Potential insecticidal activity of Sarocladium strictum, an endophyte of Cynanchum acutum, against Spodoptera littoralis, a polyphagous insect pest

2020 ◽  
Vol 24 ◽  
pp. 101524 ◽  
Author(s):  
Ashraf S.A. El-Sayed ◽  
Ahmed H. Moustafa ◽  
Hussein A. Hussein ◽  
Aly A. El-Sheikh ◽  
Samah N. El-Shafey ◽  
...  
Author(s):  
Parviz Shishehbor ◽  
Seyed Ali Hemmati

Abstract Spodoptera littoralis (Boisd) is globally recognized as a destructive polyphagous insect pest of various crops in the world. It is commonly managed by chemical pesticides, which can cause deleterious effects such as environmental pollution, toxicity to non-target organisms and the emergence of secondary pests. Hence, investigations into alternative pest control strategies such as the use of resistant host plant cultivar against S. littoralis is important. This study aimed to explore the nutritional performance of S. littoralis larvae in dependence on total anthocyanin, flavonoid, and phenol levels across 11 bean cultivars (Phaseolus and Vigna spp.) under laboratory conditions. The results revealed that the Mashhad cultivar accumulated the highest amount of total phenols (13.59 mg ml−1), whereas Yaghout and Arabi cultivars posed the lowest total phenols contents (1.80 and 1.90 mg ml−1, respectively). Across larval instars (third to sixth), the highest consumption index and relative consumption rate were recorded on the Mashhad cultivar. The lowest values of efficiency of conversion of ingested food and the efficiency of conversion of digested food of total larval instars were detected in the larvae which were reared on the Mashhad cultivar. Likewise, the lowest value of the index of plant quality (IPQ) was obtained in the Mashhad cultivar; however, IPQ was figured out at the highest level in the Arabi cultivar. Our findings show that the differential accumulation of secondary metabolites would change the nutritional quality of plants for S. littoralis. Based on the findings, the Mashhad cultivar may serve as a candidate for either integrated pest management or breeding programs aiming at controlling this pest.


2017 ◽  
Vol 108 (5) ◽  
pp. 658-666 ◽  
Author(s):  
X. Lin ◽  
Y. Jiang ◽  
L. Zhang ◽  
Y. Cai

AbstractSpodoptera litura is a widespread polyphagous insect pest that can develop resistance and cross-resistance to insecticides, making it difficult to control. Insecticide exposure has previously been linked with induction of specific olfactory-related proteins, including some chemosensory proteins (CSPs) and odorant-binding proteins (OPBs), which may disrupt detection of environmental factors and reduce fitness. However, functional evidence supporting insecticide and OBPs/CSPs mediation remains unknown. Here we fed male S. litura moths with sucrose water containing one of three insecticides, chlorpyrifos, emamectin benzoate or fipronil, and used real-time quantitative polymerase chain reaction and RNAi to investigate OBPs and CSPs expression and their correlations with survival. Chlorpyrifos and emamectin benzoate increased expression of 78% of OBPs, plus 63 and 56% of CSP genes, respectively, indicating a major impact on these gene families. RNAi knockdown of SlituCSP18, followed by feeding with chlorpyrifos or fipronil, decreased survival rates of male moths significantly compared with controls. Survival rate also decreased significantly with the downregulation of SlituOBP9 followed by feeding with chlorpyrifos. Thus, although these three insecticides had different effects on OBP and CSP gene expression, we hypothesize that SlituOBPs and SlituCSPs might mediate their effects by increasing their expression levels to improve survival. Moreover, the differential response of S. litura male moths to the three insecticides indicated the potential specificity of chlorpyrifos affect SlituCSP18 and SlituOBP9 expression.


2020 ◽  
Vol 23 (2) ◽  
pp. 1-6
Author(s):  
Helben Ismat Mohammaed ◽  
Mohammed Saeed Mirza ◽  
Feyroz Ramadan Hassan

Beauveria bassiana is an important entomopathogenic fungus that used as a biocontrol agent of insect pests. Maintaining and preserving B. bassiana cultures is essential for the effective evaluation of its potential as microbial agent against insect pest, for biodiversity studies and also for exchange of fungal material between laboratories. In the present work we evaluated the suitability of four preservation materials based on gelatin and rice to maintain the viability of B. bassiana to be used as baits for insect’s control. The gelatin amended with sugar recorded the maximum viability after 70 days of storage as 98.3% compared to 63.3% on rice media. Effective control of 80% of the ants was observed after 10 days of feeding on gelatin amended with sugar and rice bait. The results demonstrated that treatment with formulations containing conidia of B. bassiana presents insecticidal activity against ant in addition of acting as preservation materials.


2018 ◽  
Vol 42 (4) ◽  
pp. 408-419 ◽  
Author(s):  
Ellison Rosario de Oliveira ◽  
Dejane Santos Alves ◽  
Geraldo Andrade Carvalho ◽  
Bárbara Maria Ribeiro Guimarães de Oliveira ◽  
Smail Aazza ◽  
...  

ABSTRACT Fall armyworm (FAW) (Spodoptera frugiperda) is a polyphagous insect responsible for damage to several crops. Synthetic chemical insecticides and genetically modified plants are the most commonly used methods for FAW control. However, the selection of resistant populations has been reported in several studies, justifying the search for new molecules to be used in the control of S. frugiperda. The aim of the present study was to evaluate the toxicity of lemongrass (Cymbopogon flexuosus) essential oil (LEO) and its major component (citral) in relation to FAW. Additionally, the anticholinesterase activity of LEO and citral was evaluated using acetylcholinesterase (AChE) from Electrophorus electricus. The LEO was toxic to FAW when added to an artificial diet (LC50 = 1.35 mg mL-1) at the highest concentrations tested, and the median lethal time (LT50) was 18.85 h. Major components of LEO were identified by gas chromatography-mass spectrometry, and citral, the most abundant component, was used in FAW bioassays. The insecticidal activity of citral was statistically similar to that of LEO, demonstrating that citral was responsible for the insecticidal activity of LEO. Inhibition of AChE was measured, and the mean inhibitory concentration (IC50) values for LEO and citral were 650- and 405-fold higher, respectively, than that verified for the positive control (methomyl insecticide), suggesting selectivity for non-target organisms. Based on these results, citral and C. flexuosus have the potential to be applied in the development of new products for the control of S. frugiperda.


2013 ◽  
Vol 149 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Frances S. Sivakoff ◽  
Jay A. Rosenheim ◽  
Pierre Dutilleul ◽  
Yves Carrière

2021 ◽  
Author(s):  
Carolina Senhorinho Ramalho Pizetta ◽  
William Rafael Ribeiro ◽  
Amanda Lopes Ferreira ◽  
Matheus da Costa Moura ◽  
Kenny Bonfim ◽  
...  

Abstract Whitefly (Bemisia tabaci) is a polyphagous insect that causes huge damage in several horticultural crops, including tomato, by sucking nutrients from the phloem and transmitting viruses. Whiteflies are particularly difficult to manage and the use of chemicals remains the common practice, which causes the development of insecticidal resistance. Thus, there is considerable interest in the introduction of whitefly resistance by classical and molecular breeding. Here, we explored the concept of using an RNA interference construct to silence a v-ATPase gene in whiteflies interacting with transgenic tomato plants that express siRNA molecules corresponding to a fragment from the B. tabaci vATPase. PCR analyses revealed the presence of both ΔATPase and nptII transgenes in all transgenic lines. siRNA expressing lines were challenged against whitefly and revealed a mortality rate of 57.1% in transgenic line 4.4.1, while in the control the mortality was 7.6%. Mortality of 2nd instar nymphs was higher on the transgenic plants and the development of 3rd instar nymphs was slightly longer than on the control plants. Although the attraction of insects was not significantly different between treatments, the number of eggs laid by the insects on the transgenic plants was significantly lower, compared to the controls. RT-qPCR revealed a decreased expression level of endogenous v-ATPase gene in whiteflies feeding on transgenic plants. No unexpected effect was observed on the non-target insects Myzus persicae or Tuta absoluta. Results presented here may form the foundation for the generation of elite tomato varieties resistant to whitefly, a devastating insect pest.


2021 ◽  
Author(s):  
Shashan Devkota ◽  
Dakshina R. Seal

ABSTRACTAmerican serpentine leafminer, Liriomyza trifolii, is a polyphagous insect pest that feeds on a wide range of vegetable and ornamental plants around the world. To develop an effective IPM program, information on the seasonal field distribution and population dynamics of leafminer and its parasitoids is very important. Therefore, seasonal abundances and spatial distributions of, L. trifolii on snap bean and squash were studied during four crop growing periods between 2013 to 2015 in Homestead, Florida. The mean numbers of mines, larvae, pupae, emerged adults, and parasitoids on snap bean were highest at 2 weeks after planting during all four growing periods. Whereas, the mean numbers of mines, larvae, pupae, emerged adults, and parasitoids on squash were highest at 3 weeks after planting during all four growing periods. L. trifolii distributions tended to be aggregated (1 < b/β) on snap bean at 2 weeks after planting during all four growing periods but had uniform (1 > b/β) distributions on squash at 2 weeks after planting during all four growing periods. Similar results were seen on the distribution of leafminer parasitoids on both bean and squash.


2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Umar Aliyu ◽  
Sa’idu Kamal ◽  
Bashir Muhammad Abubakar ◽  
Isma’il Hassan

Tribolium castaneum is a species of beetle in the family tenebrionidae, the darkling beetle. Conventional insecticides used for controling stored product pests are expensive and arguably associated with various severe adverse side effects hence the need to develop botanical pesticides that are effective as alternative. Though Azadrachta indica has been used for the control of so many insects, review of the literature show no scientifically investigated report of its effectiveness against T. castaneum. This study was therefore designed to evaluate bioinsecticidal activity of ethanolic leaves extract of Azadirachta indica against stored Tribolium castaneum. Different concentrations (60, 70, 80, 90, and 100%) of ethanolic leaves extract of A. indica was applied on the filter paper and were allowed to dry for a reasonable time period. Control was maintained by treating the filter paper with water only. For examining the percent mortality, 15 adults was taken in the Petri dishes embedded with Whitman’s filter paper, covered with lid and tightened with scotch tape on both sides. The A. indica extracts at different concentrations tested showed insecticidal activity against T. castaneum. Further, phytochemical screening results showed that the A. indica extract have phytochemicals associated with insecticidal activity. The study has established that the ethanoloc extract A. indica is effective in managing stored product pest.


2021 ◽  
Author(s):  
Chia Lock Tan ◽  
Rosmin Kasran ◽  
Wei Wei Lee ◽  
Wai Mun Leong

The cocoa pod borer, Conopomorpha cramerella (Snellen) is a serious pest in cocoa plantations in Southeast Asia.  It causes significant losses in the crop.  Unfortunately, genetic resources for this insect is extremely scarce.  To improve these resources, we sequenced the transcriptome of C. cramerella representing the three stages of development, larva, pupa and adult moth using Illumina NovaSeq6000.  Transcriptome assembly was performed by Trinity for all the samples.  A total number of 147,356,088 high quality reads were obtained.  Of these, 285,882 contigs were assembled.  The mean contig size was 374 bp.  Protein coding sequence (CDS) was extracted from the reconstructed transcripts by TransDecoder.  Subsequently, BlastX and InterProScan were applied for homology search to make a prediction of the function of CDS in unigene.  Additionally, we identified a number of genes that are involved in reproduction and development such as genes involved in general function processes in the insect.  Genes found to be involved in reproduction such as porin, dsx, bol and fruitless were associated with sex determination, spermatogenesis and pheromone binding.  Furthermore, transcriptome changes during development were analysed.  There were 2,843 differentially expressed genes (DEG) detected between the larva and pupa samples.  A total of 2,861 DEG were detected between adult and larva stage whereas between adult and pupa stage, 1,953 DEG were found.  In conclusion, the transcriptomes could be a valuable genetic resource for identification of genes in C. cramerella and the study will provide putative targets for RNAi pest control.


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