Efficacy of Newer Insecticides against Leaf Hopper and Whitefly Infesting Brinjal and its Effect on Coccinellids (original) (raw)
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Under the laboratory conditions (28 o C±1, 70 ± 5%% relative humidity) a trial was conducted in the laboratory of Department of Entomology, University of Agriculture Faisalabad during 2012-13 to evaluate the effect of comparative toxicity of different insecticides against adults of the ladybird beetle (Coccinella septempunctata L.). In this experiment seven treatments used namely Ememectin Benzoate (Timer® 1.9 EC), Indoxacarb (Steward® 150 EC), Imidachloprid (Crown® 70 WS), Chlorpyrifos (Helmat® 40 EC), Spinosad (Tracer® 480 SC), Leufenoron (Track® 10 EC) and Acetamaprid (Astarp® 250 WP). The experiment was laid out with five replications under Completely Randomized Design (CRD). Leaf dip bioassay method was used for Coccinella septempunctata L. Probit analysis was applied for statistical analysis. Our Results showed that the most toxic chemical was Chlorpyrifos that caused 100% mortality of adults of ladybird beetle after 72 hours and imidachloprid was the safest insecticide which can be included in integrated pest management practices. The order of toxicity on the basis of mortality was Chlorpyrifos > Indoxacarb > Spinosad > Acetamaprid > Ememectin Benzoate > Leufenoron > Imidachloprid. 1. Introduction Ladybird beetles are one of the most colorful insects in many parts of the world from a human perspective. Ladybird beetles are well known for their particular role in biological ecosystems [1]. These have valuable parts in our environment and have been used in different regions of the world to control pests such as thrips aphids, mealy bugs and mites. Therefore, this bio-agent has received much attention of researchers. Many efforts are being made to protect this predator from exposure of hazardous chemicals as this insect has become an important part of modern agriculture [2]. It is usually believed that there is an important role of natural enemies in regulating the pest populations. The most severe constraint to realizing the potential of natural enemies in field crops is disruption through the widespread use of insecticides with broad toxicity to both pest and their natural enemies [3] .The Coccinellid predators can tolerate many insecticides which is an advantage over other predators. It is the most valuable bio control agent for the cotton pests, with its immature and mature stages. It is a voracious feeder of all the species of aphids [4, 5]. The extensive use of insecticides has deleterious influence on biological control agents in many crop systems, for example these insecticides have a direct or indirect effect on the population of parasitoids and predators. Sometime, the indiscriminate use of the insecticides adversely affect the population of these biological control agents and most of them killed by them. As a result of this, the natural pressure of these natural enemies on insect pests is decreased and outbreaks of the insect pests occur in many agricultural lands and sometime secondary insect pests abruptly become serious primary pests that cause economic losses to agricultural crops [6]. The use of insecticides accompanied with indigenous or exotic bio-control agents are considered as a rapid and effective control method for different insect pests with more interest [7, 8]. Problems such as insecticides resistance, pest resurgence and residues on crops are the result of the over use of Insecticides. This directed to the implementation of alternative pest management strategies, such as biological control.
Current Science, 2019
Influence of elevated CO2 and temperature (elevated condition (EC)) vis-à-vis ambient CO2 and tempera-ture (ambient condition (AC)) on plant (rice) growth, insect Nilaparvata lugens (brown planthopper (BPH)) population and insecticide (Imidacloprid) efficacy was evaluated under open top chamber conditions. EC had a positive effect on rice crop through increase in tillers numbers (18.4%), reproductive tillers (20.5%) but in-flicted negative effect on 1000-grain weight (11.7%) and grain yield (11.9%). Likewise, higher canopy cover of the plant was noticed under EC (16.1 cm) when compared to AC (12.9 cm). With respect to BPH population during 2013 and 2014, EC exhibited posi-tive effect by enhancing its mean population to 66.1 and 49.4 hoppers hill–1 respectively, compared to cor-responding 36.8 and 29.5 hoppers hill–1 under AC. With respect to Imidacloprid efficacy against BPH, LC50 was significantly lower under EC (0.044%) in comparison to AC (0.065). Similarly, in 2013 under AC, 500, 600, 700 l ha–1 spray volume caused >50% BPH mortality than 400 l ha–1 at 5 day after spray. However, during the same exposure period under EC, only 700 and 600 l ha–1 produced more than 50% mortality compared to 500 and 400 l ha–1. Positive in-fluence of EC on BPH population resulted in signifi-cantly higher yield loss (41.1%) compared to ambient (26.5%) in untreated check. Though LC50 under EC was less, higher canopy size and more BPH population resulted in increase in spray volume to cause similar mortality as of AC. The present results indicated that spray volumes of 400 and 500 l ha–1 was found insufficient to manage BPH population under EC; hence the current management strategies for BPH needs to be redefined under changing climatic conditions.
Effect of different insecticides on Coccinellid and Spider in rice field in district Allahabad, U.P
Journal of entomology and zoology studies, 2017
Rice is a seed of the grass species Oryza sativa (Asian rice) or Oryza glaberrima (African rice). As a cereal grain, it is the most widely consumed staple food for a large part of the world's human population, especially in Asia. The pooled data indicates that all insecticides were effective over control in reducing the population of coccinellids recorded at 3, 7 and 14 days after insecticidal applications. Chloropyrifos was found significantly superior (.65, .50, .77) followed by Cypermethrin (.78, .66, .85), Carboryl (.85, .69, .82), Cartaf (.85, .68, .86), Imidaclorpid (.87, .64, .83), Tiomethoxam (.90, .60, .80), Triazophos (.85, .90, .95) as compared to control (1.18, 1.31, 1.44) at 3, 7 and 14 days respectively. Percentage population reduction of coccinellids recorded at 3, 7 and 14 days after insecticidal applications. Chloropyrifos found significantly superior (41.31, 59.70, 43.18) followed by Thiomethoxam (30.25, 58.50, 50.33) as compared to other treatments Cartaf (28....
Evaluation of selected insecticides against brown planthopper and their impact on natural enemies
The present investigation on the effectiveness of different insecticides against the brown planthopper, Nilaparvata lugens (Stal.), on rice in field conditions demonstrated that pymetrozine 50% WG @ 150 g a.i./ha was found to be the most efficient chemical, recording the highest overall percent decline in BPH population, i.e., 76.88 percent and 79.86 percent after both the initial and second sprays, accordingly. Pymetrozine was succeeded by sulfoxaflor 24% SC @ 175 ml a.i./ha, which recorded 75.10 percent and 74.49 percent reduction. Pymetrozine 50% WG, with 2.21 BPH/hill after first spray and BPH/hill after second spray, had the lowest overall mean population of BPH, followed by sulfoxaflor 24% SC, with 2.38 BPH/hill after first spray and 2.28 BPH/hill after second spray. All the treatments reported safer to the population of spiders and coccinellids among them pymetrozine 50% WG recorded higher mean population of spiders 2.44 and coccinellids 1.08 per hill in comparison with untreated plot.
The nymphs and adults of white-backed planthoppers (Sogatella furcifera, Howard) remove plant sap resulting in yield loss. Indiscriminate use of insecticides, results in the development of resistance by insects and ill effects on the environment opening the new era of chemicals with novel modes of action with good bioefficacy, higher selectivity, low mammalian toxicity and safety to the environment. Therefore, the introduction of newer insecticide molecules with alternate modes of action will play a serious role in pest management programs. Hence, an experiment was conducted to evaluate the bioefficacy of ethiprole + pymetrozine against white-backed planthopper of rice (ADT-46) under laboratory and field conditions at Annamalai University, Chidambaram during 2018-20. Ethiprole + pymetrozine @ (T1-36.91 + 138), (T2-40.13 + 150) and (T3-45.47 + 170) g a.i ha-1 with standard checks T4-pymetrozine @ (150) g a.i ha-1 , T5-buprofezin @ (200) g a.i ha-1 and T6-ethiprole + imidacloprid @ (50 + 50) g a.i ha-1 were evaluated against white-backed planthopper. The standard checks were of positive control i.e., reference insecticides which is in common use The results revealed that T3 recorded the lowest population of white-backed planthopper/ hill at 15 day after spraying (1.13 hoppers/hill in August-December 2018 and 1.79 hoppers/hill in August-December 2019 respectively) giving better yield. The population of natural enemies was comparatively lower in all insecticidal treatments than in the control.
Journal of entomology and zoology studies, 2018
An experiment was conducted during Kharif season in 2016 at the Central Research Farm, SHUATS, Naini, Allahabad to observe the three applications of seven insecticides viz Imidacloprid 17.8% SL, Trizophos 25% SP, Monocrotophos 36% SL, Thiamethoxam 25% WG, Acephate 75% SP, Carbaryl 50% SP, Malathion 50% EC on natural enemies of insect pests in rice field under agro-climatic condition of Allahabad. Results were revealed that all the treatments were effective significantly to suppress the population of Coccinellids as compared with control (1.36 Coccinellids/hill). The treatment Monocrotophos was recorded lowest population of Coccinellids with (0.54 Coccinellids/hill) and found to be superior among all other treatments. This was followed by Triazophos (0.65Coccinellids /hill), Carbaryl (0.76Coccinellids /hill), Thimethoxam (0.83Coccinellids/hill), Malathion (0.87Coccinellids /hill), Imidacloprid (0.91Coccinellids/hill), Acephate (1.07Coccinellids/hill) respectively.
Phytoparasitica, 2008
Three experiments were carried out during three consecutive years to evaluate 19 insecticides and 12 tank mixtures of different groups of insecticides against the whitefly Bemisia tabaci and its predators and parasitoids under field conditions in cotton. In the first experiment, the whitefly population was lower in treatments with thiacloprid and higher in those with black warrant (a.i. alcohol) and cypennethrin; the number of predators was higher with Agri-50 and spinosad and lowest with cypermethrin, whereas percent parasitism was higher with thiacloprid and lower with methamidophos. In the second experiment, the whitefly population was lower in treatments with buprofezin, pyriproxyfen and diafenthiuron and higher in those with endosulfan, imidacloprid and thiamethoxam; the number of predators was higher with pyriproxyfen and lower with thiamethoxam, whereas percent parasitism was higher with pyriproxyfen and lower with thiamethoxam. In the third experiment, the whitefly population was lower in a treatment mixture with buprofezin + fenpropathrin and higher in that with thiamethoxam + chlorpyrifos; the number of predators was higher with buprofezin + fenpropathrin and lower with deltamethrin + triazophos and deltamethrin + chlorpyrifos, whereas percent parasitism was higher with the mixture of pyriproxyfen + chlorpyrifos and lower in imidacloprid + chlorpyrifos, betacyfluthrin + triazophos, and deltamethrin + triazophos. Effective use of these insecticides to manage whitefly infestations and to save predators and parasitoids is discussed.
Relative toxicity of three wheat herbicides to two species of Coccinellidae
Insect Science, 2010
On the High Plains of the USA, herbicides specific for broad-leaf weeds are regularly applied to winter wheat in the early spring, sometimes late enough to coincide with the colonization of fields by cereal aphids and their natural enemies. We tested the toxicity of three such herbicides, Ally (Dupont), Rave (Syngenta) and 2,4-D ester (generic), to neonate larvae of two coccinellid species important in cereal aphid biocontrol, Coleomegilla maculata DeGeer and Hippodamia convergens Guérin-Méneville. Topical treatment of larvae with 2,4-D resulted in 25% and 60% mortality in the two species, respectively, with surviving C. maculata larvae experiencing a 5% increase in developmental time. No significant effects were noted for the other two materials, save for a 2.5% increase in developmental time for C. maculata larvae exposed to Rave. No material caused significant mortality in either species when larvae were fed on prey (Schizaphis graminum Rondani) treated with herbicide 24 h earlier, although 2,4-D reduced developmental time slightly in C. maculata. When herbicide applications are delayed enough in spring to coincide with aphid activity in wheat, farmers can reduce the risk of disrupting biological control by selecting an alternative to 2,4-D.