The common bean is an important crop in Eastern Africa for smallholder farmers, yet yields are often reduced due to pests, particularly Ophiomyia spencerella and Ophiomyia phaseoli. These species are partially sympatric and commonly known as the bean fly. Here, based on the similarity of their life history and developmental biology, field data was collected over 2 years to develop a generic degree-day model for the population growth of bean fly larvae to optimise the timings for the application of management interventions. There was a good fit between the observed larval emergence in the field and that predicted by the model (average R 2 = 0.99, r = 0.96 and RMSE = 0.05). As early action is recommended for bean fly populations, the suggested 'time to act' occurs when the predicted bean fly larval population is still low yet when the predicted rate of larval population growth begins to maximise. This equated to approximately 218 degree-days from planting. The model shows good potential for practical application in bean growing areas to optimise timings for the control of bean fly populations.

Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), has become one of the main invasive species on earth since it was first found outside its native range in Africa in 2016. Integrated pest management (IPM) is a comprehensive tool that can help farmers managing pests while reducing the need of synthetic pesticides. Within an IPM strategy, proper time of planting is a critical management decision for farmers as planting too early or too late can lead to complete loss of the crop. Commonly, planting early to avoid peak infestation of FAW is recommended to farmers, however, no empirical data in Africa is available to sustain the advice. We studied the effects of planting dates of maize as well of maize growth stages on FAW density and on its local parasitoids in a field study. Three plots were setup (early, intermediate and late planting) and data was collected weekly in each plot. Plots were 20 m × 20 m to avoid small-plot effects, but the relatively large size of the plots was resource intensive and prevented replication. As such, this paper presents preliminary results due to the lack of true replicates across locations and years. Generalized Linear Models were used to model FAW density and parasitoids abundance and diversity. Our results showed an increase of egg masses over time from early to late planting. Additionally, parasitism probabilities were lower in the early planting treatment than for the intermediate and late plantings and decreased with increased maize maturity. Results on biodiversity of parasitoids show a less even trend for early and late whorl stages which are dominated by one or two species while maize reproductive stages show a more even distribution of species. Our preliminary research is the first to provide empirical evidence that planting early helps to avoid the peak activities of FAW moths. These findings provide important information for the sustainable management of FAW in Zambia with the aim to reduce chemical inputs and increase farmers’ incomes and livelihood.

Smallholder farmers are the mainstay of the agricultural economies of sub-Saharan Africa (SSA), where they produce several crops, predominantly centered on maize. Smallholder productivity remains limited resulting from a range of confounding factors, but a primary cause is loss from pests and diseases, particularly insects. To improve productivity, recommendations for the mitigation of crop loss globally include early-warning and management systems for in-season indigenous pests. There are many early-warning systems in temperate regions; however, such systems are poorly established in Africa. This is in part due to the need for a combination of pest modeling, data handling and dissemination infrastructure, capacity, and resource provision. While each of these components is progressing in Africa, the means to successfully deploy such systems remain limited. To bridge this, the development of the Pest Risk Information Service (PRISE) began in 2017 for farmers in SSA. Implemented in Kenya, Ghana, Malawi, and Zambia, PRISE developed temperature-driven phenology models for major maize, bean, and tomato pests. Using downscaled and processed Earth Observation data to drive the models, PRISE partnered with African national agencies to communicate pre- and in-season pest alerts that forecast the time to act against key insect pests. Alerts were designed to be integrated into country-specific Good Agricultural Practice (GAP) recommendations to provide a complementary package to agricultural stakeholders. End line studies with farmers showed that those who received information about the target crops including PRISE pest forecasts, generally reported better outcomes in terms of reduced losses and increased incomes compared with farmers who did not.

Globally, the coffee berry borer (CBB) Hypothenemus hampei (Ferreri) is the most severe pest of the commercial coffee species arabica coffee (Coffea arabica). Heterogenous landscapes characterize many coffee-growing areas. We studied the phenology of coffee and the abundance, and development of infestation by CBB within the context an altitudinal gradient in the coffee-growing region of Caldas, Colombia. This was between 1200 m and 1800 m (a.s.l.) from September 2019 to July 2020 covering two seasons of coffee flowering. Coffee berry phenology did not differ over the altitudinal gradient studied, but CBB abundance and berry infestation differed in quantity and timings, with lower altitudes having higher abundances and proportions of infestation than higher altitudes. In the context of CBB management, October through to December is vital for coffee farms <1500 m as CBB abundance and infestation both spike, and March to June is key for farms between 1500-1700 m for the same reasons. In conclusion, coffee farmers in highly heterogeneous landscapes will have to adjust their CBB management according to the altitude gradients of their farm.

BackgroundFarmer perceptions are highly important in influencing on-farm pest management decision-making. Biological control is extremely sustainable in the smallholder production context, but in Sub Saharan Africa (SSA) few attempts using this pest control method for arthropod pests have been successful, with one of the key reasons cited as poor involvement of farming communities and extension in the dissemination of information. Although farmers' knowledge and attitudes are hugely important for the successful implementation of biological control, they are often disregarded. Papaya mealybug (Paracoccus marginatus) (PMB) has rapidly spread and established in suitable areas across Kenya becoming a serious pest. The objective of this study is to determine smallholder farmers' knowledge, attitudes and practices towards biological control; farmers' willingness to reduce their chemical pesticide use; and levels of support for a classical biological control initiative for PMB management.MethodsHousehold surveys were conducted covering 383 farming households (148 women) in four papaya producing counties in Kenya alongside key informant interviews with eight extension agents and thirty agro-dealers, and eight focus group discussions.ResultsAlthough some farmers demonstrated awareness of the concept of biological control they lacked knowledge, experience and technical support from extension or agro-dealers. Reasons for not using biological control included inadequate awareness and concerns over efficacy and safety. Farmers expressed high levels of interest and willingness to support biological control, and were willing to reduce their chemical pesticide use to help conserve, and support the establishment of natural enemies. County, perception of biological as safe, training in IPM and gender were all highly significant factors determining farmers willingness to support biological control.ConclusionsPreviously, poor attention has been paid to farmer perceptions and participation in biological control, which has resulted in limited success in developing countries. With high levels of interest and willingness to support biological control, the next step is to engage with farming communities impacted by PMB. By building awareness and capacity, and developing a management plan with farmers that will support the release and establishment of the biological control agent, Acerophagus papayae, long-term, sustainable control of PMB in Kenya is possible.

Research on the ovarian development of insect pests helps provide key information for predicting pest occurrences, and currently, there is very limited information about the reproductive system of Ceracris kiangsu Tsai. This study aimed to assess the reproductive fitness of 321 adult female insects by using traditional methods to dissect female adults, measure female ovaries, and assess the process of egg formation. The phenotypic traits including body weight and body length were also measured and used to estimate the model of ovarian developmental stages. Four ovarian developmental stages before the oviposition were identified, and the fundamental ovarian structure of C. kiangsu displayed red dots on the matured eggs inside the calyx at ovarian developmental stage V. The accessory glands of C. kiangsu had the deepest folds at stage Ⅲ. Redundancy analysis (RDA) was used to explore the correlation between ovarian development, body weight, and body length. A significant positive correlation was observed for body weight (p = 0.001) and body length (p = 0.009), which varied with the grade of ovarian development evaluated by the ovarian developmental stage, ovarian length, ovarian width, and ovarian cross-sectional area. A partial least square (PLS) regression was used to model the ovarian developmental stage, with a stage-based PLS being identified as the more effective method, which was y = 1.509x 1 + 0.114x 2. The model provides a potentially rapid way to identify the population source as either "native" or "immigrant" from the phenotypic traits without dissection. The aforementioned model may be used to estimate adult emergence periods and identify migratory populations from their ovarian development, potentially aiding in implementing proper prevention measures.

Since its invasion in late 2016, the fall armyworm has a widespread year-round distribution within Africa where it continues to threaten cereal production, particularly maize. Most recommended control advice emphasises the need for interventions against larvae early after colonization of a new maize crop by adults followed by a later intervention if an infestation persists. The current times for action are approximate action thresholds based on scouting which are difficult to implement as early development stages are cryptic and farmers, especially smallholders, have limited time for crop assessments. To improve the impact of controls, the modelling of early and late instar larval population emergence and development in relation to physiological time from planting was developed to enable times to action to be predicted and conveyed to farmers. The two larval population emergence models were built from field fall armyworm data from maize in Zambia and validated from similar data from multiple maize sites in Kenya. A component was included in the models to allow synchronization of maize emergence with larval development. Physiological time, in degree-days, was estimated using Earth Observation land surface temperature data sets. As precise information on action thresholds is lacking for Africa, recent published data on thresholds based on economic injury levels from Colombia were used as a guide but the models can be updated when new information becomes available for Africa. The practical implementation of the models in Africa is discussed including the outcome of some recent preliminary trials with maize farmers in Kenya.

Oedaleus decorus asiaticus (Bei-Bienko, 1941) has been regarded as one of the most dominant locusts in the northern grassland, the adjacent area of agriculture and animal farmland, in China. The aims of this study were to investigate the effects of vegetation type on the oviposition behavior of this pest in an open field and the hatching success of the offspring in the following year. The results showed that vegetation type did have a significant effect on whether any egg pods were laid by O. d. asiaticus. Once the females laid eggs, vegetation type and cage number had a significant effect on the number of egg pods laid. The highest number of egg pods was found in the Cleistogenes squarrosa treatment, followed by Stipa krylovii and then Leymus chinensis, while the Artemisia frigida treatment contained the lowest number of egg pods. The O. d. asiaticus eggs laid in S. krylovii and C. squarrosa treatments had a significantly higher hatching success rate (over 53%) than the other two grasses (below 40%). In short, habitats with C. squarrosa and S. krylovii grasses are likely to be preferred by ovipositing females, thus population monitoring efforts of O. d. asiaticus should focus on these habitats.

Invasive alien species have environmental, economic and social impacts, disproportionally threatening livelihood and food security of smallholder farmers in low- and medium-income countries. Fall armyworm (FAW) ( Spodoptera frugiperda ), an invasive insect pest from the Americas, causes considerable losses on maize to smallholder farmers in Africa since 2016. The increased use of pesticides to control FAW in Africa raises concerns for health and environmental risks resulting in a growing interest in research on biological control options for smallholder farmers. In order to evaluate the occurrence of local natural enemies attacking FAW, we collected on a weekly basis FAW eggs and larvae during a maize crop cycle in the rainy season of 2018–2019 at four locations in the Lusaka and Central provinces in Zambia. A total of 4373 larvae and 162 egg masses were collected. For each location and date of collection, crop stage, the number of plants checked and amount of damage were recorded to analyse which factors best explain the occurrence of the natural enemy species on maize. Overall parasitism rates from local natural enemies at each location varied between 8.45% and 33.11%. We identified 12 different egg-larval, larval and larval-pupal parasitoid species. Location, maize growth stage, pest density and larval stage significantly affected parasitoid species occurrence. Our findings indicate that there is potential for increasing local populations of natural enemies of FAW through conservation biological control programmes and develop safe and practical control methods for smallholder farmers.

The annual plant Impatiens glandulifera (Himalayan balsam) is the most widespread in vasive non-native weed in the British Isles. Manual control is widely used, but is costly and laborious. Recently, biological control using the rust fungus Puccinia komarovii var. glanduliferae has been trialled. We designed an experiment to assess the impact of these control methods on invertebrate communities in relation to unmanaged and uninvaded habitats, and to determine whether mycorrhizal inoculation aided post-control recovery of these communities. Sixty invaded and twenty uninvaded field soil blocks were transplanted to the experiment site, where a mycorrhizal inoculum was added to half of all blocks. Biological and mechanical control treatments were applied to twenty invaded blocks independently; the twenty remaining invaded blocks were left intact. Above- and belowground invertebrate samples were collected from the blocks at the end of the growing season. Overall, aboveground invertebrate abun dance increased with the removal of I. glandulifera , and several groups showed signs of recovery within one growing season. The effect of mechanical control was more variable in belowground invertebrates. Biological control did not affect aboveground invertebrate abundance but resulted in large increases in populations of belowground Collembola. Our experiment demonstrates that mechanical removal of I. glandulifera can cause rapid increases in invertebrate abundance and that its biological control with P. komarovii var. glanduliferae also has the potential to benefit native invertebrate communities.