a wide variety of plant pathogenic fungi. The phenotypic and biochemical characteristics to differentiate among subspecies of B. subtilis vary at the regional level. In this research, Bacillus strains were isolated from the Yucatan Peninsula in Mexico and their antagonistic activities were assessed by direct confrontation in a completely randomized design. To identify the most active strains, molecular characterization was performed. For an accurate identification, partial 16S rRNA, gyrA and rpoB genes were sequenced and compared with those deposited in the GenBank. The most active strains CBCC2, CBMT2, CBMN22, CBRF24, CBCK36, CBCK47, and CBMT51 caused 32 to 78% inhibition of mycelial growth in Alternaria alternata, Helminthosporium rostratum and Curvularia lunata in direct confrontation tests; likewise the cell-free culture filtrates of these Bacillus strains showed significant differences (p£0.05) in the degree of inhibition of conidial germination of the plant pathogenic fungi. The amplification, sequencing and comparison of 16S rRNA, gyrA and rpoB genes showed that the strains had 95 to 100% identity with Bacillus subtilis subsp. inaquosorum and B. subtilis subsp. subtilis. The gyrA gene showed the highest evolutionary rate using the analysis of phylogenetic relationship within the strains studied. [ABSTRACT FROM AUTHOR]

The effects of copper (Cu2+) on photochemical efficiency, cellular viability and total phenolic content inProsopis glandulosaleaves were evaluated after 4, 8 or 12 h exposure to 0.1, 10 or 100 mM Cu2+using the tissue tolerance test. The results showed that significant reductions (p<0.003) of photochemical efficiency inP. glandulosaleaves were found after 8 h exposure to 100 mM Cu2+compared with controls leaves. The results also showed a significant increase (p<0.05) on electrolyte leakage values inP. glandulosaleaves after 4 h exposure to 100 mM Cu2+compared with control leaves. Total phenolic content inP. glandulosaleaves only differed significantly when exposed 12 h to the highest concentration of Cu2+. These results suggest that Cu2+can produce reactive oxygen species that may form hydroxyl radicals that damage proteins and lipids, which in turn causes loss of integrity and reduce photochemical efficiency of leaves. In conclusion, the photochemical efficiency and cellular viability analyses can be used as useful physiological tools to assess early changes in photosynthetic performance ofP. glandulosain response to copper pollution. [ABSTRACT FROM PUBLISHER]

The use of microbial inoculants is a viable alternative to nurture crops and increase productivity without damaging the soil. The objective of this study was to evaluate the effect of microbial inoculants on growth and productivity of habanero pepper (Capsicum chinense Jacq.) in a greenhouse conditions. The study was conducted in Conkal, Yucatan, Mexico, from September to December 2012. Three inoculants and a control (without application of inoculant) were evaluated under commercial chemical fertilizer. A completely randomized design was used and treatments were Rhizophagus irregularis (one spore mL-1), Pseudomonas spp. (1×106 cfu mL-1) and Azospirillum brasilense (1×106 cfu mL-1). ANOVA and Tukey's comparison of means (p⩽0.05) were performed using SAS. The application of inoculants was performed during transplantation and response variables were growth, productivity and foliage nutrient content (N, P, K). The plants treated with Pseudomonas spp. were significantly higher, and showed greater stem diameter and total dry biomass than the control plants 120 d after transplanting. In this same treatment the highest yield (899.84 g per plant) was obtained and fruits were larger, with greater diameter and weight. The mineral content of leaves was not different (p>0.05) between the plants treated with inoculants and those of the control. Inoculation of Pseudomonas spp. to habanero pepper during transplantation enhances growth, yield and fruit size. [ABSTRACT FROM AUTHOR]

Intercropping constitutes the traditional farming system practice used in various forms for maize production in the Yucatan peninsula. Although practiced for centuries, problems persist with competition for water, nutrients and light between crop species in traditional farming systems. Furthermore, little is known about farmers' perceptions regarding changes to traditional maize-legume intercropping systems and their interest in novel crop adoption to increase yields in the system while maintaining the practice. The objective of this study was to investigate the maize-based traditional cropping system by assessing the underlying motives and concepts of farmers to practice intercropping in the Yucatan Peninsula and to examine the association between farmers' level of knowledge about legumes and decisions to adopt intercropping and related practices therein. Farmer surveys were conducted in nine different regions of the Yucatan Peninsula. We selected Xoy, Euan, Muna, Mama, Tahdziú (Yucatan), Becal, Hecelchacam, Dzitbalché and San Antonio Sahcabchén (Campeche) which are representative of agroecological small-scale farming systems. We used a mixed methods case study analysis involving key informant interviews in eight associations of farmers. A sample frame with 73 farmers was selected in total during February 2021 and April 2021. Basic information such as land use, labor inputs, agricultural production and farmer's perceptions regarding their intercropping systems were collected. Our research shows that the primary motives for intercropping were due to the ability of intercropping to offer a more diversified range of food for human and animal consumption, as well as to take advantage of different harvest periods that this practice offers. The majority of respondents were likely to favor the idea of introducing new legume species in their maize-based cropping systems. Factors such as the type of cropping system (i.e., intercropping or monocropping), access to water and level of knowledge about legumes influenced their decision to adopt intercropping in their farming systems considerably. This paper contributes to the knowledge on the current state and farmers' perceptions of intercropping systems in the Yucatan Peninsula. [ABSTRACT FROM AUTHOR]

Micromycetes from unexplored sources represent an opportunity to discover novel natural products to control insect pests. With this aim, a strain of Acremonium masseei CICY026 isolated from a tropical sinkhole was identified, cultured on fermented rice, and its ethyl acetate extract (EAE) was evaluated against three serious phytophagous insects (Bemisia tabaci, Myzus persicae, and Rhopalosiphum padi). DNA from A. masseei CICY026 was used to confirm its identity. EAE caused settling inhibition (SI) of M. persicae and R. padi (67.5% and 75.3%, respectively). Bioassay-guided fractionation of the active EAE led to the isolation of a novel metabolite, named hexahydroacremonintriol (1), and of acremonin A glucoside (2). The structures of 1 and 2 were determined using IR, one- and two-dimensional NMR, HRMS, and confirmed by theoretical data. The aphid M. persicae was noticeably sensitive to 1 and 2 (SI: 55.6% and 67.2%, respectively), whereas R. padi was only slightly affected by 1 (SI: 59%). This new knowledge about mycobiota from these special sinkhole ecosystems will inform the development of new biorational pesticides. [ABSTRACT FROM AUTHOR]

To elucidate interactions between the antifungal cyclic lipopeptides iturin A, fengycin, and surfactin produced by Bacillus bacteria and the microtubular protein β-tubulin in plant pathogenic fungi (Fusarium oxysporum, Colletrotrichum gloeosporioides, Alternaria alternata, and Fusarium solani) in molecular docking and molecular dynamics simulations, we retrieved the structure of tubulin co-crystallized with taxol from the Protein Data Bank (PDB) (ID: 1JFF) and the structure of the cyclic lipopeptides from PubChem (Compound CID: 102287549, 100977820, 10129764). Similarity and homology analyses of the retrieved β-tubulin structure with those of the fungi showed that the conserved domains shared 84% similarity, and the root mean square deviation (RMSD) was less than 2 Å. In the molecular docking studies, within the binding pocket, residues Pro274, Thr276, and Glu27 of β-tubulin were responsible for the interaction with the cyclic lipopeptides. In the molecular dynamics analysis, two groups of ligands were formed based on the number of poses analyzed with respect to the RMSD. Group 1 was made up of 10, 100, and 500 poses with distances 0.080 to 0.092 nm and RMSDs of 0.10 to 0.15 nm. For group 2, consisting of 1000 poses, the initial and final distance was 0.1 nm and the RMSDs were in the range of 0.10 to 0.30 nm. These results suggest that iturin A and fengycin bind with higher affinity than surfactin to β-tubulin. These two lipopeptides may be used as lead compounds to develop new antifungal agents or employed directly as biorational products to control plant pathogenic fungi. [ABSTRACT FROM AUTHOR]

Eugenia winzerlingii (Myrtaceae) is an endemic plant from the Yucatan peninsula. Its organic extracts and fractions from leaves have been tested on two phloem-feeding insects, Bemisia tabaci and Myzus persicae, on two plant parasitic nematodes, Meloidogyne incognita and Meloidogyne javanica, and phytotoxicity on Lolium perenne and Solanum lycopersicum. Results showed that both the hexane extract and the ethyl acetate extract, as well as the fractions, have strong antifeedant and nematicidal effects. Gas chromatography-mass spectrometry analyses of methylated active fractions revealed the presence of a mixture of fatty acids. Authentic standards of detected fatty acids and methyl and ethyl derivatives were tested on target organisms. The most active compounds were decanoic, undecanoic, and dodecanoic acids. Methyl and ethyl ester derivatives had lower effects in comparison with free fatty acids. Dose-response experiments showed that undecanoic acid was the most potent compound with EC50 values of 21 and 6 nmol/cm2 for M. persicae and B. tabaci, respectively, and 192 and 64 nmol for M. incognita and M. javanica, respectively. In a phytotoxicity assay, medium-chain fatty acids caused a decrease of 38–52% in root length and 50–60% in leaf length of L. perenne, but no effects were observed on S.lycopersicum. This study highlights the importance of the genus Eugenia as a source of bioactive metabolites for plant pest management. [ABSTRACT FROM AUTHOR]

Backyards are family settings adjacent to the house, characterized mainly by being small-scale and diversified productive spaces. The research typologically characterized the backyards and their contribution to family food security in La Concordia municipality, Chiapas, Mexico. The research was descriptive and mixed, quantitative, and qualitative, and semi-structured interviews were applied to 130 families. For the typification, 21 variables were used, and the statistical techniques of Factorial Analysis and Clusters were applied. The cases studied were classified, according to the relevance of their production and contribution to food security, into two general groups: a) a group of backyards that is more productive and contributes to food security, which in turn includes three subtypes of backyards that differ from each other by their profile towards vegetable or poultry production for subsistence, and/or pigs as a form of savings; b) a group of less productive backyards in which other management strategies for food security are assumed and differ from each other by the level of expulsion of labor force and types of families, nuclear or extended. Poultry and plant species for multiple uses was the most frequently characteristic, regardless of the type of backyard. [ABSTRACT FROM AUTHOR]

Intercropping is the process of planting two or more crops simultaneously in the same field in order to provide greater ecosystem services (i.e. services related to sustainable land and water use, climate change mitigation, and ecosystem restoration). In southern Mexico, the cereal-legume intercropping is a traditional cropping practice that is declining overtime. This paper provides a literature review of the potential benefits and constraints of a maize-legume intercropping for small-scale farms in southern Mexico. This review explored and elucidated the different ecosystem services delivered by maize-legume intercropping systems. This information will help farmers know how to make a better use of cereal-legume intercropping systems to increase maize yields, improve their socioeconomic conditions, and enhance conservation agricultural practices in southern Mexico. [ABSTRACT FROM AUTHOR]

The whitefly Bemisia tabaci (Gennadius, 1889) is a major plant pest of horticultural crops from the families Solanaceae, Fabaceae and Cucurbitaceae in Neotropical areas. The exploration of host plant resistance and their biochemical mechanisms offers an excellent alternative to better understand factors affecting the interaction between phytophagous insect and host plant. We evaluated the survival of B. tabaci in landrace genotypes of Capsicum annuum L., and the activity of plant defense-related enzymes (chitinase, polyphenoloxidase, and peroxidase). The landrace genotypes Amaxito, Tabaquero, and Simojovel showed resistance to B. tabaci, as we observed more than 50% nymphal mortality, while in the commercial susceptible genotype Jalapeño mortality of B. tabaci nymphs was not higher than 20%. The activities of plant defense-related enzymes were significantly different among pepper genotypes (P < 0.05). Basal activities of chitinase, polyphenoloxidase and peroxidase were significantly lower or equal in landrace genotypes than that of the commercial genotype Jalapeño. The activity of plant enzymes was differential among pepper genotypes (P < 0.05). For example, the activity of chitinase enzyme generally was higher in non-infested plants with B. tabaci than those infested. Instead polyphenoloxidase ('Amaxito' and 'Simojovel') and peroxidase enzymes activities ('Tabaquero') increased in infested plants (P < 0.05). We conclude that basal activities of plant defense-related enzymes could be act through other mechanism plant induction, since plant defense-related enzymes showed a different induction response to B. tabaci. We underlined the role of polyphenoloxidase as plant defense in the pepper genotype Simojovel related to B. tabaci. [ABSTRACT FROM AUTHOR]

The high diversity of chili pepper (Capsicum annuum L.) in Mexico offers an excellent alternative to search for wild and semi-domesticated genotypes as sources of resistance to the complex Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae)-Begomovirus, which has caused enormous losses in commercial production of various horticultural crops. The goal of the present work was to characterize ex situ 18 genotypes of C. annuum from southern Mexico through 47 morphological descriptors, and to evaluate its response to the B. tabaci-Begomovirus complex. Morphological characterization showed the variables calyx annular constriction (CAC), number of branch bifurcation (NBB), and calyx pigmentation (CP) had the highest variation. Principal components analysis (PCA) of 47 morphological characteristics showed that 12 components were selected as meaningful factors. These components explained 94% of the variation. Cluster analysis showed three major clusters and seven sub-clusters. On the other hand, evaluation of the response to B. tabaci-Begomovirus showed that the genotypes have differential susceptibility to this vector-pathogen complex. Genotypes 'Chawa', 'Blanco', 'Maax' and 'X'catic' were into the low susceptibility to B. tabaci and low severity of viral symptoms. Surprisingly, the genotype 'Simojovel' showed high susceptibility to whitefly, but was grouped into genotypes with low symptom severity. This study shows the potential of native germplasm of pepper to explore sources of resistance to the B. tabaci-Begomovirus complex. [ABSTRACT FROM AUTHOR]

Background: The whitefly (Bemisia tabaci Genn.) is a widely distributed and highly harmful plant pest species. The management of B. tabaci has been typically carried out by chemical pesticides. In the last decade however, there has been an increasing interest in natural products, particularly those of plant origin, to control this pest species. In the present work, aqueous and ethanolic extracts of native plants from the flora of the Yucatán peninsula (Acalypha gaumeri, Annona squamosa, Carlowrightia myriantha, Petiveria alliaceae and Trichilia arborea) and the introduced plant Azadirachta indica were collected and evaluated for insecticidal activity against eggs and nymphs Bemisia tabaci. Results: Most of the aqueous and ethanolic extracts showed high insecticidal effects on B. tabaci eggs. The lowest LC50 values were recorded in the aqueous extracts of A. gaumeri (0.39% w/v), A. squamosa (0.36% w/v), P. alliaceae (0.42% w/v) and A. indica (0.30% /v), as well as in the ethanolic extracts of P. alliaceae (2.09 mg mL-1) and T. arborea (2.14 mg mL-1). On the other hand, B. tabaci nymphs were not affected by the aqueous extracts, but were highly sensitive to the ethanolic extracts of the tested plants. The lowest LC50 values were recorded in the ethanolic extracts of P. alliaceae (1.27 mg ml-1) and T. arborea (1.61 mg mL-1). The GC-MS analysis showed that phytol was the major component of the ethanolic extract of P. alliaceae and fatty acids were the major components of ethanolic extract of T. arborea. Conclusions: Overall, results suggest that ethanolic extracts of P. alliaceae and T. arborea leaves showed the highest insecticidal effects on eggs and nymphs B. tabaci. The extracts from P. alliaceae and T. arborea are good candidates to be developed as sources of natural insecticides for the management of immature B. tabaci since their effects were comparable with that showed by the extracts of A. indica, a well-known plant species for its insecticidal activity. [ABSTRACT FROM AUTHOR]

• Purpureocillium lilacinum solubilizes more efficiently Ca 3 (PO 4) 2 than FePO 4. • P. lilacinum enhances indole-3-acetic acid but not siderophore production. • P. lilacinum augments shoot and root biomass in pot assays. • Inoculation of P. lilacinum in Capsicum chinense increases the foliar P content. • Biofertilization of C. chinense plants enhances the chlorophyll index. Biofertilizers can increase soil fertility and plant health. This study aimed to evaluate the solubilization of inorganic P-sources and the production of siderophores and indole-3-acetic acid (IAA) by Purpureocillium lilacinum and to evaluate the effect of its inoculation on plant growth, fruit quality and yield of Capsicum chinense under greenhouse conditions. Fungus was able to enhance solubilization of Ca 3 (PO 4) 2 and FePO 4 as well as the production of siderophores and IAA. In pot trials, C. chinense plants inoculated with P. lilacinum showed higher stem diameter, fresh and dry weight of shoots and roots. Under greenhouse conditions, C. chinense plants inoculated with P. lilacinum had a greater height and a higher score on the chlorophyll index at 90 and 60 days after transplantation (dat). At 145 dat, the root weight of plants increased by 59.2%. At 90 dat, the foliar P content of C. chinense plants was enhanced by 10%. Fruit weight and size also increased by 4.3% and 9.15%, respectively, although the number of fruits per plant and fruit yield did not increase. This study indicates the suitability of P. lilacinum as biofertilizing agent based on its ability to generate beneficial effects on growth and nutrient uptake of C. chinense plants. [ABSTRACT FROM AUTHOR]

Fungal metabolites are promising alternatives for the development of biorational pesticides. In this sense, microfungi from tropical regions are valuable sources of natural compounds for pest management. With the aim of broadening the search for new eco-friendly products to manage plant pests, this study was carried out to evaluate the biological activity of 23 tropical fungal extracts on three species of phytophagous insects and a plant parasitic nematode. In addition, the active principles of the most effective extract were identified. The insect deterrent activity of fungal extracts was evaluated on the settling of aphids Myzus persicae and Rhopalosiphum padi, and on the feeding of lepidoptera larva Spodoptera littoralis; the nematostatic activity was evaluated on the mobility of Meloidogyne javanica. Active metabolites from Gliomastix masseei were identified by GC-MS techniques and by comparison with commercial standards. Results showed seven extracts with strong effect on the settling of M. persicae and R. padi (settling inhibition >80%). The calculated median of effective concentration (EC 50 ) values ranged from 8 to 38μg/cm 2 for the extracts of Clonostachys rosea and G. masseei, respectively. Bioassay-guided separation of the ethyl acetate extract of G. masseei revealed the presence of fatty acids and their derivatives, where methyl 9-octadecenoate was the most active compound with EC 50 values of 16μg and 35μg/cm 2 for M. persicae and R. padi, respectively. Extracts of C. rosea and G. masseei could be a promising option in the control of pest aphids in agriculture., (Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)