Histopatologia de lagartas de Spodoptera frugiperda (Lep., Noctuidae) infectadas por Bacillus thuringiensis aizawai e com ovos de Campoletis flavicincta (Hym., Ichneumonidae)

Dequech, Sônia Thereza Bastos; Fiúza, Lidia Mariana; Silva, Rogerio Fernando Pires da; Zumba, Roberta Cristina

doi:10.1590/s0103-84782007000100045

Cited by 10 publications

(6 citation statements)

References 8 publications

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“…Os resultados obtidos em relação ao Bta comprovam que esse patógeno é eficiente no controle de lagartas de S. frugiperda, concordando com Dequech et al (2007). O isolado Bta HD 68 induziu mortalidade de 100% em lagartas de segundo instar de S. frugiperda (Polanczyk et al, 2000).…”

Section: Resultsunclassified

Bioatividade de formulações de NIM (Azadirachta indica A. Juss, 1797) e de Bacillus thuringiensis subsp. aizawai em lagartas de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

et al. 2010

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A utilização de inseticidas botânicos e bioinseticidas constitui uma alternativa promissora para o manejo de Spodoptera frugiperda (J.E. Smith, 1797), na cultura do milho. No presente trabalho, objetivou-se avaliar o efeito de formulações comerciais de nim e de Bacillus thuringiensis subsp. aizawai - Bta sobre esta praga em laboratório. Lagartas de S. frugiperda com 10 dias de idade foram alimentadas com folhas de milho submersas na calda dos inseticidas Neemseto®, Natuneem® e Xentari® (B. thuringiensis subsp. aizawai Bta) nas concentrações 2,5; 5,0; 7,5; 10 mL ou g/L e testemunha (água). Os efeitos dos inseticidas dependeram da concentração utilizada, pois provocaram mortalidade crescente das lagartas, alongaram o período larval e reduziram o peso larval. Em alguns casos, também, reduziram o peso das pupas, a viabilidade pupal e a longevidade de adultos. Lagartas com 0-24 h de idade foram mais susceptíveis às concentrações de Neemseto® e Xentari® a 5 e 10 mL ou g/L, em relação às com 10 dias de idade. Com o aumento da concentração, os efeitos sobre o peso das pupas e viabilidade pupal foram, também, maiores em lagartas com 0-24 h de idade.

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Section: Resultsunclassified

Bioatividade de formulações de NIM (Azadirachta indica A. Juss, 1797) e de Bacillus thuringiensis subsp. aizawai em lagartas de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

et al. 2010

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“…Dequech et al. (2007) consider morphological studies an important tool to understand the mode of action of natural products. From this point of view, the findings found at the level of the intestinal ultrastructure would indicate that one of the modes of action of the grindelanes would be stress.…”

Section: Discussionmentioning

confidence: 99%

Activity of grindelanes against important maize pest Spodoptera frugiperda and their selectivity of action on non‐target environmental bacteria

Mesurado

Chalup

Ortiz

et al. 2021

Entomologia Exp Applicata

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In the search for new plant‐derived products with antifeedant and insecticidal potential against economically important insects, 11 grindelanes (two as natural acids and nine as methylated derivatives) purified from the foliar tissue of Grindelia chiloensis (Cornel.) Cabrera (Asteraceae) were evaluated against the fall armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae). Larvae of this moth are considered to be the main pest of maize that causes severe losses on local agricultural production. Remarkable alterations in feeding behavior, larval weight, larval and pupal stage lengths, and adult fertility, as well as malformations and mortality in specimens during their life cycle were noticed in the feeding preference tests and no‐choice diet assays. Antifeedant indexes (AI%) calculated in food preference bioassays reached up to 79% for the lipophilic grindelane 3b, the most potent antifeedant agent. Grindelane 7b showed a better insecticidal activity (median lethal dose, LD50 = 26.49 µg g−1) and 8b was potentially neurotoxic due to acetylcholinesterase inhibition. Ultrastructure of the middle portion of the digestive tract of larvae fed with small amounts of natural grindelane 9a supplemented to the diet revealed cell damage, and thickening of the peritrophic membrane and a striking number of mitochondria, as evident signs of defense against toxic substances ingested by the larvae. Besides, this study demonstrated that these effective insecticides did not have inhibitory effects on beneficial plant and soil bacteria which would allow ecological pest management.

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“…The verification of the location and form of action on the insect has great importance for the development of an efficient and safe insecticide (Barreto et al 2006). Morphological studies are an important tool when trying to understand the form of action of natural products may take (Dequech et al 2007). The deleterious physiological effects can be measured by growth reduction and presence of abnormalities (Mordue and Nisbet 2000).…”

Section: Histomorphological Alterations Of the Midgut By Spinosadmentioning

confidence: 99%

Sublethal Effects of Spinosad (Tracer®) on the Cotton Leafworm (Lepidoptera: Noctuidae)

Abouelghar¹,

Sakr²,

Ammar³

et al. 2013

Journal of Plant Protection Research

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Abstract:The effects of sublethal concentrations of spinosad (Tracer ® ) on development, fecundity, and food utilization, in the cotton leafworm, Spodoptera littoralis (Boisd.) were investigated. The fourth-instar larvae were fed on castor bean leaves treated with LC 25 (13.9 ppm) or LC 50 (57.8 ppm) of spinosad. Pupation and pupal weight were significantly reduced in both LC 25 and LC 50 treatments, compared with those of the controls. The fecundity rates of females in either LC 25 or LC 50 treatment were also reduced, compared with the controls. The residual activity of spinosad, applied on cotton at labeled field-and subfield-rates (200 and 70 g active substance (a.s.)/ 200 l water, respectively), was examined against the fifth-instar larvae of S. littoralis. Feeding deterrent effects were significantly demonstrated in larvae that fed on leaves collected from field plots with residual deposits of spinosad at 3 and 7 days old after application (DAA). The residual activity of spinosad on feeding and other metabolic parameters was decreased after 21 DAA indicating that the chemical started to degrade under field conditions. A histological study on midgut from larvae that previously fed on leaves treated with a concentration corresponding to the labeled-field rate of spinosad showed some alterations occurred after 48 and 96 h of treatment, compared to the normal midgut from the controls. The histological alterations included degeneration in the epithelial lining of the midgut and in the peritrophic matrix. Such histopathological effects are presumed to be responsible for the reduction in growth and food utilization caused by spinosad. It is, therefore, concluded that spinosad has sublethal effects on S. littoralis that may affect population dynamics in the field via reductions in survival and reproduction.

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Histopatologia de lagartas de Spodoptera frugiperda (Lep., Noctuidae) infectadas por Bacillus thuringiensis aizawai e com ovos de Campoletis flavicincta (Hym., Ichneumonidae)

Cited by 10 publications

References 8 publications

Bioatividade de formulações de NIM (Azadirachta indica A. Juss, 1797) e de Bacillus thuringiensis subsp. aizawai em lagartas de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

Bioatividade de formulações de NIM (Azadirachta indica A. Juss, 1797) e de Bacillus thuringiensis subsp. aizawai em lagartas de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

Activity of grindelanes against important maize pest Spodoptera frugiperda and their selectivity of action on non‐target environmental bacteria

Sublethal Effects of Spinosad (Tracer®) on the Cotton Leafworm (Lepidoptera: Noctuidae)

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