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Some botanical extracts affect the cellular immune system of insects by interfering with normal hemocyte function. This gives rise to diminution in cellular immunity and causes a decrease in insect...

The biological activity of extracts from Trichilia americana (Sesse and Mocino) T.D. Penn. (rind), Carica papaya L., Jatropha curcas L., Ricinus communis L., and Lupinus campestris Schldl. & Cham. (seeds), at 1% and 5%, were evaluated on neonates of Copitarsia decolora Guenée in ingestion bioassays. The plants that caused the highest percentage of larval mortality were T. americana at 1% and 5%, and Carica papaya at 5% with 98% and 100% and 100%, respectively. Trichilia americana was the plant with higher toxicological properties against C. decolora. Extracts in hexane, ethyl acetate, acetone, and methanol from T. americana were then evaluated at 10, 100, 300, and 1,000 ppm also in ingestion bioassays against C. decolora. Extracts of ethyl acetate and acetone at 1,000 ppm recorded the highest percentages of larval mortality of C. decolora (90% and 55%, respectively). In addition to larval mortality, feeding on T. americana extract also decreased mean larval weight, prolonged duration of the larval stage, resulted in malformed pupae and adults, and affected adult fertility and fecundity. Finally, these extracts were evaluated in a toxicity model, for which the crustacean Artemia salina Leach was used. The ethyl acetate, acetone, and hexane extracts showed no toxicity to A. salina, while the methanol extract caused 30% mortality, which is considered to be slightly toxic. Based on the results obtained, T. americana is a species with insecticidal and insectistatic activity against C. decolora and can be considered as a potential insecticide for the management of this or other insect pests.

Castor bean (Ricinus communis) seeds contain ricinine, an alkaloid with insecticidal and insectistatic activities. Elicitation with salicylic acid (SA) has proven to stress R. communis and might modify the ricinine concentration. The aim of this study was to evaluate the concentration of ricinine in the bagasse of seeds from R. communis elicited with exogenous SA under greenhouse conditions. Plants were grown and divided into five groups, which were sprayed with SA and drench with 50 mL 60 days after sowing with concentrations of SA (0, 100, 300, 600 and 900 µM). Clusters were mixed and separated according to the treatment, and dried. The seeds were ground, the oil was extracted by Soxhlet with hexane, and then the bagasse was extracted with methanol. Ricinine was determined by HPLC. Elicitation did not change the plant height or diameter, the control group had 9.17 µg mL−1 of ricinine, and the concentrations followed a hormesis curve with the peak at 300 µM of SA that had a ricinine concentration of 18.25 µg mL−1. Elicitation with SA might be a cost-effective technique to increase ricinine from R. communis bagasse.

Longhorn beetles (Coleoptera: Cerambycidae) feed during their larval stage on wood from recently dead or diseased trees and may have a wide variety of hosts. However, reports of larval hosts for Cerambycidae could be misinterpreted from field observations. The use of freshly cut branches to attract longhorn beetles is a method that provides reliable information about which hosts they use. This study reports new records of larval hosts of longhorn beetles in the tropical dry forest of San Andres de la Cal, Morelos, Mexico. In the study area, species of woody plants were sampled, from each of which sections of branches were cut and left exposed to local field conditions for two months to attract beetles. Branches were later collected and placed in emergence chambers. A total of 26 species of Cerambycidae emerged from the branches of 51 species of woody plants of the families Apocynaceae, Araliaceae, Burseraceae, Celastraceae, Convolvulaceae, Euphorbiaceae, Fabaceae, Juglandaceae, Malpighiaceae, Malvaceae, Moraceae, Oleaceae and Rubiaceae. For all 26 cerambycid species, we found previously unreported hosts, and for nine species, the hosts we report are the first recorded in the literature. The nine species whose host relationships have not been previously reported are: Euderces basimaculatus Giesbert & Chemsak 1997; E. pulcher (Bates, 1874); Elytroleptus grandis Linsley 1935; Neocompsa puncticollis asperula (Bates, 1885); Acanthoderes (Pardalisia) lacrymans (Thomson, 1865); Olenosus serrimanus Bates, 1872; Oreodera brailovskyi Chemsak & Noguera, 1993; O. copei McCarty, 2001 and Spliaenothecus picticornis Bates, 1880.

"The center of origin and domestication of Jatropha curcas L. is Mexico. This crop can be affected by several phytopathogenic fungi and insect pests that diminish the quality of the seeds. The aim of this study was to evaluate the antagonistic and enthomopathogenic activity of rhizospheric bacteria (B. subtilis, B. mojavensis, B. thuringiensis and Lysinibacillus sphaericus) against Fusarium verticillioides and Leptoglossus zonatus. The antagonistic activity of rhizobacteria was evaluated against F. verticillioides by dual culture technique on potato dextrose agar. Moreover, the effect of B. thuringiensis and L. sphaericus was evaluated on the mortality and development of L. zonatus. The results demonstrated that rhizobacteria inhibited the mycelial growth (26 to 55 %) and affected the hyphal morphology of F. verticillioides regardless of the culture medium and cultivation time tested. B. mojavensis (40.4 to 54 %), L. sphaericus (39.6 to 55 %) and B. subtilis (38.5 to 50%) caused the highest percentages of inhibition. On the other hand, B. thuringiensis and L. sphaericus showed no enthomopathogenic activity because they did not affect the mortality or development of L. zonatus."

We studied the insecticidal effect of plant extracts against larvae of Scyphophorus acupunctatus Gyllenhal (Coleoptera: Curculionidae), an important pest of Agavaceae. In the bioassays, the organic extracts of Argemone mexicana L. (Ranunculales: Papaveraceae), Allium sativum L. (Asparagales: Amaryllidaceae), Bursera grandifolia (Schltdl.) Engl. (Sapindales: Burseraceae), Chenopodium ambrosioides L. (Caryophyllales: Amaranthaceae), Prosopis laevigata (Willd.) M. C. Johnst. (Fabales: Fabaceae), and Tagetes erecta L. (Asterales: Asteraceae), which were individually incorporated into artificial diet at 500 ppm, were fed to 1st instars. The variables studied were larval, pupal, and adult weight, and larval and pupal mortality. The extracts of A. sativum, A. mexicana, P. laevigata, T. erecta, and B. grandifolia reduced larval weight by at least 50%. The greatest larval mortality was caused by the extracts of A. mexicana (53%), A. sativum (43%), and T. erecta (43%), whereas the greatest mortality of pupae was caused by extracts of T. erecta. The results suggest that A. mexicana, A. sativum, and T. erecta extracts have the greatest potential for insecticidal activity against S. acupunctatus. ResumenSe estudio el efecto insecticida de extractos vegetales en contra de larvas de Scyphophorus acupunctatus Gyllenhal (Coleoptera: Curculionidae), plaga importante de Agavaceas. Se realizaron bioensayos de ingestion empleando individualmente los extractos organicos de Argemone mexicana L. (Ranunculales: Papaveraceae), Allium sativum L. (Asparagales: Amaryllidaceae), Bursera grandifolia (Schltdl.) Engl. (Sapindales: Burseraceae), Chenopodium ambrosioides L. (Caryophyllales: Amaranthaceae), Prosopis laevigata (Willd.) M. C. Johnst. (Fabales: Fabaceae) y Tagetes erecta L. (Asterales: Asteraceae), todos ellos a una concentracion de 500 ppm. Los extractos se incorporaron en una dieta artificial, sobre la cual se colocaron larvas del primer estadio del insecto. Las variables evaluadas fueron peso y mortalidad del insecto. Los extractos de A. sativum, A. mexicana, P. laevigata, T. erecta y B. grandifolia, inhibieron en un 50 por ciento el peso larval con respecto del testigo. Los extractos que provocaron mortalidad en larvas fueron: A. mexicana (53%), A. sativum (43%) y T. erecta (43%). Asi mismo, T. erecta fue la especie que produjo la mas alta mortalidad de pupas. Estos resultados permiten posicionar a A. sativum y a T. erecta como las especies mas promisorias con actividad bioinsecticida en contra de S. acupunctatus. View this article in BioOne

En este estudio se evaluo el efecto de cuatro niveles de nitrato de potasio (KNO3: 5, 10, 15 y 20 meq L-1) en la produccion de ricinina mediante un sistema semi-hidroponico, y la actividad insecticida del extracto metanolico obtenido de hojas de Ricinus communis L contra larvas de Spodoptera frugiperda Smith. El extracto metanolico se uso para la obtencion del alcaloide, y con el se evaluo su actividad biologica contra larvas de S. frugiperda. La relacion dosis/respuesta demostro una alta correlacion positiva (R2 = 0.92, P ≤ 0.05) entre la concentracion de nitrogeno en la solucion hidroponica y el porcentaje de ricinina en las hojas. Lo mismo se observo (R2 = 0.94, P ≤ 0.05) entre el contenido de nitrogeno foliar y el porcentaje de ricinina. El uso de KNO3 como fuente nitrogenada incremento la produccion de ricinina y tambien afecto la mortalidad larval de S. frugiperda. Las LC50 determinadas para S. frugiperda fueron de 13,469.12, 15,754.34, 16,046.11 y 18,155.75 mg mL-1 para los extractos metanolicos obtenidos de hojas de plantas crecidas en las concentraciones de nitrogeno de 20, 15, 10 and 5 meq L-1 respectivamente. El incremento en la concentracion de ricinina al aumentar la concentracion de nitrogeno en la solucion hidroponica al indica que esta tecnica puede utilizarse para mejorar la produccion de este alcaloide y con ello elevar su capacidad de proteccion contra S. frugiperda

Essential oils can be used as an alternative to using synthetic insecticides for pest management. Therefore, the insectistatic and insecticidal activities of the essential oil of aerial parts of Salvia ballotiflora (Lamiaceae) were tested against the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae). The results demonstrated insecticidal and insectistatical activities against this insect pest with concentrations at 80 µg·mL(-1) resulting in 20% larval viability and 10% pupal viability. The larval viability fifty (LV50) corresponded to a concentration of 128.8 µg·mL(-1). This oil also increased the duration of the larval phase by 5.5 days and reduced the pupal weight by 29.2% withrespect to the control. The GC-MS analysis of the essential oil of S. ballotiflora showed its main components to be caryophyllene oxide (15.97%), and β-caryophyllene (12.74%), which showed insecticidal and insectistatical activities against S. frugiperda. The insecticidal activity of β-caryophyllene began at 80 µg·mL(-1), giving a larval viability of 25% and viability pupal of 20%. The insectistatic activity also started at 80 µg·mL(-1) reducing the pupal weight by 22.1% with respect to control. Caryophyllene oxide showed insecticidal activity at 80 µg·mL(-1) giving a larval viability of 35% and viability pupal of 20%.The insectistatic activity started at 400 µg·mL(-1) and increased the larval phase by 8.8% days with respect to control. The LV50 values for these compounds were 153.1 and 146.5 µg·mL(-1), respectively.

The agave snout weevil Scyphophorus acupunctatus Gyllenhal (Coleoptera: Curculionidae) is an ubiquitous insect and the main pest of blue tequila agave, Agave tequilana Weber, and other agaves. This study reports the repellent effect of the hydroethanolic extract of the castor oil plant, Ricinus communis L. (Euphorbiaceae) wild and ‘Mirante’ cultivar on the adult's behavior. Females and males visited untreated agave tissue more frequently than agave tissue treated with R. communis extracts. Insects visited agaves treated with seed extracts more frequently than those with leave extracts; therefore leaves of R. communis deserve a closer look to identify their properties and gauge their potential use as a repellent.

Bitter lupins (Lupinus spp.) are not used as a protein source because of their toxicity. However, they may have alternative uses as potential sources of natural insecticides. Quinolizidine alkaloids (QA) of three Mexican Lupinus species (Fabaceae): L. montanus (HBK), L. stipulatus (Agardh) and L. aschenbornii (Schauer), were analyzed by capillary Gas Chromatography-Mass Spectrometry. Sparteine was found in high amounts in both L. montanus and L. aschenbornii while the major alkaloids in L. stipulatus extract were aphylline and an epiaphylline-like compound. Alkaloid extracts were tested for their insecticidal activity using larvae of the Fall Armyworm, Spodoptera frugiperda (Smith); (Lepidoptera, Noctuidae) as a model pest. We compared LD50 values and mean weight of caterpillars fed with alkaloid extracts of the three species studied with those of sparteine, a widespread QA found in various lupin species. Extracts of L. montanus and L. aschenbornii were found to be as effective as sparteine and extracts L. stipulatus were found to be the most toxic against the larvae of S. frugiperda. This suggests that the various QA act differently on caterpillars, and could be used to control Spodoptera populations.

The damage caused by the fall armyworm Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) to vegetative-stage maize cultivated with chemical nitrogen fertilizers, vermicompost, and Carica papaya L. (Caricaceae) seed extract was estimated. Each shoot was infested with one first instar larva of S. frugiperda . The variables measured included the percentage of germination, length of the second and fifth leaves, stem diameter and plant height, and the estimation of damage caused by S. frugiperda larvae on maize. The results indicated that vermicompost helped seed germination on a relation 3:1 from black soil and vermicompost, the emergence was 100%, while the emergence with black soil was 80%. The ammonium sulfate increased the length of the second and fifth leaves 89.6% and 160.4% respectively, augmented the stem diameter and the plant height 290.2% and 13.3% respectively, respect to water treatment. The exogenous nitrogen sources stimulate S. frugiperda to cause more damage to the plant, the treatment urea showed 70% of damage, with phosphonitrate 62.3% and with ammonium sulfate 51.8%, when were evaluated without aqueous seed extract of C. papaya . Ammonium sulfate + aqueous extract of C. papaya seeds showed the lowest insect damage to maize with 29.6%. Se estimo el dano causado por el gusano cogollero del maiz Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) durante la etapa vegetativa de maiz cultivado con fertilizantes nitrogenados quimicos, vermicomposta, y extracto acuoso de semillas de Carica papaya L. (Caricaceae). Cada brote se infesto con una larva de primer instar de S. frugiperda . Las variables evaluadas incluyen el porcentaje de germinacion. Las variables respuesta fueron el porcentaje de emergencia, longitud de la segunda y quinta hoja, diametro de tallo y altura de la planta; asi como la estimacion de dano causado por larvas de S. frugiperda al maiz. Los resultados indicaron que la vermicomposta ayudo a la emergencia de la semilla, en una relacion 3:1 de suelo con vermicomposta alcanzo 100% de emergencia, mientras que solo con suelo, la emergencia fue de 80%; el sulfato de amonio incremento el tamano de la segunda hoja y quinta hoja 89,6 y 160,4% respectivamente, aumento el diametro de tallo y la altura de la planta 290,2 y 13,3%, respecto al tratamiento donde solo se aplico agua. Las fuentes de nitrogeno estimularon que S. frugiperda ocasionara mas dano a la planta, el tratamiento con urea presento 70% de dano, con fosfonitrato 62,3%, con sulfato de amonio fue de 51,8% sin extracto acuoso de semillas de C. papaya . El tratamiento con sulfato de amonio + extracto acuoso de semillas de C. papaya registro el menor dano del insecto al maiz con 29,6%.

Mortality and growth inhibition effect of Trichiliahavanensis, Annona cherimola, and Carica papaya seed powders were evaluated on Scyphophorus acupunctatus Gyll. (Coleoptera: Curculionidae). Seeds of T. havanensis and C. papayaat 15% were very toxic to S. acupunctatus, causing 100 and 90% larval mortality. Seed powder of A. cherimola killed 63% of the weevils. All powders inhibited the weight of the insect. Annona cherimola was the most effective, decreasing the weight of larvae, pupae, and adults 98.5, 40.6, and 45.0%. These results show that T. havanensis, C. papaya, and A. cherimola seed powders have the potential to control the S. acupunctatus weevil.