Natural Enemies Research Articles

Biocontrol efficiency of Trichoderma asperellum in managing branch canker disease of tea (Camelia sp.), its effect on vegetative growth, natural enemies and phytotoxicity

Biocontrol efficiency of Trichoderma asperellum in managing branch canker disease of tea (Camelia sp.), its effect on vegetative growth, natural enemies and phytotoxicity

Occurrence of natural enemies in maize and the predatory potential of selected arthropods against fall armyworm in Multan, Pakistan

Occurrence of natural enemies in maize and the predatory potential of selected arthropods against fall armyworm in Multan, Pakistan

Biology, impact, management and potential distribution of Aromia bungii, a major threat to fruit crops around the world

AbstractAromia bungii Faldermann (Coleoptera: Cerambycidae) is an emerging invasive pest of economically important Prunus species that is native to China, Mongolia, the Russian Far East, Korea, and Vietnam. It was recently introduced to Japan, Germany, and Italy, where it is spreading and damaging crops and ornamental trees. It exhibits an adaptable lifecycle, a high reproductive output, and the larvae live concealed under the bark of infested trees, which are traits that promote its invasiveness. Detection and monitoring of A. bungii currently rely upon visual identification of infested trees that are usually already damaged, which is inefficient and not target-specific. Current control methods rely primarily upon the labour-intensive physical removal of infested trees. Although native parasitoid natural enemies of A. bungii provide control in Chinese orchards, none are appropriate for classical biological control in invaded areas due to biosafety concerns surrounding their broad host ranges. However, entomopathogenic fungi and nematodes may provide viable options for biological control in invaded ranges. Recent advancements in semiochemical baited traps may provide sustainable, target-specific, and efficacious methods to monitor and control A. bungii. There remains much to learn about the biology and control of A. bungii, and continued advancements in the study of sustainable control tools are needed for the management of this emerging pest.

Novel records of parasitoids targeting fall armyworm, <i>Spodoptera frugiperda</i> (J. E. Smith) (Lepidoptera: Noctuidae), in rice-corn-based cropping systems in the Philippines

In the Philippines, the Fall Armyworm (FAW) was initially documented infesting corn in June 2019 and rice in May 2021. Relying on commercially available insecticides as the primary, if not exclusive, management strategy raises concerns about potential issues arising from FAW developing resistance to these chemicals, and the associated risks these insecticides pose to non-target organisms and the environment. To address these challenges, it is imperative to explore potential naturally occurring indigenous biological control agents and entomopathogens of the FAW. Regular field samplings and monitoring of FAW and its natural enemies were systematically conducted in selected municipalities of Central and Northern Luzon, as well as the Cagayan Valley regions of the Philippines. FAW larvae suspected of parasitization were collected from the field and subsequently reared in the laboratory for parasitoid emergence and other natural enemies. The parasitoids that emerged were sent to the Centre for Agriculture and Biosciences International United Kingdom (CABI UK) Diagnostic and Advisory Service for identification. Two hymenopteran parasitoids, Brachymeria lasus Walker (Family: Chalcididae) and Copidosoma floridanum (Ashmead) (Family: Encyrtidae), were identified from the lab-reared FAW larval samples. These two FAW parasitoids are new records in the Philippines and elsewhere.

Comparing various bio-intensive pest management modules in rice

Rice is the key cereal crop in the tropics, supporting diverse pests and natural enemy populations. Recurrent pest outbreaks and yield losses led farmers to rely on extensive insecticide application, disturbing the stability of rice ecosystems and increasing residues in the harvestable products. A study has been conducted to assess the impact of various modules of Bio-Intensive Pest Management (BIPM) on its conservational potential and sustainability in comparison with Farmers’ Practices (FP) in Nalgonda district of Telangana state during kharif-2020. The BIPM practices included application of farm yard manure; rice husk ash; clipping of seedlings; alleyways and weekly release of Trichogramma japonicum in the main field; wet seed treatment and foliar application with Pseudomonas fluorescens (BIPM 1), Trichoderma asperellum strain TAIK1 (BIPM 2) and Bacillus cabrialesii strain BIK3 (BIPM 3). Whereas, FP 1 with need-based insecticide spraying and FP 2 with schedule-based insecticide spraying and Untreated control with (UC) with no intervention. The observations were taken by visual counts at 15-day intervals. The incidence of Cnaphalocrocis medinalis was highest in UC (9.50), followed by BIPM 1 (7.25) and least in FP 2 (2.50) whereas the highest mean population of Apanteles sp. was found in the untreated control (13.75), followed by BIPM 3 (9.50) and least in FP 2 (4.25). The Benefit Cost Ratios (BCR) of BIPM 3 (1.68) were highest followed by BIPM 1 (1.64) and least in FP 2 (1.40) elucidating that BIPM practices can be more economically feasible. The Shannon-Wiener Index for species diversity and species evenness was higher in BIPM treatments as compared to farmers’ practices indicating the potential of these BIPM treatments in natural pest control and maintaining crop ecosystem stability.

Impact of Aphis pomi-tending Formica rufa (Hymenoptera: Formicidae) on biological parameters of Hippodamia variegata (Coleoptera: Coccinellidae).

One of the key reasons for the poor performance of natural enemies of honeydew-producing insect pests is mutualism between ants and some aphid species. The findings demonstrated that red wood ant, Formica rufa Linnaeus (Hymenoptera: Formicidae) had a deleterious impact on different biological parameters of the lady beetle, Hippodamia variegata Goeze (Coleoptera: Coccinellidae). H. variegata laid far fewer eggs in ant-tended aphid colonies, laying nearly 2.5 times more eggs in ant absence. Ants antennated and bit the lady beetle eggs, resulting in significantly low egg hatching of 66 per cent over 85 per cent in ant absent treatments. The presence of ants significantly reduced the development of all larval instars. The highest reduction was found in the fourth larval instar (31.33% reduction), and the lowest in the first larval instar (20% reduction). Later larval instars were more aggressively attacked by ants than earlier instars. The first and second larval instars stopped their feeding and movement in response to ant aggression. The third and fourth larval instars modified their mobility, resulting in increased ant aggression towards them. Adult lady beetles were shown to be more vulnerable to ant attacks than larvae. However, H. variegata adults demonstrated counterattacks in the form of diverse defensive reaction behaviours in response to F. rufa aggression.

Entomopathogens and their role in insect pest management

Agricultural production faces significant challenges due to the loss of crop yields, highlighting the need for improvements in pest management methods to enhance productivity. Crop growers are increasingly pressured to minimize the use of chemical pesticides without compromising yields. However, managing pests has become more challenging due to pesticide resistance and limited product availability. Consequently, there is an urgent requirement for alternative approaches. Entomopathogens such as fungi, bacteria, viruses, and nematodes emerge as promising alternatives to broad-spectrum chemical insecticides. They have been widely employed to control insect pests in cultivated crops, employing successful strategies such as augmentation and classical biological control. These methods involve applying or introducing bacteria, baculoviruses, fungi, and nematodes. Utilizing entomopathogens offers numerous benefits beyond their effectiveness. These advantages encompass the capacity to treat expansive areas with a sole application, ensuring safety for both humans and non-target organisms. Additionally, their use leads to decreased pesticide residues in food, the conservation of natural enemies, and a boost in biodiversity within managed ecosystems. Entomopathogens present a viable solution by offering effective pest control while addressing environmental, human health, and ecosystem sustainability concerns. The primary emphasis of this review is on the present condition of bio-formulations, the pathogenicity associated with entomopathogens, their mode of action, and the possible implementation of diverse microbial formulations aimed at achieving sustainable pest management.

From weeds to natural enemies: implications of weed cultivation and biopesticides for organic onion production.

Weed management is challenging for vegetable crops that are highly sensitive to weed competition, such as onions. Thrips (Thysanoptera: Thripidae) are major insect pests of onions, causing damage through feeding, and vectoring bacterial pathogens causing bulb rot. Both thrips and their associated pathogens are known to survive on many weed species in onion growing regions. Combining weeding with biopesticides may synergistically manage thrips and reduce disease prevalence. However, disturbances from weeding may negatively impact natural enemies. We estimated the effects of organic weed management and biopesticides on weed density, thrips and natural enemy activity, disease severity, and yield. The experiment was a randomized complete block design, with 4 replications of each weeding (control, tine-weeded twice, tine-weeded 4 times, and hand-weeded) and biopesticide (control, OxiDate 2.0, Serenade) combination. Arthropods were monitored using yellow sticky cards, and weed counts, marketable yield, and bulb rot prevalence were estimated. Hand-weeding resulted in the lowest weed density and thrips abundance. Additionally, hand-weeding produced a 9× higher yield compared to all other treatments. Significant interactions were observed between tine-weeding and biopesticide treatments on the prevalence of bulb rot. Natural enemy abundance was slightly negatively impacted by weeding, dependent on the year. DNA metabarcoding results showed high parasitoid diversity in this onion system and high numbers of reads for multiple genera containing important known biological control agents. Our study suggests hand-weeding is necessary in the southeast for maximum onion yield. Future research should focus on exploring the impact of management on natural enemy communities in onion systems on a large scale.

Combined application of entomopathogenic fungi and predatory mites for biological control of Tetranychus urticae on chrysanthemum.

Most studies on efficacy of fungal pathogens and predatory mites against Tetranychus urticae have been done on individual species in the laboratory. We evaluated fungi and predatory mites separately and together against greenhouse populations of T. urticae on chrysanthemum plants. First, effectiveness of the fungal pathogens Beauveria bassiana (Bb88) and Metarhzium anisopliae (Ma129), was compared; then, effectiveness of the predatory mites Phytoseiulus persimilis and Neoseiulus californicus. Based on the results, N. californicus and isolate Ma129 were selected and evaluated in combination. In all experiments, treatment effects were assessed for eggs and motile stages of T. urticae. The first experiment showed no significant effect of both fungal isolates on T. urticae populations, except on plants initially infested with 20 mites, where more eggs were found in the control compared to the fungal treatments. In the second experiment, both predatory mites were equally effective at reducing T. urticae populations compared with the control, regardless of initial T. urticae population density. The last experiment demonstrated that populations of T. urticae were reduced most when M. anisopliae (Ma129) and N. californicus were applied together, compared with the control and when each natural enemy was applied separately. M. anisopliae (Ma129) and B. bassiana (Bb88) isolates did not have a significant effect reducing T. urticae populations. Both predatory mites reduced T. urticae populations, regardless of T. urticae density. Combined application of M. anisopliae (Ma129) and N. californicus were more effective against T. urticae than the control or when each agent was applied separately. This article is protected by copyright. All rights reserved.

Molecular identification of Hymenopteran insects collected by using Malaise traps from Hazarganji Chiltan National Park Quetta, Pakistan.

The order Hymenoptera holds great significance for humans, particularly in tropical and subtropical regions, due to its role as a pollinator of wild and cultivated flowering plants, parasites of destructive insects and honey producers. Despite this importance, limited attention has been given to the genetic diversity and molecular identification of Hymenopteran insects in most protected areas. This study provides insights into the first DNA barcode of Hymenopteran insects collected from Hazarganji Chiltan National Park (HCNP) and contributes to the global reference library of DNA barcodes. A total of 784 insect specimens were collected using Malaise traps, out of which 538 (68.62%) specimens were morphologically identified as Hymenopteran insects. The highest abundance of species of Hymenoptera (133/538, 24.72%) was observed during August and least in November (16/538, 2.97%). Genomic DNA extraction was performed individually from 90/538 (16.73%) morphologically identified specimens using the standard phenol-chloroform method, which were subjected separately to the PCR for their molecular confirmation via the amplification of cytochrome c oxidase subunit 1 (cox1) gene. The BLAST analyses of obtained sequences showed 91.64% to 100% identities with related sequences and clustered phylogenetically with their corresponding sequences that were reported from Australia, Bulgaria, Canada, Finland, Germany, India, Israel, and Pakistan. Additionally, total of 13 barcode index numbers (BINs) were assigned by Barcode of Life Data Systems (BOLD), out of which 12 were un-unique and one was unique (BOLD: AEU1239) which was assigned for Anthidium punctatum. This indicates the potential geographical variation of Hymenopteran population in HCNP. Further comprehensive studies are needed to molecularly confirm the existing insect species in HCNP and evaluate their impacts on the environment, both as beneficial (for example, pollination, honey producers and natural enemies) and detrimental (for example, venomous stings, crop damage, and pathogens transmission).

Flowering Ocimum gratissimum intercropped in tea plantations attracts and reduces Apolygus lucorum populations.

Apolygus lucorum is one of the most important piercing-sucking insect pests of the tea plant. In this study, we assessed the attractiveness of basil plants to A. lucorum and the effectiveness of Ocimum gratissimum L. in the control of A. lucorum. The control efficiency of main volatile chemicals emitted from O. gratissimum flowers was also evaluated. Among seven basil varieties, O. gratissimum was more attractive to A. lucorum adults and was selected as a trap plant to assess its attractiveness to A. lucorum and effects on natural enemies in tea plantations. The population density of A. lucorum on trap strips of O. gratissimum in tea plantations was significantly higher than that on tea at 10-20 m away from the trap strips. Intercropping O. gratissimum with tea plants, at high-density significantly reduced A. lucorum population levels. Eucalyptol, limonene, β-ocimene, and linalool were the four dominant components in the O. gratissimum flower volatiles, and their emissions showed a gradual upward trend over the sampling period. Olfactometer assays indicated that eucalyptol and dodecane showed attraction to A. lucorum. High numbers of A. lucorum were recorded on limonene, eucalyptol, and myrcene-baited yellow sticky traps in field trials in which 11 dominant volatiles emitted by O. gratissimum flowers were evaluated. Our research indicated that the aromatic plant O. gratissimum and its volatiles could attract A. lucorum and planting O. gratissimum has the potential as a pest biocontrol method to manipulate A. lucorum populations in tea plantations. This article is protected by copyright. All rights reserved.

Stability analysis of a pine wood nematode prevention and control model with delay

Pine wilt disease is a destructive forest disease with strong infectivity, a wide spread range and high difficulty in prevention and control. Since controlling Monochamus alternatus, the vector of pine wood nematode (Bursaphelenchus xylophilus) can reduce the occurrence of pine wilt disease efficiently, the parasitic natural enemy of M. alternatus, Dastarcus helophoroides, is introduced in this paper. Considering the influence of parasitic time of D. helophoroides on the control effect, based on the mutualistic symbiosis and parasitic relationship among pine wood nematode, M. alternatus and D. heloporoides, this paper establishes a pine wood nematode prevention and control model with delay. Then, the stability of positive equilibrium and the existence of Hopf bifurcation are discussed. Besides, we obtain the normal form of Hopf bifurcation by applying the multiple time scales method. Finally, numerical simulations with two sets of meaningful parameters selected by means of statistical analysis are carried out to support the theoretical findings. Through the comparative analysis of numerical simulations, the factors affecting the control effect of pine wilt disease are obtained, and some suggestions are put forward for practical control in the forest.

Efficacy of Diamide Insecticides Delivered through Different Methods against Shoot and Fruit Borer L. orbonalis.

Many vegetables insect pests are managed by using conventional insecticides. Unfortunately, these insecticides are harmful to natural enemies, bees, predators, parasitoids and no longer have some of the insect pests have developed resistance to these insecticides. Diamides insecticides are the new generation insecticides that provide systemic way controlling many arthropod pest, but exhibit low toxicity to beneficial insects some other arthropod pests and may be promising alternative to other conventional insecticides. Field experiment was carried out to evaluate the efficacy of diamides delivered through different during Kharif, 2021-22 with 14 treatments and 2 replications.    Diamides may be delivered to brinjal crop via seedling dipping, soil drenching and foliar spraying therefore it is important to determine the most effective pest control strategy while using the least amount of active ingredients. In a case study, chlorantraniliprole flubendiamide and cyantraniliprole were used to control brinjal shoot and fruit borer, Leucinodes orbonalis (Guenee) (Lepidoptera: Pyraustidae) in brinjal. These insecticides administered as foliar spray, soil drenching and seedling dipping were compared, the treatment with foliar application of diamides gave good results as compared to soil drenching and seedling dipping. The results indicated that, diamides were superior to other insecticides used in the present investigation but they failed to give good control when applied through seedling dipping method. Highest C:B ratio (1: 6.07) and yield (47.80t/ha) was recorded in foliar spray of chlorantraniliprole 18.5 SC treated plot.

Entomofauna Associated with Corn Cultivation and Damage Caused by Some Pests According to the Planting Season on the Ecuadorian Coast

Corn (Zea mays L.) is an important cereal for food sovereignty, extensively planted due to its adaptation to various agroecological conditions. Climatic conditions and pests can affect its production. Concerning the latter, natural enemies could be considered in biological control programs. The objective of this study was to estimate the influence of the presence of insects, damage to plants and cobs, and their incidence on corn yield in two planting seasons. During the rainy (February to May) and dry seasons (Jun to October) of the year 2023, in Calceta, Lodana, and Quevedo, three important corn-growing areas on the Ecuadorian coast, corn plots of 1126 m2 were planted. The diversity of phytophagous and natural enemies was estimated. Damage to young plants and cobs was observed, and corn yield was determined. Of the 9073 insects observed, 44.2% and 55.8% constituted phytophagous and natural enemies, respectively. A moderate diversity (Shannon-H Index = 2.474–2.629 and Margalef Index = 2.734–3.110) of insects associated with corn was determined. Yield (range: 6.9 to 15.3 t) was negatively correlated with rainfall and cob damage (p < 0.05). Although precipitation is necessary for planting in rainy season, frequent and intense rains could be affect corn yield.

A new species of Micrapate (Insecta: Coleoptera: Bostrichidae) from Brazil, with a key to Brazilian species

Micrapate spinula Liu, sp. nov., is described from the cerrado savanna biome of Brazil (Mato Grosso do Sul and Minas Gerais), together with information on its biology and natural enemies. A key to the Micrapate species known from Brazil is provided.

Cold tolerance of the mealybug parasitoid Anagyrus vladimiri

AbstractWe investigated the lower thermal limits of Anagyrus vladimiri Triapitsyn (Hymenoptera: Encyrtidae), a natural enemy of mealybugs. Parasitoids were cooled to measure supercooling points and the lower lethal temperature LLT50. To investigate survival after long-term cold exposure, parasitoid adults and eggs, larvae, and pupae within their host mummy were gradually acclimated. Adults were then exposed for three days to 7 °C, 5 °C, 3 °C, and 1 °C, and immatures for varying durations to 5, 1, and − 4 °C. Parasitoids were investigated for survival and reproduction. To assess the impact of fluctuating temperature, parasitoid pupae were subjected to daily warming to 10 °C from baseline temperatures of 5 °C, 1 °C, and − 4 °C during four-day-cold exposure. Finally, eggs, pupae and adults were exposed to winter conditions in Switzerland in a semi-field setup. The LLT50 was − 17.24 °C for adults and 0.94 °C for pupae. Both values were above the supercooling points. No adult survived three days at 3 °C and lower. Likewise, no emergence occurred from eggs or larvae exposed for four days and longer to 1 °C or seven days to 5 °C. Pupae were cold-hardier surviving seven days at 5 °C and three days at 1 °C. Parasitoids surviving cold exposure were still able to reproduce. Daily warming decreased emergence of cold exposed pupae at a baseline temperature of 1 °C but not at 5 °C and − 4 °C. No eggs, pupae and adults survived winter conditions in the semi-field experiment. We thus consider A. vladimiri a chill-susceptible species with very limited cold-tolerance of the investigated population and low chances of survival during winter in Northern Switzerland.

A whole ecosystem approach to pear psyllid (Cacopsylla pyri) management in a changing climate

AbstractWhole ecosystem-based approaches are becoming increasingly common in pest management within agricultural systems. These strategies consider all trophic levels and abiotic processes within an ecosystem, including interactions between different factors. This review outlines a whole ecosystem approach to the integrated pest management of pear psyllid (Cacopsylla pyri Linnaeus) within pear (Pyrus communis L.) orchards, focusing on potential disruptions as a result of climate change. Pear psyllid is estimated to cost the UK pear industry £5 million per annum and has a significant economic impact on pear production globally. Pesticide resistance is well documented in psyllids, leading to many growers to rely on biological control using natural enemies during the summer months. In addition, multiple insecticides commonly used in pear psyllid control have been withdrawn from the UK and Europe, emphasising the need for alternative control methods. There is growing concern that climate change could alter trophic interactions and phenological events within agroecosystems. For example, warmer temperatures could lead to earlier pear flowering and pest emergence, as well as faster insect development rates and altered activity levels. If climate change impacts pear psyllid differently to natural enemies, then trophic mismatches could occur, impacting pest populations. This review aims to evaluate current strategies used in C. pyri management, discuss trophic interactions within this agroecosystem and highlight potential changes in the top-down and bottom-up control of C. pyri as a result of climate change. This review provides a recommended approach to pear psyllid management, identifies evidence gaps and outlines areas of future research.

Ecological Insights and First Confirmed Record of Ooencyrtus nezarae (Hymenoptera: Encyrtidae) on Eggs of Megacopta cribraria (Hemiptera: Plataspidae) in Tennessee and Georgia1

Abstract The kudzu bug, Megacopta cribraria (F.) (Heteroptera: Plataspidae), is native to Asia, was first detected in Georgia, USA, in 2009, and has since been recognized as a damaging pest of soybean (Glycine max (L.) Merrill; Fabales: Fabaceae) in several southeastern states. Megacopta cribraria dispersed rapidly from 2009 to 2013, after which its spread rate declined sharply. Despite this decline, established populations have remained stable. This decline may be partially attributed to natural enemies of kudzu bug. For example, the exotic egg parasitoids Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) and Paratelenomus saccharalis (Dodd) (Hymenoptera: Platygastridae) have been occasionally detected in the United States since 2016 and 2013, respectively. We recovered O. nezarae from M. cribraria eggs collected from wild patches of kudzu (Pueraria montana Lour. (Merrill) var. lobata (Willd.)) throughout summer 2017. Although the occurrence of O. nezarae in southern Georgia has been suggested based on exit holes from kudzu bug eggs, to our knowledge, this report is the first to document and confirm recovery of O. nezarae from kudzu bug eggs in both Tennessee and Georgia. In addition, at the time of collection in 2017, this recovery was the first confirmation of this species from kudzu in North America. This early-season natural enemy combined with the later-occurring entomopathogen Beauveria bassiana (Balsamo-Crivelli) Vuillemin may reduce and maintain kudzu bug densities, which could lessen economic impacts on soybean producers.

An Eretmocerus Species, Parasitoid of Aleurocanthus spiniferus, Was Found in Europe: The Secret Savior of Threatened Plants

This study focuses on the first detection in Europe of a parasitoid Eretmocerus sp. gr. serius (Hymenoptera: Aphelinidae) on the Orange Spiny Whitefly, Aleurocanthus spiniferus (Quaintance) (Hemiptera: Aleyrodidae). Through extensive field surveys, this study investigates the occurrence of the aphelinid in several regions across central and southern Italy. Different sites were monitored to investigate the Eretmocerus sp. gr. serius parasitization rate on A. spiniferus, shedding light on its potential as a biological control agent against the invasive whitefly pest. The research results offer a hopeful prospect for progressing sustainable and eco-friendly methods in handling A. spiniferus infestations in citrus crops, highlighting the importance of natural enemies in integrated pest management programs. The research emphasizes the importance of the recently discovered parasitoid for European agriculture, paving the way for inventive approaches in pest control and cultivation practices.

Incidence of Insect Pests and Its Natural Enemies of Cabbage (Brassica oleracea var. capitata) in Relation to Weather Parameters under Field Conditions

The study was carried out in the field at the Horticultural Polyhouse, College of Agriculture, Rajendranagar, during the rabi season of 2022–2023. In the field, aphid infestation peaked in the last week of November (48th SMW), while lepidopteran pests (tobacco caterpillar, DBM, and leaf webber) peaked in January (3rd, 2nd, and 1st SMW, respectively). Coccinellids, syrphids, and spiders had average populations of 0.80, 0.21, and 0.03 correspondingly. Aphids were shown to have a non-significant link with weather factors, showing negative correlations with maximum temperature, sunshine, wind, and rainfall and positive correlations with minimum temperature and RH I & II. While leaf webber and DBM showed a non-significant negative connection with sunshine and wind speed, they displayed a non-significant positive correlation with maximum temperature, RH I & II, and rainfall. Additionally, they showed a strong inverse relationship with evaporation. The maximum and minimum temperatures were shown to have a non-significantly positive connection with tobacco caterpillar and semilooper.