scholarly journals ​Screening of Black Gram Genotypes against Major Pod Borers

Author(s):  
Abhishek Yadav ◽  
Gaje Singh ◽  
Amit Yadav ◽  
Hem Singh ◽  
Veer Singh ◽  
...  

Background: Blackgram (Vigna mungo L.) is an important pulse crop occupying a unique position in Indian agriculture and it stands fourth in area and production among the pulses. The popularity of this pulse is due to its nutritional and industrial values. Blackgram crop is attacked by a number of insect pests from sowing to harvest in the field as well as in storage condition. Among these insects-pests pod borers i.e. spotted pod borer, Maruca vitrata (Geyer) and gram pod borer, Helicoverpa armigera (Hubner) are serious insect-pests of black gram causing seed and pod damage. Therefore, keeping these views in mind, the present study was conducted. Methods: Present investigations were carried out during Kharif season of 2018 and 2019 to identify the resistant cultivars that are less susceptible to spotted pod borer and gram pod borer in black gram. Result: Fifteen black gram genotypes were screened against pod borers i.e. M. vitrata and H. armigera. When the data of both years were pooled, the two genotypes viz., KU-99-05 and Azad Urd-1 were found with minimum pod infestation of 7.67 and 9.67 per cent, respectively and categorized as resistant (R) against M. vitrata. The four genotypes KU-99-05, Azad Urd-1, Shekhar-2 and PU-6 were classified as resistant (R) against H. armigera with minimum pod infestation of 5.83, 6.17, 8.50 and 9.83 per cent, respectively during both the consecutive seasons (Kharif, 2018 and 2019).

2020 ◽  
Vol 113 (2) ◽  
pp. 974-979
Author(s):  
Prince C Addae ◽  
Mohammad F Ishiyaku ◽  
Jean-Batiste Tignegre ◽  
Malick N Ba ◽  
Joseph B Bationo ◽  
...  

Abstract Cowpea [Vigna unguiculata (L) Walp.] is an important staple legume in the diet of many households in sub-Saharan Africa. Its production, however, is negatively impacted by many insect pests including bean pod borer, Maruca vitrata F., which can cause 20–80% yield loss. Several genetically engineered cowpea events that contain a cry1Ab gene from Bacillus thuringiensis (Bt) for resistance against M. vitrata were evaluated in Nigeria, Burkina Faso, and Ghana (West Africa), where cowpea is commonly grown. As part of the regulatory safety package, these efficacy data were developed and evaluated by in-country scientists. The Bt-cowpea lines were planted in confined field trials under Insect-proof netting and artificially infested with up to 500 M. vitrata larvae per plant during bud formation and flowering periods. Bt-cowpea lines provided nearly complete pod and seed protection and in most cases resulted in significantly increased seed yield over non-Bt control lines. An integrated pest management strategy that includes use of Bt-cowpea augmented with minimal insecticide treatment for protection against other insects is recommended to control pod borer to enhance cowpea production. The insect resistance management plan is based on the high-dose refuge strategy where non-Bt-cowpea and natural refuges are expected to provide M. vitrata susceptible to Cry1Ab protein. In addition, there will be a limited release of this product until a two-toxin cowpea pyramid is released. Other than South African genetically engineered crops, Bt-cowpea is the first genetically engineered food crop developed by the public sector and approved for release in sub-Saharan Africa.


2021 ◽  
Author(s):  
Madhurima Chatterjee ◽  
Jyoti Yadav ◽  
Maniraj Rathinam ◽  
Kesiraju Karthik ◽  
Gopal Chowdhary ◽  
...  

Abstract Insect pests are one of the major biotic stresses limiting yield in commercially important food crops. The lepidopteran polyphagous spotted pod borer, Maruca vitrata causes significant economic losses in legumes including pigeonpea. RNAi-based gene silencing has emerged as one of the potential biotechnological tools for crop improvement. We report in this paper, RNAi in M. vitrata through exogenous administration of dsRNA encoding three functionally important genes, Alpha-amylase (α-amylase), Chymotrypsin-like serine protease (CTLP) and Tropomyosin (TPM) into the larval haemolymph and their host-delivered RNAi in pigeonpea. Significant decline in the expression of selected genes supported by over-expression of DICER and generation of siRNA indicated the occurrence of RNAi in the dsRNA-injected larvae. Additionally, the onset of RNAi in the herbivore was demonstrated in pigeonpea, one of the prominent hosts, by host-delivered RNAi. Transgenics in pigeonpea (cv. Pusa992), a highly recalcitrant crop, were developed through a shoot apical meristem-targeted in planta transformation strategy and evaluated. Plant level bioassays in transgenic events characterized and selected at molecular level showed mortality of M. vitrata larvae as well as reduced feeding when compared to wild type. Furthermore, molecular evidences for down regulation of target genes in the insects that fed on transgenics authenticated RNAi. Considering the variability of gene silencing in lepidopteran pests, this study provided corroborative proof for the possibility of gene silencing in M. vitrata through both the strategies.


2012 ◽  
Vol 102 (5) ◽  
pp. 589-599 ◽  
Author(s):  
T.A. Agunbiade ◽  
B.S. Coates ◽  
K.S. Kim ◽  
D. Forgacs ◽  
V.M. Margam ◽  
...  

AbstractThe legume pod borer, Maruca vitrata, is an endemic insect pest that causes significant yield loss to the cowpea crop in West Africa. The application of population genetic tools is important in the management of insect pests but such data on M. vitrata is lacking. We applied a set of six microsatellite markers to assess the population structure of M. vitrata collected at five sites from Burkina Faso, Niger and Nigeria. Observed polymorphisms ranged from one (marker 3393) to eight (marker 32008) alleles per locus. Observed and expected heterozygosities ranged from 0.0 to 0.8 and 0.0 to 0.6, respectively. Three of the loci in samples from Nigeria and Burkina Faso deviated significantly from Hardy-Weinberg Equilibrium (HWE), whereas no loci deviated significantly in samples from Niger. Analysis of molecular variance (AMOVA) indicated that 67.3% level of the genetic variation was within individuals compared to 17.3% among populations. A global estimate of FST=0.1 (ENA corrected FST=0.1) was significant (P⩽0.05) and corroborated by pairwise FST values that were significant among all possible comparisons. A significant correlation was predicted between genetic divergence and geographic distance between subpopulations (R2=0.6, P=0.04), and cluster analysis by the program STRUCTURE predicted that co-ancestry of genotypes were indicative of three distinct populations. The spatial genetic variance among M. vitrata in West Africa may be due to limited gene flow, south-north seasonal movement pattern or other reproductive barriers. This information is important for the cultural, chemical and biological control strategies for managing M. vitrata.


Author(s):  
Prince Christopher Addae ◽  
Y. Anani Bruce ◽  
Iliyasu M. Utono ◽  
Mumuni Abudulai ◽  
Fousseni Traore ◽  
...  

AbstractThe evolution of resistance to the Bacillus thuringiensis (Bt) toxins by insect pests is a major threat to Bt technology. However, the rate of resistance can be slowed with appropriate integrated insect resistance management (IRM) strategies. Surveys were conducted to identify alternate host species for Maruca vitrata (commonly called the legume pod borer or Maruca) that could serve as refuges for Pod-Borer Resistant (PBR) cowpea in three West African countries (Ghana, Nigeria, and Burkina Faso). Survey sites included 25 in northern Ghana, 44 in northern Nigeria, and 52 in north-central and southwestern Burkina Faso. Alternate hosts of Maruca identified from plant species belonging to the Fabaceae family that showed signs of Maruca damage on cowpea tissues were collected and dissected. Larvae that were found during these dissections were reared to adult moths in the laboratory then identified to species. The alternate host plants including species of Crotolaria, Sesbania, Tephrosia, and Vigna were the most frequently encountered among sites and locations. Flowering and podding of these plants overlapped with flowering and podding of the nearby (~200 m) cowpea crop. Abundance of these wild hosts and overlapping flowering patterns with the cowpea crop in most locations have the potential to sustain ample numbers of Bt susceptible Maruca that will mate with possible resistant Maruca and deter resistance development. Further quantitative studies, however, are required from each location to determine if actual Maruca production from alternate hosts is sufficient for a PBR IRM strategy. If verified, this approach would be compatible with the high dose/refuge IRM strategy that includes alternate hosts and non-Bt crops as refuges.


2019 ◽  
Vol 14 (1) ◽  
pp. 69-72 ◽  
Author(s):  
Nasiya Beegum AN ◽  
Madhu Subramanian

Trichomes are the morphological features present on the surface of plants, which provide resistance to several insect pests. A pot culture experiment with 48 cowpea accessions were conducted to evaluate the effect of trichomes in cowpea on infestation by spotted pod borer, Maruca vitrata. Significant variation in terms of damage to pods due to spotted pod borer was observed. The number of trichomes per unit area was significantly and negatively correlated (-0.441) with per cent damage. However, the length of trichomes on pods has no significant correlation with per cent damage.


2012 ◽  
Vol 1 (2) ◽  
pp. 275 ◽  
Author(s):  
E. O. Egho ◽  
E. C. Enujeke

<p>Studies were conducted to test the effectiveness of native soap against cowpea insect pests during the late cowpea cropping season in two agro-ecological zones-Asaba and Abraka, Delta State. Four major insect pests, namely the cowpea aphid, <em>Aphis craccivora</em> Koch, the legume flower bud thrips, <em>Megalurothrips sjostedti </em>Tryb, the legume pod borer, <em>Maruca vitrata </em>Fab and pod sucking bugs were studied. The experiment was made up of five treatments-1, 2 and 3 percent concentrations of native soap, cypermethrin (as conventional chemical and check) and a control. Each treatment was replicated three times. The experiment was arranged into a randomised complete block design (RCBD). The results showed that all the major insect pests occurred in the study areas but were more at Asaba compared to Abraka. Native soap was effective against <em>A. craccivora </em>and flower bud thrips population at Asaba. <em>Maruca vitrata </em>was not affected by soap application. Grain yield was high at Abraka and significantly (P&lt;0.05) higher than Asaba. The use of native soap as non-conventional insecticide in cowpea insect pests management appears promising, more so as it is not expensive and safe to handle. Farmers may prefer it to synthetic chemical pesticides with their associated dangers.</p>


2021 ◽  
Vol 95 ◽  
Author(s):  
R. Pervez ◽  
U. Rao

Abstract The legume pod-borer, Maruca vitrata Fabricius (Lepidoptera: Crambidae) (LPB), is an important insect pest of pigeon pea. Chemical pesticides are generally employed to manage this pest, but because of the soil residue issues and other environmental hazards associated with their use, biopesticides are also in demand. Another benign alternative is to use entomopathogenic nematodes (EPNs) to manage this vital pest. In the present study, the infectivity of ten native EPNs was evaluated against LPB by assessing their penetration and production in the LPB. The effectiveness of the promising EPNs against second-, third- and fourth-instar LPB larvae was also studied. Heterorhabditis sp. (Indian Agricultural Research Institute-Entomopathogenic Nematodes Rashid Pervez (IARI-EPN RP) 06) and Oscheius sp. (IARI-EPN RP 08) were found to be most pathogenic to LPB, resulting in about 100% mortality within 72 h, followed by Steinernema sp. (IARI-EPN RP 03 and 09). Oscheius sp. (IARI-EPN RP 04) was found to be the least pathogenic to LPB larva with 67% mortality. Maximum penetration was exhibited by Heterorhabditis sp. (IARI-EPN RP 06) followed by Oscheius sp. (IARI-EPN RP 08), whereas the lowest rate of penetration was exhibited by Oscheius sp. (IARI-EPN RP 01). The highest rate of production was observed with Oscheius sp. (IARI-EPN RP 08), followed by Oscheius sp. (IARI-EPN RP 04 and 10). Among the tested instars of the LPB larvae, second-instar larvae were more susceptible to EPNs, followed by third- and fourth-instar larvae. The results indicate that Heterorhabditis sp. (IARI-EPN RP 06) and Oscheius sp. (IARI-EPN RP 08) have a good potential to the manage LPB.


2021 ◽  
Vol 40 (3) ◽  
pp. 583-594
Author(s):  
Anil Kumar ◽  
Ranjana Jaiwal ◽  
Rohini Sreevathsa ◽  
Darshna Chaudhary ◽  
Pawan K. Jaiwal

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