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

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

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

Field efficacy of phytoextracts, antagonists and chemical fungicides with native approach for controlling banded leaf and sheath blight in maize

Experiments on maize (Zea mays L.) were carried out aiming to control banded leaf and sheath blight (BLSB) caused by fungus, Rhizoctonia solani Kuhn with six treatments represented by different fungicides, antagonists and phytoextracts against control receiving no spray with three replicates of each under field conditions during two consecutive years from 2019 to 2020. In 2019, the higher Percent Disease Control (44.85%) and Percent Yield Increase (62.10%) both were estimated in plot treated with SAAF (carbendazim 12% WP + mancozeb 63% WP) followed by the plot where seed was treated with bavistin (carbendazim 50% WP). The grain yield was higher in plots treated with SAAF followed by leaf stripping method. Almost similar trends of disease control were observed in 2020. The lower percent disease index (47.67% PDI) with higher yield (4660 kg/ha) was recorded from the plot sprayed with SAAF@3 g/L during knee high and subsequent spray after 15 days interval followed by leaf stripping technique (lower 3-4 leaves from ground surface) as compared to control plot (PDI- 93.67% and yield-1393.33 kg/ ha). The results showed that, the combined treatment with fungicides i.e. seed treatment with bavistin before sowing and twice spraying of SAAF during knee height stage at 15 days interval followed by leaf stripping technique were effective to control banded leaf and sheath blight disease of maize to increase the yield

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

Enhancing Genetic Gain in Potato Clones through Phenotyping Late Blight Resistance

Late blight, caused by Phytophthora infestans (Mont.) de Bary, is a devastating disease of potato (Solanum tuberosum L.). To identify potential sources of resistance to the disease, 32 clones received from the National Potato Research Program (NPRP) were evaluated under natural conditions at the National Maize Research Program Rampur, Chitwan in 2018 and 2019. Potato cultivars Desire, Kufri Jyoti, and Farmers local were used as moderately resistant, susceptible, and highly susceptible checks, respectively. The experiments were laid out in α-lattice design with two replications. Each experimental plot of 3.6 m2 was seeded as two 3m long rows with 0.6 and 0.25 m row and plant spacing, respectively. Agronomic practices were followed as recommended by NPRP. The disease severity was measured based on a percentage of leaf area infected using disease scale of (1 to 9) at three times in seven days intervals. Disease severity values were converted into the area under disease progress curve (AUDPC). During harvest, the total yield and its components were recorded. Potato clones differed significantly (P ≤ 0.01) for disease severity, yield, and yield components. The results revealed high genetic variability, heritability, and genetic gain for disease parameters, tuber yield, and its components. Six clones (CIP311622.9, PRP277072.122, PRP146971.135, PRP147072.27, CIP311350.27, and PRP146971.117 had lower area under disease progress curve AUDPC) values (274.25 to 421.03), showed higher resistant in both years and yielded more tuber yield (~20 t/ha) than other clones. These clones could be used to develop late blight resistant, high yielding potato varietie

Evaluation of Barley Genotypes Against Spot Blotch Disease in Inner Tarai Region of Nepal

Spot blotch caused by Bipolaris sorokiniana (Sacc. in Sorok.) Shoem. is an important disease of barley (Hordeum vulgare L.). A total of 126 barley genotypes received from Hill Crops Research Program, Kabre, Dolakha having SoluUwa as a susceptible check and Bonus as a resistant check were evaluated as barley disease screening nursery (BDSN) under natural epiphytotic condition at National Maize Research Program, Rampur, Chitwan during winter seasons of 2017 and 2018. The nursery was planted in augmented design. The resistant and susceptible checks were repeated and planted after each 10 tested entries. The unit plot size was 2 rows of one meter length for each genotype planted continuously with 25cm row to row spacing. The seed rate was 100 kg/ha. The recommended fertilizer dose of 23:30:0 N:P2O5:K2O kg/ha was applied. The double digit scale (00 to 99) was used to measure overall foliar infection on the whole plant during flowering, soft dough and hard dough stages. Other agronomic practices were followed as per recommendation. Genotypes B86019-1K-3K-0K3, ACC 2087, ACC 2441, ACC GHv-06816, ACC 1597, ACC 1612, ACC 2059 and ACC 2032 were resistant against spot blotch disease. Similarly, 32 barley genotypes were moderately resistant and rest of the tested genotypes were susceptible to the disease. The selected resistant barley genotypes can be used in crossing program and/or promoted for further testing to develop spot blotch resistant varieties for inner Tarai region of Nepal