Mariana Oliveira Breda

Bioactivity of Piper hispidinervum (Piperales: Piperaceae) and Syzygium aromaticum (Myrtales: Myrtaceae) Oils, with or without Formulated Bta on the Biology and Immunology of Spodoptera frugiperda (Lepidoptera: Noctuidae)

ABSTRACT The combination of essential oils and Bacillus thuringiensis Berliner may represent an interesting control strategy. Thus, the study tested the following hypothesis: the combination of long pepper oil (Piper hispidinervum L.) and clove (Syzygium aromaticum L.) oils in two concentrations with Xentari WG (Bta) yields a more effective control of Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) affecting biological and reproductive parameters and leading to changes in the levels of phenoloxidase and nitric oxide in the hemolymph of the pest. The results demonstrate that only long pepper oil, at the highest concentration with Xentari WG (Bta), promotes reduced larval survival. However, both oils with or without the insecticide interfere in the biology and humoral immunity of S. frugiperda. All treatments caused a decrease in the amount of eggs, except for the clove oil at both concentrations without Bta. Therefore, the use of these oils is a promising alternative for the integrated management of S. frugiperda; however, its association with Bta demonstrated no significant increase in their efficiency.

Lethal and sublethal responses of Sitophilus zeamais populations to essential oils

The present study aimed to assess the lethal and sublethal responses of five populations of S. zeamais to the essential oils of Ocimum basilicum and Piper hispidinervum, through toxicity, locomotor behavior (flight and walking activities) and physiological (respiration rate and body mass) evaluations. The populations of S. zeamais were obtained from Machado—MG, Paracatu—MG, Piracicaba—SP, Recife—PE and Tunápolis—SC. To estimate the LC50 of each oil for each population, fumigation tests were performed. The population from Recife exhibited the lowest instantaneous rate of increase (ri) as well the lowest consumption of grain mass. However, Piracicaba was considered the susceptibility pattern, presenting the lowest LC50 for both essential oils, no statistical difference was observed among populations or treatments in the flight activity bioassays. The essential oils effect on walking activity and respiration rates varied among populations. The population from Recife presented the highest walked distance and walk speed, with the lowest resting time and number of stops, as well as the lowest respiration rate and body mass. The present study highlights the importance of the study on population responses, as the five populations of S. zeamais exhibited different patterns of toxic and behavioral effects when subjected to the essential oils of P. hispidinervum and O. basilicum.

Efeito repelente de azadiractina e óleos essenciais sobre Aphis gossypii Glover (Hemiptera: Aphididae) em algodoeiro

A repelencia de inseticidas botânicos tem se destacado como uma tatica promissora no controle alternativo de pragas agricolas e urbanas, podendo ser um dos componentes do manejo integrado de pragas. Objetivou-se com este trabalho identificar a repelencia de inseticidas botânicos sobre femeas apteras de Aphis gossypii Glover. Testes com chance de escolha foram realizados com discos de folha de algodoeiro, imersos nas caldas dos inseticidas e testemunha (agua destilada com DMSO a 2%). Utilizou-se azadirachtina (0,075%) e os oleos essenciais de Piper hispidinervum CDC, P. aduncum L., Cymbopogon winterianus (L.), C. citratus (D.C.) Stapf, Foeniculum vulgare Mill, Syzygium aromaticum (L.) Merrill e Perry, Cinnamomum zeylanicum Blume, Schinus terebinthifolius Raddi e Chenopodium ambrosioides L. na concentracao de 0,05%. C. citratus, C. winterianus, P. aduncum, S. terebinthifolius, azadirachtina e C. zeylanicum apresentaram os maiores percentuais de repelencia, 100; 84; 66,67; 64; 60,87 e 48% respectivamente e reduziram a producao de ninfas em 100; 92; 42,9; 87,5; 80,65 e 89,74%, apresentando resultados significativos pelo teste do χ2 ao nivel de 10% de probabilidade. Nos testes com F. vulgare (χ2 = 3,66, P = 0,05) as femeas de A. gossypii foram atraidas significativamente para os discos tratados e ocorreu um aumento na producao de ninfas nos resultados obtidos para F. vulgare (χ2 = 5,87, P = 0,02) e C. ambrosioides (χ2 = 14,31, P = 0,001).

Inseticidas botânicos aplicados sobre Aphis gossypii e seu predador Cycloneda sanguinea em algodão-colorido

The objective of this work was to evaluate the effects of botanical insecticides on Aphis gossypii and its predator Cycloneda sanguinea, in naturally colored cotton. The botanical insecticides based on azadirachtin, aqueous extract of nim seeds, and castor oil were tested at the concentrations from 0 to 2%, 0 to 2.5%, and 0 to 3%, respectively. The bioassays were performed in laboratory conditions, in a completely randomized design. Aphid mortality ranged from: 64 to 100% for azadirachtin; 12 to 92% for nim aqueous extract; and 8 to 68% for castor oil. The instantaneous rate of increase reached negative values starting from concentrations of: 1.25%, for azadirachtin; 2.25%, for nim aqueous extract; and 3.0%, for castor oil emulsion. All insecticides were toxic to the first instar larvae of the predator, with mortality values from 96.7 to 100%, for azadirachtin and nim aqueous extract, and from 50 to 100% for castor oil emulsion. For the 4th instar larvae, mortalities ranged from 87.5 to 100% for azadirachtin; from 73.3 to 100% for nim aqueous extract; and from 43.3 to 100% for castor oil emulsion. The tested insecticides are promising for A. gossypii management, although they are not selective toward C. sanguinea.

Lufenuron impact upon Anthonomus grandis Boheman (Coleoptera: Curculionidae) midgut and its reflection in gametogenesis

The insecticide Match® (lufenuron), one of the main insect growth regulators used in pest control, has been presented as a viable alternative against the boll weevil, Anthonomus grandis (Coleoptera: Curculionidae), by inhibiting chitin synthesis. Thus, this study aimed to examine whether Match® interferes in the synthesis of the peritrophic matrix, leading to changes in the midgut epithelium, resulting in nutritional deficiency and reflecting, thereby, in the gametogenesis process of A. grandis. Floral cotton buds were immersed in the insecticide solution (800μL of Match®+200mL of distilled water) and offered to the adult insects. The midguts of the insects were evaluated after 24 and 120h after feeding. The gonads were evaluated after 120h. The results showed that Match®, in both evaluation periods, induced histopathological alterations such as disorganization, vacuolization and desquamation of the midgut epithelium; histochemical modifications in the distribution patterns of carbohydrates, although without quantitative changes; and a strong decrease in protein levels. No apoptosis were observed, however, there was an increase in the number of regenerative cell nests. In the testicles, a reduction in the amount of spermatozoids and reduced carbohydrate levels were observed, but no difference in protein levels. The ovarioles presented structural disorganization of follicular cells, yolk reduction and decrease in protein levels, however, no change in carbohydrates levels was noted. Therefore, it is concluded that Match® performs histopathologic and histochemical alterations in the midgut epithelium and the gonads of A. grandis adults, reflecting in the gametogenesis process, presenting itself as a promising tool in the management of this pest on cotton crops.

Sublethal Effects of Essential Oils From Eucalyptus staigeriana (Myrtales: Myrtaceae), Ocimum gratissimum (Lamiales: Laminaceae), and Foeniculum vulgare (Apiales: Apiaceae) on the Biology of Spodoptera frugiperda (Lepidoptera: Noctuidae)

Abstract Spodoptera frugiperda (Smith 1797) (Lepidoptera: Noctuidae) is a major pest of maize, Zea mays L. Its control is often achieved through repeated applications per season of insecticides, which may lead to adverse effects on the ecosystem. Thus, the study of alternative methods with less environmental impact has expanded to include the use of essential oils. These oils are products of the secondary metabolism in plants, and their insecticidal activity has been widely demonstrated in populations of many pest insects. This study evaluated the insecticidal activities of essential oils from Eucalyptus staigeriana, Ocimum gratissimum, and Foeniculum vulgare on Spodoptera frugiperda. Gas chromatography–mass spectrometry profiles and contact toxicity of these oils as well as their sublethal effects on larvae and reproductive parameters in adults were evaluated. All three oils had sublethal effects on S. frugiperda; however, the oil of O. gratissimum showed the best results at all doses tested. These essential oils may have promise for control of S. frugiperda.

The Sublethal Effects of Insecticides in Insects

Studies related to the effect of insecticides on insect pests and nontarget organisms, such as natural enemies, are traditionally accessed by the estimative of lethal effects, through mortality data. Due to the limitations of the traditional methods, recent studies in the past three decades are assessing the sublethal effects of insecticides upon several important biological traits of insect pests and natural enemies. Besides mortality, the sublethal dose/concentrations of an insecticide can affect insect biology, physiology, behavior and demographic parameters. In this chapter, many sublethal effects of insecticides were addressed for several chemical groups, such as botanical insecticides, carbamate, diamide, insect growth regulators, neonicotinoid, organochlorides, organophosphates, pyrethroid and others. An accurate assessment of these effects is crucial to acquire knowledge on the overall insecticide efficacy in the management of pest insect populations, as well as on their selectivity toward nontarget organisms.

Histological and Histochemical Changes by Clove Essential Oil Upon the Gonads of Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae)

Spodoptera frugiperda es un insecto polifago que causa perdidas economicas a varias cosechas en Brasil y es el mayor obstaculo para la produccion de maiz. Este estudio esta centrado en el control alternativo, con productos botanicos que se estan expandiendo y ofrecen una amplia variedad de moleculas que interfieren con diferentes parametros biologicos de plagas de insectos. Por tanto, se puso a prueba la hipotesis de que el aceite esencial de clavo de olor afecta la espermatogenesis. La histoquimica de los ovarioles y la fertilidad de S. frugiperda. Los resultados mostraron que el aceite esencial de clavo de olor afecta la gametogenesis de los ovarioles en S. frugiperda, lo que incide negativamente en su reproduccion, demostrando ser una herramienta prometedora para el control de esta plaga.

Injuries caused by frankliniella spp. (thysanoptera: thripidae) on seedless grapes

Thrips of the genus Frankliniella cause significant reduction on grape production. Little is known about its decision making approach in integrated pest management and information on thrips injuries to the vine is scarce, hindering the control of this pest. This study aimed to determine the species of thrips and injuries that cause damage to berries in seedless grapes clusters. The trial was conducted in an area cultivated with Vitis vinifera L., variety Thompson Seedless, using a randomized block design with five treatments and four replications. The treatments consisted of artificial infestation (zero, two, four and eight thrips per inflorescence), and treatment determined by the monitoring system of the grower. Each replication consisted of three plants with 10 inflorescences, which were artificially infested with thrips and covered with nonwoven fabric bags. During the cluster thinning, pre-harvest cleaning and harvest, the numbers of injuried berries and the berries with injuries were evaluated. The thrips species identified were: Frankliniella schultzei (Trybom), Frankliniella brevicaulis Hood, Frankliniella gemina Bagnall, Frankliniella gardeniae Moulton, and Frankliniella sp. A positive and significant correlation was observed between the number of injuries per fruit and the level of thrips infestation, obtained by the equation y = 2.55 + 48.54x (F= 59.98; P= 0.0001; r2= 0.51). The results suggest that the presence of a whitish halo around a small scar on fruit is associated with the presence of adult Frankliniella spp.

Resistance of Lima Bean (Phaseolus lunatus L.) to the Red Spider Mite Tetranychus neocaledonicus (Acari: Tetranychidae)

The red spider mite, Tetranychus neocaledonicus (Acari: Tetranychidae) can be an important pest on lima bean (Phaseolus lunatus L.). Thus, the objective of this work was to assess the antibiosis and antixenosis effects of lima bean genotypes on T. neocaledonicus, through the evaluation of performance parameters as well as the host preference for food and oviposition. Nine lima bean genotypes from the Active Bank of Germplasm of the Federal University of Piauí – BGP / UFPI were screened. To assess antibiosis parameters, eggs of T. neocaledonicus were individually placed on leaf disks of each genotype. The period and survival of the different stages of development (larvae, protonymph, deutonymph and adult), pre-oviposition, oviposition and post-oviposition period, longevity and fecundity of females were evaluated, and fertility life table parameters were calculated. In choice tests, adult females of T. neocaledonicus were used. The numbers of mites and eggs were counted for each genotype. The protonymph, egg-adult, longevity and oviposition period, fertility life table parameters, as well as the food and oviposition preference were affected by lima bean genotypes. We found that some genotypes reduced adult female longevity, increased the larval and egg-adult period, decreased oviposition period, negatively affected the fertility life table parameters, reducing the net reproductive rate (Ro), the intrinsic rate of increase (rm) and the finite rate of increase (λ), while increasing the population doubling time (DT), exhibiting a reliable antibiosis effect upon T. neocaledonicus. Nevertheless, these same genotypes were the most preferred for food and oviposition. By contrast, some other genotypes reduced the adult female longevity and oviposition period, elongated the larval period and affected fertility life table parameters, demonstrating an antibiosis effect upon T. neocaledonicus. Moreover, these other genotypes were among the less preferred for food and oviposition, exhibiting an additional antixenosis effect. Thus, our results demonstrate that the genotypes of lima bean may present distinct levels of resistance to T. neocaledonicus, and this resistance may be an important tool for Integrated Pest Management. This is one of the first studies aiming to describe mite resistance sources in lima bean.