Evaluation of insecticidal efficacy against maize leaf aphid [Rhopalosiphum maidis (Fitch)] under inner terai condition of Nepal

Field experiments were carried out at the National Maize Research Program in Rampur, Chitwan, with the objective of comparing the effectiveness of insecticides in the field for controlling maize leaf aphid (Rhopalosiphum maidis Fitch) during the winter season of 2019 and 2020. The design of the experiment was randomized complete block with four replications. The plot size was 6 rows of 5 m long with the spacing of 60cm × 25cm. Maize hybrid Rampur Hybrid-14 (RML-86/RML-96) was used as experimental variety. The efficacies of five insecticides viz., thiomethoxam 25% w/w 0.2g/L (T1), acetamiprid 20%WP 2g/L (T2), flonicamid 50% WG 0.5g/L (T3), neemix 3ml/L(T4), imidacloprid 0.5ml/L(T5) and untreated control (T6) were used as experimental treatments. The recommended dose of fertilizer was 180: 60: 40 N: P2O5: K2O kg/ ha with farm yard manure 10 t/ha and seed rate was 20kg/ha. Data on aphid incidence, severity, yield and yield components were recorded. All the tested insecticides significantly (P≤0.05) reduced the plant infestation caused by maize aphid, and thereafter increased the grain yield of maize compared to control. However, newer insecticide flonicamid 50% WG 0.5g/L was found as the most effective insecticide with lower aphid colony per plant (2.85), aphid score (2.63), aphid infested plant (7.33%) and higher crop yield (7904.79kg/ha). The application of insecticides prior to their severe infestations is necessary for the efficient control of the maize leaf aphid. The research findings will assist maize farmers in choosing and applying the best insecticide to ensure efficient management of maize leaf aphid with high yield

Life cycle study of maize stem borer (Chilo partellus Swinhoe) under laboratory condition at National Maize Research Program, Rampur, Chitwan, Nepal

Maize stem borer (Chilo partellus swinhoe) is one of the major threatening global pests of maize and considered as the national top priority entomological research problem in Nepal. The Life cycle of maize stem borer was studied under laboratory condition at National Maize Research Program (NMRP), Rampur, Chitwan, Nepal during 2018. Development of stem borer undergoes following stages like egg, larvae, pupa and adult. Eggs and different instars of maize stem borer larvae were collected from maize fields were put with host materials (maize leaf and stem) to become different instars of larva, pupae and finally turned to adults. Eggs were harvested from adults and kept on blotting paper which was kept inside petriplates and reared for adults. Their life span in each stage (egg, larva and pupa) and the fecundity of adults recorded. Daily room temperature and relative humidity (RH) in laboratory conditions were recorded. The Egg incubation period ranged from 4-7 days and hatched generally in the early morning (6-8 AM). The complete larvae period ranged from 29 to 36 days while pupal period was ranged from 7 to 12 days. The average male pupal length was found 13 mm and female was 16 mm long. The fecundity of C. partellus Swinhoe was recorded 150-160 eggs per female. The Oviposition period was  4 days and adult male survived for 4-7 days while female for 4-9 days. The average life cycle of C. partellus completed in (44-48) days during summer whereas (60-64) days during winter at average room temperature of (26-27° C) and RH of (70-80%). These results have important implications to know the survival and development of pest including effective pest management strategy

Verification of disease management technology on lentil against Stemphylium blight at farmer’s field in Nepal

Technologies generated from lentil (Lens culinaris Medik) stemphylium blight (Stemphylium botryosum Walr) management experiments were verified at farmers field of 5 districts viz., Chitawan, Rautahat, Dang, Parsa and Banke during two winter seasons of 2013-2014 and 2014- 2015. The experiment was laid out in randomized complete block design with factorial arrangement of treatments and replicated 4 times. The plot size was 340 m2 (1 Kattha) with 25 cm row to row spacing. There were altogether 3 factors of the experiment i.e. year (2013-2014 and 2014-2015), location (5 districts) and package of practice (improved and farmers practice). The higher crop yield (1142.50 kg/ha) with lower disease index (34.95%) and higher benefit cost ratio of 2.42 were recorded in the farmers field of Banke district following seed rate (30 kg/ha), 8 hour primed improved variety (Black lentil), fertilizer doze of (20:40:20 NPK kg/ha+ 1 kg/ha B basal doze) and subsequent 3 sprays of Dithane M-45 @ 2.5 g/l of water at 10 days interval

Antifungal assessment of plant extracts, biocontrol agents and fungicides against Fusarium verticillioides (Sacc.) causing ear rot of maize

Saabunud / Received 28.03.2021 ; Aktsepteeritud / Accepted 13.06.2021 ; Avaldatud veebis / Published online 13.06.2021 ; Vastutav autor / Corresponding author: Subash Subedi [email protected] rot is a prominent biotic threat of maize causing significant yield loss and poor quality of grains. The antifungal activity of aqueous extract of Acorus calamus L., Xanthoxylum armatum DC., Azadirachta indica A. Juss., Lantana camera L. and Artemisia indica Willd at three different concentrations (1, 2 and 3% W/V), four chemical fungicides viz., Dithane M-45 (Mancozeb 75% WP), SAAF (Carbendazim 12% + Mancozeb 63% WP), ACME-COP (Copper oxychloride 50% WP) and Bavistin (Carbendazim 50% WP) at (500, 1000 and 1500 ppm) and three biocontrol agents (BCA) namely Trichoderma viride, Trichoderma harzianum and Trichoderma koningii were investigated against Fusarium verticilliodes (Sacc.) causing ear rot of maize. The experiment was carried out by poisoned food and dual culture techniques in a completely randomized design with five replications under laboratory conditions at National Maize Research Program, Rampur, Chitwan during the summer season of 2019. F. verticillioides showed significant growth inhibition in all the treatments compared to control. The A. calamus even at a lower dose (1% W/V on PDA) was able to check completely the growth of pathogen (4.00 mm). The mycelial growth inhibition per cent of A. calamus, L. camera, X. armatum, A. indica, and Artemisia indica at 3% W/V was 95.50, 51.13, 45.50, 42.12 and 35.36% respectively. In the case of fungicides, at 1500 ppm, the maximum antifungal potential was observed with SAAF (86.32%) followed by Dithane M-45 (80.27%), Bavistin (64.80%) and ACME-COP (59.42%). Antagonist Trichoderma viride completely overgrows F. verticillioides and covers the entire medium surface and exhibit more than 60% inhibition on the 7th day of incubation. The antifungal components from these plant extracts, fungicides and antagonists explored in this study need to be tested further in field experiments to control the ear rot of maize

Field Screening of Lentil Genotypes Against Aphid Infestation in Inner Tarai of Nepal

Twenty lentil (Lens culinaris Medik) genotypes received from Grain Legumes Research Program, Khajura, Banke were screened for relative tolerance against aphid (Aphis craccivora Koch.) at the research field of National Maize Research Program, Rampur, Chitwan during winter seasons of two consecutive years 2016 and 2017. The design of the experiment was Randomized Complete Block having three replications. The unit plot size was 4m × 1 m with 25cm row to row spacing and continue plant to plant spacing was maintained and net harvested plot was 4 square meters. The recommended dose of fertilizer was 20:40:20 N:P2O5:K2O kg/ha and seed rate 30 kg/ha. Insect data were collected based on aphid population found at apical twigs (10 cm) per plant and scoring was done during flowering and pod formation stage. The grain yield was recorded. All screened genotypes differed significantly (p<0.05) on aphid population and grain yield.  Genotypes, ILL 9924, RL 83, ILL 10856, ILL 6458 and RL 67 were less susceptible with higher grain yield. These results have important implications for the development of aphid tolerant high yielding lentil variety in inner Tarai of Nepal

A review on important maize diseases and their management in Nepal

ABSTRACT In Nepal, maize ranks second after rice both in area and production. In recent years, maize area and production has shown a steady increase, but productivity has been low (2.46 t/ha). The major maize producing regions in Nepal are mid hill (72.85%), terai (17.36%) and high hill (9.79%) respectively. A literature review was carried out to explore major maize diseases and their management in Nepal. The omnipresent incidence of diseases at the pre harvest stage has been an important bottleneck in increasing production. Till now, a total of 78 (75 fungal and 3 bacterial) species are pathogenic to maize crop in Nepal. The major and economically important maize diseases reported are Gray leaf spot, Northern leaf blight, Southern leaf Blight, Banded leaf and sheath blight, Ear rot, Stalk rot, Head smut, Common rust, Downy mildew and Brown spot. Information on bacterial and virus diseases, nematodes and yield loss assessment is also given. Description of the major maize diseases, their causal organisms, distribution, time and intensity of disease incidence, symptoms, survival, spreads, environmental factors for disease development, yield losses and various disease management strategies corresponded to important maize diseases of Nepal are gathered and compiled thoroughly from the available publications. Concerted efforts of NARC commodity programs, divisions, ARS and RARS involving research on maize pathology and their important outcomes are mentioned. The use of disease management methods focused on host resistance has also been highlighted

Efficacy of Trichoderma isolates against Sclerotium rolfsii causing collar rot of lentil

Lentil collar rot disease caused by Sclerotium rolfsii Sacc. is an  important disease causing significant yield loss in Nepal. Seven Trichoderma spp. isolates collected from different regions of Nepal were tested for their capacity to inhibit mycelial growth of Sclerotium rolfsii in in-vitro condition. Experiment was conducted in Completely Randomized Design with four replications in the plant pathology laboratory of Grain Legumes Research Program, Khajura, Banke during 2020. Dual culture method was performed to assess the efficacy of Trichoderma isolates. Trichoderma spp. isolates inhibited mycelial growth of S. rolfsii to various degrees ranging from 48.33-72.47% after 120 hours of inoculation. Maximum colony inhibition of S. rolfsii (72.47%) was obtained by Kapilvastu isolate followed by Nepalgunj isolate (67.72%). Minimum colony inhibition of S. rolfsii (48.33%) was obtained by Mangalpur, Chitwan isolate followed by Rampur, Chitwan isolate (49.33%). Among seven Trichoderma isolates, two isolates (Kapilbastu and Nepalgunj) showed good antagonistic activity against S. rolfsii and were also highly competitive in in-vitro condition. These isolates would therefore be useful in biological disease management

Predatory publishing: A threat to the credibility of science

Predatory journals pose a global threat to science. Young scientists and scholars are easy victims of the predatory publications. Predatory publications reduce the accuracy, reliability, and validity of the scientific works published. The predatory publications are worthless, just a waste of time, resources, money, and efforts. Predatory publications undermine the value of legitimate publications. In order to discourage predatory publications, educational and research institutions should set the rules for publication in the journals that must be indexed in web of science, Journal Citation Reports (JCR, Clarivate Analytics, formerly Thomson-Reuters) or other famous scientific databases such as Scopus, DOAJ, PubMed, and MEDLINE. Citation of articles from predatory journals should be discouraged. The students, academics, and researchers should be careful to avoid predatory publications to maintain their credentials

Field assessment of blackgram (Vigna mungo L. Hepper) genotypes against major insect pests in subtropical region of Nepal

Direct damage due to insect pests is one of the major causes limiting the yield potential of blackgram (Vigna mungo L. Hepper) in Nepal. A total of 17 blackgram genotypes were screened for resistance to major insect pests, including aphid (Aphis craccivora Koch.), whitefly (Bemisia tabaci Genn.), hairy caterpillar (Spilosoma obliqua Walker) and pod borer (Helicoverpa armigera Hubner) in National Maize Research Program, Rampur, Chitwan during summer season of 2018 and 2019. The design of the experiment was randomized complete block having three replications. Genotypes were sown on first week of August in a unit plot size of 4 rows of 2 m long with 40 cm row to row spacing and continue plant to plant spacing was maintained and net harvested plot was 3.2 square meters. The recommended dose of fertilizer was 20:40:20 N:P2O5:K2O kg/ha and seed rate 25 kg/ha. The package of agronomic practices was followed as per national recommendation. Data on insects were collected by counting the number of insects per plant. The yield and yield components were recorded at harvest. All screened genotypes differed significantly (p<0.05) for insect population, yield and yield components. From two years field data, three genotypes BLG0069-1, BLG0036-1 and BLG0079-1 had lower number of above mentioned insect populations, exhibited more resistant in both years and produced higher grain yield (~1.5 t/ha) than other genotypes. These genotypes might be useful for the development of major insect pest tolerant high yielding blackgram variety in subtropical region of Nepal