Beneficial Insects Research Articles

Beneficial Insects for Biological Pest Control in Greenhouse Cannabis Production

A greenhouse cannabis cultivation took place in Agriculture university of Athens in order to quantify the efficiency of beneficial insects as a main method of pest management. Cannabis plants grown in two greenhouses and beneficial insects were released only in one greenhouse as a means to investigate the efficacy against pests by the comparison with the control greenhouse. Measurements included the visual estimation of infestation, the recording of pest species and populations, and the comparison of infestations and yields amongst greenhouses. Our results indicate that beneficial insects could control pest populations up to 100%. Even though the environmental conditions were not optimal and consecutive pest infestations were observed throughout the duration of our study, the beneficial insects successfully managed the pest populations. In conclusion, biological control with beneficial insects is a very effective method for pest management in greenhouse cannabis production.

A Comparison of IPM and Organic Farming Systems Based on the Efficiency of Oophagous Predation on the Olive Moth (Prays oleae Bernard) in Olive Groves of Southern Iberia

The olive moth, Prays oleae (Bernard, 1788) (Lep., Praydidae), is one of the most common insect pests affecting the olives groves of the Mediterranean basin. Current farming practices are largely oriented to optimize the effectiveness of beneficial insects, among which the common green lacewings (Neur., Chrysopidae) stand out. Two different types of management models, organic and IPM, were compared in this study, which was conducted in olive groves in the regions of Andalucía (Spain) and Alentejo (Portugal). During 2020 and 2021, fruit samples were periodically collected, analyzing the population parameters (POP) and potential attack on the fruit (%PA), as well as the predatory impact (%PRED), which has allowed the estimation of the final attack (%FA), and derived fruit recovery rates (%REC). The results show that in organic olive groves of both countries, the infestation parameters (POP, %PA) were significantly higher than in IPM ones. However, predation rates were also higher in organic olive groves, which resulted in REC rates of between 75% and 80%, reducing FA rates to values of approximately 10% and 20% in Portugal and Spain, respectively. In contrast, in the IPM olive groves, significantly lower predation values were recorded, with lower REC rates than in the organic olive groves; the rates were very similar in both countries (ca. 54%), which led to a higher percentage of fruit loss (%FA) equivalent to 22% (Portugal) and to 34% (Spain). This paper discusses potential drivers influencing differences in the population values and percentages of infestation by P. oleae observed, as well as the differences in the final attack rates between olive groves of both countries, subject to the same type of agricultural management.

Farmers’ Perceptions and Knowledge of Country Bean (Lablab purpureus L.) Insect Pests, and Diseases, and Their Management Practices, in Bangladesh

Country bean (Lablab purpureus L.), a popular vegetable in Bangladesh, is severely affected by insect pests and diseases. Farmers’ perceptions of insect pests, diseases, and their management are critical constraints to the establishment of an effective and sustainable pest management approach for this crop. A comprehensive survey was conducted with 300 country bean farmers from six districts of Bangladesh to assess farmers’ perceptions and knowledge of the insect pests and diseases of country bean, and their management practices. The survey results show that country bean farmers have been facing varying pest problems for more than ten years. They could identify eight pests and only one beneficial insect species in their fields, including thrips and jute weevil, as new pests. Among the pests, aphids and pod borers were common in all surveyed areas. More than 80% of farmers said their bean plants were severely affected by bean yellow mosaic virus and white mold diseases. Farmers also mentioned that insect pests and diseases together caused 30–40% yield losses of this crop. About 76% of the farmers solely depended on different chemical pesticides for the production of country bean. Growers frequently used insecticides from the organophosphorus and neonicotinoid groups, and fungicides from the triazole group, to manage pests associated with this crop. Farmers start applying pesticides from the seedling stages, at three-day intervals, maintaining only two- to four-day pre-harvest intervals (PHI). Our findings provide insight into the importance of developing sustainable pest management approaches for country bean production in Bangladesh.

Pyrethroid induced terato-genicity and genotoxicity

Pesticide has become an integral part of modern agriculture. Pyrethroids are biodegradable that is why uses of this pesticide being in large amounts, and due to their not being used properly, they affect harmful insects as well as many beneficial insects and many different types of organisms and humans. Produced effects such as neurotoxic, genotoxic and teratogenic effects. Cypermethrin (CYP), a class-II type of pyrethroid pesticide has been studied in many organisms for its various adverse effects, but its teratogenic and genotoxic effect has not been much studied in birds. So, in this review conclude the genotoxic and teratogenic potential of different type of pyrethroid in various animals.

Substrate and moisture content effects on pupation of the black soldier fly (Diptera: Stratiomyidae)

The black soldier fly (BSF)Hermetia illucens (L.) (Diptera: Stratiomyidae) is a beneficial insect species of great environmental and economic potential. Previous studies showed that providing a suitable pupation substrate can accelerate BSF pupation and increase pupation rate. However, the effect of substrate moisture content and the possible interactions between substrate type and moisture content on BSF pupation have not been investigated. In this study, we tested the effects of two pupation substrates (vermiculite and wood chips) and nine moisture levels (dry, 18.8, 37.5, 56.3, 75.0, 93.8, 112.5, 131.3, and 150.0%) on BSF pupation rate and depth. Substrate type and moisture content both affected BSF pupation rate and depth. Compared with the ‘no substrate’ treatment, neither substrate reduced BSF prepupal mortality without adding water, but the presence of dry substrate increased pupation rate by more than 8%. Within the range used in this study, moisturising substrates reduced BSF prepupal mortality by up to 88% for vermiculite and 95% for wood chips, and increased pupation rate by up to 9% for vermiculite and 6% for wood chips. In all substrate treatments more than 99% of the pupae were found in the top 4 cm, and more than 85% were found in the top 2 cm depth. The tendency of BSF to pupate deeper than 2 cm depended on substrate type and moisture content, and the effect of moisture content on pupation depth followed a parabolic trend. Based on our data, the proportions of BSF pupae presenting deeper than 2 cm would be the highest when the moisture content is around 20% for vermiculite and 70% for wood chips. Our results provide clues for selecting suitable substrate, moisture content, and substrate depth to facilitate BSF pupation.

The sustainable transformation of the Colombian cattle sector: Assessing its circularity

Circular food systems are increasingly acknowledged for their potential to contribute to the transition towards sustainable futures. In a circular food system, the use of finite and limited resources is minimized, and nutrients in residual streams and inedible biomass for humans are reused as inputs in the bioeconomy. Livestock has become relevant in this narrative for upcycling nutrients contained in food by-products and grass resources into nutritious food for humans without using human-edible resources. Evaluating on-going national sustainability initiatives in the livestock sector is key to determine if circularity elements are already represented and to identify new opportunities and pathways for the future. In this paper we synthetize the environmental actions promoted by different initiatives driving the sustainable transformation of Colombian cattle production systems and assess the inclusion of circularity elements in these actions. The proposed environmental actions were concentrated in the conservation of remaining natural ecosystems, zero-deforestation and the sustainable intensification of cattle production through silvopastoral and paddock rotational systems. Circularity was addressed by some initiatives via the use organic fertilizers and the use of manure as fertilizers or feedstock for bioenergy generation. However, given that cattle farming is often practiced in low-input systems where the collection of by-products for reutilization (e.g., manure) is not always feasible, these actions are expected to have limited impact in the sector. Silvopastoral systems can positively promote circularity by creating the conditions for internal nutrient recycling via litterfall, biological nitrogen fixation, phosphorus solubilization, and presence of beneficial insects. However, to avoid food-feed competition and to remain circular, these should only be installed in agricultural areas unsuitable for crop production. In areas where crops can grow, other production systems that prioritize the production of plant biomass for human consumption (i.e., agrosilvopastoral systems, mixed crop-livestock systems or forms of crop intercropping) should be considered.

Pollinator biological traits and ecological interactions mediate the impacts of mosquito-targeting malathion application

Mosquito adulticides are perceived by the public as detrimental to nontarget arthropods, contributing to declines of native and beneficial insects. However, the actual impact of adulticides on nontarget arthropods in nature needs to incorporate biological and ecological elements. Here, we investigated the effect of biological/behavioral traits (butterfly roosting at different heights, roosting in sites underneath foliage, bumblebee hive usage) and interactions (parasitism, predation) of pollinators (butterflies and bumblebees) that could mediate the impacts of malathion application in manipulative semi-field experiments in Florida, USA. Roosting height from the spray route had a significant negative relationship with mortality of butterflies treated with ULV malathion, with high survival at the highest roosting height (7 m), but butterflies roosting among vegetation did not have higher survival. Bumblebees with hive access had significantly higher survival than bumblebees without hive access. Host plants treated with ULV malathion significantly reduced parasitism of monarch eggs by Trichogramma platneri, but increased predation of monarch caterpillars by Polistes paper wasps. These data provide insight into the realistic impacts of adulticide applications on pollinators in nature which will enable mosquito control districts to better limit nontarget effects of adulticide treatments and may help to address concerns related to potential nontarget effects.

Landscape diversity influences the arthropod species diversity in the rice field

Landscape diversity is one of the key drivers for maintaining ecosystem services in agricultural production by providing vital habitats and alternative food sources for beneficial insects and pollinators within the agricultural landscapes. The landscape structure, land uses, and diversity differ between geographic locations. However, how the changes of landscape structure and land use diversity affect the arthropod diversity in a geographic area is poorly understood. Here, we tested the impact of landscape diversity on the rice locations in Bangladesh. Results ranged from highly diversified to very highly diversified in Chattogram (>7.9), to highly diversified (0.590.79) in Satkhira and moderately (0.390.59) to less diversified (0.190.39) in Patuakhali. These significant different landscape diversities influenced the arthropod diversity in rice fields. Arthropod species diversity increases with the increase in the Land Use Mix (LUM) index. The maximum tillering stage of rice growth harbored higher abundance and species diversity in rice fields. Moreover, we found that vegetation is the most important factor influencing the abundance of arthropods. Extensive agriculture and forest contributed substantially to predicting arthropod richness. Meanwhile, barren land and high-density residential land as well as intensive agriculture had large impact on species diversity. This study indicates that landscape diversity plays a vital role in shaping the species diversity in rice fields, providing guidelines for the conservation of arthropod diversity, maximizing natural pest control ecosystem service and more secure crop production itself.

Conserving diversity in Irish plant-pollinator networks.

Beneficial insects provide valuable services upon which we rely, including pollination. Pollinator conservation is a global priority, and a significant concern in Ireland, where over half of extant bee species have declined significantly in recent decades. As flower‐visiting insects rely on flowering plants, one way to conserve and promote pollinator populations is to protect high‐quality habitat. We analyzed the structure of insect–flower interactions from multiple habitat categories in a large database of interactions from Ireland. Our primary goals were to compare spatial and temporal variation in Irish network structures, compare Irish networks to published networks from other countries, and provide evidence‐based recommendations for pollinator conservation in Ireland by identifying well‐visited plant species that may promote high pollinator diversity, abundance, and functional complementarity. Habitat types within Ireland differed substantially: seminatural grasslands had the highest pollinator species richness and largest number of unique pollinator species, while intensively managed habitats exhibited negative asymmetry (more plant than pollinator species). This negative asymmetry is notable because most plant–pollinator networks exhibit a positive asymmetry. Within intensively managed habitats, agricultural and urban habitats differed. Urban habitats had the highest number of non‐native plant species while agricultural habitats had the lowest pollinator species richness. We also found Irish networks varied across the growing season, where July had the highest plant and insect species richness. When comparing Irish networks to published networks from other countries, we found Irish networks had a higher ratio of plant species to pollinator species, and that this difference was most evident in agricultural habitats. This ratio means the typical network asymmetry (more pollinator than plant species) was flipped (more plant than pollinator species) in the Irish network. We conclude that conserving seminatural grasslands in Ireland will be an essential component of pollinator conservation and identify thirty‐five plant species important for restoring seminatural habitats.

Effect of Maize–Legume Intercropping on Maize Physio-Agronomic Parameters and Beneficial Insect Abundance

In developing countries, intercropping is commonly used to boost land productivity and agricultural benefits. However, in the Yucatan region of Mexico, maize (Zea mays L.) yields remain low, despite consistent fertilizer and pesticide inputs in traditional intercropping systems. Furthermore, little is known about the photosynthetic mechanisms that occur when maize plants interact with legumes, and there is a lack of understanding of how intercropping systems affect other organisms in the system, such as beneficial and insect pest population dynamics. A field experiment was carried out on the Yucatan Peninsula in 2021 to assess the impact of maize–legume intercropping systems on maize yield, physiological characteristics as evaluated by gas exchange measurements, and the abundance of beneficial insects in traditional and novel maize intercropping systems. The experiment was carried out with a randomized complete block design with three replicates. Treatments included maize intercropped with a novel legume, crotalaria (Crotalaria juncea L.), maize intercropped with a traditional legume, cowpea (Vigna unguiculata (L.) Walp.), and sole maize as a control. Significant differences in plant height were shown at growth stages V12 (45 days after sowing) and VT (60 days after sowing). No differences were observed in stem diameter, leaf area index, or chlorophyll content. The maize/cowpea intercrop increased the photosynthesis rate by 12.9% and 9.84% in the maize/crotalaria and sole maize, respectively (p < 0.001), and transpiration rate by 6.5% and 8.5% in the maize intercropped with crotalaria and sole maize treatments, respectively (p < 0.001), of maize plants. No significant effects on stomatal conductance or water use efficiency were observed, but the carbon intercellular rate was reduced by 9.74% and 9.15 when compared to the maize/crotalaria and the sole maize treatments, respectively. Overall, intercropping treatments attracted more beneficial insects than sole maize. For predators, the families that stood out were Coccinelidae, Formicidae, Araneidae, Thomisidae, Syrphidae, Chrysomelidae, Oxypidae, Vespidae, Reduviidae, Carabidae, Asilidae, Salthicidae, Dolichopodidae, while among parasitoids, the most frequent families were Eurytomydae, Braconidae, Tachinidae, Pteromalidae, Scelionidae, and Figitidae. In comparison to the maize/cowpea and maize/crotalaria treatments, the sole maize treatment resulted in a grain yield increase of 24.5% and 32%, respectively. However, sole maize was not statistically different to that of maize/cowpea intercropping. In conclusion, our findings suggest that maize/cowpea intercropping could be a viable alternative to sole maize cropping systems for enhancing maize yield and the abundance of beneficial insects, without increasing interspecific competition with the maize crop. Therefore, the maize/cowpea intercropping system represents a sustainable planting alternative for promoting maize grain yield and also promoting edible legume production within the system. Furthermore, the outcomes of this study can serve as a theoretical framework for increasing maize–legume intercropping profitability under growing conditions on the Yucatan Peninsula.

Betulin, Synthesized by PpCYP716A1, Is a Key Endogenous Defensive Metabolite of Peach against Aphids.

Wild pest-resistant germplasms employ secondary metabolites to withstand insect attacks. A close wild relative of the cultivated peach, Prunus davidiana, displays strong resistance to green peach aphids by utilizing metabolites to cope with aphid infestation; however, the underlying mechanism of aphid resistance remains mostly unknown. Here, metabolomic analysis was performed to explore the changes in metabolite levels in P. davidiana after aphid infestation. The data revealed that betulin is a key defensive metabolite in peaches that protects against aphids and possesses potent aphidicidal activity. Further toxicity tests demonstrated that betulin was toxic to pests but not to beneficial insects. Additionally, transcriptomic and phylogenetic analyses revealed that the cytochrome P450 gene PpCYP716A1 was responsible for betulin synthesis─this finding was confirmed by the heterologous expression of this gene. This study revealed a strategy whereby plants harness defense metabolites to develop resistance to pests. These findings may facilitate controlling such pests.

Sown wildflowers between vines increase beneficial insect abundance and richness in a British vineyard

Abstract Traditional vineyards are generally intensive monocultures with high pesticide usage. Viticulture is one of the fastest‐growing sectors of English agriculture, although there is currently limited research on habitat management practices. In a vineyard in East Sussex, England, we tested five inter‐row ground cover treatments on their potential in supporting beneficial insects: two commercially available seed mixes (meadow mix and pollen and nectar mix), a wild bee seed mix (formulated based on pollinator foraging preferences), natural regeneration, and regularly mowed grass. Over two years, from May to August, we conducted monthly floral surveys and insect surveys using transect walks and pan traps. The abundance and richness of flowers in the natural regeneration treatment were twice that of the regularly mown inter‐row treatment. By year 2, the abundance of “total insects” sampled was significantly higher in the wild bee mix compared to mown. Likewise, there was a significant effect of treatment type on pollinator richness, with a higher mean richness found in wild bee mix. Solitary wasp family richness was highest in the natural regeneration treatment and lowest in the mown treatment. Given the rapid growth and lack of specific environmental recommendations for British viticulture, we demonstrate a simple and effective approach for supporting beneficial insects and ecosystem services. Promotion of perennial wildflowers through sowing or allowing natural regeneration in inter‐row ground cover in vineyards has the potential to boost biodiversity in vineyards on a large scale if widely adopted.

Field and Cage Studies Show No Effects of Exposure to Flonicamid on Honey Bees at Field-Relevant Concentrations.

Simple SummaryThe effects of pesticides on honey bees are of great concern to beekeepers and the general public. In particular, a class of pesticides called neonicotinoids has been found in some studies to affect bee learning and colony function. A pesticide classified as a neonicotinoid, flonicamid, has been detected in the residue analyses of honey and pollen samples for a published study, and that compound was tested at three concentrations (0, 50, and 250 parts per billion (ppb)) in sugar syrup in a field study with bee colonies and in two cage studies. Colony population levels, hive weight changes, thermoregulation, and CO2 concentrations were measured in the field study, and syrup consumption, thermoregulation, and survivorship by worker bees were measured in the cage studies. No significant treatment effects of the pesticide exposure were observed in either the field or the cage studies. These results support the idea that flonicamid is safe for honey bees at these concentrations. Publishing such results when they occur is important, so people use safe pesticides when they need them.The extent to which insecticides harm non-target beneficial insects is controversial. The effects of long-term exposure on honey bees to sublethal concentrations of flonicamid, a pyridinecarboxamide compound used as a systemic insecticide against sucking insects, were examined in a field study and two cage studies. The field study involved the continuous weight, temperature, and CO2 monitoring of 18 honey bee colonies, 6 of which were exposed over six weeks to 50 ppb flonicamid in sugar syrup, 6 exposed to 250 ppb flonicamid in syrup, and 6 exposed to unadulterated syrup (control). Treatments were derived from concentrations observed in honey samples in a published study. No effects were observed on foraging activity, hive weight gain, thermoregulation, or average CO2 concentrations. However, Varroa mite infestations may have also contributed to experimental variability. The two cage studies, in which cages (200 newly-emerged bees in each) were exposed to the same flonicamid concentrations as the field study and kept in a variable-temperature incubator, likewise did not show any experiment-wide effects on survivorship, thermoregulation, or syrup consumption. These results suggest that field applications of flonicamid that result in concentrations as high as 250 ppb in honey may be largely safe for honey bees.

Adult female exposure to mild ultraviolet radiation reduces longevity but not egg load in two parasitoid wasps

AbstractInsects can be exposed to ultraviolet (UV) radiation throughout their lifecycle when they rest, forage, and mate. The negative effects that such highly energetic photons can have on insect fitness are not well‐known, especially for natural exposure during the adult stage. Adult insects are considered to be more resistant to UV radiation than their immature stages, but this assumption is supported by only a few studies on a restricted set of pest species. We conducted the first investigation of the vulnerability of parasitoid adults to UV exposure, by assessing the longevity and potential fecundity of female Telenomus podisi Ashmead and Trissolcus utahensis Ashmead (Hymenoptera: Scelionidae) receiving low doses of UV‐A and visible radiation daily in the laboratory. Parasitoids died up to 2× faster with increasing levels of UV radiation, and, to a lesser extent, of visible radiation. There was no effect of UV radiation on maximum egg load resulting from oogenesis in early adulthood. This study on beneficial insects indicates that the physiological consequences of cumulative exposure to even mild doses of more energetic optical radiation, particularly in the UV range, should not be underestimated in natural and managed ecosystems.

Laboratory Risk Assessment of Three Entomopathogenic Fungi Used for Pest Control toward Social Bee Pollinators.

The use of fungal-based biopesticides to reduce pest damage and protect crop quality is often considered a low-risk control strategy. Nevertheless, risk assessment of mycopesticides is still needed since pests and beneficial insects, such as pollinators, co-exist in the same agroecosystem where mass use of this strategy occurs. In this context, we evaluated the effect of five concentrations of three commercial entomopathogenic fungi, Beauveria bassiana, Metarhizium anisopliae, and Cordyceps fumosorosea, by direct contact and ingestion, on the tropical stingless bees Scaptotrigona depilis and Tetragonisca angustula, temperate bee species, the honey bee Apis mellifera, and the bumble bee Bombus terrestris, at the individual level. Furthermore, we studied the potential of two infection routes, either by direct contact or ingestion. In general, all three fungi caused considerable mortalities in the four bee species, which differed in their response to the different fungal species. Scaptotrigona depilis and B. terrestris were more susceptible to B. bassiana than the other fungi when exposed topically, and B. terrestris and A. mellifera were more susceptible to M. anisopliae when exposed orally. Interestingly, increased positive concentration responses were not observed for all fungal species and application methods. For example, B. terrestris mortalities were similar at the lowest and highest fungal concentrations for both exposure methods. This study demonstrates that under laboratory conditions, the three fungal species can potentially reduce the survival of social bees at the individual level. However, further colony and field studies are needed to elucidate the susceptibility of these fungi towards social bees to fully assess the ecological risks.

Neonicotinoid Residues in Earthworms and Ground Beetles under Intensive Sugar Beet Production: Preliminary Study in Croatia

Neonicotinoids are pesticides widely used for pest control in agriculture with undesirable effects on pollinators. However, other beneficial insects are exposed to insecticides that are not lethal to them but may accumulate and affect their vital characteristics. The objective of this study was to determine neonicotinoid residues in two types of beneficial soil organisms. The first group includes ground beetles (family: Carabidae, order: Coleoptera). They are important in the food web within existing ecosystems, especially in agricultural areas. The second group includes earthworms (family: Lumbricidae, order: Opisthopora) as humifiers, important members of the soil fauna. Fauna was collected at two sugar beet growing areas in Croatia under intensive sugar beet management. Ground beetles were collected from six plots of sugar beet fields treated with imidacloprid and thiamethoxam or left untreated with neonicotinoids. Earthworms were collected from the eight fields involved in four-year sugar beet crop rotation (sugar beet, maize, soybean, oilseed rape). Detection of neonicotinoid residues was performed by LC-MS/MS, SPE-QuEChERS method. The limit of quantification (LOQ) was 0.001 mg/kg. In ground beetles, the highest concentration of imidacloprid was detected at 0.027 mg/kg, while the residues of thiamethoxam and clothianidin were below LOQ. The highest concentration of imidacloprid in earthworms was 0.2141 mg/kg, while residues of thiamethoxam did not exceed 0.0008 mg/kg. This is the first study of this kind on Croatian territory and provides a valuable first insight into the ecotoxicological status of beneficial soil fauna. More comprehensive studies are needed to assess the extent of accumulation in and to take further steps regarding conservation programs for beneficial soil organisms.

Determination of Silicon Accumulation in Non-Bt Cotton (Gossypium hirsutum) Plants and Its Impact on Fecundity and Biology of Whitefly (Bemisia tabaci) under Controlled Conditions

Considering the resistance development-potential of whitefly (Bemisia tabaci) against control tactics with limited action mechanisms, the present study investigated the accumulation of two different silicon (Si) sources (SiO2 and K2SiO3) in cotton plants. The tested dose rates (0, 200, and 400 mg/L) of both Si sources were applied directly to the soil or through foliar application on cotton leaves. Moreover, a laboratory bioassay was also conducted to evaluate the performance of applied Si sources against the oviposition preference and biology of B. tabaci. A significantly higher Si accumulation, reduction in oviposition preference, and prolonged developmental period of all nymphs and total life cycle of B. tabaci was observed in the case of foliar-applied silicon. Similarly, among Si sources, a significant decline in the number of oviposited eggs and delay in the developmental period of B. tabaci was observed in the case of SiO2, followed by K2SiO3. Moreover, cotton plants subjected to SiO2 treatments possessed higher Si contents in their leaves than K2SiO3 treated plants. The results further revealed that both Si sources showed promising results at their higher concentrations regarding the tested parameters of Si accumulation, fecundity, and developmental period of B. tabaci. Our results strongly suggest that among emerging pest control strategies in cotton plants lies the use of foliar application of Si, which can also be incorporated in different integrated pest management programs due to its safety for humans and beneficial insect fauna.

Preliminary studies on the parasitism rate of larval parasitoids of the diamondback moth (Plutella xylostella) L. (Lepidoptera: Plutellidae) in the Ashanti region of Ghana

The diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) is the most important pest of the brassicas worldwide. Over the years, management of this pest has largely relied on conventional insecticides, with well-documented negative impacts. Biological control using indigenous natural enemies is a promising way to manage the pest while reducing the use of synthetic insecticides. However, due to the negative impact of synthetic insecticides on beneficial insects, the number of natural enemies in the agroecosystem is often below the levels that may have significant pest reduction. Here, we assessed the range and parasitism rates of the larval parasitoids of P. xylostella in the Ashanti Region of Ghana. On the whole, one hymenopteran endo-parasitoid species, Cotesia plutellae, was identified in the P. xylostella larval samples. In all, the percentage of field parasitism of P. xylostella larvae ranged between 11% and 23%. Given the percentage of parasitism in this preliminary study, we are of the view that there is potential in relying on endemic parasitoids to biologically manage P. xylostella if conditions in agroecology are improved to encourage the survival of these beneficial insects.

The immune deficiency and c-Jun N-terminal kinase pathways drive the functional integration of the immune and circulatory systems of mosquitoes.

The immune and circulatory systems of animals are functionally integrated. In mammals, the spleen and lymph nodes filter and destroy microbes circulating in the blood and lymph, respectively. In insects, immune cells that surround the heart valves (ostia), called periostial haemocytes, destroy pathogens in the areas of the body that experience the swiftest haemolymph (blood) flow. An infection recruits additional periostial haemocytes, amplifying heart-associated immune responses. Although the structural mechanics of periostial haemocyte aggregation have been defined, the genetic factors that regulate this process remain less understood. Here, we conducted RNA sequencing in the African malaria mosquito, Anopheles gambiae, and discovered that an infection upregulates multiple components of the immune deficiency (IMD) and c-Jun N-terminal kinase (JNK) pathways in the heart with periostial haemocytes. This upregulation is greater in the heart with periostial haemocytes than in the circulating haemocytes or the entire abdomen. RNA interference-based knockdown then showed that the IMD and JNK pathways drive periostial haemocyte aggregation and alter phagocytosis and melanization on the heart, thereby demonstrating that these pathways regulate the functional integration between the immune and circulatory systems. Understanding how insects fight infection lays the foundation for novel strategies that could protect beneficial insects and harm detrimental ones.

Ocimum gratissimum Linn. (Lamiaceae) essential oil for the management of Exorista sorbillans Wiedemann (Diptera: Tachinidae) menace of silkworm in seriecosystem

• Ocimum gratissimum is a potential candidate for management of E. sorbillans. • Non polar fraction of the leaf extract was found effective against uzi fly. • Essential oil was more effective than non-polar petroleum ether extract. • Thymol and carvacrol were the major constituents. • The efficacy of the oil is attributed to combination of individual oils. Although they act as biocontrol agents, Tachinid parasitoids attack economically beneficial insects, inviting the adoption of control measures against them. The uzi fly, Exorista sorbillans , infests silkworms incurring heavy loss. It is difficult to control such parasitoids as the larval stage is endoparasitic, and insecticides cannot reach them without subjecting the silkworms to potential risks. We selected the leaves of Ocimum gratissimum L. for testing their toxicity potential against E. sorboillans because of its low selective toxicity to Antheraea assamensis Helfer larvae. Assay for adulticidal efficacy of the leaf extracts showed the petroleum ether extract to be the most effective. But the essential oil (LC50 of 0.42%) was even more effective. GC–MS analysis of the oil revealed the presence of twenty-seven compounds with a high percentage of thymol (26.17%), indicating the plant oil as thymol rich chemotype. Thymol was the dominant constituent in the active fraction. The oil and constituents caused rapid death on topical application, indicating a higher penetration rate. We propose the exploration of the essential oil and its constituents as a sustainable solution for controlling E. sorbillans infestation of silkworms in the future.