Influence of Abiotic Factors on Population of Aphid Complex and Its Coexisting Natural Enemies in Mustard Agroecosystem

A field experiment was conducted to determine the population build-up of mustard aphid and their natural enemies in relation to abiotic factors at TCA, Dholi during the Rabi season of 2018-19 and 2019-20 respectively. The incidence of mustard aphid started in the 2nd and 3rd SMW of 2019 and 2020 respectively and reached maximum in 8th SMW in both the years. However, the predatory activity of coccinellids, syrphid larvae and spiders were started from 3rd SW with their peak activity at 3rd and 4th week of February in both the years. Mustard aphid population exhibited positive correlation with maximum temperature (0.347 & 0.543), minimum temperature (0.317 & 0.152) and negative correlation with relative humidity (-0.083 & -0.479) during 2019 & 2020 respectively and rainfall (-0.35) during 2020. However, natural enemies viz., coccinellids, syrphid larvae and spiders exhibited positive correlation with Tmax, Tmin, rainfall and negative correlation with RH in both the years.

Purification, Characterization and Bioefficacy of Legume Lectins against Mustard Aphid

Background: Lectins are carbohydrate binding proteins which perform diverse roles in plants. One important role is in plant defense. These proteins hold great potential as entomotoxic proteins as a part of integrated pest management. Methods: Lectins were purified and characterized from seeds of two legumes, Glycine max-Soybean and Lens culinaris-Lentil, employing ammonium sulfate fractionation and ion exchange chromatography. Bioefficacy of the purified lectins was evaluated against mustard aphid.Result: Lectins isolated from seeds of soybean (Glycine max agglutinin GMA-I, II) and lentil (Lens culinaris agglutinin LCA-I) were purified upto 9.30 (GMA-I), 4.60 (GMA-II) and 8.70 (LCA-I) fold, respectively. Lectin characterization revealed that soybean agglutinin and lentil agglutinin were specific towards D-Galactose and D-mannose, respectively. Insect bioassay was carried out with five different concentrations (10, 20, 30, 40, 50 µg/ml) of purified lectins of soybean and lentil against mustard aphid. The lethal concentration LC50 value for GMA-I was obtained as 32.1 µg/ml with a 95% confidential interval of 18.2 to 40.5 µg/ml and that of LCA-I was 19.1 µg/ml with a 95% confidential interval of 9.3 to 26.8 µg/ml. Lentil lectin (LCA-I) with lower LC50 value, was found to be the potential candidate for integrated pest management.

Relative incidence of aphid (Lipaphis erysimi) and Alternaria blight on mustard in sub-mountainous region of Punjab

Aim: To study the relative incidence of mustard aphid and Alternaria blight on different rapeseed-mustard varieties to assess their resistant or tolerant and most suitable variety for sub-mountainous area of Punjab. Methodology: The experiment was conducted on four mustard varieties (RLM-619, PBR-97, PBR-357 and Giriraj) with five replications in randomized block design during two crop seasons, i.e. Rabi 2018-19 and 2019-20 under sub-mountainous areas of Punjab. Aphid population was recorded at weekly interval. Disease severity was calculated using 0-5 rating scale and per cent disease intensity was calculated. Results: RLM-619 variety exhibited the lowest aphid infestation (7.92 and 8.96%) and minimum per cent disease intensity (28.0 and 33.33%) on leaves and siliqua (33.33 and 38.33%) which also gave highest yield (739.33 kg acre-1 and 735.67 kg acre-1) during the year 2018-19 and 2019-20. The lowest seed yield (487.67 kg acre-1 and 480.67 kg acre-1) was recorded in variety Giriraj, which was found susceptible to aphid infestation and Alternaria blight. Interpretation: RLM-619 exhibited tolerance against aphid and Alternaria blight, hence, this variety may be used as a key component under integrated pest and disease management in sub-mountainous area of Punjab in future.

INTEGRATED PEST MANAGEMENT OF MUSTARD APHID, LIAPHIS ERYSIMI (KALT.) ON RAPESEED CROPS IN GOKULESHWOR, BAITADI

An experiment was conducted at Gokuleshwor, Baitadi to evaluate the management practices of Lipaphiserysimi (Kalt.) during Rabi season in 2017/18.Field experiment was laid out in a randomized complete block design (RCBD) with 5 treatments and 3 replications. The treatments were:1) jholmol @250 ml/litre of water2) 2) Altineem @2.5ml/litre of water 3) Cow urine @250 ml/litre of water 4) Mustard cake @25kg/ha and 5) untreated (control). Each plot consists of 2m*2m (4m2). Field experiment showed that the highest reduction of Lipaphiserysimi (Kalt.) was achieved in jholmol followed by altineem but these two treatments were statistically at per during almost all the spray times. Thus, jholmol might be the best option in eco-friendly management of Lipaphiserysimi (Kalt).