COMPARATIVE EFFICACY OF SOME INSECTICIDES AGAINST MAIZE APHID (Rhopalosiphum maidis) AND ITS INFLUENCE ON NATURAL ENEMIES IN MAIZE ECOSYSTEM

The maize aphid, Rhopalosiphum maidis is one of the most serious pests of maize crop in Bangladesh. Nowadays, it becomes a major barrier for production of maize due to create hamper of pollination. In the present research investigation, the field efficacy of some insecticides was evaluated against maize aphid infestation and their toxic effects were also studied on some natural enemies in the maize ecosystem. To achieve the research goal, a field experiment was conducted on maize at the Entomology Field Laboratory, Department of Entomology, Bangladesh Agricultural University (BAU), Mymensigh during Rabi season of 2017-18. The experiment was set up in Randomized Complete Block Design (RCBD) with five treatments (Imidagold 20SL@ 0.1, 0.3 & 0.5ml/L; Ambush 1.8EC@ 1.5, 2.5 & 3.0ml/L; Hadhak 45WP@ 0.2, 0.4 & 0.6g/L; Suspend 5SG@ 0.5, 1.0 & 1.5 g/L and Heron 5EC @ 0.5, 1.0 & 1.5ml/L) and three replications for each treatment. Maize viz. BARI Hybrid Butta-09 was used as experimental crop. Data were collected on percent reduction of plant infestation & population of natural enemies, yield attributes and benefit cost ratio (BCR). Result clearly indicated that these mentioned parameters were highly significant with the application of insecticides. However, Imidagold 20SL@ 0.5ml/L resulted in the greatest (77.27%) percent reduction of maize plant infestation, the highest (623.51) number of grain per cob, the maximum (39.74g) 100 grain weight, the highest (10.02 t/ha) grain yield, the highest (63.27%) percent grain yield over control and maximum (1.56) benefit cost ratio compared to others tested insecticides which was statistically similar with the dose of 0.3ml/L of Imidagold 20SL. And then, this result was followed by Ambush 1.8EC, Hadhak 45WP, Suspend 5SG and Heron 5EC, respectively. Besides, the highest (93.67%) percent cumulative mean of maize plant infestation, the lowest (330.45) number of grain per cob, minimum (13.43g) 100 grain weight, the lowest grain yield (3.68 t/ha) and the lowest benefit cost ratio (0.95) were obtained from untreated control. With a view to know the toxic effect of different insecticides, the percent reduction of population of natural enemies was counted at 2 days, 5 days and 7 days after spraying. In all field trials, the harmful effects of the five insecticides were in the following rank order (least harmful to most harmful): Imidagold 20SL

EFFECTS OF CLIMATE CHANGE ON AGRICULTURE AND ITS MITIGATION THROUGH CLIMATE SMART AGRICULTURE PRACTICES IN NEPAL

Climate change has caused serious effect on agriculture production. The global population is increasing and to meet their demand for fuel, food, and fiber, Farmer should adopt sustainable agriculture practices which provides resilience to climate change and uplifts the farmers’ livelihood. Climate-smart agriculture practices are taken as eco-friendly practices that help to enhance production sustainably with minimum effect on resources and environments. These practices include No-tillage, reduced tillage, Intercropping, integrated pest management, Rainwater harvesting, use of information and communication technology, etc. As women are an integral part of agriculture production and are more vulnerable to climate change, the Gender-responsive approach needs to be addressed which helps to close the gender gap in agriculture. Nepal, as a vulnerable country in terms of climate change, is adopting different programs and policies at the national and local level to tackle climate change. Climate-smart villages(CSV) in Nepal are practicing different CSA practices at the farm level to secure foods and livelihoods.

A REVIEW ON: CITRUS GREENING, ITS HISTORY, SYMPTOMS AND MANAGEMENT TACTICS

Citrus greening disease or haunglongbing was critically reviewed with respect to history, symptoms and management tactics. It has been evident that citrus greening disease has emerged as a potential threat in the citrus growing areas of the world including Nepal also. It has been proven that greening disease is major cause of citrus decline; hence necessary steps should be taken for the control of citrus greening disease.

LAND SUITABILITY EVALUATION USING GIS FOR VEGETABLE CROPS AT SHARADANAGAR, CHITWAN, NEPAL

The present research was conducted at Chitwan district of Sharadanagar to evaluate land suitability integrating with Geographical Information System (GIS) technology-incorporates the multi criteria evaluations (MCE) and analytic hierarchy process (AHP) in 2014.

QUALITY RETENTION OF LITCHI (LITCHI CHINENSIS SONN.) BY USING POLYPROPYLENE BAG AND LOW TEMPERATURE

This experiment was conducted to observe the postharvest behaviors of litchi for using low temperature (4 °C) and polypropylene (PP) bags of different thickness. The two-factor experiment was conducted in a completely randomized design with three replications. Total 8 treatments are implemented in this study. The experiment consisted of two factors: Factor A: Temperature (T1: Ambient temperature, T2: 4ºC temperature) and Factor B: Polypropylene bag (P1: unwrapped, P2: 50µ PP bag, P3: 75µ PP bag, P4: 100µ PP bag. In case of low temperature (4 °C), litchi retained its 50% color at 10th days of storage, highest shelf life (21.33 days), highest moister content (83.3%) & highest amount of vitamin C (35.61 mg/100g) were found at 3rd day of storage. In case of different thickness of polypropylene bags, litchi kept in 75µ PP bags retained its 100% color up to 4th day of storage, shelf life (16.34 days), maximum moister content (83.14%) & maximum amount of vitamin C (35.78 mg/100g) were found at 3rd day of storage. It can be possible to save a large amount of litchi fruits every year from postharvest decay by using low temperature (4 °C) and 75µ PP bag.

RESPONSE OF POTATO (SOLANUM TUBEROSUM L.) TO THE APPLICATION RATES OF BIOCHAR AND NUMBER OF IRRIGATIONS

A split-plot experiment was conducted to determine the response of potato to application rate of biochar (0, 2, 4 and 6 t/ha , main plots) and number of irrigations (once, twice and thrice a month, sub-plots) in 3 replications as a pot trial in a screen house at Khumaltar during winter season of 2018 and 2019. Biochar was produced from Lantana camara by semi-pyrolysed technique in a Kon Tiki drum. Plastic pots with 26 cm of diameter were used to meet the 25 cm plant spacing of potato recommended in Nepal. The early maturing (90 days) released variety ‘Desiree’ was used for the trial. Observations were recorded on plant and tuber attributes. The results revealed that the influence of biochar rates was positive over zero biochar on plant height, root fresh weight, root dry weight, stem fresh weight and tuber dry weight. The effect of biochar @ 2/ha had similar effects to the rates of 4 t/ha and 6 t/ha rates. Irrigation treatments were significantly different for plant height, number of tubers per plant, root fresh weight, stem and leaf fresh weight, tuber fresh weight, root dry weight and tuber dry weight. Among the irrigation schedules, irrigating twice and thrice a month had similar effects but they were different from one irrigation. Interactions of biochar @ 2 t/ha with one, two or three irrigations were superior to the interactions of biochar @ 0 t/ha with one and two irrigations for tuber dry weight and total dry weight.

DAMAGING NATURE OF FALL ARMYWORM AND ITS MANAGEMENT PRACTICES IN MAIZE: A REVIEW

Fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a polyphagous pest which is arising as one of the major threats to agricultural crop production. It has around 80 host species that cause severe damage to cereals and vegetable crops. This pest was first discovered in Africa (2016) and first collected and reported in Nepal at Nawalparasi district on 9th may 2019. The larvae of FAW are found on young leaves, leaf whorls, tassels or cobs according to their growth stages. First instar larvae scrape leaves and shows pin-hole symptoms and window-pane feeding symptoms whereas in the later vegetative stages, damage results in skeletonised leaves and heavily windowed whorls. If climatic condition for pest establishment is suitable this pest could cause approximately 100% crop loss in maize if not managed in time. Regular scouting, push and pull method, black light traps, commonly available botanicals like neem locally available materials like ash and some recommended insecticides with recommended dose can be used for the control of fall armyworm. There is an urgent need for developing ecologically sustainable, economically profitable, and socially acceptable integrated pest management strategies to mitigate the impacts of the fall armyworm and not just rely on single management practice.

COMPARATIVE EFFICACY OF SOME NEWER INSECTICIDES AGAINST RICE LEAF FOLDER (CNAPHALOCROSIS MEDINALIS GUEN.) AND THEIR EFFECTS ON NATURAL ENEMIES IN RICE ECOSYSTEM

In the present study, some new generation insecticides were evaluated against rice leaf folder (RFL) infestation and their toxic effects were also observed on some natural enemies in the rice ecosystem. Data were collected on percent hill infestation, percent leaf infestation, number of moths/sweep, grain yield (t/ha) and abundances of natural enemies/m2. Results clearly showed that Serput (Bifenthrin) 2.5EC @ 2.0 ml/L water resulted in the greatest reduction of RFL and increased the grain yield compared to the untreated control which was followed by Envoy (Fipronil) 50SC @ 1.0 ml/L, Libsen (Spinosad) 45SC @ 0.40 ml/L, Acemida (Acephate + Imidacloprid) 51.8WDG @ 1.0 g/L, Suspend (Emamectin benzoate) 5SG @ 1.0 g/L, Combi-DT (Deltamethrin + Triazophos) 36EC @ 0.50 ml/L and Altima plus (Thiamethoxam + Emamectin benzoate) 40WG @ 0.20 g/L respectively. To know the toxic effect of selected insecticides, abundances (number/m2) of some natural enemies were counted at 7 days after given each spray. It was found that the highest numbers of natural enemies (m2) were recorded in the untreated control plot. In all field trials, the harmful effects of the seven insecticides were in the following rank order (least harmful to most harmful): Suspend 5SG, Serput 2.5EC, Envoy 50SC, Libsen 45SC, Acemida 51.8WDG, Altima plus 40WG and Combi-DT 36EC. Based on the reduction in rice leaf folder infestation, increase in grain yield and compatibility with natural enemies, Serput 2.5EC @ 2.0 ml/L proved to be the best among all the selected insecticides.

RESPONSE OF SULPHUR AND ZINC NUTRITION TO THE SEED YIELD AND OIL CONTENT OF MUSTARD (CV. BARI SARISHA-14)

The role of different nutrient elements is well established in plant metabolism. However, different crops respond differently in relation to their growth and yield. An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh to evaluate the response of sulphur and zinc nutrition to the seed yield and oil content of mustard (cv. BARI Sarisha-14). It, laid out in RCBD with three replications was consisted of four levels of sulphur (0, 20, 40 and 60 kg ha-1) and Zn (0, 1, 2, 3 kg ha-1). It was observed that 60 kg Sulphur ha-1 gave significantly highest seed yield, oil content and harvest index owing to the highest number of branches plant-1, siliqua plant-1, seeds siliqua-1 and 1000-seed weight. Conversely, 0 kg Sulphur ha-1 provided the lowest seed yield and oil content of mustard. Again, the highest number of braches plant-1, siliqua plant-1 and seeds siliqua-1 was found at 3 kg zinc ha-1 which resulted in the highest seed yield, oil content and harvest index. The lowest performance of the yield components and yield was observed at 0 kg zinc ha-1. Interaction effect between 60 kg sulphur ha-1 and 3 kg zinc ha-1 provided the highest seed yield and stover yield because of the highest number of branches plant-1 and seeds siliqua-1 and the worst yield performance was a observed at the control treatment. Therefore, the application of sulphur and zinc at the rate of 60 kg ha-1 and 3 kg ha-1, respectively could be applied for BARI sarisha-14 for higher seed yield.

EFFICACY OF COMMERCIAL INSECTICIDES AGAINST FRUIT AND SHOOT BORER, LEUCINODES ORBONALIS GUENEE OF BRINJAL, SOLANUM MELONGENA L. IN DHADING, NEPAL

A study was conducted from January to June 2019 in Dhading district to identify the effective commercial insecticide against fruit and shoot borer of brinjal (Leucinodes orbonalis). A field experiment was conducted in Randomized Completely Block Design with five treatments (T1: Spinosad @ 1 ml/ 3 liters, T2: Chlorantraniliprole 1 ml/ 3 liters, T3: Cypermethrin 3 ml/ 1 liter, T4: Neem 3 ml/ 1 liter and T5: Control) and four replications. Result indicated that the fruit infestation percent and shoot damage reduction percent, fruit infestation reduction percent were highly significant with the application of insecticides. The shoot damage percent and fruit damage percent was the lowest with spinosad followed by chlorantraniliprole, cypermethrin and Neem. Thus, spinosad is the most effective insecticides for the management of fruit and shoot borer of brinjal in field conditions.