Key Pest Research Articles

Efficacy of selected biopesticides on key pests of chilli pepper for increased productivity in Ghana

Chilli pepper is an important food and cash crop in Ghana. Unfortunately, production and marketing are constrained by many insect pests. In this study, the efficacy of five different biopesticides: Neemazal® (Azadirachtin 0.3% w/w EC), Agro blaster® (Pyrethrin I and II 1% w/w), Bypel 1® (Pieris rapae 10000PIB/mg + Bacillus thuringiensis 16000 IU/mg), Cryptogran® (Cryptophlebia leucotreta Granulovirus ≥ 5.1010 OBs/ml) and Attack® (Emamectin benzoate 1.9% w/w EC) were assessed against the major insect pests of chilli pepper. These pests included the false codling moth (FCM), thrips, whiteflies and fruit flies. The study was conducted during the minor and major cropping seasons of 2019 and 2020, respectively, using RCBD plot design in two locations (Legon and Begoro) in southern Ghana. All five tested biopesticides reduced the infestation of the target insect pests. Neemazal® and Attack® were more efficacious than the other three biopesticides in controlling FCM. For fruit flies, the infestation in Neemazal® and Attack® treated plots varied between 0.69 ± 0.60 to 12.84 ± 0.91% and 1.40 ± 0.69 to 9.72 ± 1.27%, respectively against 3.82 ± 0.67 to 21.87 ± 2.14% in control plots. Neemazal®, Bypel 1® and Attack® significantly reduced thrips population compared to other biopesticides. Apart from Neemazal® and Attack®, Agro blaster® also reduced whiteflies population compared to control plots. The highest yields were recorded in Neemazal® (3.17 ± 0.33 to 4.35 ± 0.22 t/ha) and Attack® (3.05 ± 0.21 to 4.55 ± 0.25 t/ha) treated plots against 2.12 ± 0.31 to 3.06 ± 0.37 t/ha in the control. Therefore, these two biopesticides are promising and could be used as part of integrated pest management (IPM) against chilli pepper insect pests in Ghana.

Sublethal effects of chlorantraniliprole on biological characteristics, detoxifying enzyme activity and gene expression profile in the Allium mongolicum Regel leaf beetle Galeruca daurica (Coleoptera: Chrysomelidae)

AbstractAllium mongolicum Regel leaf beetle, Galeruca daurica (Coleoptera: Chrysomelidae) is rampantly harmful in Inner Mongolia grassland. However, the current management strategies for this pest still heavily rely on chemical control using traditional insecticides or those with novel action. In the study, we conducted an indoor bioassay to evaluate the sublethal effects of chlorantraniliprole on the biological characteristics. Additionally, we assessed the activity of detoxification enzymes, specifically the primary enzymes carboxylesterase (CarE) and cytochrome P450, and insect's secondary metabolic enzymes, namely glutathione S‐transferase (GST) and uridine diphosphate glycosyltransferase (UGT), as well as its gene expression profile. The developmental period of the 3rd instar larvae of G. daurica was significantly prolonged after treatment with chlorantraniliprole, which negatively affected the hatching, pupation and diapause rates as well as their body weight. The larvae showed different dynamics of the enzyme activities within 24 h of chlorantraniliprole treatment. Different sublethal concentrations of chlorantraniliprole showed an inducing effect on the activities, while no significant difference in activity was observed for P450. Expression profiling of detoxifying enzyme genes screened by transcriptome data has revealed that 6 CarE, 2 GST, 7 UGT and 31 P450 genes were up‐regulated. In conclusion, chlorantraniliprole's sublethal effect on 3rd instar G. daurica larvae resulted in a deceleration of their growth and developmental processes and significantly increased the activity levels of CarE, GST and UGT. The detoxifying proteins encoded by up‐regulation genes may involve in the detoxification metabolism of chlorantraniliprole. Our results provide a basis for understanding the molecular mechanisms of chlorantraniliprole action and detoxification in this key grassland insect pest.

The application of allelopathy in integrated pest management systems to control temperate European crop pests: a systematic map

BackgroundPesticides perform vital roles within agriculture but growing concern for their impact on the environment and non-target organisms has created a market for biopesticides with fewer ecological impacts. One source of biopesticides is allelochemicals, here defined as compounds released by an organism that have an inhibitory or stimulatory effect on neighbouring organisms. The focus of this study is allelopathic plants and their inhibitory effects on invertebrate herbivorous agricultural pests of temperate Europe. A systematic map is required to describe the current state of research and collate evidence.MethodsTwo academic databases were searched for relevant studies in temperate climates. The results were imported into EPPI-Reviewer, duplicates removed, studies screened and data extracted into a searchable database following the inclusion criteria and coding tool set out in the protocol. Screening consistency was checked at each stage using 5% of the studies. Critical appraisal was not conducted. Each unique combination of key variables (pest, plant, allelochemical, application method, intervention form) was treated as a separate datapoint or experiment. The data was then analysed and cross-tabulated to produce descriptive statistics and heatmaps.ResultsThis systematic map produced a database which included 243 studies containing 717 experiments from 5550 initial results. Research was unevenly distributed among all key variables with a distinct bias towards extracted allelochemical experiments under laboratory conditions. Allyl isothiocyanate was the most studied allelochemical and of the 99 identified chemical groups, flavonoids and glucosinolates were the most frequent. A wide range of pest and plant species were identified. Brassicas were the most studied plant family and Lepidoptera the most studied pest order. Physical living plants, as opposed to plant extracts or isolated allelochemicals, were predominantly studied in terms of resistance. Allelopathy application methods were not specified in the abstract of 22% of experiments and only 10% of experiments were conducted under field conditions.ConclusionAllelopathy has been studied in the context of temperate invertebrate pest control in some breadth but little depth and key pest species have not been targeted. The map highlighted significant gaps in the evidence base and a distinct lack of field studies or studies comparing application methods. It contains insufficient evidence to guide policy or management decisions, but provides a research tool and indicates areas for future studies including highlighting topics for secondary research. Critical appraisal is needed to determine allelopathic affect and future search strings should detail all application methods.Protocol registrationThe a-priori protocol was peer-reviewed and published through PROCEED (Kiely C, Randall N. Collaboration for Environmental Evidence: PROCEED. How have allelopathic plants been used within integrated pest management systems to control European crop pests in arable and field vegetable systems in temperate climates?: A Systematic Map Protocol. 2022. https://www.proceedevidence.info/protocol/view-result?id=14. Accessed 5 Jan 2023.).

Emerging trends in insect sex pheromones and traps for sustainable management of key agricultural pests in Asia: beyond insecticides—a comprehensive review

Emerging trends in insect sex pheromones and traps for sustainable management of key agricultural pests in Asia: beyond insecticides—a comprehensive review

Diseases and Pests Harmful to Honeybees (Apis spp.) and Their Management Tactics: A Review

Honeybees (Apis spp.) play a vital role in pollination and contribute significantly to global agriculture. However, the health and survival of honeybee colonies are threatened by a range of harmful insect pests and diseases. This review provides an overview of the major pests and diseases that impact honeybee colonies and explores the diverse management tactics employed to mitigate their effects. The primary focus is on key pests such as the Varroa mite (Varroa destructor), which inflicts considerable damage by parasitizing adult bees and their brood, facilitating the transmission of debilitating viruses. Management strategies for Varroa mites encompass chemical treatments, integrated pest management (IPM) approaches, and organic treatments to curtail mite populations and prevent colony collapse. Another significant threat discussed is the small hive beetle (Aethina tumida), a beetle species that disrupts hives by laying eggs in comb and consuming stored resources. Hive manipulation, traps, and chemical controls are among the tactics utilized to control small hive beetle populations and mitigate their impact. The review also addresses wax moths (Galleria mellonella and Achroia grisella), which target hive comb, potentially causing comb destruction and honey fermentation. Hive maintenance, freezing, and pheromone traps are outlined as effective strategies to combat wax moth infestations. Additionally, the review covers Nosema infections (Nosema apis and Nosema ceranae), and microsporidian parasites that compromise adult bee health by weakening immune systems and reducing foraging efficiency. Hive hygiene, medications, and genetic selection are explored as methods to manage Nosema infections and bolster colony resilience. To effectively manage these harmful pests and diseases, a holistic and integrated approach is recommended. Beekeepers are encouraged to remain informed about the latest research findings and implement appropriate measures, considering local conditions and sustainable beekeeping practices. By combining scientific knowledge with practical application, the resilience of honeybee colonies can be enhanced, ensuring the vital role they play in pollination and global food security.

Unraveling the effect of temperature and humidity on the life cycle of Diatraea saccharalis (Lepidoptera: Crambidae) and the impact on pest outbreaks.

Temperature and humidity are considered the main abiotic factors that affect both the development and survival of ectothermic organisms. In this study, we estimated the development time as well as the thermal requirements of the sugarcane borer, Diatraea saccharalis (Fabricius, 1794; Lepidoptera: Crambidae), a key insect pest of sugarcane and discussed the influence of temperature and relative humidity and its infestation intensity in a scenario of climate change. The models Brière-1 and Ikemoto-Takai provided the best fit to the data of development rate versus temperature. The average life cycle (from egg to adult) ranged from 39.21 ± 4.84 at 32 °C to 137.10 ± 7.47 at 18 °C days. The thermal constant and average base temperature were 547.69 degree-days and 13.64 °C, respectively. The number of larval instars varied from 4 to 7 depending on the temperature, being higher at lower temperatures. The thermal range comprised the interval from 16.7 °C to 33.9 °C and the optimum temperature was estimated as 27.4 °C. Locations with elevated temperature (≥25 °C) and high relative humidity (≥70%) presented larger populations of D. saccharalis. Our findings show that the infestation pressure of this species is highly influenced by both temperature and humidity, and the studied models allow to forecast pest outbreaks. In the context of climate change, information about the thermal range and the optimum temperature contributes to predicting the spatial-temporal distribution of D. saccharalis and, consequently, aids decision making in pest management.

UAV-based Herbicide Application for Efficient Weed Management in Direct-seeded Rice

Background: Weeds are the key pest, which reduce crop productivity. Direct-seeded rice is very prone to early-stage weed infestation during initial crop development. Cultural and mechanical methods are difficult due to unavailability of labour and poor work efficiency. Hence, use of herbicides is an effective method for timely weed control. However, the efficacy of agrochemicals depends on the efficiency of spraying equipment. Conventional knapsack sprayers are used most often to spray herbicides but they are highly time-consuming, labour intensive and labour drudgery practices. Hence, the current experiment was aimed to study the efficiency of unmanned aerial vehicles (UAVs) on weed management. Methods: A field experiment was conducted at Tamil Nadu Agricultural University, Coimbatore during summer, 2022 to evaluate the efficacy of UAV-based herbicide application in direct-seeded rice. The study comprised of five weed management treatments such as pre emergence application of pretilachlor with safener and pyrazosulfuron through both UAV and knapsack sprayer and unweeded check as control. The experimental plot was laid out in a randomized block design with four replications. Result: The experimental findings showed that the application of pre-emergence pretilachlor significantly reduced the density and dry weight of grasses, sedges and broad leaved weeds in knapsack application. Moreover, it was found on par with UAV application of same herbicide without any phytotoxicity to rice seedlings. From the experiment, the application of pre-emergence pretilachlor through UAV is found to be more effective for timely weed control during early stages in direct-seeded rice, which reduce the labour intensity and drudgery than knapsack application.

Investigation of Deep Learning Approaches for Identification of Important Wheat Pests in Central Anatolia

Artificial intelligence-based systems play a crucial role in Integrated Pest Management studies. It is important to develop and support such systems for controlling wheat pests, which cause significant losses in wheat production which is strategic importance, particularly in Turkey. This study employed various pre-trained deep learning approaches to identify key wheat pests in the Central Anatolia Region, namely Aelia spp., Anisoplia spp., Eurygaster spp., Pachytychius hordei, and Zabrus spp. The models' classification success was determined using open and original datasets. Among the models, the ResNet-18 model outperformed others, achieving a classification success rate of 99%. Furthermore, each model was tested with original images collected during field studies to assess their effectiveness. The results demonstrate that pre-trained deep learning models can be utilized for the identification of important wheat pests in Central Anatolia as part of Integrated Pest Management.

Dynamic monitoring of the insecticide resistance status of Bemisia tabaci across China from 2019-2021.

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a major agricultural insect pest that causes severe economic losses worldwide. Several insecticides have been applied to effectively control this key pest. However, owing to the indiscriminate use of chemical insecticides, B. tabaci has developed resistance against these chemical compounds over the past several years. From 2019 to 2021, 23 field samples of B. tabaci were collected across China. Twenty species were identified as the Mediterranean 'Q' type (MED) and three were identified as MED/ Middle East-Asia Minor 1 mixtures. Subsequently, resistance of the selected populations to different insecticides was evaluated. The results showed that 13 populations developed low levels of resistance to abamectin. An overall upward trend in B. tabaci resistance toward spirotetramat, cyantraniliprole and pyriproxyfen was observed. In addition, resistance to thiamethoxam remained low-to-moderate in the 23 field populations. These findings suggest that the overall resistance of the field-collected B. tabaci populations has shown an upward trend over the years in China. We believe our study can provide basic data to support integrated pest management and insecticide resistance management of field B. tabaci in China. © 2023 Society of Chemical Industry.

Interactions between Phaedrotoma scabriventris Nixon (Hymenoptera: Braconidae) and Zaeucoila unicarinata Ashmead (Hymenoptera: Figitidae), endoparasitoids of Liriomyza sativae Blanchard (Diptera: Agromyzidae)

Liriomyza sativae Blanchard is a key pest of melon (Cucumis melo L.) in Brazil and a target of biological control using parasitoids. Even though they share similar niches and competitive interactions can occur, Phaedrotoma scabriventris Nixon and Zaeucoila unicarinata Ashmead are potential candidates for controlling L. sativae in melon. Here, we investigated interactions between P. scabriventris (Ps) and Z. unicarinata (Zu) under laboratory conditions. We evaluated: (1) puparia to verify both parasitism and the interactions between parasitoid immature stages; and (2) emerged adults to verify host mortality due to parasitism, host stinging, host feeding, and parasitoid sex ratios. We observed in the dissected puparia that P. scabriventris predominated in all three forms of interaction evaluated. In addition, predation and physical combats were observed between immature stages of both parasitoids. When we consider the emerged adults, both species showed a similar parasitism rate in isolation (P. scabriventris, 19.40 ± 3.57 % and Z. unicarinata, 17.60 ± 4.54 %). The sequential interaction (Zu → Ps) significantly decreased the parasitism by Z. unicarinata (4.92 ± 0.14 %) compared to its parasitism rate in isolation. The greatest total parasitism rate was observed when both species simultaneously (Ps + Zu) parasitised the larvae (51.28 ± 3.08 %). Phaedrotoma scabriventris and Z. unicarinata caused the greatest non-reproductive larvae mortality under the isolated exposure forms (35.90 ± 2.55 % and 37.00 ± 4.60 %, respectively). The sex ratio decreased significantly only in P. scabriventris (22.62 % of females) in the sequential interaction (Ps → Zu). Our results indicate that both P. scabriventris and Z. unicarinata should be used in combination in the control of L. sativae in melon.

Laboratory-Induced Bifenthrin, Flonicamid, and Thiamethoxam Resistance and Fitness Costs in Rhopalosiphum padi.

The bird cherry-oat aphid, Rhopalosiphum padi (L.) (Hemiptera: Aphididae) is one of the most economically important pests of wheat crops worldwide. Thiamethoxam, bifenthrin, and flonicamid are extensively used insecticides for controlling this key pest. However, the indiscriminate use of chemical insecticides has led to the development of resistance in insects. In this study, we assessed the development of selection-induced resistance to bifenthrin, flonicamid, and thiamethoxam under controlled laboratory conditions. Additionally, we employed the age-stage, two-sex life table method to examine the fitness of R. padi. After ten generations of selection, bifenthrin-, flonicamid-, and thiamethoxam-resistant strains of R. padi were developed with resistance levels of 34.46, 31.97, and 26.46-fold, respectively. The life table analysis revealed a significant decrease in adult longevity and fecundity in these resistant strains compared to susceptible strain. Furthermore, the key demographic parameters such as net reproductive rate (R0) and reproductive days exhibited a significant reduction in all resistant strains, while the intrinsic rate of increase (r) and finite rate of increase (λ) were decreased only in resistant strains to bifenthrin and thiamethoxam. Taken together, these findings provide a comprehensive understanding of laboratory-induced insecticide resistance evolution and the associated fitness costs in R. padi. This knowledge could help to design resistance management strategies against this particular pest of wheat.

The Preference of Thrips tabaci for Allium cepa, Allium fistulosum, and Allium roylei

Thrips tabaci Lind. (Thysanoptera: Thripidae) is a key pest of onions worldwide. It causes both direct and indirect damage to onion crops, resulting in high yield losses. Today, the Integrated System of Production and Plant Protection requires onion growers to use onion- thrips-resistant cultivars. It has become apparent that the improvement of existing onion cultivars may not be a sufficient, so it is necessary to search for desirable plant traits related to disease and pest resistance among existing and wild cultivars. For this purpose, we conducted bioassays on the possible preference of T. tabaci for three different cultivars of Allium cepa L., namely, Alibaba, Bila, Tęcza, one cultivar Kroll of Welsh onion, Allium fistulosum L., and the wild species Allium roylei Stearn. The settling preference and the oviposition rate of female onion thrips were evaluated using choice and no-choice laboratory tests, respectively. During the bioassay, on leaf sections of the A. roylei species, a significantly higher number of T. tabaci females was recorded compared to the cv. Tęcza of the A. cepa species and the cv. Kroll of the A. fistulosum species in each observation period. Significantly more thrips settled on cv. Kroll compared to Alibaba and Bila. Regarding the results obtained on A. cepa, significantly fewer females were found on cv. Bila compared to cv. Tęcza. Opposite results were observed in a combination of cvs. Tęcza–Alibaba, where significantly more insects settled on the leaves of cv. Alibaba. Statistically significant differences between cultivars/species were found in the number of hatched larvae on the leaves of the tested cultivars/species of onion. The lowest number of larvae hatched from eggs laid on A. roylei, as compared to A. fistulosum and the cultivars of A. cepa, except for Bila.

Genetic connectivity constrained by natural barriers in a key agricultural pest: insights from mitochondrial DNA analysis

In the context of anthropogenic global change, the study of landscape effects on species movement has garnered increasing attention. Landscape genetics offer indirect yet attractive means to capture species dispersal events across generations and their interaction with landscapes. However, landscape genetic patterns tend to exhibit significant variations across taxa and rely on the molecular makers adopted. Here, we investigated how landscapes influence population connectivity of an important tea pest, Empoasca onukii, using mitochondrial DNA sequences of 1,518 individuals from 57 locations in mainland China and offshore islands. We analyzed the inter-population genetic divergence and integrated multiple models to explicitly quantify their association with geographic distance, environmental heterogeneity, and landscape barriers. Analyses revealed a reduction in gene flow on islands, along the Yangtze River, and across mountainous regions of Western China. Models explicitly detected the predominant contributions of topographic complexity to population divergence and evidenced that mountains may serve as effective dispersal barriers for E. onukii. These results suggest that the limited gene exchange resulting from low population connectivity among mountains might generate the observed patterns of mitochondrial genetic variations, which contrasts the climate-related pattern previously observed on microsatellites. The findings enhance our comprehension of the evolutionary and epidemic dynamics of E. onukii, and highlight the demand of considering species-specific traits when studying population landscape genetic patterns. Moreover, the study emphasizes the necessity of employing multiple molecular markers to comprehensively elucidate landscape effects on population connectivity across diverse species for valuable insights into biodiversity conservation, pest control, and other management decisions.

Landscape structure influences natural pest suppression in a rice agroecosystem

Agricultural landscapes are constantly changing as farmers adopt new production practices and respond to changing environmental conditions. Some of these changes alter landscape structure with impacts on natural pest control, pesticide use, and conservation of biodiversity. In rice agroecosystems the effect of landscape structure on natural enemies and pest suppression is often poorly understood. Here we investigate the effect of landscape composition and configuration on a key pest of rice, the brown planthopper (Nilaparvata lugens). Using N. lugens as sentinel prey coupled with predator exclusions, we investigated landscape effects on herbivore suppression and rice grain yield at multiple spatial scales in two regions of Bangladesh. Ladybird beetles and spiders were the most abundant natural enemies of N. lugens with landscape effects observed at all scales on ladybird beetles. Specifically, ladybird beetles were positively influenced by road edges, and fallow land, while spiders were strongly influenced only by rice phenology. Predator exclusion cages showed that N. lugens abundance significantly increased in caged plots, reducing rice gain yield. We also used an estimated biocontrol service index that showed a significant positive relationship with landscape diversity and a significant negative impact on pest density and yield loss. These results suggest that promoting fallow lands and fragmented patches between rice fields could lead to more sustainable insect pest management in rice agroecosystems, potentially reducing the practice of prophylactic insecticide use.

The insect pests of coffee and their management practices in the main coffee growing region in Kenya

Coffee farming in Kenya is a major source of income for over 800,000 farmers. Globally, the Kenyan coffee is renowned for its high quality. Most of the Kenyan coffee is produced in the Mt. Kenya region. Its production faces many challenges that include infestation by a complex of insect pests. A field survey covering eight (8) main coffee-growing counties and 485 households in the Mt. Kenya region was conducted in May 2022. The survey aimed to establish the key insect pests in the region, and their distribution and management practices applied by the farmers. The survey established eight (8) insect pests as of major importance in the region. These included the Coffee Berry Borer (Hypothenemus hampei), Thrips (Diarthrothrips coffeae), Leaf miners (Leucoptera spp), Yellow Headed Borer (Dirphya nigricornis), White Borer (Anthores leuconotus), Green scales (Coccus alpinus), Kenya Meallybugs (Planococcus kenyae) and Antestia bugs (Antestiopsis spp). Their occurrence ranged from 5 to 66%. The C. alpinus (66%) occurred in all the surveyed counties, Agro-Ecological Zones (AEZs) and coffee farms’ households. The D. nigricornis (57%) was the second most common insect pest. The C. alpinus, D. nigricornis, Leucoptera spp and H. hampei dominated the “Lower” coffee zone and were less dominant in Upper Midland 1(UM 1). Farmers used insecticides, plant extracts, and physical, mechanical, cultural, and field sanitation approaches to control the pests. Insecticides at 79% was the most widespread practice used by coffee farmers. This study and its findings are key to Agricultural extension services in providing focused technical advisory services to coffee farmers based on specific insect pests per the Agro-Ecological Zones from the Mt Kenya region. Keywords: Agro-ecological zones, insect pests, infestation, management practices.

Increasing catches of adult moth pests (Lepidoptera: Tortricidae) in pome fruit with low‐intensity LED lights added to sex pheromone/kairomone lure‐baited traps

AbstractStudies of moth pests (Lepidoptera: Tortricidae) of pome fruit in Washington State, USA, evaluated the addition of low‐intensity light‐emitting diode (LED) lights to traps baited with sex pheromone or kairomone lures. Species included codling moth (CM), Cydia pomonella (L.), oriental fruit moth (OFM), Grapholita molesta (Busck), oblique banded leafroller (OBLR), Choristoneura rosaceana (Harris), and eye‐spotted budmoth (ESBM), Spilonota ocellana (Denis and Schiffenmüller). Lures included (E,E)‐8,10‐dodecadien‐1‐ol (codlemone) plus (E,Z)‐2,4‐ethyl decadienoate (pear ester) and acetic acid (AA) (Combo) and a blend of pear ester, (E)‐4,8‐dimethyl‐1,3,7‐nonatriene, pyranoid linalool oxide, and AA (4K) for CM; a three‐component OFM sex pheromone ((E)‐8‐dodecen‐1‐yl‐acetate, (Z)‐8‐dodecen‐1‐yl acetate, and (Z)‐8‐dodecen‐1‐ol) plus codlemone and terpinyl acetate plus AA for OFM; and 2‐phenylethanol and AA for OBLR and ESBM. Traps baited with only LEDs were not attractive for any of these tortricids. The addition of a LED to lure‐baited traps increased male and female catches 2‐12‐fold across the four pest species. The proportional increase in CM catches with the LEDs was similar with both the Combo and 4K lures. Traps baited with the 4K lure caught significantly more CM with a UV LED than with either blue or green LEDs. The proportion of females caught in traps that were mated did not change with the use of the lights across species. Significantly more CM of both sexes were caught in the adhesive on the side of the liner nearest the LED. The addition of LEDs sometimes increased the by‐catch of minute insects, but liners' saturation was never a factor impacting targeted moth catch. Adding the LED light significantly increased the catch of ESBM in CM‐baited traps and CM in OFM‐baited traps, respectively. The development of inexpensive, dual‐modality traps that add a light stimulus to a kairomonal‐based lure may improve direct control of these key orchard pests via female removal.

Sublethal and transgenerational effects of lufenuron on biological characteristics and expression of reproductive related genes in the fall armyworm, Spodoptera frugiperda

The fall armyworm, Spodoptera frugiperda, is a notorious polyphagous pest that causes serious economic losses in crucial crops and has invaded Africa and Asia. Lufenuron is widely used for controlling S. frugiperda in China, owing to its high toxicity against this key pest, and less pollution and little impact on natural enemies. In the present study, the sublethal and transgenerational effects of lufenuron on S. frugiperda were investigated to provide in-depth information for the rational use of lufenuron. Results showed that the development time and pupae weight were not significantly affected following exposure of females to LC10 and LC25 and male S. frugiperda to the LC10 of lufenuron. However, LC25 exposure significantly reduced pupal and total development time and pupae weight of male S. frugiperda. The longevity of S. frugiperda adults was prolonged by lufenuron and the fecundity of S. frugiperda treated with LC10 of lufenuron was significantly increased by 40% compared to the control. In addition, our study demonstrated that the LC25 of lufenuron had transgenerational effects on the progeny generation. The development time of female S. frugiperda whose parents were exposed to LC25 of lufenuron was significantly decreased compared to the control. And then, the expression profiles of Vg, VgR, JHEH, JHE, JHAMT, JHBP, CYP307A1, CYP306A1, CYP302A1 and CYP314A1 genes involved in insect reproduction and development were analyzed using Quantitative Real-Time PCR (RT-qPCR). Results showed that Vg, VgR, JHE, JHAMT, and CYP306A1 were significantly upregulated at the LC10 of lufenuron, which revealed that these upregulated genes might be linked with increased fecundity of S. frugiperda. Taken together, these findings highlighted the importance of sublethal and transgenerational effects under laboratory conditions and these effects may change the population dynamics in the field. Therefore, our study provided valuable information for promoting the rational use of lufenuron for controlling S. frugiperda.

Combined use of zoophytophagous mirids for sustainable biological protection of greenhouse tomato crops

Tuta absoluta and Bemisia tabaci are two key worldwide tomato pests. In response to chemical control limits, the use of zoophytophagous mirid predators as biocontrol agents is being increasingly studied and proposed for the management of these pests. However, the use of some mirid species and in particular Nesidiocoris tenuis, which naturally occurs in European tomato crops, is controversial due to its ability to inflict significant damage on tomato plants (necrotic rings) in parallel of its high predation capacity. Combining other mirid species such as Macrolophus pygmaeus and Dicyphus errans with N. tenuis could reduce the population growth of T. absoluta and of B. tabaci, while maintaining N. tenuis populations below a critical crop damage threshold. In this study, we tested the effect of combining N. tenuis with M. pygmaeus (at two densities: 10 and 15 individuals per plant) and with or without D. errans (five individuals per plant) on the abundance of all insects (predators and pests) for 8 weeks. We also measured leaf damage by T. absoluta and plant and flower damage (necrotic rings, flower abortion rate) by N. tenuis. We found that the combined presence of D. errans, M. pygmaeus and N. tenuis rapidly and significantly reduced the densities of B. tabaci adults, and T. absoluta larvae and damage compared to when M. pygmaeus (with both densities) was only present with N. tenuis. The presence of D. errans was critical to reduce N. tenuis population growth and necrotic rings on tomato plants, while higher densities of M. pygmaeus density reduced the rate of aborted flowers by N. tenuis. The manipulation of M. pygmaeus densities added to the presence of D. errans could provide a sustainable solution to control multiple pests simultaneously while reducing the damaging phytophagous activity of N. tenuis in tomato crops.

Management of San Jose Scale (Quadraspidiotus perniciosus) by HMOs and Insecticides in Apple Orchards of Kashmir, India

Apple is attached by number of insect pests, among them San Jose Scale (Quadraspidiotus perniciosus) is key pests. San Jose scale (SJS) attacks temperate fruit crop in the state of J&K. It sucks sap from, twigs, branches, and fruits, weakens the plant and the fruits having scale infestation is rendered unthrifty and unmarketable. The pest causes great loses to apple in quantity and quality and debilities apple tree by vigour and health. The objective of this study was to examine efficacy of HMOs as dormant sprays at different concentrations to manage San Jose scale (Quadraspidiotus perniciosus Comstock) and two insecticides viz Chlorpyriphose 25EC and Dimethoate 30Ec at different concentrations were checked for their bio-efficacy in same orchard in late spring during 2021-22. On the basis of pooled data for years for revealed that highest cumulative mean mortality (79.48%) was recorded with the application of Bal spray at concentration of 2.5% followed by 77.56%. mortality of SJS @ 2.5% concentration by HP oil. Chlorpyriphose recorded 71.98% pooled mean mortality at 0.03 5 concentration.

Temporal transcriptomic profiling elucidates sorghum defense mechanisms against sugarcane aphids

BackgroundThe sugarcane aphid (SCA; Melanaphis sacchari) has emerged as a key pest on sorghum in the United States that feeds from the phloem tissue, drains nutrients, and inflicts physical damage to plants. Previously, it has been shown that SCA reproduction was low and high on sorghum SC265 and SC1345 plants, respectively, compared to RTx430, an elite sorghum male parental line (reference line). In this study, we focused on identifying the defense-related genes that confer resistance to SCA at early and late time points in sorghum plants with varied levels of SCA resistance.ResultsWe used RNA-sequencing approach to identify the global transcriptomic responses to aphid infestation on RTx430, SC265, and SC1345 plants at early time points 6, 24, and 48 h post infestation (hpi) and after extended period of SCA feeding for 7 days. Aphid feeding on the SCA-resistant line upregulated the expression of 3827 and 2076 genes at early and late time points, respectively, which was relatively higher compared to RTx430 and SC1345 plants. Co-expression network analysis revealed that aphid infestation modulates sorghum defenses by regulating genes corresponding to phenylpropanoid metabolic pathways, secondary metabolic process, oxidoreductase activity, phytohormones, sugar metabolism and cell wall-related genes. There were 187 genes that were highly expressed during the early time of aphid infestation in the SCA-resistant line, including genes encoding leucine-rich repeat (LRR) proteins, ethylene response factors, cell wall-related, pathogenesis-related proteins, and disease resistance-responsive dirigent-like proteins. At 7 days post infestation (dpi), 173 genes had elevated expression levels in the SCA-resistant line and were involved in sucrose metabolism, callose formation, phospholipid metabolism, and proteinase inhibitors.ConclusionsIn summary, our results indicate that the SCA-resistant line is better adapted to activate early defense signaling mechanisms in response to SCA infestation because of the rapid activation of the defense mechanisms by regulating genes involved in monolignol biosynthesis pathway, oxidoreductase activity, biosynthesis of phytohormones, and cell wall composition. This study offers further insights to better understand sorghum defenses against aphid herbivory.