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Secondary metabolites produced by the fermentation of Streptomyces avermitilis bacterium are powerful antiparasitic agents used in animal health, agriculture and human infection treatments. Avermectin is a macrocyclic lactone with four structural components (A1, A2, B1, B2), each of them containing a major and a minor subcomponent, out of which avermectin B1a is the most effective parasitic control compound. Avermectin B1a produces two homologue avermectins (B1 and B2) that have been used in agriculture as pesticides and antiparasitic agents, since 1985. It has a great affinity with the Cl-channels of the glutamate receptor, allowing the constant flow of Cl- ions into the nerve cells, causing a phenomenon of hyperpolarization causing death by flaccid paralysis. The purpose of this work was to gather information on the production of avermectins and their biocidal effects, with special emphasis on their role in the control of pests and phytopathogenic diseases. The literature showed that S. avermitilis is an important producer of macrocyclic lactones with biocidal properties. In addition, avermectin contributes to the control of ectoparasites and endoparasites in human health care, veterinary medicine and agriculture. Importantly, avermectin is a compound that is harmless to the host (no side effects), non-target organisms and the environment. [ABSTRACT FROM AUTHOR]

Bactericera cockerelli causes damage to nightshade crops in Mexico, causing millions of pesos in losses to producers; for its control, chemical insecticides have been used, which over time has generated resistance in the insect, causing its control to be more difficult year after year. New alternatives are sought for the control of this pest, among which the use of resistance inducers that are effective and environmentally friendly stands out; menadione sodium bisulfite (MSB) is an effective alternative with low environmental impact that has proven to be an activator of plant defenses and has insecticidal effects. In the present work, tests were carried out to determine the effects of MSB on the survival and development of the insect. Cohorts with B. cockerelli eggs were established, using three tomato plants of the Río Grande variety in each of the entomological cages, to test the effect of menadione on the development and survival of the insect B. cockerelli. According to the data obtained, no significant differences were found in the days of development of the immature stages of the insect, while in the survival data the MSB treatments had the highest mortalities, of 42 to 80%, demonstrating that MSB causes the mortality of B. cockerelli nymphs. [ABSTRACT FROM AUTHOR]

Copyright of Revista Mexicana de Ciencias Agrícolas is the property of Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Phytotoxicity caused by secondary metabolites of botanical extracts is a drawback in agriculture. The objective of this study was to evaluate the phytotoxic effects of methanolic extracts of Crotalaria longirostrata and Argemone mexicana on the germination and physiological variables of tomato seedlings. The results indicated that high doses of both extracts (Clong500 and Amex500) inhibited tomato seed germination, while their mixture (Cl50 + Am50) promoted germination by 100%. At 30 days after transplanting (dat), the plant height increased by 15.4% with a high dose of C. longirostrata (Clong500) compared to the control. At 30 dat, the vigor index displayed a notable increase with Cl50 + Am50, reaching 29.5%. The root length increased with the mean dose of A. mexicana (Amex95) at 10, 20, and 30 dat (59.7%, 15.1%, and 22.4%, respectively). The chlorophyll content increased with Amex95 by 66.1% in 10 dat, 22.6% at 20 dat, and 19.6% at 30 dat. On the other hand, Amex95 had a higher nitrogen content throughout the trial. Amex95 produced the greatest increase in root dry weight by 731.5% and 209.4% at 10 and 20 dat. The foliage dry weight increased by 85.7% at 10 dat with Amex95 and up to 209.7% with Amex50 at 30 dat. The present investigation reveals the ability of the extracts to stimulate tomato growth at low and medium doses, though at high doses they exhibit allelopathic effects. [ABSTRACT FROM AUTHOR]

Copyright of Scientia Agropecuaria is the property of Scientia Agropecuaria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Universitaria is the property of Universidad de Guanajuato/Acta Universitaria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Mexicana de Ciencias Agrícolas is the property of Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Entomología is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Informacion Tecnica Economica Agraria is the property of Asociacion Interprofesional para el Desarrollo Agrario (AIDA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ecosistemas y Recursos Agropecuarios is the property of Universidad Juarez Autonoma de Tabasco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Investigación y Ciencia de la Universidad Autónoma de Aguascalientes is the property of Universidad Autonoma de Aguascalientes, Direccion General de Investigacion y Posgrado and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Mexicana de Ciencias Agrícolas is the property of Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Antifungal activity of zinc oxide (ZnO) and ZnO nanoparticles (ZnO NPs) was evaluated on the control of Fusarium oxysporum Schltdl. (Nectriaceae) under laboratory and greenhouse conditions. In vitro evaluation, poisoned culture media was prepared, and an explant was placed in the centre of solid medium. The experimental design was completely randomized with 18 treatments. Mycelial growth and conidia concentration were evaluated. Subsequently, three treatments (3,000, 1,500, 100 ppm) of ZnO NPs and ZnO were chosen for their evaluation in the greenhouse in tomato plants of Floradade variety under a randomized block design. Inoculation was carried out with a 1x107 conidia per mL suspension of F. oxysporum, when the plants presented the third pair of true leaves. Later, the application of different concentrations of ZnO and ZnO NPs was carried out; in this investigation, the incidence and severity and plant height were evaluated into account to determine the treatment effect on F. oxysporum. In vitro, the best treatments in mycelial growth inhibition were the high concentrations of ZnO NPs from 1,600 to 3,000 ppm with 81%–83%, and in the sporulation of the fungus, they were also those that inhibited from 82.57% to 83.85%. In greenhouse, the treatments that reached the highest plant height were ZnO NPs from 1,500 to 3,000 ppm, with a range of 166.0–175.40 cm, with a severity on the scale of 0.40–0.80 and an incidence of 20%–40%. ZnO NPs have a potential application as an antifungal agent and can be used to control the spread of F. oxysporum in tomato plants, in addition to improving the promoter effect related to the Zinc activity as a precursor in auxins synthesis, cytokinins and gibberellins biosynthesis, as well as the induction of higher activity of antioxidant enzymes useful in response to the pathogens attack. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Entomología is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Phytoparasitic nematodes constitute one of the main pathogens that affect the cultivation of the coffee tree Coffea arabica L., causing reductions in yield between 15 and 60%. The objective of this research was to evaluate the effectiveness of the biological extracts of the nematicide Nemaxxion XT Plus, for the control of the nematodes Meloidogyne incognita and Pratylenchus sp., associated with the cultivation of coffee. Five treatments with five replications were considered under a randomized complete block design: Nemaxxion XT Plus (2 L ha-1 , 4 L ha-1 , 6 L ha-1 ), Nemacur® 400 CE and control. Nematode populations were counted in 100 g of soil before applying the treatments and 120 days after the experiment was installed. For counting, the nematodes were extracted by the Baerman funnel method. For M. incognita, the number of second instar juveniles, adult males and females, was counted and for Pratylenchus sp., the filiform adult males and females were counted. The evaluation demonstrated the effectiveness of the treatments for the control of nematode populations, these treatments presented a considerable reduction of the populations, with an average survival of 1.2-3.4 nematodes of M. incognita and 2.2-4.4 nematodes of Pratylenchus sp., of these, Nemaxxion XT Plus at 6 L ha-1 presented the greatest population reduction and efficiency over the two populations, with 99.08 and 92.87% respectively, presenting itself as an alternative for a more sustainable agriculture. [ABSTRACT FROM AUTHOR]

Monascus purpureus is used in the food industry as a natural pigment, mainly by Asian countries; however, this fungus produces a mycotoxin called citrinin, which causes diseases such as hepatotoxicity, teratogenicity, tumors and mutations, in mammals. This fungus was found in Serbia in corn and lucerne silage. The objective of this work was to identify the presence of the Monascus purpureus fungus in corn, oats, triticale and lucerne silage, the sampling was carried out in the periods of November December 2017 and April-May 2018, in the states of Jalisco, Zacatecas, Aguascalientes and Guanajuato of the Mexican Republic, silage isolation was carried out in the middle of Papa Dextrosa Agar (PDA), they were morphologically and molecularly identified. 63 different strains were obtained, seven were Monascus purpureus, one in lucerne, two in corn, two in oats and two in triticale. This research reports, for the first time, the presence of Monascus purpureus fungi in corn, oats, triticale and lucerne silages. [ABSTRACT FROM AUTHOR]

Fusarium oxysporum and Rhizoctonia solani are causal agents of chili wilt and cause losses up to 80% in the crop in Mexico. The inadequate use of chemical fungicides has generated problems of resistance, this was not observed with microbial agents, so they were evaluated in the biocontrol of wilt of chili in experimental plots where F. oxysporum and R. solani were identified as causal agents of the illness. Trichoderma spp., Bacillus spp., mixture of microbial propagative ferment, thiabendazole and control, were applied on a plot of 800 m2 with six varieties of chili. The treatments Trichoderma and propative ferment showed low percentages of incidence and severity, high yield with Trichoderma in HS-52 and Coloso (15.67 and 13.89 t ha-1). Trichoderma treatments and propagative fermentation promote the biocontrol of chili wilt caused by F. oxysporum and R. solani and increase yield. [ABSTRACT FROM AUTHOR]

Copyright of Revista Mexicana de Ciencias Agrícolas is the property of Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Mexico is the leading producer, consumer and exporter of avocado in the world. The study of soil macrobiotics becomes more important in the avocado wilt complex because in these pathology biotic and abiotic causative agents can be implicated, being the Oomycete Phytophthora cinnamomi Rands the main radical disease of avocado cultivation. The objective of the present investigation was to evaluate the dynamics of the in vitro growth of Phytophthora cinnamomi in alternative culture media. In the months of October and November 2016, root samples were collected from avocado trees (Persea americana Mill. Var. Hass) in the INIFAP experimental orchard located in San Juan Nuevo Parangaricutiro, Michoacán. The isolates were identified morphologically and molecularly. The measurements of the growth diameters of each strain were recorded in vitro according to time. Linear regression was carried out using generalized linear models (GLM) to obtain the parameters of intercept and slope, significance of the regression and the R2 value adjusted. The analyzes were carried out using the statistical program R 3.4. According to the results obtained, the culture medium Rye-agar was the most efficient for the proliferation of P. cinnamomi. [ABSTRACT FROM AUTHOR]

Copyright of TIP Revista Especializada en Ciencias Químico-Biológicas is the property of Universidad Nacional Autonoma de Mexico, Facultad de Estudios Superiores Zaragoza and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ten tomato varieties were examined for resistance to Tetranychus urticae by bioassays on leaf discs. A colony of T. urticae from different ornamental crops of Saltillo, Coahuila, Mexico, was established in bean seedlings (Phaseolus vulgaris L.) in a Biotronette chamber. At 25 ±2 °C, 60- 70 HR and 12:12 h L: D. According to the design of the experiment, the females were placed in leaf discs of the 10 tomato varieties under study in a proportion of 10 disc with 90 repetitions, the behavior was evaluated based on survival, repellency and mortality. Subsequently, 100 freshly mated and fertilized one-day-old females were transferred to discs of tomato leaves (Solanum lycopersicum L.) of 1.3 cm in diameter of cultivars ‛Tsan-101', ‛Toro', ‛Saladette' and ‛Cereza' in such a way that each experimental unit included 1 female per disk. The demographic parameters in this experiment showed a lower growth potential of this pest in the cultivars ‛Tsan-101' and ‛Toro' than in ‛Saladette' and ‛Cereza'. [ABSTRACT FROM AUTHOR]

Copyright of Revista Mexicana de Ciencias Agrícolas is the property of Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of the present investigation was to evaluate the chemical control of trips Frankliniella occidentalis Pergande (Thysanoptera:Thripidae) with the application of four seed products (thiodicarb, acephato, bifenthrin + imidacloprid and thiametoxan + lambda cyalotrina) with two doses; one according to the dosage of the commercial house and the other 50% smaller, in the variety Roque 1. A randomized block design with four repetitions, 10 treatments and two controls, a hybrid (Ares®-Unisem) was used and a white one. The sampling of the density of trips was carried out by means of a manual aspirator and blue traps, the samplings were made from the emergence of the plants and during eight weeks, carrying out two samplings per week. The results show that the treatment with thiamethoxane + lambda cyalotrine presented the lowest density of trips with a value of 1.53 trips per plant, while the absolute control was the one with the highest value with 2.14. [ABSTRACT FROM AUTHOR]

Phytoparasitic nematodes are one of the main pathogens that affect the cultivation of coffee trees (Coffea arabica L.), reducing the yield between 10 and 70%. The objective of this study was to evaluate the biological effectiveness of the nematicide of biological origin Nemmax, for the control of Meloidogyne incognita, Pratylenchus spp. and Dorylaimus spp., associated to this crop in Motozintla, Chiapas, in 2014. Two population samplings were carried out, one prior to the application of treatments, and another one to the 120 days later, obtaining the number of nematodes in 100 g of floor. The Nemmax treatments (at doses of 2, 4 and 6 L ha with 3 applications), Nemacur 400 CE (Fenamiphos) (3 L has one application) and an absolute control. In the control of Meloidogyne incognita, a significant difference was observed in treatment 5 (133.2), which represents the control, since an increase in the population of the nematodes was observed, compared with the other treatments, which were statistically equal, presenting the same differences for Pratylenchus spp. With the nematode Dorylaimus spp., statistical differences were presented, with treatment 5 (249.6) with the greatest difference, 4 (18), 1 (8.2), 2 (6) and 3 (3.4). Treatment 3, of Nemmax at a dose of 6 L/ha was the one that presented the lowest population of the filiform nematodes of the genus Meloidogyne incognita, Pratylenchus spp. and Dorylaimus spp. [ABSTRACT FROM AUTHOR]

Thirty eight isolates of Phytophthora cinnamomi from five counties in Michoacan, Mexico, were genetically analyzed using amplified fragment length polymorphisms (AFLP) to determine the genetic variability and the existing relationships among the avocado isolates. The amplifications showed 296 bands. A genetic dissimilarity matrix was obtained in this trial by means of the multiple coupling coefficient and the hierarchical grouping method, also called non-weighted average method. The resulting dendogram showed two levels of association. The isolates were classified within two main groups associated with the geographical location from which they were obtained. The analysis and determination of the confidence levels demonstrated that these geographical groups are strong. [ABSTRACT FROM AUTHOR]

Xylella fastidiosa es una de las enfermedades más importantes a nivel mundial, el manejo de sus vectores es una de las estrategias más viables para su control. La presente investigación se realizó en el Laboratorio de Entomología y Acarología del Departamento de Parasitología Agrícola de la Universidad Autónoma Agraria Antonio Narro (UAAAN). Se evaluaron 21 extractos de plantas sobre Cuerna costalis proveniente de muestreos de vid y nogal, estos se multiplicaron sobre frijol bajo condiciones de laboratorio. Para el establecimiento del ensayo se utilizó el método de prueba 005 del IRAC con ligeras modificaciones, en un arreglo completamente al azar con 8 concentraciones y 10 repeticiones evaluando a las 120 h. La mortalidad se corrigió acorde a Abbott (1925) y se realizó un Análisis Probit, asimismo se determinaron los principales compuestos fitoquímicos presentes en los extractos mediante el espectrofotómetro infrarrojo. Los resultados muestran una alta susceptibilidad a los extractos de uña de gato (Mimosa zygophylla), sangre de drago (Jatropha dioica), pimienta negra (Piper nigrum), canela (Cinnamomum verum), y mezquite (Prosopis laevigata) con una CL50 de 1166, 1275, 1433, 1459, y 1478 ppm, respectivamente. Los metabolitos presentes en la mayoría de los extractos eficientes fueron ácido tartárico, 1,8-cineol, eugenol, grupos de saponinas, flavonoides, y compuestos fenólicos. Xylella fastidiosa is a very important disease worldwide. Vector management is one of the viable strategies for control. This research was done in the Entomology and Acarology Laboratory of the Department of Agricultural Parasitology at Universidad Autónoma Agraria Antonio Narro (UAAAN). Twenty-one plant extracts were evaluated on Cuerna costalis from grapevine and pecan samples, subsequently multiplied on beans under laboratory conditions. IRAC test method 005 was used with slight modifications, using a completely randomized design with eight concentrations and 10 replications evaluated at 120 hours. Mortality was corrected according to Abbott (1925) and a Probit analysis was done. The main phytochemical compounds in the extracts were determined using an infrared spectrophotometer. Results showed high susceptibility to cat's claw extracts (Mimosa zygophylla), dragon's blood (Jatropha dioica), black pepper (Piper nigrum), 1166, 1275, 1433, 1459, 1478 ppm, respectively. The metabolites in most of the extracts were tartaric acid, 1, 8-cineole, eugenol, saponin groups, flavonoids, and phenolic compounds. [ABSTRACT FROM AUTHOR]

The objective was to determine differences in antioxidant enzyme activity and total phenol concentration in Mexican lime plants (Citrus aurantifolia (Christm.) Swingle), Persian lime (Citrus latifolia Tanaka); and Valencia sweet orange (Citrus sinensis (L.) Osbeck). Infected under natural field conditions with Candidatus Liberibacter asiaticus (CaLas), in Bustamante, Tamaulipas, Mexico. The presence of CaLas was determined by qPCR. We determined the enzymatic activity of phenylalanine ammonia lyase (PAL), which is activated by pathogen attack; the peroxidase involved in wall lignification in response to infection; the α-amylase which degrades starch and accumulates in vascular tissue; and phenolic compounds involved in defense functions. A contrasts analysis was performed. Total protein concentration showed significant differences between species (P<0.0001). With a mean of 6.1 and 6.37 mg of protein per g of fresh tissue for infected Mexican lime trees, and sweet orange negative CaLas. The peroxidase activity presented a significant difference for Persian lime (P=0.0341), with a mean of 1.96 U.mg of protein-1. In sweet orange, higher α-amylase activity was observed in CaLas infected trees (1.19 U.mg protein-1). The concentration of PAL and total phenols did not show significant differences between species. In the present study it was observed that CaLas influences the enzymatic activity of Citrus species. [ABSTRACT FROM AUTHOR]

Xanthomonas axonopodis pv. Phaseoli (Xap) (Smith) is the bacterium that causes common bacterial blight in bean plants (Phaseolus vulgaris L.) characterized by irregular necrotic staining with yellow halo on leaves, stems, and fruits with crop yield reduction. The taxonomy of this pathogen has been changing due their genetic variability. Infected seeds are one of the most efficient forms of disease dispersal between cultivated areas, the infection and bacterial multiplication in the host tissue often depend on the virulence factors and their secretion system. Management methods that are used to counter the disease in the field have not been effective, however, the constant search for new approaches as the use of biocontrol agents and resistance inducers, open new prospects for control. [ABSTRACT FROM AUTHOR]

Xanthomonas axonopodis pv. phaseoli (Xap) (Smith) es la bacteria que ocasiona el tizón común bacteriano del frijol (Phaseolus vulgaris L.) síntoma que se caracteriza por la aparición de manchas con aspecto de tizón con un halo amarillo en hojas, tallos, y frutos reduciendo así el rendimiento del cultivo. La taxonomía de este patógeno ha sido muy cambiante debido a su variabilidad genética. La semilla infectada es la forma más eficiente de dispersión de la enfermedad entre las áreas cultivadas, el éxito de la infección y la multiplicación bacteriana en el tejido hospedero frecuentemente depende de factores de virulencia y del sistema de secreción. Los métodos de manejo que se emplean para contrarrestar la enfermedad en campo no han sido efectivos, no obstante, la constante búsqueda de nuevos enfoques como el empleo de agentes de biocontrol e inductores de resistencia, abren nuevas expectativas para su control. [ABSTRACT FROM AUTHOR]

Maize (Zea mays L.) is the most representative crop of Mexico, mainly because of its social, cultural, and economic importance. The objective of this research was to identify genotypes with natural resistance to damage by fall armyworm, Spodoptera frugiperda (J.E. Smith), and corn earworm, Helicoverpa zea (Boddie), and their relationship with ear rot caused by Fusarium spp. Link (Nectriaceae). Samples were collected from September to November 2019 from hybrids and native maize in nine plots in Puebla and Morelos states. Ear rot pathogens and Lepidoptera found in plots were morphologically identified; ear rot incidence, severity, and damage caused by the pests were evaluated. Data of ear rot, leaf damage, and ear damage were adjusted by arcsine square root and analysis of variance (ANOVA), and means were compared by a Tukey multiple range test (p = 0.05). Fusarium spp. was found with 15.04 to 32.01% severity; damage by fall armyworm and corn earworm ranged from 23.63 to 46.96%, with galleries as long as 4.77 cm. The amount of ear rot was proportional to damage by Lepidoptera, demonstrating relationship between injury by these insects and ear rot severity caused by Fusarium spp. in hybrids and native cultivars in different areas, cultural practices, and production systems. Genotypes more resistant to damage by pests were Black Native from San Miguel, Teotlalco, Puebla; Pioneer 30F35 from Contla, Puebla; Pioneer P4028W from Tetelilla, Morelos; and Pioneer P4028W from Tepalcingo, Morelos. [ABSTRACT FROM AUTHOR]

The maize weevil, Sitophilus zeamais Motschulsky, is the most important pest of stored maize, Zea mays L. The pest causes estimated losses of 5-10% worldwide. Oil extracts from plants show promise to control maize weevil with important advantages over conventional insecticide, such as non-toxicity to humans, biodegradability, and ecosystem safety. The objective of this research on maize weevils in laboratory conditions was to determine the insecticidal effect of 10 plant oils: garlic, Allium sativum L.; cinnamon, Cinnamomum verum J.; hot pepper, Capsicum annuum L.; clove, Syzygium aromaticum L.; mint, Mentha piperita L.; black pepper, Piper nigrum L.; rosemary, Rosmarinus officinalis L.; rue, Ruta graveolens L.; thyme, Thymus vulgaris L. and allyl (commercial product). Residual film was used to test plant oils at five concentrations: 9,000, 7,000, 5,000, 3,000, and 1,000 ppm. The number of weevils killed was counted at 72 hours, and treatment means were compared using a Tukey multiple separation test. PC-Probit analysis determined LC50 and LC95. Most weevils, 52.47 and 60.38%, were killed by garlic and black pepper oils, respectively; at 9,000 ppm; fewer than 50% were killed with the other plant oils. Use of garlic and black pepper oil might be an alternative method to manage this insect pest in stored maize. [ABSTRACT FROM AUTHOR]