Effect of entomopathogenic fungi on the control of the coffee berry borer in the laboratory

Among the management and control tactics of the coffee berry borer Hypothenemus hampei (Ferrari), there is the use of entomopathogenic fungi. Due to the importance of prospecting isolates of entomopathogenic fungi for the control of the coffee berry borer, the objective of this study was to evaluate the efficiency of 26 isolates of entomopathogenic fungi in the control of this insect pest in the laboratory. The coffee berry borers were immersed in a solution adjusted to the concentration of 1 to 3 × 108 conidia/mL of each isolate and the control treatment (sterilized water). After seven days total mortality and confirmed mortality were evaluated. The isolates that caused the highest mortality and two commercial isolates were selected for evaluation of lethal concentration (LC50 and LC90) and lethal time (LT50 and LT90). Coffee berry borers were treated at different conidia concentrations for lethal concentration to assess total and confirmed mortality. For a lethal time, the coffee berry borers were treated at the concentration of 108 conidia/mL of the selected isolates, and, after two days and every 24 hours until the eighth day, the number of dead individuals was verified. Among the 26 isolates evaluated, 24 presented mortality higher than the control treatment, and three presented mortality higher than 85%. In the LC50 and LC90 assays, the IBCB 353 and IBCB 364 isolates were more lethal to H. hampei. In the LT50 and LT90 assays, the IBCB 66 and IBCB 353 isolates caused lethality in a shorter time.

Insect galls of Restinga de Marambaia (Barra de Guaratiba, Rio de Janeiro, RJ) / Galhas de insetos da Restinga de Marambaia (Barra de Guaratiba, Rio de Janeiro, RJ)

Abstract Thirty-one morphotypes of insect galls and two flower damages were found on 16 families, 22 genera and 24 plant species in Restinga de Marambaia (Barra de Guaratiba, Rio de Janeiro, RJ). Fabaceae and Myrtaceae were the plant families with the greatest richness of insect galls (4 and 6 morphotypes, respectively), and the greatest number of galled plants (four and three species, respectively). Galls were mostly found on leaves and stems (77% and 10%, respectively). The galling insects are represented by Diptera, Lepidoptera, and Hemiptera. The majority of the galls (81%) were induced by gall midges (Cecidomyiidae: Diptera).

Resumo Foram encontrados 31 morfotipos de galhas de insetos e dois danos em flores em 16 famílias, 22 gêneros e 24 espécies de plantas, na Restinga de Marambaia (Barra de Guaratiba, Rio de Janeiro, RJ). Fabaceae e Myrtaceae foram as famílias de plantas com maior riqueza de galhas (4 e 6 morfotipos, respectivamente) e maior número de espécies com galhas (quatro e três espécies, respectivamente). As galhas predominaram nas folhas e caules (77% e 10%, respectivamente). Os insetos galhadores estão representados por Diptera, Lepidoptera e Hemiptera. A maioria das galhas (81%) foi induzida por Cecidomyiidae (Diptera).

Resource allocation in Copaifera langsdorffii (Fabaceae): how supra-annual fruiting affects plant traits and herbivory?

AbstractPlants have limited resources to invest in reproduction, vegetative growth and defense against herbivorous. Trade-off in resources allocation promotes changes in plant traits that may affect higher trophic levels. In this study, we evaluated the trade-off effect between years of high and low fruiting on the investment of resources for growth and defense, and their indirect effects on herbivory in Copaifera langsdorffii. Our questions were: (i) does the resource investment on reproduction causes a depletion in vegetative growth as predicted by the Carbon/Nutrient Balance hypothesis (CNBH), resulting in more availability of resources to be allocated for defense?, (ii) does the variation in resource allocation for growth and defense between years of high and low fruiting leads to indirect changes in herbivory? Thirty-five trees located in a Cerrado area were monitored during 2008 (year of high fruiting) and 2009 (year of no fruiting) to evaluate the differential investment in vegetative traits (biomass, growth and number of ramifications), plant defense (tannin concentration and plant hypersensitivity) and herbivory (galling attack and folivory). According to our first question, we observed that in the fruiting year, woody biomass negatively affected tannin concentration, indicating that fruit production restricted the resources that could be invested both in growth as in defense. In the same way, we observed an inter-annual variation in herbivorous attack, and found that plants with higher leaf biomass and tannin concentration, experienced higher galling attack and hypersensitive reaction, regardless years. These findings suggested that plants’ resistance to herbivory is a good proxy of plant defense and an effective defense strategy for C. langsdorffii, besides the evidence of indirect responses of the third trophic level, as postulated by the second question. In summary, the supra-annual fruiting pattern promoted several changes on plant development, demonstrating the importance of evaluating different plant traits when characterizing the vegetative investment. As expected by theory, the trade-off in resource allocation favored changes in defense compounds production and patterns of herbivory. The understanding of this important element of insect-plant interactions will be fundamental to decipher coevolutionary life histories and interactions between plant species reproduction and herbivory. Besides that, only through long-term studies we will be able to build models and develop more accurate forecasts about the factors that trigger the bottom-up effect on herbivory performance, as well the top-down effect of herbivores on plant trait evolution. Rev. Biol. Trop. 64 (2): 507-520. Epub 2016 June 01.

ResumenLas plantas tienen recursos limitados para invertir en reproducción, crecimiento vegetativo y defensa contra herbívoros. El cambio en la distribución de recursos promueve variaciones en rasgos vegetales, que pueden afectar los niveles tróficos superiores. Durante dos años consecutivos de alta y baja inversión reproductiva se evaluó el cambio de recursos entre crecimiento vegetativo y defensa, y su efecto indirecto sobre la herbivoría en Copaifera langsdorffii. Nos preguntamos: i) ¿La inversión de recursos para la reproducción causa reducción del crecimiento vegetativo, como predice la hipótesis de equilibrio carbono/nutrientes, haciendo posible gastar más recursos en defensa? ii) ¿La variación en distribución de recursos para crecimiento y defensa entre años de alta y baja fructificación modifica indirectamente la herbivoría? Se monitorearon treinta y cinco árboles durante 2008 (gran fructificación) y 2009 (sin fructificación) en un área de vegetación de cerrado (Brasil), para evaluar la inversión diferencial en rasgos vegetativos (biomasa, crecimiento y No. de ramificaciones), defensa (concentración de taninos e hipersensibilidad vegetal) y herbivoría. De acuerdo a nuestra primera pregunta, se observó que en el año de fructificación la biomasa leñosa afectó negativamente la concentración de taninos, indicando que la producción de frutos redujo los recursos que podían invertirse en crecimiento y defensa. Además, la resistencia de las plantas y el ataque de agallas fueron influidos positivamente por la concentración de taninos y la biomasa foliar, lo que sugiere que la resistencia de los árboles a la herbivoría es un buen indicador de defensa vegetal y una estrategia efectiva de defensa de C. langsdorffii, además hay evidencia de respuesta trófica indirecta, como se postula en la segunda pregunta. En resumen, el patrón de fructificación supra-anual provoca varios efectos en el desarrollo de las plantas, mostrando la importancia de evaluar diversos rasgos vegetales al caracterizar la inversión de recursos de una especie. Como se esperaba, el cambio en la distribución de recursos modifica la producción de compuestos de defensa y los patrones de herbivoría. El entendimiento de este elemento importante de las interacciones insecto-planta será fundamental para descifrar la historia natural coevolutiva y las interacciones entre reproducción vegetal y ataque herbívoro. Además de eso, solo a través de estudios a largo plazo vamos a ser capaces de construir modelos y desarrollar pronósticos más precisos acerca de los factores que desencadenan el efecto de abajo hacia arriba en el rendimiento de la herbivoría, así el efecto de arriba hacia abajo de los herbívoros sobre la evolución de las plantas.

Analysis on the arcelin expression in bruchid pest resistant wild pulses using real time RT-qPCR.

Arcelin, the antimetabolic protein from wild pulses is a known natural insecticidal molecule. Wild pulses with high arcelin content could serve as potential source to increase the levels of insect resistance in cultivated pulse crops. In this study, arcelin (Arl) gene expression was screened in seven stored product insect pest resistant wild pulse varieties using real time RT-qPCR. Arcelin gene specific real time PCR primers were synthesized from arcelin mRNA sequence of the wild pulse variety, Lablab purpureus. The results revealed different levels of arcelin gene expression in the tested varieties. Canavalia virosa registered significantly high content indicating its suitability for utilization of arcelin gene in developing stored product insect pest resistance with other cultivated pulses.

Efeito da temperatura e umidade relativa do ar no desenvolvimento de Liriomyza sativae Blanchard (Diptera: Agromyzidae) em Vigna unguiculata / Effect of temperature and relative-humidity on the development of Liriomyza sativae Blanchard (Diptera: Agromyzidae) in Vigna unguiculata

This research aimed to study the influence of temperature and relative-humidity (RH) on the development of Liriomyza sativae Blanchard during the egg-adult period, in cowpea, to provide essential information for future biological control projects against the pest. An inverse relation was observed between temperature increase in the range from 15°C to 32°C and development duration. Larval survival was not affected in the temperature range studied, while a high mortality of pupae was observed at 32°C (59.9 percent). RH did not affect the development time of the immature stages, although it influenced their survival. The lower developmental temperature threshold obtained for the egg-adult period was low (7.3°C) when compared with other species of Liriomyza, and was rather low for the larval stage (3.4°C). Based on the thermal requirements for L. sativae, it was possible to estimate the occurrence of 24.5 annual generations at a melon producing region in state of Rio Grande do Norte, Brazil. For laboratory rearing aimed at biological control pest programs, the best rearing conditions are 30°C and 50 percent RH for the larval stage and 90 percent RH for the pupal stage.

A pesquisa teve como objetivo estudar a influência da temperatura e da umidade relativa do ar (UR) no desenvolvimento de Liriomyza sativae Blanchard, durante o período ovo-adulto, em feijão caupi, para fornecer subsídios a futuros projetos de controle biológico da praga. Verificou-se uma relação inversa entre o aumento da temperatura na faixa de 15°C a 32°C e a duração do desenvolvimento. A sobrevivência larval não foi afetada na faixa térmica estudada, enquanto a 32°C houve alta mortalidade de pupas (59,9 por cento). A UR não afetou a duração dos estágios imaturos, embora tenha influenciado a sua sobrevivência. O limiar térmico inferior de desenvolvimento obtido para o período ovo-adulto foi baixo (7,3°C), se comparado a outras espécies de Liriomyza, e bastante reduzido para a fase larval (3,4°C). De acordo com as exigências térmicas constatadas para L. sativae foi possível estimar a ocorrência de 24,5 gerações anuais na região produtora de melão, em Mossoró, RN. Para criações de laboratório, visando à implementação de programas de controle biológico da praga, as melhores condições são temperatura de 30°C e UR de 50 por cento para a fase de larva e 90 por cento para o estágio de pupa de L. sativae.

Depredación pre-dispersiva de semillas en tres poblaciones del árbol Enterolobium contortisiliquum (Fabaceae)

Pre-dispersal seed predation in three populations of the tree Enterolobium contortisiliquum (Fabaceae). Predation is an important selective force that has shaped different strategies related to size, quantity and production time of fruits, seeds and seed reserves. The seeds of E. contortisiliqum are predated by the bruchid Merobruchus bicoloripes. We collected 1 300 fruits from 26 trees in San Salvador de Jujuy (Jujuy province), Castañares, and San Lorenzo (Salta province) Argentina. San Lorenzo is the wettest and highest site, while Castañares is the driest and lowest site. Jujuy is in the middle. In the laboratory, the fruits from each site were weighted and divided in three groups (small, medium and big). We counted the mature and predated seeds per fruit. In San Lorenzo, seed predation was higher in medium sized fruits while in Castañares and Jujuy seed predation was higher in both medium and bigger fruits. However, only in San Lorenzo we found a significant difference in preference for medium size fruits. Rev. Biol. Trop. 57 (3): 781-788. Epub 2009 September 30.

La depredación se ha postulado como una importante fuerza selectiva que ha moldeado distintas estrategias relacionadas con el tamaño, la cantidad y el tiempo de producción de semillas, frutos y el contenido de reservas. Las semillas de Enterolobium contortisiliqum son depredadas por el brúquido Merobruchus bicoloripes. Se estudiaron tres poblaciones de E. contortisiliquum en relación al tamaño de los frutos, a la producción de semillas por fruto, y a la depredación de semillas, comparando la variabilidad dentro y entre poblaciones. Se recolectaron 1300 frutos de 26 árboles en San Salvador de Jujuy (Jujuy), Castañares y San Lorenzo (Salta). Los frutos se pesaron y se contaron las semillas viables y depredadas. San Lorenzo es el sitio más húmedo y de mayor altitud, y Castañares el de menor altitud y más seco. En San Lorenzo encontramos una mayor preferencia de depredación en frutos medianos. En Castañares y San Salvador de Jujuy, a pesar de que los frutos medianos y grandes presentaron mayores niveles de depredación, no encontramos diferencias en la preferencia por alguna clase de tamaño. Los mayores niveles de depredación se encontraron en Castañares y S. S. de Jujuy.

Life history parameters of Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) at different environmental conditions on two bean cultivars / Estadísticos vitales de Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) a diferentes condiciones ambientales en dos cultivares de fríjol

Life-history parameters of the greenhouse whitefly Trialeurodes vaporariorum (Westwood), an important pest of bean crops in Colombia, were determined in environmental control chambers on two dry bean (Phaseolus vulgaris) cultivars (cv.). Trialeurodes vaporariorum longevity on cv. Chocho decreased as temperature increased from 22.6 d at 19ºC to 5.9 d at 26ºC. Fecundity was significantly lower at 19ºC (8.6 eggs/female), as compared to 22ºC (32.6 eggs/female) and 26ºC (33.3 eggs/female) on cv. Chocho. Fecundity on cv. ICA-Pijao was much higher (127.2 eggs/female) than on cv. Chocho (32.6 eggs/female) at 19ºC. The intrinsic rate of population increase (r m) was highest at 22ºC (0.061), intermediate at 19ºC (0.044) and lowest at 26ºC (0.035) on cv. Chocho, and was 0.072 on cv. ICA-Pijao at 19ºC. Life history parameters of T. vaporariorum are compared to those of one of its natural enemies, the parasitoid Amitus fuscipennis MacGown & Nebeker. Finally, data are presented on the distribution of the parasitoid related to the altitude for the Valle del Cauca, Colombia.

Se determinaron los estadísticos vitales de la mosca blanca Trialeurodes vaporariorum (Westwood), una plaga importante del cultivo del fríjol en Colombia, en cámara ambiental en dos cultivares (cv.) de fríjol. La longevidad media de T. vaporariorum en el cv. Chocho fue mayor a 19ºC (22.6 d), intermedia a 22ºC (17.5 d) y menor a 26ºC (5.9 d). En el cv. ICA-Pijao la longevidad media fue de 35.5 d a 19ºC. La fecundidad media total fue 8.6, 32.6 y 33.3 huevos por hembra a 19, 22 y 26ºC, respectivamente en el cv. Chocho. La fecundidad en el cv ICA-Pijao fue mucho más alta, 127. 2 huevos por hembra, a 19ºC, que la del cv. Chocho. La tasa intrínseca de crecimiento poblacional (r m) fue más alta a 22ºC (0.061), intermedia a 19ºC (0.044) y más baja a 26ºC (0.035) en el cv. Chocho. Ella fue de 0.072 a 19ºC en el cv. ICA-Pijao. Se comparan los estadísticos vitales de T. vaporariorum con los de su enemigo natural, el parasitoide Amitus fuscipennis MacGown & Nebeker y se zonifica la distribución del parasitoide en el Valle del Cauca, Colombia.

Influence of leaflet age in anatomy and possible adaptive values of the midrib gall of Copaifera langsdorffii (Fabaceae: Caesalpinioideae)

Gall inducing insects most frequently oviposit in young tissues because these tissues have higher metabolism and potential for differentiation. However, these insects may also successfully establish in mature tissues as was observed in the super-host Copaifera langsdorffii. Among C. langsdorffii gall morphotypes, one of the most common is a midrib gall induced by an undescribed species of Cecidomyiidae. Following this ‘host plant and gall-inducing insect’ model, we addressed two questions: 1) Do the age of the tissues alter the gall extended phenotype? 2) Do gall morphological and anatomical features influence the adaptive value of the galling insect? For anatomical and histometrical studies, transverse sections of young and mature, galled and ungalled samples were prepared. Galls in young leaflets presented higher potential for cell division and greater nutritive reserves, whereas galls in mature leaflets perhaps provide more protection against natural predators and desiccation. Host organ age at the time of oviposition may influence plant cell fates and consequently the interpretation of the adaptive value of insect galls. Rev. Biol. Trop. 57 (1-2): 293-302. Epub 2009 June 30.

Aspectos biológicos de Bemisia tabaci (Genn) biótipo B (Hemiptera: Aleyrodidae) em seis genótipos de feijoeiro / Biological aspects of Bemisia tabaci (Genn) B biotype (Hemiptera: Aleyrodidae) on six bean genotypes

A mosca-branca é um dos insetos mais prejudiciais à cultura do feijoeiro, devido principalmente à intensa sucção de seiva e à transmissão do vírus do mosaico dourado. O uso de cultivares resistentes ao inseto é uma ferramenta importante no seu controle. Ensaios foram conduzidos em laboratório, avaliando-se aspectos biológicos de Bemisia tabaci biótipo B para os seguintes genótipos de feijoeiro: Arc 3s, Arc 5s, G13028, G11056, Arc 1 e Porrillo 70. As plantas (estágio IV-1) foram infestadas por moscas-brancas durante um dia e os ovos e ninfas foram observados até a emergência dos adultos. A longevidade e a fecundidade dos insetos emergidos também foram avaliadas. Ninfas alimentadas no genótipo Arc 3s (26,5 dias) tiveram o período de desenvolvimento mais longo, seguidas de G11056 (25,9 dias) e G13028 (25,3 dias). Houve um alongamento de 5,5 dias no período de desenvolvimento dos insetos em Arc 3s quando comparado com Porrillo 70. Altas taxas de mortalidade das ninfas nos genótipos Arc 3s e G11056 (94,7 e 83,1 por cento, respectivamente) indicam que tais materiais podem apresentar resistência do tipo não-preferência para alimentação e/ou antibiose. Assim, embora a longevidade e a fecundidade do inseto não tenham sido afetadas quando criado nos genótipos resistentes (Arc 3s, G11056, G13028 e Arc 5s), sugere-se que tais materiais sejam utilizados em programas de melhoramento de feijoeiro visando à resistência a B. tabaci biótipo B.

The silverleaf whitefly is one of the most harmful pests that attack bean crops, mainly for extracting large quantities of phloem sap and transmitting the bean golden mosaic virus. Resistant germoplasm plants can be an important method for controlling this pest. The biological aspects of Bemisia tabaci B biotype on bean (Phaseolus vulgaris) genotypes were evaluated. The tests were conducted under laboratory conditions, with the following genotypes: Arc 1, Arc 3s, Arc 5s, G13028, G11056 and Porrillo 70. The bean plants in a stage IV-1 were infested during one day with silverleaf whiteflies. Afterwards the eggs and nymphs were observed until adult emergence. Longevity and fecundity of emerged insects were also evaluated. The longest development time occurred for nymphs fed on Arc 3s genotype (26.5 days), following by G11056 (25.9 days) and G13028 (25.3 days). The development period was 5.5 days longer in Arc 3s when compared with Porrillo 70. Also, the wild genotypes Arc 3s and G11056 showed higher mortality rates (94.7 percent and 83.1 percent, respectively), which may suggest antibiosis and/or feeding nonpreference resistance type. For this reason, although longevity and fecundity were not influenced when the whitefly fed on resistant genotypes (Arc 3s, G11056, G13028 and Arc 5s), those genotypes can be used for bean breeding program towards B. tabaci B biotype.

Primeiro registro de Platycorypha nigrivirga Burckhardt (Hemiptera: Psylloidea), em Tipuana tipu (Benth), no Brasil / First record of Platycorypha nigrivirga Burckhardt (Hemiptera: Psylloidea), in Tipuana tipu (Benth), from Brazil

É relatada pela primeira vez a ocorrência de Platycorypha nigrivirga Burckhardt (Hemiptera: Psyllidae, Acizzinae) no Brasil. A praga foi recentemente observada no Paraná, causando danos em folhas e brotações de Tipuana tipu (Benth.) em áreas urbanas. P. nigrivirga suga a seiva do floema e causa encarquilhamento, manchas e queda de folhas. Seus excrementos se acumulam sobre as folhas propiciando o aparecimento de fumagina ou caem em grande quantidade sobre os carros sujando-os como se fossem respingos de tinta branca e pegajosa.

The occurrence of Platycorypha nigrivirga Burckhardt (Hemiptera: Psyllidae, Acizzinae), is reported for the first time, in Brazil. The psyllid was observed causing injuries on leaves and shoots of Tipuana tipu (Benth.), in urban areas of Paraná State. P. nigrivirga are tiny sap-sucking insects that feed on phloem and cause curling, stains and fall of leaves. The excrements of these insects accumulate on the leaves propitiating fungus growth on the leaves, or they fall in great amount on the cars dirtying them as if they were sparkling of white and sticky ink.

A review of evolution of oviposition guilds in the Bruchidae (Coleoptera)

Uma revisão das guildas de oviposição em Bruchidae (Coleoptera). Os bruquídeos apresentam três guildas de oviposição caracterizadas por períodos e maneiras diferentes de postura. Algumas espécies somente ovipositam nos frutos enquanto presos à planta (Guilda A), outras somente em sementes expostas de frutos enquanto ainda estão na planta (Guilda B) e algumas apenas em sementes livres no substrato (Guilda C). Uma espécie de planta pode ser infestada nas três condições, outras somente por duas e outras por apenas uma condição. Muitos artigos científicos têm sido publicados antes e após o conceito das guildas e, ao que parece, o comportamento primitivo dos bruquídeos provavelmente foi o de ovipositar sobre os frutos, com as larvas penetrando através de sua parede para se alimentarem das sementes (Guilda A). Como a evolução dos frutos foi direcionada para a dispersão das sementes e, possivelmente, fuga da predação por bruquídeos, estes desenvolveram outras maneiras para se alimentar de sementes (Guilda B e C). Os dados indicam que cerca de 78% dos bruquídeos ovipositam em frutos e 22% se incluem nas Guildas B e C. Nesse trabalho são revistos e discutidos os artigos científicos sobre guildas de oviposição e a evolução de bruquídeos, bem como acrescentados novos dados.

Aspectos biológicos de Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera, Bruchidae) em Phaseolus vulgaris L., cv. Carioca (Fabaceae), sob condições de laboratório / Biological aspects of Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera, Bruchidae) on Phaseolus vulgaris L., cv. Carioca (Fabaceae), under laboratory conditions

Zabrotes subfasciatus is a serious pest of common beans, P. vulgaris L.. In Brazil there are several studies dealing with resistance of bean genotypes to this insect, while other studies have emphasized the utilization of oils and powders from plants to repel their attack. In this paper, fecundity, fertility, pattern of oviposition, life cycle and longevity were evaluated for a Brazilian stock from the Goiás State on P. vulgaris cv. Carioca, at 30°C and 70 percent R.H. The mean fecundity was 38 eggs per female and 73 percent of viability. Egg laying showed an aggregated pattern. Males and females lived an average of 13 and 9 days, respectively. The total life cycle lasted for about 28 days.

Performance of Uscana mukerjii (Mani) for the control of Callosobruchus maculatus (Fab.) and allied bruchid species.

Investigations have been carried out on the relative preference of U. mukerjii to four common species viz., C. maculatus, C. analis, C. chinensis and Zabrotes subfasciatus of store bruchids. Results show correspondence between the acceptance/contact ratio and the total number of eggs laid by the parasitoid for Callosobruchus species. U. mukerjii shows maximum preference on C. maculatus followed by C. analis, C. chinensis and Z. subfasciatus in the decreasing order. Z. subfasciatus has been the least preferred host having 2-3% parasitization in choice situation. Percentage emergence of the adults and females differ insignificantly from each other in Callosobruchus species. In no choice experiments, U. mukerjii laid sufficient number of eggs in the eggs of C. chinensis and Z. subfasciatus but less number of eggs in a choice situation due to competition with the preferred host. As is evident, U. mukerjii gives the first preference to primary host C. maculatus. Moreover, the congeneric species i.e C. analis and C. chinensis are given more preference than Z. subfasciatus.

Effect of solvent residues of Vitex negundo Linn. and Cassia fistula Linn. on pulse beetle, Callosobruchus maculatus Fab. and its larval parasitoid, Dinarmus vagabundus (Timberlake).

Effect of solvent residues of Vitex negundo L. and Cassia fistula L. leaves (0.5 and 1%) was studied on egg laying and adult emergence of Callosobruchus maculatus Fab. and on percentage of larval parasitism by Dinarmus vagabundus (Timberlake). Cowpea seeds treated with methanol and aqueous extract of Vitex, at these concentrations (0.5 and 1%), significantly reduced the number of eggs and emergence of F1 adults of C. maculatus. Both Vitex and Cassia extracts did not affect the percentage of parasitism by D. vagabundus on C. maculatus grubs.

Anti-tick effect observed in mature plants of tropical legumes stylosanthes humilis and stylosanthes hamata

El efecto anti-garrapata de plantas maduras de las leguminosas tropicales stylosanthes humilis y stylosanthes hamata, fue evaluado en parcelas experimentalmente infestada con larvas de garrapata boophilus microplus, utilizando al pasto cenchurus ciliaris como tratamiento testigo. El efecto fue evaluado contando el número total de larvas vivas recuperadas de las parcelas experimentales por la técnica de bandera de doble recorrido durante un periodo de cuatro semana. El efecto anti-garrapata observado en ambas especies de stylosanthes no mostró diferencias entre ellas (p<0,05), el porcentaje de sobrevivencia de larvas fue del 5,1 por ciento para S. hamata. En la primera especie el efecto anti-garrapata fue menor que el reportado en plantas jóvenes, pero en S. hamata este efecto fue similar en plantas maduras y jóvenes. Es necesario realizar más estudios para complementar el conocimiento que tiene acerca de estas plantas y establecer su uso en condiciones de campo

Plantas hospederas de Bemisa tabaci (Homoptera: Aleyrodidae) en Cuba / Host plants of Bemisia tabaci (Homoptera: Aleyrodidae)

The sweetpotato whitefly, Bemisia tabaci, is an important pest of tomatoes and beans, among other crops, which transmits viral diseases. Since the second quarter of 1989 a significant population increase of this pest has been noted in several cultivated plants. From 1989 to 1992, a survey was done throughout the country, chiefly in vegetable and bean-producing areas. They occur in 119 species (42 families), a great increase over the previous record of four species. Worldwide, this report represents 50 species and six families which are new records

Trichoderma spp. en el control biológico de colletotrichum lindemuthianum (sacc.etmagn.) Scribb, agente de la antracnosis del frijol (phaseolus vulgaris l.) / Trichoderma spp. in the biological control of colletotrichum lindemuthianum (sacc. etmagn.) scribb, agent of the bean anthracnose (phaseolus vulgaris l.)

Para seleccionar especies de trichoderma con mejor desempeño antagónico sobre razas de colletotrichum lindemutianum in vitro, fueron utilizadas las técnicas de cultivos pareados y la del papel celofán. Se utilizaron las especies de trichoderma harzianum (t25), t. koniingii (t15), t. pseudokonigii (t26), t.aureoviride (t10) y t. viride (tr2), además de las razas de colletotrichum lindemuthianum Ba2 y Ba10. En el test de apareamiento, se verificó que las 5 especies de trichoderma, causaron alteraciones morfológicas en las hifas de las 2 razas del fitopatógeno, evidenciando un posible antagonismo. El test del papel celofán, con la raza Ba2, mostró que t.harzianum y t. viridem, causaron una disminución apreciable en el diametro de las colonias, en relación a las otras especies. Con la raza Ba10, se verificó que t. koningii, t. harzianum, t. aureoviride y t. viride, causaron una disminución apreciable en los diámetros de las colonias en orden creciente, siendo t. viride la más eficiente. T. pseudokoningii, no causó reducciones apreciables sobre la raza ba10