RELATIVE TOXICITY OF SOME CHEMICAL PESTICIDES AGAINST JUTE HAIRY CATERPILLAR (SPILOSOMA OBLIQUA W.) IN TOSSA JUTE (CORCHORUS OLITORIUS L.)

Pesticides have been a major contributor to the growth of agricultural productivity and food supply. Pesticides were a key factor in significant agricultural productivity growth during the last century and continue to be a critical factor in reducing crop damage. Fifteen insecticides were investigated to select their effective and economic doses against Hairy caterpillar in a Tossa Jute variety during April-October’ 2020 at the Department of Entomology, Manikganj and Narayanganj, Bangladesh Jute Research Institute (BJRI), Bangladesh following Randomized Completely Block Design with three replications. All new insecticides with a standard were found effective for controlling jute hairy caterpillar giving 95.38, 94.55, 95.19, 92.85, 93.59, 94.22, 93.49, 93.62, 89.84, 95.72, 93.56, 93.38, 94.42, 95.39, 91.34 and 95.41 % at Manikganj; 95.78, 93.32, 93.97, 93.18, 92.09, 92.49, 93.74, 92.93, 92.29, 93.69, 93.95, 93.17, 95.31, 94.99, 92.11 and 94.53 % reduction of infestation at Narayanganj at 5th day after spray over control plot respectively. In Manikganj, the highest fibre yield (3.66 t/ha) was found in the plot treated with Rock 20 EC and the lowest (2.96t/ha) was found in Reset 20WDG treated plot. In case of Narayanganj, the highest fibre yield (3.85 t/ha) was found in the plot treated with Proxy 20 EC and the lowest (2.79t/ha) was found in Daman treated plot. These insecticides can be recommended for the farmer’s use to control jute hairy caterpillar.

The Use of Synthetic Herbivory-Induced Plant Volatiles That Attract Specialist Parasitoid Wasps, Cotesia vestalis, for Controlling the Incidence of Diamondback Moth Larvae in Open Agricultural Fields

We evaluated the effectiveness of using a blend of volatiles that attract Cotesia vestalis, a specialist parasitoid wasp of diamondback moth (DBM) larvae, to control DBM larvae on cabbage plants under open field conditions. We set three dispensers of the synthetic C. vestalis attractant together with one sugary-food feeder in a cabbage plot (10 m × 1 m; the treated plot) on one side of a pesticide-free open agricultural field (approximately 20 m × 20 m) from June to September in 2010 and July to August in 2011. On the other side of the field, we created a control cabbage plot of the same size in which neither dispensers nor a feeder was set. The incidences of DBM larvae and C. vestalis cocoons in the control and treated plots were compared. In 2010, the incidence of DBM larvae in the treated plot was significantly lower than that in the control plot. Poisson regression analyses in 2010 showed that the rate of increase in the number of C. vestalis cocoons along with an increase in the number of DBM larvae in the treated plot was significantly higher than that in the control plot. In 2011, the incidence in both the treated and control plots remained low (five larvae per plant or less) with no significant difference between the plots. Poisson regression analyses in 2011 showed that the number of C. vestalis cocoons in the treated plot was significantly higher than that in the control plot, irrespective of the number of DBM larvae. This 2-year field study suggested that the dispensers recruited native C. vestalis from the surrounding environment to the treated plot, and the dispensers controlled the number of DBM larvae in 2010 when the density of DBM larvae exceeded the economic injury levels for the cabbage crop. We also compared the incidences of other arthropods in the control and treated plots. The incidences of Pieris rapae larvae and Plusiinae spp. were not affected by the treatments. The number of aphids in the treated and control plots was inconsistent between the 2 years. Based on these 2-year results, the possible use of C. vestalis attractants in open agricultural fields is discussed.

Promotion of Growth, Chlorophyll Content and Yield of Rice by a New Drug at Ultra High Dilution

Application of synthetic fertilizers reduces natural fertility of soil and contaminates ground water. Some photosynthesis inhibitors at ultra-high dilution (UHD) increase photosynthesis, growth and yield of crops. A weedicide Paraquat at UHD enhanced growth and yield of potatoes in fields. This weedicide was serially diluted with distilled water and manually succussed in 30 steps following the method of preparation of homeopathic dilutions called potencies. In this way the 30th potency of Paraquat called Paraquat 30cH was prepared and preserved in 90 % ethanol. Paraquat 30cH was diluted with water 1:1000 (v/v) and sprayed on rice plants in a field measuring 0.3125 acre. The control plot of the same area was situated 300 meters away from the test plot. Three treatments were given at an interval of 7 days. Treated plot showed increased growth, chlorophyll content and yield of rice significantly as compared to control. The UHD of the weedicide produced exactly the opposite effect of the crude material on plants. The increased growth and yield of rice by Paraquat 30cH may be due to enhancement of photosynthesis of treated plants. The UHD of Paraquat increased yield of rice by 19.35% over the control.

Effect of Previous Crops and Fertilizers Management of Stem Amaranth in Vegetables – Vegetables - Rice Cropping System

Aims: To determine the effect of previous crops and fertilizers management on yield and yield parameters of stem amaranth (Amaranthus tricolor L.) in vegetables-vegetables-rice cropping system. Study Design: A randomized complete block design (RCBD) with six treatment combinations having four replications was used for the experiment. Place and Duration of Study: The field experiment was conducted in kharif-1 seasons (April to June) 2018 and 2019 at the research field of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh. Methodology: The layout was kept undisturbed for the cropping sequence over two years. Factor-A had three previous crops under the cropping system as P1= Potato (Potato - Stem Amaranth - T. Aman rice), P2= Garlic (Garlic -Stem Amaranth -T. Aman rice), P3= Cauliflower (Cauliflower -Stem Amaranth - T. Aman rice) and Factor-B had two level of fertilizers management as F1= Organic fertilizer (N based organic compost), F2= Inorganic fertilizer (Estimated inorganic fertilizer dose based on the soil test value without cow dung). The data were recorded on plant height, leaves per plant, stem diameter, stem yield (t ha-1) and stem dry matter content (%) during harvesting time. Results: Significantly maximum plant height was observed (93.5cm) in inorganic fertilizer treated plot under previous crop cauliflower which was followed by (93.0cm and 75.0cm) under garlic and potato, respectively. Whereas, minimum plant height (61.8cm) receiving organic source of fertilizers when the previous crop was potato in 2019. The interaction of previous crops and fertilizer application showed significant variation on leaves per plant of stem amaranth both in 2018 and 2019. Stem diameter showed the same trend as that of stem dry matter and resulted insignificant influence due to previous crops and fertilizers management over the two years. In 2018, significantly higher stem yield was observed (38 t ha-1) in inorganic fertilizer treated plot under previous crop cauliflower which was followed by (36.1 t ha-1and 35.5 t ha-1) under garlic and potato, respectively. Whereas, lower stem yield (20.0 t ha-1) receiving inorganic source of fertilizers when the previous crop was cauliflower. Higher stem yield was observed (51.4 t ha-1) in (F2P2) treated plot which was followed by (44 t ha-1) under F2P3 and F2P1, respectively. Whereas, lower stem yield (22.0 t ha-1) receiving F1 source of fertilizers when the previous crop was P3 in 2019. Conclusion: The experimental results of this study have shown that previous crops had a positive impact on the yield parameters of stem amaranth like plant height in 2018 and leaf numbers of plant both in 2018 and 2019. Interaction effect of previous crops and fertilizers management exerted significant variations only on leaves per plant of amaranth both in 2018 and 2019. Moreover, fertilizers management showed significant variation for plant height in 2019 and for stem yield both in 2018 and 2019.Therefore, it was concluded that stem amaranth after previous crop garlic with soil test based inorganic fertilizer could be high yielding and N based organic compost could be moderate yielding under Garlic- Amaranth – T. Aman cropping system.

Effects of soil and water conservation measures on plant species diversity: Wenago, Southern Regional State, Ethiopia.

Ethiopia including the study area are faced with deforestation, land degradation, soil erosion problems primarily caused by anthropogenic activities such as clearing vegetation for the purpose of agricultural use, fuel wood, Charcoal, construction and the reaction of conservation measures to restore deforested vegetation is too weak. The aim of the study was to investigate the effect of soil and water conservation (SWC) measures on plant species diversity by comparing between treated plot areas and non-treated plot areas. The data collection method was mainly drawn through plant measurements, inventory, GPS, household servey, key informant interview, focus group discussion, Office reports. To analyze the collected data, Shannon – wiener diversity index (H1) and Sorensen similarity coefficient indices (Is) calculation methods was employed. Based on the interview, direct observation, shannon’s diversity analysis and GPS results, the findings revealed that noticeable vegetation cover and plant species diversity have been observed in treated plot areas than non-treated plot areas in the last 10 years period.. This implies that well managed and protected homegardens and area exclosures have better plant species diversity than open grazing fields and communal lands. With these findings, it is rational to conclude that SWC measures have a positive effect on vegetation cover, Plant species diversity, richness and restoration. Thus, it is worth to recommend that conservation priority should be given to the more affected open grazing and communal lands.

Evaluation of Biological Approaches for Controlling Shoot and Fruit Borer (Earias vitella F.) of Okra Grown in Peri-Urban Area in Bangladesh

Irrational applications of insecticides on vegetable crops are very common in Bangladesh, resulting in harmful consequences for the environment and human health. Therefore, a study was conducted to evaluate the efficacy of biological and botanical insecticides on okra shoot and fruit borer grown in open fields. Four insecticides were used in this study, namely Bacillus thuringiensis (Bt), Spinosad 45 SC, Abamectin 1.8 EC, and Azadirachtin 1% EC an untreated control. The experiment used a randomized complete block design (RCBD) with three replications. The results showed that the rate of shoot infestation was the lowest in the Spinosad-treated plot (3.80%), and the highest was in the control (20.67%). The lowest fruit infestation (3.56%) was recorded in the treated plot of Spinosad. The rate of reduction of fruit infestation over control was 80.69, 60.14, 56.45, and 55.58% in the plots treated with Spinosad, Bt, Azadirachtin, and Abamectin, respectively. Consequently, the Spinosad-treated plot attained the highest yield (8.65 t ha−1), which was followed by the plots treated with Azadirachtin (6.74 t ha−1), Bt (6.28 t ha−1), and Abamectin (6.12 t ha−1). The highest net return and benefit–cost ratio (BCR) were 542.36 US$ and 2.64, obtained respectively from the Spinosad-treated plot. The second highest BCR (1.70) was obtained from the Azadiratin-treated plot, and the lowest BCR (1.18) was recorded in the Abamectin-treated plot. Therefore, the studied insect management practices could be incorporated to attain higher yields and economic benefits for growing okra in Bangladesh.

Testing of bio-rational and synthetic pesticides to manage cabbage aphid (Brevicoryne brassicae L.) in cabbage field at Rampur, Chitwan, Nepal

Cabbage aphid (Brevicoryne brassicae L.) is an important pest of cabbage which reduces the yield and quality of the cabbage head. Farmers haven been using chemical pesticides to manage them but unfortunately these practices are toxic for human health, biodiversity and the environment. The study was conducted to test the efficacy of different bio-rational insecticides along with the chemical insecticide. ‘Green Coronet’ cabbage variety was used and the field experiment was laid out in the experimental farm of Agriculture and Forestry University (AFU), Rampur, Chitwan during the winter season of 2014. The Experiment was designed in randomized complete block design with having 7 treatments (bio-rational insecticides with chemical and control) and 3 replications. Plot size was 5.76 m2 (2.4m×2.4m) and spacing of 1 m was maintained between each blocks and plots. Field experiment showed that the highest reduction of cabbage aphid was obtained in Dimethoate (30 EC) treated plot followed by Derisom treated plot. The highest yield of cabbage head was obtained in Dimethoate treated plots (66.47 mt/ha) which was significantly at par with the Derisom (58.79 mt/ ha) treated plots. The yield for other treated plots were 47.60 mt/ha for Margosom, 43.77 mt/ha for Verticillium, 41.63 mt/ ha for Cow urine, 36.77 mt/ ha for Spinosad and control (33.45 mt/ ha) in terms of cabbage head yield. And, at the same time, natural enemies’ population was significantly lower to Dimethoate treated plots compared to bio-rational insecticides. Thus, Derisom (Derris based botanical) might be the best viable alternative in eco-friendly management of cabbage aphid considering cabbage head yield and protection of natural enemies. It was also evident from the research that Margosom (Neem based botanical) was found beneficial not only to conserve natural enemies in the cabbage field but also to minimize cabbage aphid population.

Integrated pest management approach to control thrips of roses

The experiment was conducted at established rose garden of Regional Agricultural Research Station, Bangladesh Agricultural Research Institute, Jashore during 2017-18 and 2018-19 winter season (November-April). The experiment was laid out in a RCBD design with three dispersed replications. Four treatment combination were as follows: T1 =IPM package-1: Mechanical control + Sticky trap (Blue and White) + weekly spray of Azadirechtin (Bio-neem plus 1EC) @ 1.0ml/L of water, T2 = IPM package-2: Mechanical control+ Sticky trap (Blue and White)+ spray of Thiamethoxam 20% (Virtako 40SC) @ 1.5 ml/L of water, T3 = IPM package-3: Mechanical control+ Sticky trap (Blue and White)+ weekly spray Chlorphenapyr (Intrepid 10EC) @ 1 ml/L of water and T4 = Farmers practice: weekly spray Imidacloprid (Imitaf 20SL) @ 0.5ml/L of water. For mechanical control hand picking was done and harmful insect also classified as the most direct and the quickest way to remove clearly visible pests. Two color stiky trap (white and blue) were set up in each line. The lowest number of rose thrips was found in IPM package 2 (6.36 in 2017-18 and 3.03 in 2018-19) and highest in farmer’s practices (14.36 in 2017-18 and 12.40 in 2018-19). The lowest percent flower infestation of rose was recorded in IPM package 2 (9.98 to 17%) and the highest in Farmers practice (19.72 to 32.66%). The highest yield (864000 no./ha in 2017-18 and 535932 no./ha) was recorded from IPM package 2 and the lowest in farmers practice (438750 no./ha in 2017-18 and 388857 no./ha). The results revealed the highest MBCR was observed in IPM package-2 (Mechanical control+ Sticky trap (Blue and White) + spray of Thiamethoxam 20% (Virtako 40SC) @ 1.5 ml/L of water.) treated plot (17.2 to 49.7) in both the year. Finally, it may be recommended that IPM package 2 is very much effective to control thrips of rose as well as high yield and more economic return. Progressive Agriculture 31 (2): 89-93, 2020

EXTENT OF DAMAGE OF RICE BUG (Leptocorisa Acuta) AND ITS CONTROL WITH INSECTICIDES

The rice bug, Leptocorisa acuta is one of the major and destructive pests of rice. The experiments were conducted to study on the extent of damage of rice bug, Leptocorisa acuta and to determine the efficacy of five insecticides. The experiments were laid out in a Randomized Complete Block Design (RCBD) with three replications of each treatment. From the study it was found that the infestation rate was in linear progress and the hill infestation was 5.42 to 13.75%, panicle infestation was 27.27 to 54.55%, grain infestation was 4.70 to 7.58% and partial grain infestation was 1.82 to 2.58% respectively. After using different treatments, it was found that the maximum percent of infestation was observed in control and minimum was in Malathion 57 EC treated plot. The maximum no. of grain per panicle was observed in case of Malathion 57 EC (206.4), whereas the minimum was observed in Control (172.6) plot. Malathion and Neem oil showed similar effect when yield was compared while the minimum yield was observed in control treatment. The efficacy of insecticides was ranked as Malathion 57 EC > Azadiractin 2% > Chlorpyrifos 20 EC > Voliam flexi 300 SC > Imidacloprid 17.8 SL. The efficacy of all insecticides on the infestation of rice at different time intervals indicate that all the toxicity of all the products decreases with the progress of time after application. It can be recommended that Malathion 57 EC was most effective chemical in controlling rice bug.

Growth, productivity and nutrient uptake of aerobic rice (Oryza sativa L.) as influenced by different nutrient management practices

A field experiment was undertaken to study the effect of nutrient management on rice cv. Puspa (IET-17509) during pre-kharif season of 2013 and 2014. The experiment was conducted at Rice Research Station, Bankura with eleven different nutrient management practices i.e., N1 = N, P2O5, K2O @ 60, 30, 30 kg ha-1 (RDF);N2 = RDF + Vermicompost @ 2.5 t ha-1; N3 = RDF + FYM @ 5 t ha-1 ; N4 = FYM @ 5 t ha-1, N5 = Vermicompost @ 2.5 t ha-1 ; N6 = RDF + glyricidia (well decomposed) as green manure @ 3 t ha-1; N7 = RDF + ZnSO4 @ 20 kg ha-1 N8 = RDF + borax @ 2 kg ha-1 ; N9 = RDF + Vermicompost @ 2.5 t ha-1 + ZnSO4 @ 20 kg ha-1 ; N10 = RDF +Vermicompost @ 2.5 t ha-1 + borax @ 2 kg ha-1 ; N11 = RDF + Vermicompost @ 2.5 t ha-1 + ZnSO4 @ 20 kg ha-1 + borax @ 2 kg ha-1 respectively in randomized block design comprising of three replications. The result of experiment revealed that rice plot fertilized with the combination of NPK @ 60:30:30 + VC + ZnSO4@ 20 kg ha-1 + borax @ 2 kg ha-1 recorded the highest grain yield of 4.45 t ha-1 which was 56.69 % higher (2.84 t ha-1) than the FYM treated plot. Organic substitution by FYM and vermicompost (VC) had failed to register the significant impact on growth, yield and nutrient uptake. Nutrient uptake and residual nutrient status was also highest in NPK @ 60:30:30 kg ha-1 + VC @ 2.5 t ha-1 + ZnSO4 @ 20 kg ha-1+ borax @ 2 kg ha-1 fertilized plot.