Dynamique des parasitoïdes larvaires de &lt;i&gt;Helicoverpa armigera&lt;/i&gt; (Lepidoptera : Noctuidae) dans la zone des Niayes au Sénégail

Diatte, Mamadou; Brévault, Thierry; Sall-Sy, Dienaba; Diarra, Karamoko

doi:10.4314/ijbcs.v12i1.31

Cited by 7 publications

(5 citation statements)

References 18 publications

(24 reference statements)

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“…In Senegal, arthropod pest complex can cause damage in field-grown (Labou et al, 2016a;Diatte et al, 2018b). However, many ecosystems have a great diversity of entomological species that plays an important role in natural regulation Tendeng et al, 2017;Diatte et al, 2018a). Very active during the night, adults of the FAW can move up to a distance exceeding 100 km (FAO, 2017).…”

Section: Discussionmentioning

confidence: 99%

The fall armyworm <i>Spodoptera frugiperda</i> (J.E. Smith), a new pest of maize in Africa: biology and first native natural enemies detected

Tendeng¹,

Labou²,

Diatte³

et al. 2019

Int. J. Bio. Chem. Sci

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The fall armyworm (FAW), Spodoptera frugiperda is a real threat to food security. It is able to totally destroy the cereal crops in a country. It can cause famine in Sub-Saharan Africa where cereals are subsistence crops. Reported in Africa in 2016, the FAW succeded to colonize 47 countries in one year. Its migration capacities wich are of around 100 km per night can allow it have fully infest a country like Senegal (ca 200 000 km²) in less than a week. The FAW is very difficult to fight because resistant to several insecticides. Invasive species often invade a new environment without their natural enemies, which promotes their multiplication and damage to crops. To estimate the generation number per year and evaluate the impact of biological control of indigenous natural enemies on the FAW, larvae were collected in maize fields and monitored in the laboratory. The results show that the development cycle of S. frugiperda takes 25 days on average, that is to say fifteen (15) generations per year. The study confirms the presence of three species of native natural enemies, a nematode Hexamermis sp. and two Hymenopterans Chelonus sp. and Campoletis sp. detected for the first time in West Africa on FAW larvae. The overall parasitism rate is 25.8%. These native natural enemies are a very promising means of control against FAW populations. The introduction of agricultural techniques to promote the maintenance and the proliferation of the FAW auxiliaries is an alternative to the use of pesticides.

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Section: Discussionmentioning

confidence: 99%

The fall armyworm <i>Spodoptera frugiperda</i> (J.E. Smith), a new pest of maize in Africa: biology and first native natural enemies detected

Tendeng¹,

Labou²,

Diatte³

et al. 2019

Int. J. Bio. Chem. Sci

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“…Le Push-pull est une association culturale qui augmente la biodiversité végétale (Ogot et al, 2017). La biodiversité végétale joue un rôle déterminant dans l'équilibre des populations d'insectes (Labou et al, 2016;Diatte et al, 2018). Elle augmente l'impact des ennemis naturels dans la régulation des populations de ravageurs.…”

Section: Introductionunclassified

Effet de la technologie Push-pull sur le contrôle naturel de la chenille légionnaire du maïs au Sénégal

Baldé¹,

Labou²,

Tendeng³

et al. 2022

Int. J. Bio. Chem. Sci

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Chenille légionnaire est un ravageur du maïs récemment signalé en Afrique. Sa grande capacité de migration lui permet de coloniser des milieux variés. La lutte chimique, souvent utilisée contre ce ravageur est inefficace et pollue l’environnement. L’objectif de cette étude était d’évaluer les effets de la technologie Push-pull sur le contrôle naturel de la chenille légionnaire en culture de maïs. L’essai a été effectué dans le bassin arachidier du Sénégal sur deux parcelles de 900 m2. La parcelle Push-pull associe le maïs au Desmodium intertum (Mill) en intercalaire et le Brachiaria cv mulato sur le contour. Des échantillonnages hebdomadaires des ravageurs et des prédateurs sur cinquante pieds de maïs ont été effectués au hasard dans chaque parcelle. Les chenilles collectées ont été suivies au laboratoire jusqu’à l’émergence des parasitoïdes ou des adultes de S. frugiperda. Les paramètres de croissance végétative ont été également notés durant tout le cycle de la culture. La parcelle Push-pull présentait la plus grande biodiversité entomologique. Le ravageur S. frugiperda, malgré sa forte pullulation, a été totalement contrôlé par les ennemis naturels dans la parcelle Push-pull. Les résultats ont montré que la technologie Push-pull augmente le rendement du maïs. The armyworm is a maize pest recently reported in Africa. Its great migratory capacity allows it to colonise various environments. The chemical control often used against this pest is ineffective and pollutes the environment. The objective of this study was to evaluate the effects of Push-pull technology on the natural control of armyworm in maize. The trial was carried out in the groundnut basin of Senegal on two 900 m2 plots. The Push-pull plot combined maize with Desmodium intertum (Mill) as an intercrop and Brachiaria cv mulato on the contour. Weekly sampling of pests and predators on fifty maize plants is carried out at random in each plot. The collected caterpillars were followed in the laboratory until the emergence of parasitoids or adults of S. frugiperda. Vegetative growth parameters were also recorded throughout the crop cycle. The Push-pull plot showed the highest entomological biodiversity. The pest S. frugiperda, despite its high outbreak, was completely controlled by natural enemies in the Push-pull plots. The results showed that the Push-pull technology increases maize yield.

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“…2 H. armigera also infests cotton, pigeonpea, maize, tomato, etc., and has now spread to formerly nonhost plants. 3,4 Control of Helicoverpa with chemicals has led to pest resistance and severe environmental damage. 5 H. armigera develops resistance quickly due to efficient inactivation mechanisms and displays resistance toward Bt-containing transgenic plants.…”

Section: ■ Introductionmentioning

confidence: 99%

“…H. armigera also infests cotton, pigeonpea, maize, tomato, etc., and has now spread to formerly nonhost plants. , Control of Helicoverpa with chemicals has led to pest resistance and severe environmental damage H.…”

Section: Introductionmentioning

confidence: 99%

New Frontiers in Pest Control: Chitosan Nanoparticles-Shielded dsRNA as an Effective Topical RNAi Spray for Gram Podborer Biocontrol

Kolge

Kadam

Galande

et al. 2021

ACS Appl. Bio Mater.

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Chickpea pod borer, Helicoverpa armigera, displays resistance to chemical insecticides and transgenics. The potential nontransformative RNAi approach of specific gene silencing by mRNA breakdown through exogenous double-stranded (dsRNA) delivery to Helicoverpa faces problems of degradation by nucleases and insect gut pH. We demonstrate that chitosan nanoparticles (CNPs) effectively mediate specific dsRNA delivery against Helicoverpa armigera juvenile hormone methyltransferase (JHAMT) and acetylcholine esterase (ACHE) target genes. Ionotropically synthesized cationic CNPs (100 nm size, +32 mV charge) loaded dsRNA efficiently and protected it effectively from degradation by nucleases and insect gut pH. Tagging CNPs with Calcofluor fluorescence illustrated its efficient uptake in columnar insect gut cells. The potential of CNPs-mediated dsRNA delivery was elucidated with effective silencing of green fluorescent protein transformed Sf9 cells. Furthermore, CNPs–dsRNA complexes were stable for 5 d on leaf surfaces, and their ingestion with leaf effectively silenced H. armigera JHAMT and ACHE genes to suppress related enzyme activities and caused 100% insect mortality. Further, in planta bioassay with CNPs–dsRNA spray confirmed the RNAi induced insect mortality. Moreover, CNPs–dsRNA fed nontarget insects Spodoptera litura and Drosophila melanogaster were unaffected, and no toxicity was observed for CNPs in cell line studies. Remarkably, only two low dose (0.028 g/ha) topical CNPs-ache-dsRNA sprays on chickpea displayed reduced pod damage with high yields on par with chemical control in the field, which was followed by CNPs-jhamt-dsRNA nanoformulation. These studies can pave the way for the development of topical application of CNPs–dsRNA spray as a safe, specific, innovative insecticide for sustainable crop protection.

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Dynamique des parasitoïdes larvaires de <i>Helicoverpa armigera</i> (Lepidoptera : Noctuidae) dans la zone des Niayes au Sénégail

Cited by 7 publications

References 18 publications

The fall armyworm <i>Spodoptera frugiperda</i> (J.E. Smith), a new pest of maize in Africa: biology and first native natural enemies detected

The fall armyworm <i>Spodoptera frugiperda</i> (J.E. Smith), a new pest of maize in Africa: biology and first native natural enemies detected

Effet de la technologie Push-pull sur le contrôle naturel de la chenille légionnaire du maïs au Sénégal

New Frontiers in Pest Control: Chitosan Nanoparticles-Shielded dsRNA as an Effective Topical RNAi Spray for Gram Podborer Biocontrol

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