Key Pest Research Articles

Impacts of rainfall and rainfall anomalies on the population dynamics of rodents in southeast Asian rice fields.

The mechanisms that regulate multi-annual population dynamics of rodent pest species of cereal crops is often unknown. Better knowledge of such aspects can aid pest management and in turn improve food security and human health. The patterns and processes of the population dynamics of Rattus argentiventer, in rice fields of Indonesia, and Rattus tanezumi, in rice fields of the Philippines were assessed in this article. The meta-analysis of trapping data over 20 years in Indonesia, and 16 years in the Philippines indicated that rodent populations in rice fields did not show a regular multi-annual pattern. Rattus argentiventer populations in Indonesia responded to less rainfall from the current year. Rattus tanezumi populations in the Philippines responded positively to both rainfall and rainfall anomaly with a 1-year time lag. Our study of long-term population data indicates that certain combinations of rainfall parameters could be useful to predict years when there is higher rodent abundance in rice fields. The key rodent pest species in rice fields in Indonesia (R. argentiventer) and the Philippines (R. tanezumi) differ, and the populations of each species respond differently to rainfall anomalies. Other factors such as crop cover and water availability may also be important and should be considered in future work. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Remote Monitoring of Coffee Leaf Miner Infestation Using Machine Learning

The coffee leaf miner (Leucoptera coffeella) is a key pest in coffee-producing regions in Brazil. The objective of this work was to evaluate the potential of machine learning algorithms to identify coffee leaf miner infestation by considering the assessment period and Sentinel-2 satellite images generated on the Google Earth Engine platform. Coffee leaf miner infestation in the field was measured monthly from 2019 to 2023. Images were selected from the Sentinel-2 satellite to determine 13 vegetative indices. The selection of images and calculations of the vegetation indices were carried out using the Google Earth Engine platform. A database was generated with information on coffee leaf miner infestation, vegetation indices, and assessment times. The database was separated into training data and testing data. Nine machine learning algorithms were used, including Linear Discriminant Analysis, Random Forest, Support Vector Machine, k-nearest neighbors, and Logistic Regression, and a principal component analysis was conducted for each algorithm. After optimizing the hyperparameters, the testing data were used to validate the model. The best model to estimate miner infestation was RF, which had an accuracy of 0.86, a kappa index of 0.64, and a precision of 0.87. The developed models were capable of monitoring coffee leaf miner infestation.

Target and non-target effects of insecticide use during ornamental milkweed production.

There are widespread public efforts to conserve wildlife in urbanized landscapes via the installation of nursery-grown plants that support Lepidoptera taxa. Insecticides are commonly used during nursery production to suppress key plant pests, and many products have extended periods of toxicity and affect a wide range of herbivore taxa. While there are plentiful toxicological data on bee species, predominantly the Western honey bee (Apis mellifera L.), little is known about how insecticides affect nonpest lepidopterans. Lepidoptera has different modes of exposure (e.g., leaf-feeding) and differences in susceptibility to insecticide target sites compared to bees. Consequently, many products compatible with bee conservation pose an uncertain risk to nonpest lepidopterans and thus may represent an under-recognized conflict with conservation efforts. Using the monarch butterfly (Danaus plexippus, L.), tropical milkweed (Asclepias curassavica, L.), and oleander aphid (Aphis nerii, Fonscolombe, 1841) system, we conducted leaf and whole-plant feeding assays to evaluate effects of acute and chronic monarch exposure to industry standard and alternative reduced-risk insecticides used during nursery production. We also evaluated the efficacy of these insecticides against their target pest, the oleander aphid. Our results indicate that insecticides used to control pests on ornamental milkweed can cause monarch larval mortality up to 4 wk after treatment application. Furthermore, the duration of aphid suppression is often shorter than the duration of adverse effects on monarchs. This study demonstrates a conflict between insect pest management and Lepidoptera conservation during ornamental plant production and has implications for the conservation value of ornamentals after retail sale.

Efficacy of Insecticides against Sucking Insect Pests in Groundnut

The study evaluated various insecticide treatments targeting thrips, Scirtothrips dorsalis Hood and leafhoppers, Empoasca kerri Pruthi, key pests in groundnut cultivation during the summer 2021 and 2022. Among the treatments, seed treatment with imidacloprid 18.5% + hexaconazole 1.50% FS, along with foliar spray of acetamiprid 20% SP, showed notable effectiveness. This approach led to superior pest management, resulting in higher pod yield, net returns, and a favourable benefit-cost ratio. Comparable performance was observed with other treatments, including seed treatment with thiamethoxam 30 FS + acetamiprid 20% SP foliar spray and seed treatment with imidacloprid 60 FS + acetamiprid 20% SP foliar spray. Notably, seed treatments were found to be safer for natural enemies compared to foliar sprays and combinations thereof.

Screening of Pearl Millet Genotypes for Resistance to Shoot Fly <i>Atherigona approximata</i> Malloch and Ear Head Worm <i>Helicoverpa armigera</i> (Hubner)

Pearl millet [Pennisetum glaucum (L.) R. Br.] is the sixth most important cereal crop and widely grown on 30 million ha in the arid and semi-arid tropical regions of Asia and Africa. Shoot fly, Atherigona approximata Malloch and ear head worm Helicoverpa armigera Hubner are the key pests of pearl millet and can reduce yield up to 15-20 and 36.67%, respectively. The present study was planned to evaluate 31 promising genotypes for resistance to A. approximata and H. armigera. GHB-744 and HHB-67 were found free from A. approximata infestation while the Raj-171 (3.13%), GHB-732 (3.71%), AHB-1200 (4.30%), GHB-905 (4.41%), Kaveri Super Boss (4.44%) and MPMH-21 (4.81%) were found moderately resistant to A approximata at 28 days after germination. Likewise, AHB-1200 (1.33 larvae/ 5 ear heads) followed by GHB-732 (1.67 larvae/ 5 ear heads) and GHB-905 (2.00 larvae/ 5 ear heads) were found moderately resistant to H. armigera.

Effectiveness and residual activity of four common insecticides used in the Mississippi Delta to control tarnished plant bugs in cotton.

The tarnished plant bug, (TPB) Lygus lineolaris Palisot de Beauvois (Hemiptera: Miridae) is a key pest of cotton in the midsouth region and some areas of the eastern United States. Its control methods have been solely based on chemical insecticides which has contributed to insecticidal resistance and shortened residual periods for control of this insect pest. This study was conducted over a two-year period and examined the efficacy and residual effect of four commercial insecticides including lambda-cyhalothrin (pyrethroid), acephate (organophosphate), imidacloprid (neonicotinoid), and sulfoxaflor (sulfoxamine). The effectiveness and residual effects of these insecticides were determined by application on cotton field plots on four different dates during each season using three different concentrations (high: highest labeled commercial dose (CD), medium: 1/10 of the CD, low: 1/100 of the CD) on field cotton plots. Four groups of cotton leaves were randomly pulled from each treated plot and control 0-, 2-, 4-, 7-, and 9-days post treatment (DPT) and exposed to a lab colony of TPB adults. One extra leaf sample/ plot/ spray /DPT interval (0-2-4-7-9-11) during 2016 was randomly collected from the high concentration plots and sent to Mississippi State Chemical Laboratory for residual analysis. Mortality of TPB adults was greatest for those placed on leaves sprayed with the organophosphate insecticide with mortalities (%) of 81.7±23.4 and 63.3±28.8 (SE) 1-day after exposure (DAE) on leaves 0-DPT with the high concentration for 2016 and 2017, respectively, reaching 94.5±9.5 and 95.4±7.6 6-DAE each year. Mortality to all insecticides continued until 9 and 4-DPT for high and medium concentrations, respectively. However, organophosphate (39.4±28.6) and pyrethroid (24.4±9.9) exhibited higher mortality than sulfoxamine (10.6±6.6) and the neonicotinoid (4.0±1.5) 7-DAE on 9-DPT leaves with the high concentration. Based on our results using the current assay procedure, TPB adults were significantly more susceptible to contact than systemic insecticides and due to its residual effect, organophosphate could kill over 80% of the TPB population 7-DPT.

CHEMICAL COMPOSITION AND INSECTICIDAL EFFICACY OF VITEX NEGUNDO L. ESSENTIAL OIL AGAINST FALL ARMYWORM, SPODOPTERA FRUGIPERDA (J. E. SMITH)

The fall armyworm, Spodoptera frugiperda, is a key pest ofmaize crops in tropical and subtropical regions and has developed resistanceagainst synthetic pesticides and Bacillus thuringiensis toxins. Thus,the experiments were designed to evaluate the chemical analysis andinsecticidal efficacy of Vitex negundo against S. frugiperda.Chemical analysis of V. negundo essential oil revealed a total of 36compounds, and the oil contained more monoterpenes (68.16%) than sesquiterpenes(22.21%) and diterpenes (13.56%). For the ovicidal and insecticidal activities,the essential oil was found to be most effective, with a median lethalconcentration (LC50) value of 51.31 µL/mL and 0.29 L/larvae, respectively.Larval antifeedant and growth inhibitory activity of essential oil werepositively correlated (R2 = 0.9645) and (R2 = 0.9727) with oil concentrations,respectively. Therefore, the V. negundo essential oil can be used forthe development of bioinsecticides to control S. frugiperda, a highlyinvasive and polyphagous pest, which will replace chemical pesticides.

Machine learning provides insights for spatially explicit pest management strategies by integrating information on population connectivity and habitat use in a key agricultural pest.

Insect pests have garnered increasing interest because of anthropogenic global change, and their sustainable management requires knowledge of population habitat use and spread patterns. To enhance this knowledge for the prevalent tea pest Empoasca onukii, we utilized a random forest algorithm and a bivariate map to develop and integrate models of its habitat suitability and genetic connectivity across China. Our modeling revealed heterogeneous spatial patterns in suitability and connectivity despite the common key environmental predictor of isothermality. Analyses indicated that tea cultivation in areas surrounding the Tibetan Plateau and the southern tip of China may be at low risk of population outbreaks because of their predicted low suitability and connectivity. However, regions along the middle and lower reaches of the Yangtze River should consider the high abundance and high recolonization potential of E. onukii, and thus the importance of control measures. Our results also emphasized the need to prevent dispersal from outside regions in the areas north of the Yangtze River and highlighted the effectiveness of internal management efforts in southwestern China and along the southeastern coast. Further projections under future conditions suggested the potential for increased abundance and spread in regions north of the Yangtze River and the southern tip of China, and indicated the importance of long-term monitoring efforts in these areas. These findings highlighted the significance of combining information on habitat use and spread patterns for spatially explicit pest management planning. In addition, the approaches we used have potential applications in the management of other pest systems and the conservation of endangered biological resources. © 2024 Society of Chemical Industry.

Land consolidation impacts the abundance and richness of natural enemies but not pests in small‐holder rice systems

Abstract Traditional small‐holder agricultural landscapes in southern China are being consolidated to increase mechanisation levels in agriculture, but it is unclear how this influences rice arthropod communities in these landscapes. Here, based on a six‐year study in 20 rice fields, we evaluated the impact of land consolidation on arthropod communities, crop damage, and rice yield. We also analysed how effects of land consolidation were moderated by the proportion of large semi‐natural habitat patches and insecticide use. We found that, compared to consolidated fields, rice fields in traditional farmlands had a higher abundance and family richness of natural enemies, but a similar abundance of rice pests. Land consolidation did not significantly interact with the proportion of large semi‐natural habitat patches or insecticide application, in terms of affecting arthropods. The proportion of semi‐natural habitat reduced the negative effect of insecticide application on key rice pests, but no equivalent interaction occurred for natural enemies. Synthesis and applications: Land consolidation can have negative impacts on the abundance and richness of natural enemies, but not pests in small‐holder rice systems, and these impacts are independent from insecticide application and proportion of semi‐natural habitat in the landscape. We recommend the implementation of agri‐environmental measures or re‐establishing field margin vegetation during the consolidation process to mitigate these potential negative effects, although trade‐off between enhancing crop yields and preserving rice arthropod biodiversity should be considered. We encourage future research to focus on the detailed assessment of the function of linear habitats for a better understanding of the impact of land consolidation.

Detection of bean damage caused by Epilachna varivestis (Coleoptera: Coccinellidae) using drones, sensors, and image analysis.

The Mexican bean beetle, Epilachna varivestis Mulsant (Coleoptera: Coccinellidae), is a key pest of beans, and early detection of bean damage is crucial for the timely management of E. varivestis. This study was conducted to assess the feasibility of using drones and optical sensors to quantify the damage to field beans caused by E. varivestis. A total of 14 bean plots with various levels of defoliation were surveyed aerially with drones equipped with red-blue-green (RGB), multispectral, and thermal sensors at 2 to 20 m above the canopy of bean plots. Ground-validation sampling included harvesting entire bean plots and photographing individual leaves. Image analyses were used to quantify the amount of defoliation by E. varivestis feeding on both aerial images and ground-validation photos. Linear regression analysis was used to determine the relationship of bean defoliation by E. varivestis measured on aerial images with that found by the ground validation. The results of this study showed a significant positive relationship between bean damages assessed by ground validation and those by using RGB images and a significant negative relationship between the actual amount of bean defoliation and Normalized Difference Vegetation Index values. Thermal signatures associated with bean defoliation were not detected. Spatial analyses using geostatistics revealed the spatial dependency of bean defoliation by E. varivestis. These results suggest the potential use of RGB and multispectral sensors at flight altitudes of 2 to 6 m above the canopy for early detection and site-specific management of E. varivestis, thereby enhancing management efficiency.

Metaflumizone susceptibility baseline, reproduction, locomotion, and respiration responses on the Hypothenemus hampei

Coffee berry borer (CBB) is the world's primary coffee pest. Recently, metaflumizone was registered for the control of CBB. This study investigated the susceptibility baseline, reproduction, locomotion, and respiration responses in the CBB (Hypothenemus hampei) exposed to metaflumizone. Lethal concentration (LC10, LC50, and LC99) values for metaflumizone were determined for seventeen populations from Brazil. Coffea arabica fruits infested with the CBB were collected during 2020–2021 from regions with significant coffee production. Metaflumizone reduced the respiration rate of H. hampei from 0.51 to 0.22 μL CO2 h−1 at LC50 for up to 3 h after insecticide exposure. A low concentration (LC10) of metaflumizone showed a stable respiration rate for H. hampei. The locomotion and reproduction (number of eggs) of H. hampei were affected. The recommended diagnostic concentration for H. hampei was 58.0 mg a.i. L−1. Our findings suggest that metaflumizone-based insecticides can be an effective alternative for use in rotation with insecticides of different chemical groups to control this key pest.

Developing and implementing an integrated pest/disease management in apple for smallholder farms in Yantai, China

Yantai is one of the main apple production areas in China; however, apple production in Yantai is severely hampered by many pests and diseases. In this region, most apple are grown by smallholder farmers. To improve pest and disease management with minimal pesticide use, we developed an integrated pest/disease management specifically designed for apple production where fruit bagging practice is adopted by smallholder farmers to protect fruit from pest and pathogen attacks. This new management (called ‘164’ IPM approach) was developed from both published and local empirical knowledge on key pests and pathogen. This approach includes one set of ecological management measures throughout the season, six key periods for scheduled application of pesticides, and four periods where management is based on predicted pest/disease risks. Field evaluation showed that this management approach is simple and practical for use by smallholder farmers and can effectively manage key pests and pathogens, and reduce pesticide input by about 40% whilst increasing income by 5%. Currently, this management approach is being promoted and adopted by smallholder farms in Yantai, and will be further expanded for use in other regions considering relevant pests/diseases and climatic characteristics.

Positional Effects of Bottle-Baited Traps in Reducing Infestation Level of Coffee Berry Borer Hypothenemus Hampei Ferrari in Kilimanjaro Region, Tanzania

Coffee berry borer (CBB) is among the key insect pests of coffee worldwide. The use of bottle-baited traps has been in practice in several coffee-growing areas including Tanzania. However, there is limited information about the influence of height and spacing of commonly used bottle-baited traps in managing CBB in coffee-growing areas in the country. Therefore, the objective of this research was to evaluate the effect of height where traps were placed (0.6, 1.2, and 1.6 m) on the reduction of infestation level of coffee berry borers at different developmental stages of coffee fruit (green and red fruit) under field conditions. The experiment followed a completely randomized block design with a factorial arrangement and four replications, three (lower, middle, and upper) levels of height and spacing were placed for 7 months. The number of captured CBB and damaged berries percentage was evaluated. The data were analyzed by R Software (2021) through an analysis of variance and means were separated by Turkey’s (0.05). A significant minimum berries damage (0.26%) as an implication of the lowest CBB infestation level was shown at the height of 0.6 m (for all stages of berries). On the other hand, at the red berries stage, the lowest damage (11.12%) was observed at the height of 1.6 m. Generally, this study deduced that the lower the height from which the traps are placed, the lower the infestation level of CBB hence reducing crop damage by the pest.

Seasonal Incidence of <i>Tetranychus urticae</i> Koch on Brinjal under Protected Cultivation

The two-spotted spider mite Tetranychus urticae Koch is a key pest of many vegetable crops under protected cultivation. The seasonal incidence of two-spotted spider mite on brinjal in four seasons was studied under protected cultivation in 2020 and 2021. Two peaks were observed in mite population during the period of investigation. First peak was observed from mid-September i.e. during 38th and 39th SMW (5.4 to 5.6 mites/2 cm leaf area) to first fort night of October i.e. 40th, 41st and 42nd SMW (5.0 to 5.4 mites/2 cm leaf area), in 2020. Second peak was observed during April i.e. 15th, 17th and 18th SMW (5.0 to 5.8 mites/ 2 cm leaf area) to May i.e. 20th, 21st and 22nd SMW (5.0 to 6.0 mites/ 2 cm leaf area) in 2021. The multiple correlation coefficients between the population and abiotic factors were worked out from July 2020 to June 2021. The active stages were found significantly positively correlated with maximum temperature and non-significantly positively correlated with minimum temperature. The morning relative humidity was non-significantly negatively correlated with the population of eggs and significantly negatively correlated with active stages.

A comparison of flower borders and intercropping flowering plants for enhancing biological control of key pests in strawberry

A comparison of flower borders and intercropping flowering plants for enhancing biological control of key pests in strawberry

Interactions of Opuntia ficus-indica with Dactylopius coccus and D. opuntiae (Hemiptera: Dactylopiidae) through the Study of Their Volatile Compounds.

Opuntia ficus-indica has always interacted with many phytophagous insects; two of them are Dactylopius coccus and D. opuntiae. Fine cochineal (D. coccus) is produced to extract carminic acid, and D. opuntiae, or wild cochineal, is an invasive pest of O. ficus-indica in more than 20 countries around the world. Despite the economic and environmental relevance of this cactus, D. opuntiae, and D. coccus, there are few studies that have explored volatile organic compounds (VOCs) derived from the plant-insect interaction. The aim of this work was to determine the VOCs produced by D. coccus and D. opuntiae and to identify different VOCs in cladodes infested by each Dactylopius species. The VOCs (essential oils) were obtained by hydrodistillation and identified by GC-MS. A total of 66 VOCs from both Dactylopius species were identified, and 125 from the Esmeralda and Rojo Pelón cultivars infested by D. coccus and D. opuntiae, respectively, were determined. Differential VOC production due to infestation by each Dactylopius species was also found. Some changes in methyl salicylate, terpenes such as linalool, or the alcohol p-vinylguaiacol were related to Dactylopius feeding on the cladodes of their respective cultivars. Changes in these VOCs and their probable role in plant defense mechanisms should receive more attention because this knowledge could improve D. coccus rearing or its inclusion in breeding programs for D. opuntiae control in regions where it is a key pest of O. ficus-indica.

Thiamethoxam-Induced Intergenerational Sublethal Effects on the Life History and Feeding Behavior of Rhopalosiphum padi

Thiamethoxam, a second-generation neonicotinoid insecticide is widely used for controlling sap-sucking insect pests including Rhopalosiphum padi. The current study aimed to investigate the life-history parameters and feeding behavior of R. padi following treatments with sublethal concentrations of thiamethoxam. The lethal concentration 50 (LC50) value of thiamethoxam against adult R. padi was 11.458 mg L−1 after 48 h exposure. The sublethal concentrations of thiamethoxam (LC5 and LC10) significantly decreased the adult longevity, fecundity, and reproductive days in the directly exposed aphids (F0 generation). In the progeny R. padi (F1), the developmental durations and total prereproductive period (TPRP) were decreased while the adult longevity, fecundity, and reproductive days (RPd) were increased at both thiamethoxam concentrations. The demographic parameters including the net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) were prolonged only at the LC5 of thiamethoxam. The EPG results indicated that the sublethal concentrations of thiamethoxam increases the total duration of non-probing (Np) while reducing the total duration of E2 in directly exposed aphids (F0). Interestingly, the E2 were significantly increased in the progeny generation (F1) descending from previously exposed parental aphids (F0). Overall, this study showed that thiamethoxam exhibited high toxicity against directly exposed individuals (F0), while inducing intergenerational hormetic effects on the progeny generation (F1) of R. padi. These findings provided crucial details about thiamethoxam-induced hormetic effects that might be useful in managing resurgences of this key pest.

Field Evaluation of Biological and Conventional Insecticides for Managing Multiple Insect Pests in Cotton

Abstract Cotton, Gossypium hirsutum (L.), is an economically important crop in the United States that is plagued by a complex of insect pests. Two key pests of cotton in the midsouthern United States are the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), and bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae). A suite of highly effective synthetic insecticides is typically used for control of these pests. However, it is unclear how the combined management of these two insect pests with biological insecticides impacts the economics of cotton production. To address this shortcoming, we conducted a field experiment in the Mississippi Delta over 2 yr to study the effects of synthetic and biological insecticides for control of the tarnished plant bug and bollworm on cotton yield. The results indicated the control of tarnished plant bug with synthetic insecticides had the most significant impact on cotton yield and net returns. The conventional tarnished plant bug treatment also significantly increased bollworm density and damage, but these increases did not significantly alter yield or net return in non–Bacillus thuringiensis (Bt) or Bt cottons. The economic benefit of a conventional approach to tarnished plant bug control with synthetic insecticides was US$438.07/ha in non-Bt and $700.88/ha in Bt cotton relative to those treated with a biological insecticide. The biological insecticides used for this study were ineffective at significantly altering yield or net return. However, for insect management in cotton to be sustainable, alternatives must be found to complement conventional synthetic insecticides.

Nut bush pesticide limits: urgent need for a comprehensive strategy to address current and emerging insect pests and insecticide options in the Australian macadamia industry.

In Australia, macadamia orchards are attacked by four main insect pest groups. Management and control of three of these key pests currently relies on broad-spectrum insecticides whose long-term future is questionable. Of the 23 insecticides registered for use in macadamia in Australia, 19 face issues affecting their availability and 12 are presently not approved in the EU, the USA or Canada. These international markets may refuse produce that does not adhere to their own insecticide use standards, hence Australian produce may be excluded from market access. Many of the potential replacement integrated pest management methods of pest control are generally considered less effective by the industry and have not been adopted. There are 17 insect pest groups identified by the industry, any of which have potential to become major problems if broad-spectrum insecticide options become unavailable. Thirteen pest groups need urgent attention as they are at risk of losing current effective control methods, and no replacement solutions have yet been developed. The lag period for research and development to identify new chemical and biological control solutions means there is now an urgent need for the macadamia industry to craft a strategy for sustainable pest management for each pest. Critically, this industry strategy needs to address the vulnerabilities identified in this paper, identify potential solutions for any cases of market failure and consider funding mechanisms to address these gaps. On economic and sustainability grounds, potential biological control options should be explored, especially in cases where insecticide control options are vulnerable. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Viability and virulence of freeze-dried Beauveria bassiana, Metarhizium acridum, and Hirsutella thompsonii isolates under non-refrigerated conditions in Ghana

ABSTRACT The necessity of cold storage for mycoinsecticides poses a logistical challenge in tropical Africa, where maintaining consistent refrigeration is a major obstacle. To investigate alternative preservation methods, our study evaluates conidial-based freeze-dried formulations of Beauveria bassiana (IMI 389521), Metarhizium acridum (IMI 330189), and mycelial-based freeze-dried formulations of Hirsutella thompsonii (IMI 327488 and IMI 391722). Propagules were cryoprotected with lactose, mannitol, and raffinose, encapsulated, and freeze-dried in plastic and glass vials. Bioformulations in glass vials were cryoprotected with mannitol only. Viability (CFU/g each day) of bioformulations, following 16-weeks-storage, and their virulence (at 1 × 107 conidia mL−1 in six days) against key pests of maize and cassava in Africa (larger grain borer, variegated grasshopper and cassava green mite) were determined under ambient laboratory conditions in Ghana. Our results show that non-freeze-dried conidia of B. bassiana and M. acridum had significantly higher viability and efficacy than freeze-dried versions, when stored under non-refrigerated conditions (averaging 27.7°C, 78.8% RH). Freeze-dried H. thompsonii mycelia were neither viable nor virulent against cassava green mite. Freeze-dried B. bassiana and M. acridum in plastic vials remained viable for 12 weeks, while in glass vials they were viable for seven weeks. Freeze-dried B. bassiana in both plastic and glass vials caused 38–43% mortality in larger grain borer, and M. acridum caused 45–82% mortality in variegated grasshopper. Further, conidia cryoprotected with lactose had significantly higher viability and mortality than raffinose and mannitol. Our research contributes to mycoinsecticide development, particularly in the context of storage and application challenges in tropical climates.