Economic Threshold Level Research Articles

Discrete-time host-parasitoid model incorporating dynamic regulatory factor for integrated control measures

In the realm of integrated pest management (IPM), the intensity of IPM should be dynamically adjusted over time according to pests in practical applications. To address this, we involve a dynamic regulatory factor of the IPM into the discrete model rather than switching system. Further, the existence and local stability of the fixed points and interesting bifurcation diagrams have been analysed and provided. Numerical investigations validate the theoretical results and reveal a diverse and intricate dynamical behaviour of the proposed system, which can be confirmed by a more detailed bifurcation analyses at the economic threshold level as the regulatory factors and intensity of IPM vary. The results illustrate that adjusting the intensity of IPM not only maintain the density of host at the threshold level, but also lead to an increase in parasitoid. The modelling methods and main results developed here provide valuable insights for formulating optimal control strategies.

Management of mustard aphid (Lipaphis erysimi) on rapeseed mustard (Brassica napus) using biopesticides under organic farming conditions

Aim: To manage mustard aphid, Lipaphis erysimi Kalt on rapeseed-mustard through neem formulations, which are the safest, eco-friendly and cost effective and can hold promise to keep this pest below economic threshold levels. Methodology: The neem formulations, AZA5% @ 30,40,50 and100ml per acre, AZA1% @ 200, 250 and 300 ml per acre and AZA 0.15% @ 800, 900 and 1000 ml per acre were evaluated against L. erysimi on rapeseed- mustard under organic farming conditions at Organic Research Area of School of Organic Farming, Punjab Agricultural University, Ludhiana during 2020-21 and 2021-22. Results: A highest efficacy against L. erysimi with 83 and 84.99% treated over untreated control plots was recorded with AZA 5% @100 ml per acre at 5 days of spray during both years of study, followed by AZA 1% @ 300 ml per acre (61.84%) and AZA 0.15% @ 1000 ml per acre (59.33%). The coccinellid population at 10 days after spray was non-significant (0.03 to 0.21), but numerically more in untreated control plots. The highest seed yield was recorded in AZA 5% @ 100 ml (18.38 q ha-1), AZA1% @ 300 ml (16.70q ha-1) and AZA 0.15% @ 1000 ml (15.75 q ha-1) over untreated control plots (13.91q ha-1). The highest economic returns were obtained with AZA 5% @ 100ml (Rs.22408.72 ha-1), AZA 1% @ 300ml (Rs.16424.22 ha-1) and AZA 0.15% @ 1000ml (Rs.10285.68 ha-1) treatment, respectively. Interpretation: Management of L. erysimi on rapeseed mustard can be obtained with AZA 5% @ 100 ml, which caused 84 per cent reduction over control at 5 days after spray and also gave net returns of Rs.22408.72q ha-1, which will not only increase the farm income but is eco-friendly in nature. Key words: Azadirachtin, Biopesticide, Lipaphis erysimi, Organic farming, Rapeseed- mustard

Evaluation of Critical Period of Crop Weed Competition for Enhanced Weed Management and Yield of Summer Pearl Millet

The field experiment was conducted at Instructional farm of Department of Agronomy, Navsari Agriculture University, Navsari during summer season of 2021 to 2023 to study critical crop-weed competition in summer pearl millet. There were 10 treatments comprising of initial weed free periods of 10, 20, 30 and 40 days after sowing (DAS) and weedy 10, 20, 30 and 40 DAS along with weedy till harvest (un-weeded check) and weed free till harvest (weed free check), were replicated thrice in the randomized block design. Results revealed that maintaining a weed-free condition from 20 to 40 DAS significantly increased the yield of pearl millet, whereas the lower yield was recorded when weeds were allowed to grow during this period. The maximum competition between crop and weed was between 20 to 40 DAS, which can be considered as critical period of crop-weed competition. To avoid the yield loss, integrated weed management can effectively overcome the problems of weed shift and development of resistance in weeds and reduce the weed seed bank and manage the weeds below the economic threshold level to avoid any economic loss in summer pearl millet.

Optimizing Insecticide Application: Evaluating Frequency and Timing for Effective Management of Pink Bollworm Infestation

The pink bollworm (Pectinophora gossypiella), a significant pest affecting cotton crops, necessitates an optimized approach to insecticide application. This study investigates the critical factors of frequency and timing in insecticide application to enhance the efficacy of pest control measures. An experiment conducted at the Main Agricultural Research Station (MARS), University of Agricultural Sciences Raichur, focused on managing pink bollworm in Bt cotton using newer insecticides registered for cotton. Various spray frequencies and intervals were tested as part of an ETL (Economic Threshold Level) and prophylactic spray regimen. The results indicated that the treatment T1, which involved four sprays of profenofos 50 EC, chlorantraniliprole 18.50 SC, emamectin benzoate 5 SG, and bifenthrin 10 EC at 65, 80, 95, and 110 days after sowing (DAS), respectively, showed the lowest incidence of pink bollworm larvae, green boll damage, bad boll opening, locule damage, and the highest rate of good boll opening. This performance was comparable to treatment T5, which followed the same spraying schedule but with spinetoram 11.70 SC and fenpropathrin 10.00 EC instead of emamectin benzoate and bifenthrin, and treatment T9, which employed an ETL-based spray schedule using chlorantraniliprole 9.3 + lambda-cyhalothrin 4.6 ZC. Similarly, the highest yield of seed cotton was obtained from treatment T1 (18.10 q/ha), which was statistically equivalent to treatments T5 (18.12 q/ha) and T9 (18.10 q/ha). Additionally, the cost-benefit analysis revealed the highest benefit-cost ratio in treatment T1 (1.55), followed by treatments T9 (1.46) and T5 (1.44).

Advances in the Integrated Pest Management of Quinoa (Chenopodium quinoa Willd.): A Global Perspective.

Since ancestral times, quinoa (Chenopodium quinoa Willd.) has been cultivated in the Andean regions. Recently, this pseudocereal has received increasing international attention due to its beneficial properties, such as adaptation and resilience in the context of global change, and the nutritional value of the grains. As a result, its production areas have not only increased in the highlands of South America but have also expanded outside of its Andean origins, and the crop is currently produced worldwide. The key pests of quinoa in the Andean region are the gelechiid moths Eurysacca melanocampta and Eurysacca quinoae; in other parts of the world, new pest problems have recently been identified limiting quinoa production, including the gelechiid Scrobipalpa atripicella in North America and Europe and the agromyzid fly Amauromyza karli in North America. In this review, the status of quinoa pests in the world is presented, and different aspects of their integrated management are discussed, including sampling methodologies for pest monitoring, economic threshold levels, and various control strategies.

Comparative evaluation of biological control programs and chemical pesticides for managing insect and mite pests in cucumber greenhouses: a sustainable approach for enhanced pest control and yield

BackgroundCucumber plants are susceptible to several economically damaging pests, including whiteflies, aphids, thrips and spider mites. This study aimed to evaluate the efficacy of two biological control programs, utilizing different releases of bio-agents, in comparison with chemical control method. The bio-agents used were the aphid parasitoid Aphelinus albipodus Hayat and Fatima (Hymenoptera: Aphelinidae), the green lacewing Chrysoperla carnea (Steph.) (Neuroptera: Chrysopidae) and the predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) in two release rates; low and high. Additionally, a chemical pesticides treatment was included for comparison in managing the pests in cucumber greenhouses during the winter seasons of 2022 and 2023, in Egypt. Abundances of whitefly, aphids, thrips and spider mites were recorded weekly throughout the study.ResultsThe aphid population in the greenhouse with high release rate (BIO 2) showed the highest reduction, with percentages of 84.55 and 89.88% in 2022 and 2023, respectively. Both greenhouse with low release rate (BIO 1) and BIO 2 exhibited significant reductions in the whitefly population, with proportions of 71.31 and 72.01% in 2022, and 82.05 and 85.94% in 2023, respectively. The thrips population also experienced notable reductions in both BIO 1 and BIO 2 greenhouses, with percentages of 72.08 and 75.71% in 2022, and 59.93 and 61.38% in 2023, respectively. However, the pesticide treatment demonstrated the lowest reduction in populations of aphids, whitefly and thrips in both seasons. Nevertheless, in all treatments in the two evaluated seasons, the high release rate of the predatory mite, P. persimilis (15 individuals/m2), proved to be highly effective in maintaining the mite populations below the economic threshold level. However, the population density of the two-spotted spider mite, Tetranychus urticae Koch. (Acari: Tetranychidae), increased in the pesticide-treated greenhouse, indicating the development of resistance to pesticides. Although the tested programs resulted in similar yields, the biological control approach offered the advantage of pesticide-free produce and reduced production costs.ConclusionFor pest management in cucumber growing in greenhouses during winter, it is recommended to use biological control agents at a low release rate at the early occurrence of pests. This approach can help minimize pest populations effectively.

Assessment of economic threshold level for onion thrips

The present experiment was carried out the to determine the economic threshold level of onion thrips. The economic threshold level of T. tabaci is determined using the pesticide application technique. So the Economic Injury Level (EIL) of T. tabaci on onion plants can be determined as the number of thrips follows the value of ET levels for the detected peaks ranging between 4-5 individuals/leaf during the study. As the results of the pesticide application technique, the thrips mean numbers and mean yield of onion plants were correlated significantly during the two years. Results of chi-square analysis (R2) indicated that the values of the economic damage threshold of T. tabaci infested onion plants were 7 thrips/plant, while the economic injury level was 9.6 thrips/ plant during the study.

Parasitic Nematodes of Sugarcane: A Major Productivity Impediment and Grand Challenges in Management.

Sugarcane is an important cash crop grown in 137 countries, accounting for 80% of global sugar production. It supports the livelihood of more than 100 million people and up to 25% of the rural population in some countries. Plant-parasitic nematodes are one significant constraint in sugarcane production and can lead to a loss of up to 30% in productivity. More than 300 species of parasitic nematodes have been discovered in sugarcane soil. Owing to limited data, the potential damage to sugarcane crops caused by parasitic nematodes is often underestimated. The main nematodes present in sugarcane fields are root-lesion (Pratylenchus spp.), spiral (Helicotylenchus spp.), root-knot (Meloidogyne spp.), dagger (Xiphinema spp.), stunt (Tylenchorhynchus spp.), ring (Criconemella spp.), and stubby (Paratrichodorus spp.). Among these, Meloidogyne javanica and Pratylenchus zeae are the most damaging nematode species. Management of nematodes is a challenging task as there are no clear symptoms of their presence, and they often come in multiple species with varying levels of pathogenicity. Moreover, the management options available are not always effective. Integrated nematode management is a sustainable strategy for controlling nematode infestations. It involves using all possible methods to suppress the parasitic nematode population in a compatible manner and reduce it below economic threshold levels. This article focuses on the challenges of managing nematodes in sugarcane and highlights the opportunity for implementing a sustainable nematode management strategy.

Mite Species Exceeding the Economic Damage Threshold in the Tea Plantation Areas in Türkiye and Population Dynamics in the 2nd and 3rd Harvesting Periods

The main goal of this study was to determine the mite species exceeding the economic damage threshold level during the 2nd and 3rd harvesting periods and population levels. This study was carried out in tea plantation areas in Artvin, Rize and Trabzon provinces from july to october in the second and third harvesting periods of 2023. Tea leaves were collected from the field by random sampling method by determining 3 districts from each province two times per month (Artvin; Sarp, Hopa Arhavi, Rize; Ardeşen, Çayeli, Derepazarı, Trabzon; Of, Sürmene 1, Sürmene 2). As a result of our study, it was determined that Polyphagotarsonemus latus (Acari: Tarsonemidae), the most common species, exceeded the economic damage threshold in all months and in all locations. Especially in the samples collected from Sarp region in September, the number of mites per leaf was recorded as 116,73. Brevipalpus phoenicis (Prostigmata: Tenuipalpidae) was detected as a second most common species and found at exceeded EDT in all months in the Sarp region. The same situation was observed in Çayelin in September. Both mite species that exceeded economic damage threshold (yellow tea mite and flat mite) were most frequently observed in september. Tetranychus urticae, Tydeus californicus, Calacarus carinatus, Tuckerella sp., mite species were found at some study points, and number of individuals did not exceed economic damage threshold except Calacarus carinatus Hopa region october samples.

A Review on Fall Army Worm <I>Spodoptera frugiperda</I> (J E Smith) Invasion in Ghana: Current Status

The fall army worm Spodoptera frugiperda (J E Smith) (Lepidoptera: Noctuidae) which invaded Africa in 2016 continue to pose food security threat due to its destructive effect on maize. This article assesses current research outputs, management strategies and future projections. Levels of infestation vary across districts, ranging from 12 to 88% with corresponding leaf damage score of 2 to 7 and larval density of 0.16 – 1.44/ plant on farmers’ maize field. Infestation and damage levels were higher in 2021 than in 2020 possibly due to gradual withdrawal of free insecticide by government. Several indigenous practices were employed by farmers during early invasion but synthetic insecticides usage assumed high acceptance. Some commercial microbials and botanicals showed significant efficacy. Results from indigenous entomopathogenic nematodes and fungi are satisfactory and are under field validation. A number of predators and parasitoids identified have shown varied level of suppression. Mass release of parasitoids, complemented with entomopathogens will put the infestation below economic threshold levels in most maize fields.

Interference and threshold level of Sida rhombifolia on Chenopodium quinoa Willd. crop

Studies on interference and economic threshold level (TL) of weeds on quinoa are scarce. Thus, the goal of this study is to determine the interference and the TL of Sida rhombifolia (arrowleaf sida) on quinoa varieties. The experiment was organized using a completely randomized design, with four replicates. The treatments were composed of quinoa varieties (Q 1303, Q 1331 and Q 1324) in competition, respectively, with ten densities of arrowleaf sida (0, 12, 16, 18, 128, 252, 432, 524, 584, and 756; 0, 24, 88, 104, 112, 124, 160, 164, 260 and 320; 0, 16, 72, 104, 116, 144, 156, 160, 228 and 304 plants m-2). The variables evaluated were: plant density, soil coverage, leaf area, dry mass of weed shoots; and the variables related to quinoa were: grain yield, control cost, price per bag and control efficiency. Quinoa variety Q 1303 showed greater competitive ability with arrowleaf sida than Q 1331 and Q 1324. The values of TL varied from 1.79 to 11.60 plants m-2 for the Q 1303 variety, which demonstrated higher competitiveness with arrowleaf sida, while the lowest TL values varied from 0.80 to 6.91 plants m-2 for Q 1234 and Q 1331 varieties, showing less competitiveness in presence of the competitor. The TL values decreased with the increases in grain yield, in the price of the quinoa bag, in the efficiency of weeding and in the reduction of the control cost of arrowleaf sida, justifying the adoption of weed control measures.

Investigating the second whitefly population outbreak within a decade in the cotton growing zone of North India.

The whitefly, Bemisia tabaci (Gennadius), is a polyphagous and major pest of cotton worldwide. Both adults and nymphs of B. tabaci affect the crop by causing direct and indirect damage. A severe whitefly outbreak was experienced during 2015 on cotton in North India and this was followed by a profound infestation during 2022. The present research rigorously examined whether the proliferation in the whitefly population was an outbreak or the result of a multi factor resurgence. During 2015, whitefly counts remained above the economic threshold level (ETL) between 28th and 35th Standard Meteorological Week (SMW). However, during 2022 above ETL population was observed in 27th SMW and it persisted until 36th SMW. The peak incidence of the whitefly was noticed during 31st and 29th SMW in 2015 and 2022, respectively. The early pest build up in 2022 and longer persistence (≥10 weeks) over the cotton season resulted in more damage to cotton crop. Additionally, pest survillence across the zone on the farmers' fields during 2022 revealed 44.4 per cent spots (585 out of 1,317 locations) above ETL while the corresponding locations in 2015 was 57% (620 out of 1,089). Thus, in 2022 infestation was not uniform in the entire zone wherein only few blocks of Punjab, Haryana and Rajasthan states of India experienced severe infestations of the whitefly. This study reports the complex of factors including weather, delayed sowing, use of tank mixtures/ subleathal doses of insecticides, pest resurgence etc. that might have possibly contributed to these upsurges in whitefly on cotton in north India.

A study of integrated pest management models with instantaneous and non-instantaneous impulse effects.

The occurrence of pests and diseases during agricultural production affects the quality and quantity of agricultural products. It is important to evaluate the impact of various factors on pests to achieve optimal results of integrated pest management (IPM) during its implementation. In this paper, we considered the transient and non-transient effects of chemical control on pests and the effects on natural enemies at different times, and developed a corresponding pest control model. Detailed studies and comparisons were conducted for spraying pesticides either more or less frequently as compared to strategies for releasing natural enemies. The threshold conditions for global asymptotic stabilization of the pest extinction period solution was obtained. Using two-parameter and sensitivity analysis techniques, the parameters affecting the variation of the threshold were discussed. By comparing these two pest control strategies, we found the existence of optimal application and release frequencies. Finally, in order to control pests below the economic threshold level, the state-dependent pest model was numerically investigated. The results show that the presence or absence of chemical control of pests can depend on the values taken for the parameters in the model. Based on this information, pest control experts can make decisions about the best spraying time and the best release rate.

Biology of shoot and fruit borer, Earias vittella Fabricius (Noctuidae: Lepidoptera) on okra

The biology of fruit and shoot borer (Earias vittella F.) was studied under the natural conditions in the instructional farm of Uttar Banga Krishi Viswavidyalay in pre-kharif, kharif and post-kharif on okra. The study revealed that the egg incubation in pre-kharif, kharif and post-kharif revealed that the egg incubation were 3.18±0.40, 3.61±0.70 and 4.25±0.67 and larval period were 11.00±0.88, 11.00±0.82 and 13.01±1.81 during corresponding seasons respectively. The pupal period in pre-kharif, kharif and postkharif were 13.01±1.81; 11.00±0.82; 10.97±2.15 days respectively. The adult male longevities observed were 3.64±0.67, 5.60±0.70 and 7.33±0.97 during pre-kharif, kharif and post-kharif. On the other hand female longevities observed were about 7.45±1.57b; 8.87±1.10; 9.41±1.51 days in corresponding seasons respectively. The female fecundity during pre-kharif, kharif and post-kharif were 91.55±10.93, 117.55b±10.60 and 132.04±5.83 eggs in their lifetime. The pre-oviposition during pre-kharif, kharif and post-kharif were 1.64±0.50, 1.52±0.53 and 1.88±0.57 and the oviposition periods in corresponding seasons were 2.73±0.47, 3.22±0.79 and 4.32±0.52. While post-oviposition periods in pre-kharif, kharif and post-kharif were 3.09±0.70, 4.14±0.63 and 3.23±0.92 respectively. Its total life-cycle was completed in 27.45±1.57, 31.60±1.90 and 41.35±2.55 days during pre-kharif, kharif and post-kharif respectively. Higher fecundity may lead to faster population growth that may surpass the economic threshold level (ETL), even though the shoot and fruit borer’s life cycle is longer in Kharif and post-kharif. Thus, it may be said that the kharif and poskharif seasons are the most susceptible to shoot fruit and shoot borer infestation.

Sustainable Strategies for the Control of Pests in Coffee Crops

Coffee is a worldwide commodity, and both coffee-producing and coffee-consuming countries have real concerns about environmental problems and economic growth strategies based on the efficient use of resources. Because this crop is a perennial, pests can significantly affect coffee production, causing considerable yield losses and threatening coffee supply and security. The presence of insects and control strategies for coffee pests is becoming a challenge. Environmental sustainability, conservation of biodiversity, and safety of the coffee seed must go hand in hand with the economic sustainability of coffee growers. This is especially important, as there has been an increase in demand for coffee and new consumer interest in differentiated quality coffee. Regular pest control methods based only on the use of synthetic pesticides are no longer effective or sustainable due to the development of insecticide resistance and negative effects on the environment, human health, and biodiversity. Thus, to ensure better control and ecological sustainability, it is crucial to reduce pesticide use by adopting original alternative strategies to maintain pest populations below the economic threshold level and towards reaching the European Green Deal. In this review, we collect information available for sustainable control of the principal coffee pests in Colombia: coffee berry borer (CBB), Hypothenemus hampei; Monalonion velezangeli; coffee root mealybugs; coffee leaf miner: Leucoptera coffeella; and the coffee red spider mite: Oligonychus yothersi. The control strategies include deep knowledge of the biology of insects and the coffee plant, their relationship with weather and habitats, as well as natural controllers. These control strategies do not involve the use of insecticides, are ecologically friendly and novel, and can be applied in other coffee-producing countries.

Weed interference period and economic threshold level in barley

Weed interference period and economic threshold level in barley

Plant-parasitic nematodes, a looming threat to turmeric cultivation in India: results of recent surveys

Summary Turmeric (Curcuma longa) is a major spice of Indian origin. Turmeric is commonly used in Ayurvedic and Siddha medicine, and also in Indian cuisine. India produces nearly 1.2 million tonnes (Mt) of turmeric annually and is one of the world’s largest producers. Turmeric production is limited by a number of biotic and abiotic factors. Among the biotic factors, plant-parasitic nematodes (PPN) are important. They include Meloidogyne spp., Pratylenchus spp., Radopholus similis and Rotylenchulus reniformis. However, the information about the distribution, density and prominence of plant-parasitic nematodes and their interrelation with soil types is very scarce. Hence, the present comprehensive nematode survey was undertaken in the major turmeric-producing states of India: Tamil Nadu, Andhra Pradesh, Telangana and Odisha. The results indicated that Meloidogyne spp., R. reniformis, Pratylenchus spp., R. similis, Hoplolaimus spp., Helicotylenchus spp. and Tylenchorhynchus spp. were associated with turmeric. The most abundant nematodes were Meloidogyne spp. (115 individuals (100 cm3 soil)−1), followed by R. reniformis (68 (100 cm3 soil)−1) and Pratylenchus spp. (50 (100 cm3 soil)−1). The frequency of occurrence ranged from 0 to 60%, with Meloidogyne spp. (60%) and R. reniformis (51%) being the most common. Meloidogyne spp. (38%) and Pratylenchus spp. (19%) were the most prominent nematodes in plant samples. Overall, Meloidogyne spp. followed by Pratylenchus spp., R. reniformis and R. similis were the key nematodes associated with the turmeric crop in all the four states. Further, we have identified hotspot areas for the plant-parasitic nematodes, namely: Meloidogyne spp. (16), Pratylenchus spp. (16), R. reniformis (20), and R. similis (5) on the basis of the economic threshold level. The interrelationship of soil type and nematode distribution was also investigated.

A brief overview of pest complex in soybean [Glycine max (L.) Merill] and their management

Brazil is the leading producer of soybean and India stands 5th in position in terms of production. In India soybean is mainly grown as a kharif season crop. Soybean, the 'wonder crop', is a rich edible oil and protein source. It is one of the most attractive Agricultural crops in the world. But unfortunately, this crop is also attractive to dozens of insect pests that infest this crop throughout the growth period, like the girdle beetle,stem fly, semilooper, pod borer, leaf miner, tobacco caterpillar, and many sucking pests like whitefly, aphid, thrips, leaf hopper, etc. These insect pests are one of the major constraints in the productivity of soybean. So, an elaborate knowledge of these insect pests is very necessary to tackle this issue. This article discusses different insect pests that attack soybean crops in their different growth stages, along with their other hosts, bionomics, and typical damage symptoms. This article also covers the Incidence of different insect pests and pest-predator profiles during the kharif period. The economic threshold level (ETL) of important insect pests and their integrated management are mentioned here for better management of the pests.

Biological Control as Part of the Soybean Integrated Pest Management (IPM): Potential and Challenges

Soybean production is usually performed on large scales, requiring simple but efficient pest management to be successful. Soybean fields are inhabited by several species of arthropods, demanding constant development of management practices to prevent pest outbreaks. More recently, stink bugs have become the most important pest group of soybeans in the Neotropics, responsible for up to 60% of the applied insecticides in Brazil. Natural enemies represent an important mortality factor that can keep the damage caused by stink bugs below the economic threshold levels without additional control actions. Thus, Conservation Biological Control (CBC) strategies can be adopted to preserve or even promote the increase in such natural enemies in the fields, or alternatively, massive releases of biocontrol agents in Augmentative Biological Control (ABC) programs could be adopted. Simple practices such as reducing insecticide use (with the adoption of economic thresholds), prioritizing harmless insecticides or biopesticides, and planting resistant soybean cultivars have been adopted in Brazil with positive results. The challenges to increasing the adoption of more complex stink bug management in commodity crops such as soybean may be overcome using the more recent economic incentives in the global agenda of decarbonized agriculture. The potential and challenges of conservation and augmentative biological control are further discussed in this review.

Double-stranded RNA mediated knockdown of sucrase gene induced mortality and reduced offspring production in Aphis gossypii.

The importance of gut sucrase in maintaining osmotic equilibrium and utilizing phloem contents as a carbon source has been widely investigated and proven in sap-sucking insects. In the present study, silencing of Aphis gossypii sucrase1 (Agsuc1) was carried out by double-stranded RNA (dsRNA), which would be lethal to it due to disruption of osmotic balance. The dsRNA corresponding to Agsuc1 was synthesized by two methods, i.e., in vitro synthesis using T7/SP6 RNA polymerase and in vivo synthesis by bacterial expression, i.e., Escherichia coli strain HT115 transformed with the L4440 vector system. Oral delivery of double-stranded Agsuc1 synthesized in vitro (dsAgsuc1) and in vivo (HT115Agsuc1) induced around 50% mortality in nymphs of A. gossypii. Moreover, the number of offspring produced by the survived aphids decreased by 39-43%. Parthenogenetic reproduction of the aphids is the critical factor for their fast population build-up, leading to yield losses of economic significance. Thus, the present study demonstrated that the silencing of the Agsuc1 gene reduced the aphid population by killing it and inhibited the population buildup by reducing the number of offspring produced by the survived aphids, likely to result in a significant reduction in crop damage. The production of dsRNA by bacterial expression is a cost-effective method. It has the potential to be used as a biopesticide. The sucrase gene is an excellent putative target gene for RNAi against A. gossypii. It could be used to develop a transgenic plant that produces dsAgsuc1 to keep A. gossypii populations below the economic threshold level.