Efficacy of Citrullus colocynthis seed extract on Earias vittella, Fabricius, (Lepidoptera: Noctuidae): environment sustainable approach

Earias vittellaFabricius, 1794 (Noctuidae: Lepidoptera) is deliberated to be one of the most destructive pests of cotton and okra vegetation in the world including Asia. The pest has established resistance to various synthetic insecticides. The use of bio-pesticide is one of the unconventional approaches to develop a vigorous ecosystem without harming non- target pests and beneficial natural insect fauna. In the present study, the toxicity levels of Citrullus colocynthis seed extract have been evaluated against the populations of E. vittellaunder standardized laboratory conditions. The toxic effects of C. colocynthis on development periods, protein contents and esterase activity of the life stages of E. vittella were also evaluated. The toxicity levels of methanol, ethanol, hexane, water and profenofos were evaluated on the 1st instar larvae of E. vittella. LC30 and LC80 concentrations exhibited the effectiveness of methanol-based C. colocynthis seed extract against 1st instar larvae of E. vitella. The enhanced larval and pupal periods were revealed in treated samples during the comparison with untreated samples. The intrinsic rate of increase, net reproductive rate in the LC30 and LC80 concentrations exposed larvae remained less than the control treatment. Fecundity, the esterase activity and protein contents were declined in LC30 and LC80 treated samples as compared to the control. The present findings suggest that C. colosynthis extracts based botanical insecticides are beneficial, ecosystem sustainable and can be integrated with insect management programs from environment safety perspective.

The Impact of Microbial and Botanical Insecticides on Grape Berry Moths and Their Effects on Secondary Pests and Beneficials

According to the European Directive 2009/128/EC and the subsequent provisions activated in member states, conventional pesticides should be progressively replaced by “non-chemical tools and/or measures”. The identification of reliable alternatives to pesticides is crucial to achieve this objective. A European project (PURE) was funded to investigate this topic with reference to annual and perennial crops. In this framework, a number of natural insecticides, in particular microbial and botanical ones (Bacillus thuringiensis subsp. kurstaki, Beauveria bassiana, azadirachtin, pyrethrins and spinosad) were selected to test their effectiveness against grape berry moths, the key pests in most European vineyards. Trials were conducted in 2011 and 2012 in two experimental vineyards located in Italy (Tuscany and Veneto regions), following a randomized block design. Additional investigations were carried out in the Veneto region during 2013. Trial results stressed the high performance of spinosad and B. thuringiensis in controlling berry moth densities and the related damage. The use of B. bassiana mixed with B. thuringiensis did not significantly improve the impact of B. thuringiensis alone. Azadirachtin, and especially pyrethrins, proved to be less effective on berry moths than previous insecticides. The use of selected insecticides caused side-effects on a number of secondary pests, in particular leafhoppers. In 2011, densities of Empoasca vitis were more abundant in spinosad-treated plots probably because of a reduced egg parasitism rate. One year later, population densities of Zygina rhamni were more abundant on spinosad and pyrethrin-treated plots. This trend was confirmed on spinosad-treated plots in the last experimental year. At the same time, spinosad and pyrethrins significantly reduced the predatory mite populations compared to other treatments. The use of these insecticides in viticulture is discussed in the framework of organic viticulture and Integrated Pest Management (IPM).

Effects of Peganum harmala L. Seed Extract on Culex pipiens (Diptera: Culicidae)

Mosquito-borne diseases result in the loss of life and economy, primarily in subtropical and tropical countries, and the emerging resistance to insecticides is increasing this threat. Botanical insecticides are promising substitutes for synthetic insecticides. This study evaluated the larvicidal and growth index of Culex pipiens of four solvent extracts of Terminalia chebula, Aloe perryi, and Peganum harmala against Cx. pipiens. None of the 12 extracts exhibited larvicidal potential against third instars except the ethyl acetate extract of P. harmala. After 24 h of exposure, the LC50 value was 314.88 ppm, and the LC90 value was 464.19 ppm. At 320 ppm, the hatchability was 25.83%, and it resulted in 100% mortality. In addition, the eggs treated with the EtOAc extract of P. Harmala exhibited a long larval period compared with the control. The larval period continued for 12 days, and the pupal period took three days in the treatment groups. The growth index data also exhibited a decrease (0.00–7.53) in the treated groups compare with 8.5 in the control. The transformation of eggs into adults decreased with increasing concentrations. This paper is the first report on the development and growth index of Cx. pipiens potential using P. harmala seeds.

Seasonal incidence and efficacy of botanical insecticides against Painted bug, Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae) in Indian mustard (Brassica juncea genotype RH 725)

Bagrada hilaris (Burmeister) is a serious pest of Brassica crops in the North-Western region of India, inflicting crop yield losses. Therefore, the present study was conducted on seasonal incidence and management of B. hilaris in Brassica juncea genotype RH 725 at farmer’s field, Kolana village, Aravalli Hills Region, Rewari, Haryana, India during Rabi, 2019-20 and 2020-21. This study laid out the trial in a randomized block design with three replications and six treatments viz., Neem Seed Kernel Extract (NSKE) @ 7%, Nimbecidine @ 0.03%, Neem oil @ 5%, NSKE @ 5%, Neem oil @ 7% and control (unsprayed). Observations on the incidence of B. hilaris showed that it appeared from 5th Standard Meteorological Week (SMW) (0.34 bugs plant-1) and attained peak during 10th SMW with 5.77 bugs plant-1. The incidence of B. hilaris exhibited significant positive correlation with maximum (r=0.852, p<0.05) and minimum (r=0.900, p<0.05) temperature, rainfall (r=0.763, p<0.05) and wind velocity (r=0.959, p<0.05). Spray of Neem oil @ 7% (83.01 %) was the most effective in reducing the B. hilaris population over control followed by NSKE @ 7% (81.48 %), while NSKE @ 5% (68.85 %) confirmed least effective. Seed yield in different treatments varied from 1440.5 kg ha-1 (NSKE @ 5%) to 1590 kg ha-1 (Neem oil @ 7%) against 1216 kg ha-1 in control. The highest incremental cost-benefit ratio was registered with NSKE @ 7% (1: 7.70) followed by Nimbecidine @ 0.03% (1: 7.41) and NSKE @ 5% (1: 6.25). The present investigation signified that the study on the seasonal incidence of B. hilaris in relation to weather parameters could provide information for planning pest control and management strategies. The botanicals could be used as eco-friendly and economical substitutes for chemical insecticides at farmer’s fields against this insect pest.

Insecticidal Triterpenes in Meliaceae: Plant Species, Molecules and Activities: Part Ⅰ (Aphanamixis-Chukrasia)

Plant-originated triterpenes are important insecticidal molecules. The research on insecticidal activity of molecules from Meliaceae plants has always received attention due to the molecules from this family showing a variety of insecticidal activities with diverse mechanisms of action. In this paper, we discuss 102 triterpenoid molecules with insecticidal activity of plants of eight genera (Aglaia, Aphanamixis, Azadirachta, Cabralea, Carapa, Cedrela, Chisocheton, and Chukrasia) in Meliaceae. In total, 19 insecticidal plant species are presented. Among these species, Azadirachta indica A. Juss is the most well-known insecticidal plant and azadirachtin is the active molecule most widely recognized and highly effective botanical insecticide. However, it is noteworthy that six species from Cedrela were reported to show insecticidal activity and deserve future study. In this paper, a total of 102 insecticidal molecules are summarized, including 96 nortriterpenes, 4 tetracyclic triterpenes, and 2 pentacyclic triterpenes. Results showed antifeedant activity, growth inhibition activity, poisonous activity, or other activities. Among them, 43 molecules from 15 plant species showed antifeedant activity against 16 insect species, 49 molecules from 14 plant species exhibited poisonous activity on 10 insect species, and 19 molecules from 11 plant species possessed growth regulatory activity on 12 insect species. Among these molecules, azadirachtins were found to be the most successful botanical insecticides. Still, other molecules possessed more than one type of obvious activity, including 7-deacetylgedunin, salannin, gedunin, azadirone, salannol, azadiradione, and methyl angolensate. Most of these molecules are only in the primary stage of study activity; their mechanism of action and structure–activity relationship warrant further study.

Bioactivities of Lamiaceae, Myristicaceae, and Myrtaceae plant oils against Nilaparvata lugens Stâl. (Hemiptera: Delphacidae)

Essential oil (EO) plants have properties as botanical insecticides. Some of them come from the families of Lamiaceae, Myristicaceae, and Myrtaceae. A plant belonging to the Lamiaceae includes patchouli (Pogostemon cablin), while the Myristicaceae includes nutmeg (Myristica fragrans), and the Myrtaceae includes clove (Syzygium aromaticum) and cajuput (Melaleuca cajuput subsp. cajuputi). This research aimed to evaluate toxicity, feeding inhibition, and oviposition deterrent from four EO plants from the Lamiaceae, Myristicaceae, and Myrtaceae to brown rice planthopper Nilaparvata lugens (Hemiptera: Delphacidae), the main pest of rice. The results showed that cajuput and patchouli oil gave more potent toxicity to N. lugens with LC50 and LC95 were 0.016% and 4.87% for cajuput oil and 0.019% and 5.25% for patchouli oil. Cajuput oil at 0.002% deterred oviposition 51.74% and inhibited feeding on 0.016% as many as 71.52% with strong enough criteria to the fourth instar nymphs of N. lugens. Patchouli oil deterred oviposition from 0.002% as much as 61.15% and inhibited feeding on 0.019% as many as 68.73% with strong enough criteria. The highest oviposition deterrent was 83.2% on patchouli oil at the concentration of 0.188%, whereas the highest feeding inhibition was 82.78% on cajuput oil at the concentration of 0.169%.

Prospects of neem and citronella oil against Pseudococcus longispinus (hemiptera: Pseudococcidae) on Phalaenopsis

Synthetic insecticides are still widely used in gardens and greenhouses of ornamental crops to reduce populations of insect pests and preserve flower quality. The improper and unwise use of synthetic insecticides has caused various negative impacts on humans, insect pests, and the environment. Therefore, the quest for unharmed insecticides and environmentally friendly is being sought. The purpose of this study was to examine the effectiveness of botanical insecticide formulation of neem and citronella oil to control long-tailed mealybug Pseudococcus longispinus. Four insecticide concentrations of neem, citronella oil and its mixtures (0.5, 1, 1.5, 2 per cent) were tested for their effectiveness by adding each with Latron at 0.5% as an emulsifier. Bioassays were performed in the laboratory by spraying insecticides on Phalaenopsis leaves infested with P. longispinus groups of one size class, mostly represented by the third instar nymphs. The results revealed that all insecticides tested caused mortality after 24 hours. The combination of neem and citronella in 1.5% provided adequate protection by reducing P. longispinus populations by up to 86%. Thus, botanical insecticides can be recommended as a viable alternative to synthetic insecticides against P. longispinus which infested orchids.

Botanical Insecticides and their Potential as Anti-Insect/Pests: Are they Successful against Insects and Pests?

In low-income countries, subsistence and transitional farms frequently use botanical insecticides. The shortage or high cost of industrial pesticides also prompts their use. Botanical insecticides are also prescribed by agricultural and development programs and certain development organizations. However, since insecticidal proof of their effectiveness and protection might not be sufficient or usable, this may be called into question. While insecticidal botanicals have been extensively studied, there has yet to be a fusion that focuses especially on the domestic synthesis of biopesticides that work infield and storage effectively. In this chapter, we look at the effectiveness of botanicals (neem, garlic, and essential oil) that are used as insecticides. In addition, this chapter also focuses on research carried out on the use of these essential oils as insecticides. Processes that use variable amounts of ingredients and concentrations and ratios of active ingredients can have varying impacts on the efficacy of plant-based biological insecticides. Finally, using home-made insecticides would reduce the losses that occur during food production and enable us to use environment-friendly pest management methods.

Comparative efficacies of insecticides and botanicals against rice gall midge, Orseolia oryzae (Wood-Mason) and their effect on the parasitoid Platygaster oryzae in rice ecosystem of Odisha, India

A field experiment was carried out to determine the comparative efficacy of newer insecticides with botanical insecticides, viz., Chlorantraniliprole 0.4G @ 10 kg ha-1, Fipronil 5 SC @ 1500 ml ha-1, Acephate 95 SG @ 750 g ha-1, Lambda cyhalothrin 4.9 CS @ 550 ml ha-1, Thiamethoxam 25 WG @ 150 g ha-1 @ Carbofuran 3 CG @ 30 kg ha-1, Carbosulfan 25 EC @ 875 ml ha-1, Cedarwood oil @ 1000 ml ha-1, Azadirachtin 0.03 EC @ 2500 ml ha-1, applied at 20 and 35 DAT, against rice gall midge, Orseolia oryzae (Wood-Mason) in rice during kharif, 2019 and 2020. All the treatments were effective for gall midge. Lambda cyhalothrin 4.9 CS @ 550 ml ha-1 was significantly superior (>80% reduction over control) for gall midge management and grain yield was 4.75 t ha-1. Both botanical and untreated plots had more number of parasitized gall midge (40- 53.3%) than other chemical treated plots.

Toxicological Stability of Ocimum basilicum Essential Oil and Its Major Components in the Control of Sitophilus zeamais

Essential oils (EOs) are widely recognized as efficient and safe alternatives for controlling pest insects in foods. However, there is a lack of studies evaluating the toxicological stability of botanical insecticides in stored grains in order to establish criteria of use and ensure your efficiency. The objective of this work was to evaluate the toxicological stability of basil essential oil (O. basilicum) and its linalool and estragole components for Sitophilus zeamais (Motschulsky) adults in corn grains by fumigation. The identification of the chemical compounds of the essential oil was performed with a gas chromatograph coupled to a mass selective detector. Mortality of insects was assessed after 24 h exposure. After storage for six (EO) and two months (linalool and estragole) under different conditions of temperature (5, 20, and 35 °C) and light (with and without exposure to light), its toxicological stability was evaluated. Studies revealed that the essential oil of O. basilicum and its main components exhibited insecticidal potential against adults of S. zeamais. For greater toxicological stability, suitable storage conditions for them include absence of light and temperatures equal to or less than 20 °C.