Identification of Semiochemicals from Cowpea, Vigna unguiculata, for Low-input Management of the Legume Pod Borer, Maruca vitrata

Field experiment was carried out during 2018 cropping season to evaluate the effect of planting dates on incidence of legume pod borer Maruca vitrata on cowpea (Vigna unguiculata) varieties. The treatments consist of five varieties of cowpea (local variety, SAMPEA 6, SAMPEA 7, SAMPEA 8 and SAMPEA 10) which were sown at three different dates, 7th (early), 24th (Mid) August and 7th (early) September, 2018. The experiment was laid out in a Randomized Complete Block Design (RCBD) replicated three times. The number of M. vitrata larva on flowers, damaged pods and weight of grains were determined. The result showed that first sowing nearly August had less infestation by M. vitrata than those in mid August and differs significantly (P≤0.05) from those sown in September. All varieties sown in early and mid August had less M. vitrata infestation and produced higher grain yield of 533.33kg and 395.06 kg on SAMPEA 7 and SAMPEA 8, respectively compared to those sown in early September: 256.79 and 197.53 on SAMPEA 7 and SAMPEA 10, respectively. Local variety and SAMPEA 6 were the varieties with higher mean number of M. vitrata, higher pod damage and low grain yield. Therefore, SAMPEA 7 can be utilized in breeding program for the management of pod borer.

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Infectivity of entomopathogenic nematodes against the legume pod-borer, Maruca vitrata Fabricius, infesting pigeon pea

Journal of Helminthology ◽

10.1017/s0022149x21000043 ◽

2021 ◽

Vol 95 ◽

Author(s):

R. Pervez ◽

U. Rao

Keyword(s):

Entomopathogenic Nematodes ◽

Agricultural Research ◽

Insect Pest ◽

Indian Agricultural Research Institute ◽

Pigeon Pea ◽

Fourth Instar ◽

Maruca Vitrata ◽

Pod Borer ◽

Legume Pod Borer ◽

Maximum Penetration

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.

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