A survey was conducted during June-July 2006 in Chitwan to find out the natural infestation of rice root-knot nematode (Meloidogyne graminicola Golden & Brichfield) in rice nurseries. Thirty nurseries were surveyed and 100 seedlings from each nursery were evaluated. Field survey revealed that M. graminicola was widely distributed in most rice growing areas of Chitwan District. Rice root-knot disease was more prevalent in dry bed condition than wet bed. Most of the farmers grew seedlings in upland (dry) soil and there was more rice root-knot disease and second stage juvenile (J2) population in both nursery soil and seedling root. The galled (diseased) seedlings had significantly shorter roots and shoots. Most of the farmers did not know about the nematode problem and did not follow any management practices to control it in nurseries and/or in the main field. This indicated high risk of multiplication of the nematodes and huge loss in rice production. Thus, it is essential to manage M. graminicola in rice nurseries in order to produce healthy seedlings.
Pot experiment was conducted during July-September 2006 to evaluate some organic amendments such as sesame (Sesamum indicum) biomass, buckwheat (Fagopyrum esculentum) biomass, neem (Azadirachta indica) leaves, chinaberry (Melia azedarch) leaves and chicken manure @ 1, 2 and 3 t ha -1 each against the rice root-knot nematode (Meloidogyne graminicola Golden & Birchfield) in direct seeded rice. The treatments were replicated five times in a randomized complete block design. The number of second stage juveniles (J2) of M. graminicola was significantly low in chicken manure @ 3 t ha -1 . The root knot severity index was significantly low in sesame @ 3 t ha -1 , chinaberry @ 3, 2 or 1 t ha -1 , neem @ 3 t ha -1 and chicken manure @ 2 or 3 t ha -1 amended soil but root lesion severity index was lower only in chicken manure @ 2 t ha -1 treated plots. The fresh shoot weight and length were significantly high in chicken manure amendment @ 2 or 3 t ha -1 at 45 th day after seeding. However, the fresh root weight, length, number of leaves and number of J2 recovered from the roots were non-significant.
Alternaria blight in mustard cause heavy damage to the foliar parts resulting into poor growth and development of plants and thereby reduces seed yield. Inorder to manage Alternaria infestation in mustard seed for yield maximization, an experiment was conducted in the plant protection laboratory in Nepal Polytechnic Institute, Bharatpur, Chitwan in 2018, using Completely Randomized Design (CRD) with four replicates. Five treatments i.e.Uthane M-45 (2g/kg), Neem powder (3 g/kg), Bojho powder (4g/kg), Trichoderma harzianum, (107 Conidia/mL) and control (without treatment) were used for seed treatment of local variety of Mustard. Four hundred seeds for each treatment (25 seeds in each petriplate) were plated using triple layers of moistened blotter paper in petriplate and incubated at (27±20C) for 2 days and followed deep freezing for 24 hrs. Data of disease incidence and seed germination were recorded in 3, 7 and 10 days after incubation (DAI). Seedling vigor and seedling weight were also recorded at 5 DAI. The percentage of Alternaria spp incidence on seeds at different DAI showed highly significant with respect to different treatments. Application of Uthane M-45 and T. harzianum significantly reduced the seed-borne infection of Alternaria spp. as compared to control. At 3 DAI Uthane M-45 completely checked the pathogen however, only 4% and 5% disease incidence was observed in 7 DAI and 10 DAI respectively. Bio control agent Trichoderma harzianum was found next best alternative after Uthane M-45 to control disease. Plant extract Bojho powder and Neem powder were found better than control to check the disease. Furthermore, highest germination (76%) was observed in Trichoderma treatment whereas, lowest germination was found in control.
Fall armyworm, Spodoptera frugiperda is an invasive and notorious pest of maize in many countries including Nepal. Several approaches of integrated management have been adopted for its control, chemical being the most popular choice in the farmers’ fields. Efficacy of such chemical pesticides for fall armyworm is interpreted as per the location, season, time and crops. In some cases, insect pests are always increasing the pesticide resistance. Hence to minimize the confusion of insecticide efficiency in various levels of understanding in the farmers’ level, field research was conducted in October 2021 to April, 2022. Seven different treatments (azadirachtin, chlorantraniliprole, emamectin benzoate, spinosad, spinetoram, imidacloprid and control) were tested in a four replicated RCBD design. Two sprays were made in twenty-days after seeding and fifteen-days after first spray in openfield condition. Minimum damage across various stages of maize plant was recorded inspinosad sprayed plots followed by spinetoram, chlorantraniliprole and emamectin benzoate, respectively. Maize yield was also recorded highest in spinosad and spinetoram sprayed plots. Highest score of damage was recorded in imidacloprid treated plots. This study further proved spinosad and spinetoram are the most popularly applied insecticides for the fall armyworm management.
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