Heliocheilus Albipunctella Research Articles

Optimization of the releases of the parasitoid Habrobracon hebetor Say in jute bags containing different support diets of Corcyra cephalonica Stainton for the management of the millet ear miner Heliocheilus albipunctella de Joannis in the Zinder region of Niger

Optimization of the releases of the parasitoid Habrobracon hebetor Say in jute bags containing different support diets of Corcyra cephalonica Stainton for the management of the millet ear miner Heliocheilus albipunctella de Joannis in the Zinder region of Niger

Effect of augmentative releases of the parasitoid, <i>Habrobracon hebetor</i> Say (Hymenoptera: Braconidae) using plastic cups on <i>Heliocheilus albipunctella</i> De Joannis (Lepidoptera: Noctuidae) in the Sahelian region of Burkina Faso

The most important insect pest of the millet crop in Burkina Faso is the Millet Head Miner (MHM), Heliocheilus albipunctella De Joannis (Lepidoptera: Noctuidae). To reduce its damage, the use of the parasitoid, Habrobracon hebetor Say (Hymenoptera: Braconidae) constitutes the most promising control strategy. The present study aims to know the effect of augmentative releases of H. hebetor on this pest using a new parasitoid release technique. This new technique release consists of a recycled plastic cups containing Corcyra cephalonica Stainton larvae parasitized individually at different times (8, 12 and 24 hours) by H. hebetor females. These cups were installed in the millet fields of different villages (release villages) to control this pest H. albipunctella by H. hebetor, and maitained the control villages that didn’t receive any release. Our findings showed that plastic cups containing parasitized larvae at different times can be used to produce parasitoids. Thus, C. cephalonica larvae parasitized in 24 hours produced 280 H. hebetor, unlike larvae parasitized in 8 and 12 hours. Emerged H. hebetor had a male-biased sex ratio when the time of parasitism of C. cephalonica larvae by H. hebetor females was 24h. Releasing parasitoids into millet fields reduced the length of mines by 3.80 cm and two times higher parasitism of the pest by H. hebetor in the villages where parasitoids were released as compared to control villages. Finally, a millet yield gain of 31% was obtained in the parasitoid released fields. This new release technique of H. hebetor could be used in biological control programmes against MHM in the Sahel.

Bioecology of the millet head miner, Heliocheilus albipunctella De Joannis (Lepidoptera : Noctuidae) in the Sahelian zone of Burkina Faso

Pearl millet, Pennisetum glaucum (L.) R.Br., main cereal crop in the Sahelian zone of Burkina Faso, is attacked by the millet head miner, Heliocheilus albipunctella De Joannis (Lepidoptera: Noctuidae) which causes considerable damage. Previous studies on this pest have been conducted on ecology, biology and biological control. However, knowledge of some bioecological parameters of H. albipunctella remains to be elucidated. This is necessary in order to strengthen existing control strategies for more effective control of the pest. Thus, the work carried out for two consecutive years in 2015 and 2016 showed that the proportion of adults captured in light traps was four females for one male. The rate of gravid females was between 73 and 100%, whether they were fed by honey solution or fasting. In addition, no adults of H. albipunctella were captured in the dry season. To ensure their progeny, females prefer lay eggs on 1/3 extension and fully expanded panicles. They have a lifespan of 4 days and live longer than males. The average egg hatch rate was more than 89% with a survival rate for stage 1 (L1) larvae ranging from 41 to 88% on millet panicles depending on the number of L1 present on the millet panicle. In farmers' fields, the damage caused by MHM is important with more than 40% of panicles destroyed. In addition, no female lays eggs on a panicle that has previously received eggs from another female. The implications of these results for control strategies against this pest are discussed.

Genetic variation and diversity of pearl millet [Pennisetum glaucum (L.)] genotypes assessed for millet head miner, Heliocheilus albipunctella resistance, in West Africa

Pearl millet (Pennisetum glaucum L.), the major source of minerals and dietary energy for people living in the semi-arid regions of Sahel, is regularly damaged by millet head miner, Heliocheilus albipunctella. In order to identify the plant-based resistance sources for millet head miner along with high grain Fe and Zn, we have screened forty pearl millet genotypes, using an artificial infestation method. Analysis of variance revealed significant differences in the genotypes tested for head miner resistance. The genotypes Gamoji, ICMP 177001, ICMP 177002, ICMV 177003, ICMV IS 90311, LCIC9702, Souna 3, ICMV IS 94206 and PE08043 exhibited antibiosis resistance mechanism to Heliocheilus albipunctella with appreciable agronomy and grain yield when compared with the susceptible check ICMV IS 92222. The genotypes Faringuero, ICMV 167005, ICMV IS 99001, Sadore local, SOSAT-C88, and ICMP 177004 exhibited tolerance to head miner damage with good per se performance. The genotypes ICMP 177001, ICMP 177002, ICMV 177003, and Moro exhibited resistance to millet head miner and had consistent grain Fe content across seasons (ranging from 44 to 70 ppm). Association between the head miner resistance and morphological traits showed a positive and significant correlation of larval production index (%) with head miner damage (r = 0.59**). Grain Fe and Zn contents exhibited negative association with panicle length and grain yield indicating proper care should be taken in breeding for these traits. Hence, the identified resistance sources can be effectively utilized in breeding head miner resistant pearl millet OPV’s/hybrids, with high grain yield including Fe and Zn concentrations, to overcome the hunger and malnutrition seen in populations living in the semi-arid tropics.

Field performance of the parasitoid wasp, Trichogrammatoidea armigera (Hymenoptera: Trichogrammatidae) following releases against the millet head miner, Heliocheilus albipunctella (Lepidoptera: Noctuidae) in the Sahel

The effectiveness of the egg parasitoid Trichogrammatoidea armigera Nagaraja (Hymenoptera: Trichogrammatidae) in controlling Heliocheilus albipunctella de Joannis (Lepidoptera: Noctuidae), a major insect pest of pearl millet in the Sahel was assessed during two consecutive years in Niger on-station and on-farm conditions. We found that released T. armigera were able to find and parasitize host eggs within pearl millet fields both on-station and in farmers’ fields. On-station releases of T. armigera led to an average 4.86-fold increase in T. armigera parasitism compared to control fields, where no parasitoids were released. Likewise, on-farm releases of T. armigera led to up to 5.31-fold more egg parasitism by T. armigera in release fields than in control. Our results suggest the effectiveness of T. armigera and lays the groundwork for using T. armigera in augmentative biological control of H. albipunctella in the Sahel.

Birds and bats contribute to natural regulation of the millet head miner in tree-crop agroforestry systems

A better understanding of environmental factors driving natural pest regulation is a major challenge for designing sustainable cropping systems. The objective of the present study was to assess the association between vegetation openness in traditional tree-crop agroforestry systems in Senegal, richness and abundance of vertebrates including insectivorous birds and bats, and their contribution to the natural regulation of crop pests. The millet head miner (MHM), Heliocheilus albipunctella (Lepidoptera, Noctuidae), a major constraint to increasing millet crop productivity in sub-Saharan Africa, was selected as a model system. Ten sites separated by at least one km from each other were selected in a 100 km2 study area in the Peanut basin in Senegal. In each site, a pair of millet fields distant from at least 100 m each was selected according to a gradient of vegetation openness within a 100-m radius buffer with sampling plot (5 × 5 m) at the center. Nine insectivorous bird and bat species were recorded in millet fields over the 2017 cropping season and their predator status was confirmed by direct observation or DNA detection in fecal samples. Grain losses were reduced when panicles were accessible to birds and bats, confirming their net contribution to pest regulation. At a local scale, tree diversity and vegetation openness were important predictors of the abundance of insectivorous village weaver birds and grey-headed sparrows, respectively. Some tree species (soapberry trees and neems) indirectly contributed to natural regulation of the MHM likely by providing refuges to insectivorous vertebrates whereas other tree species (baobabs) provided disservices as possible refuges for the MHM moths. Further research is needed to better understand relationships between tree cover, food web interactions and natural pest suppression, so that specific conservation measures such as habitat management can be designed to improve pest control.

Efficacy of augmentative release of the parasitoid wasp Bracon hebetor against the pearl millet headminer

The yield losses in pearl millet, estimated to be about 85%, are mainly due to millet headminer, Heliocheilus albipunctella . This study is aimed at determining the status of this serious insect pest in the pearl millet production system within the groundnut basin of Senegal and to assess the efficacy of augmentative releases of its parasitoid wasp, Bracon hebetor , to control it. The study area was divided into three homogenous blocks (Northern, Southern and Eastern parts) where a set of three villages was selected for release of the parasitoid and another three as control villages where no releases were made. The results revealed that in all the villages where the parasitoid was released, an increase in larval mortality due to parasitism ranging between 9% and 26% was recorded in comparison with the control villages. Consequently, damages recorded were significantly lower in the villages with parasitoid releases.

Timing of releases of the parasitoid Habrobracon hebetor and numbers needed in augmentative biological control against the millet head miner Heliocheilus albipunctella

Heliocheilus albipunctella de Joannis (Lepidoptera: Noctuidae) is one of the major insect pests of pearl millet in the Sahel. The native parasitoid, Habrobracon hebetor Say (Hymenoptera: Braconidae), is currently being promoted for augmentative biological control of the pest in the Sahel. The current study was carried out to identify the right time for releases of the parasitoid using either pearl millet growing stage, or pest occurrence as reference, and to determine the optimal number of parasitoids needed to cover a given area. Our results indicate that release of parasitoids at the panicle emergence stage or six weeks after first sight of eggs of H. albipunctella lead to highest parasitism of H. albipunctella larvae by H. hebetor. The dose of 800 parasitoids for a distance of 3 km radius was enough for controlling H. albipunctella. The implications of the results are discussed toward cost effective and practical recommendation adapted to the Sahelian conditions.

Deciphering host-parasitoid interactions and parasitism rates of crop pests using DNA metabarcoding

An accurate estimation of parasitism rates and diversity of parasitoids of crop insect pests is a prerequisite for exploring processes leading to efficient natural biocontrol. Traditional methods such as rearing have been often limited by taxonomic identification, insect mortality and intensive work, but the advent of high-throughput sequencing (HTS) techniques, such as DNA metabarcoding, is increasingly seen as a reliable and powerful alternative approach. Little has been done to explore the benefits of such an approach for estimating parasitism rates and parasitoid diversity in an agricultural context. In this study, we compared the composition of parasitoid species and parasitism rates between rearing and DNA metabarcoding of host eggs and larvae of the millet head miner, Heliocheilus albipunctella De Joannis (Lepidoptera, Noctuidae), collected from millet fields in Senegal. We first assessed the detection threshold for the main ten endoparasitoids, by sequencing PCR products obtained from artificial dilution gradients of the parasitoid DNAs in the host moth. We then assessed the potential of DNA metabarcoding for diagnosing parasitism rates in samples collected from the field. Under controlled conditions, our results showed that relatively small quantities of parasitoid DNA (0.07 ng) were successfully detected within an eight-fold larger quantity of host DNA. Parasitoid diversity and parasitism rate estimates were always higher for DNA metabarcoding than for host rearing. Furthermore, metabarcoding detected multi-parasitism, cryptic parasitoid species and differences in parasitism rates between two different sampling sites. Metabarcoding shows promise for gaining a clearer understanding of the importance and complexity of host-parasitoid interactions in agro-ecosystems, with a view to improving pest biocontrol strategies.

Towards development of a parasitoid cottage industry of the parasitoid wasp Habrobracon hebetor (say): optimum rearing and releases conditions for successful biological control of the millet head miner Heliocheilus albipunctella (De Joannis) in the Sahel

Augmentative biological control by the parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is the most promising strategy to control millet head miner, Heliocheilus albipunctella (De Joannis) a major insect pest of pearl millet in the Sahel. As H. hebetor survival is somehow challenging during the nine month long off-season when the host, H. albipunctella is in diapause, there needs to be a sufficient supply of parasitoids for fresh release each year. Therefore, the aim of this study was to establish a small-scale parasitoid rearing process adjusted to the Sahel conditions that can be scaled-up as necessary. We conducted experiments to fine-tune and standardize the rearing technique of H. hebetor for cottage industrial use. The results showed that parasitoids fed with 30% honey solution and supplied daily with one late-larval-stage Corcyra cephalonica Stainton (Lepidotera, Pyralidae) produced highest number of progeny. The optimal times for mating and egg fertilization, was achieved when a male and female pair was confined for 24 h in a 30-cc vial. Our findings indicated that, compared with the conventional rearing method -2 females supplied once with 25 C. cephalonica larvae-, this new method resulted in 14-times greater parasitoid production. Furthermore parasitoid female can be stored for up to three weeks at fluctuating 23–32°C temperature and 25%–80% relative humidity for numbers accumulations prior to on-farm augmentative releases without altering its fitness.

An Updated Review of Research on Heliocheilus albipunctella (Lepidoptera: Noctuidae), in Sahelian West Africa

In the Sahelian region of West Africa, pearl millet, which is a major subsistence food crop supporting families’ livelihoods, is regularly attacked by the millet head miner/spike worm, Heliocheilus (=Raghuva) albipunctella de Joannis (Lepidoptera: Noctuidae). The pest infestation levels, damage ratings, and yield losses vary within and among countries because of differences in millet cultivars, the planting period, the onset time and seasonal distribution of rains, synchronization of moth flight with head development stages, and pest control practices. Egg laying by moths and the distribution of larval populations are governed by the development stages of millet head and the soil type. Rainfall patterns affect the distribution of diapaused pupae. The implications of this information for future pest control strategies are discussed in this review. Control measures including the planting of pest tolerant/resistant cultivars, the application of chemical pesticides, and the abundance of natural enemies have had significant impacts on larval mortality but have limited application. In recent years, augmentative releases of the larval ectoparasitoid, Habrobracon hebetor Say (Hymenoptera: Braconidae), have been tested in a pilot project in Burkina Faso, Mali, Niger, and Senegal. Because of the success of the program and the increasing demand for parasitoids farmers cooperatives are being engaged in producing parasitoids for the large-scale distribution of ‘ready-to-use’ bags containing braconids. This would sustain continuous availability and generate profitable businesses. To achieve this goal, farmers’ economic problems and technical challenges need to be resolved at the village level, and marketing avenues need to be established.

Effect of landscape diversity and crop management on the control of the millet head miner, Heliocheilus albipunctella (Lepidoptera: Noctuidae) by natural enemies

The pearl millet head miner, Heliocheilus albipunctella, is a major constraint to increasing crop productivity in sub-Saharan Africa. In the absence of any insecticide application by farmers, its control mostly relies on the action of natural enemies.The objective of the present study is to identify crop management and landscape features affecting biocontrol services by natural enemies. A set of 45 millet fields were selected in a 20 ∗ 20 km area in Senegal, from the analysis of high resolution satellite images (Pleiades), and hypotheses on relative abundance of millet fields and semi-natural habitats (mainly trees) in the agricultural landscape. A biocontrol service index (BSI) was computed for each field over two cropping seasons by experimentally excluding natural enemies from naturally egg-infested millet panicles. Information on crop management was collected through farmer’s interviews. An information theoretical approach and model averaging were performed to rank the effect of landscape metrics on BSI at eight spatial scales (from 250 to 2000 m).The BSI was generally high (77%) but highly variable among fields (0–100%), and was greater in compound fields compared to bush fields. The BSI also increased with the abundance of tree patches and the diversity of vegetation in a 1750 m-buffer around millet fields.Results support previous studies stressing the importance of semi-natural areas and vegetation diversity to support pest regulation by natural enemies. Further research is needed to better understand relationships between agroforestry systems and biological control, to promote ecologically-intensive solutions for reducing crop losses.

Designing a field sampling plan for landscape-pest ecological studies using VHR optical imagery

The objective of this study was to develop an easily replicable sampling methodology using very high spatial resolution (VHSR) optical imagery to study the effect of landscape composition on crop pest incidence and biological control. The methodology was developed for the millet head miner (MHM), Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae), a key pest of millet in Senegal (West Africa). The sampling plan was developed according to two main hypotheses: (i) pest incidence increases with millet abundance in the landscape, and (ii) biological control increases with the abundance of semi-natural habitats in the landscape. VHSR satellite imagery (<1 m) provided from a Pléiades sensor was used to map and to quantify the landscape elements. Covering a square region of 20 × 20 km, a hierarchical, broad-scale land cover map focusing on crop (millet and peanut crops) and tree (tree vegetation) categories was produced and validated with ground truth data. Then, the landscape variables (tree density index and millet crop density index) were calculated based on a regular grid of 100 ha for each cell size covering the study area; the variables were then split into three density classes (low-medium-high) representative of the full landscape heterogeneity and combined into nine landscape patterns. Finally, according to sampling capacity, track accessibility, and statistical constraints, 45 field sites, including five replicates for each landscape pattern, were validated and selected for pest monitoring.

Economic feasibility of an augmentative biological control industry in Niger

Farmers in Niger are vulnerable to high millet yield losses due to the millet head miner, Heliocheilus albipunctella De Joannis (Lepidoptera: Noctuidae), for which pest control options are limited. Researchers have developed a procedure to multiply and spread an augmentative biological control agent Habrobracon hebetor Say (Hymenoptera: Braconidae) which is effective in limiting millet yield losses due to the pest. This study assesses the economic viability of small businesses to produce and sell biological control agents. It analyzes the profitability of the businesses under alternative pricing regimes given estimated costs to produce and distribute biological control agents. The economic assessment provides budget analysis for potential businesses and discusses options for scaling, price setting, and organizing. Our study suggests that the small H. hebetor industry should turn a profit in Niger at relatively low prices for the biological control agents of $3.00-$4.00 per bag with 15 bags needed per village. Competitive wages are achievable for the businesses that sell to at least 13 villages. Each business would hire three workers from late May to late August. Commercialization of H. hebetor would generate opportunities for wide geographic distribution of the technology on a sustainable basis in Niger.

Field dispersal of the parasitoid wasp Habrobracon hebetor (Hymenoptera: Braconidae) following augmentative release against the millet head miner Heliocheilus albipunctella (Lepidoptera: Noctuidae) in the Sahel

ABSTRACTPearl millet is one of the major staple food crops in Sub-Sahelian Africa, and the millet head miner (MHM) [Heliocheilus albipunctella] is its major pest, causing serious economic damage in the maturity period. We studied the dispersion patterns of the endogenous ectoparasitoid, Habrobracon hebetor (Hymenoptera: Braconidae), after augmentative releases in pearl millet fields for biological control of the MHM, in 2010 and 2011 in Burkina Faso and Niger. The parasitoids were released using 15 jute bags per release site. Parasitoid dispersion was indirectly monitored through weekly assessments of MHM parasitism by H. hebetor at different distances from release points (0, 3 and 5 km) and in control villages (15 km). Our findings indicate that the jute bags released approximately 900–1000 parasitoids per site over a period of three weeks. This initial parasitoid population led to higher parasitism of MHM larvae at the site of dissemination compared to farms at distances of 3 and 5 km. However, usually after five weeks, successive generations of H. hebetor dispersed up to 3 km, causing high levels of MHM larval mortality, which sometimes is similar to those of the release points. Based on these results, we recommend the release of parasitoids at sites spaced 3 km for timely and more efficient control of MHM populations.

DNA sequencing to help identify crop pests and their natural enemies in agro-ecosystems: The case of the millet head miner Heliocheilus albipunctella (Lepidoptera: Noctuidae) in sub-Saharan Africa

Better knowledge of natural enemy communities and their relative contribution to biological control is needed to design ecology-based pest management in agro-ecosystems. Here, we investigated the arthropod communities of pearl millet-based agro-ecosystems in sub-Saharan Africa (Senegal), with a focus on natural enemies of the millet head miner (MHM), Heliocheilus albipunctella (de Joannis).A set of 105 millet fields was monitored over the 2014–2016 growing seasons. Arthropods were sampled at three successive phenological stages, from panicle emergence to grain maturity. Eggs and larvae from Lepidoptera pests were collected to assess their identity and relative contribution to the biological control of parasitoids. Morphological identification combined with Sanger and Illumina DNA sequencing, using the COI full barcode (658 bp) and the COI mini-barcode (133 bp) respectively, was carried out to characterize arthropod samples.MHM was by far the main herbivore on millet, with a relative abundance of 97%. Predators were mostly ants (28%), earwigs (Forficula senegalensis, 26%), mirids (20%), spiders (12%), carabid larvae (7%), flower bugs (Orius maxidentex, 6%), and ladybirds (Declivitata hamata, 1%). In all, 13 primary parasitoid species were collected, including five new species. Parasitism was dominated by three key species, including Trichogrammatoidea armigera (12.4% of egg parasitism), Copidosoma primulum and Schoelandella spp. (46 and 32% of larval parasitism, respectively). A primary reference database including standard and mini-barcode sequences of specimens attributed to species (15) was designed as a reliable tool for assisting arthropod identification. The results will be helpful when selecting candidates for augmentative biological control in millet-based agro-ecosystems in sub-Saharan Africa.

Methylation analysis revealed salicylic acid affects pearl millet defense through external cytosine DNA demethylation

ABSTRACTThe cytosine DNA methylation and demethylation have a role in regulating plant responses to the environment by affecting the promoter regions of most plant defense-related genes through the CpG islands or the CCGG motifs. Salicylic acid, a defense and signaling plant hormone, is seen playing crucial role in the variation of the methylome. In this study, the effects of salicylic acid and feeding of the millet headminer (Heliocheilus albipunctella de Joannis) on pearl millet DNA methylome changes were evaluated through MSAP epigenotyping during panicle development. The results showed that millet headminer feeding increased the level of genomic methylation while application of salicylic acid caused DNA demethylation occurring mostly at external cytosine and accompanied by a decrease of the number of larvae per panicle. This suggests that hemimethylation (external cytosine methylation) has key role in regulating defense responses and conferring tolerance to pearl millet through salicylic acid application.

Field persistence of Habrobracon hebetor (Say) (Hymenoptera: Braconidae) following augmentative releases against the millet head miner, Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae), in the Sahel

Biological control by augmentative releases of the parasitoid wasp Habrobracon hebetor Say (Hymenoptera: Braconidae) is a promising strategy for controlling the millet head miner (MHM), Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae). A current biological control program in the Sahel region involves inoculative releases of the parasitoid each growing season, but this is prohibitively expensive. The present study aimed to quantify residual parasitism of MHM in years after augmentative release. We also investigated the impact of two successive annual releases of H. hebetor on MHM parasitism. Two successive releases did not increase parasitism, but slightly reduced MHM damage in terms of number of mines and their length. Parasitism levels decreased in subsequent years if no additional parasitoids were released. Nevertheless, in the first year after release, parasitism levels in release villages remained significantly higher than in control villages. These findings suggest that augmentative releases could be carried out biennially instead of annually. Possible means of enhancing parasitoid survival between seasons are discussed.

Augmentative on-farm delivery methods for the parasitoid Habrobracon hebetor Say (Hymenoptera: Braconidae) to control the millet head miner Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae) in Burkina Faso and Niger

Augmentative on-farm delivery methods for the parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) to control the millet head miner (MHM) Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae) were investigated in Burkina Faso from 2011 to 2012 and in Niger in 2012. Our findings indicate that 7 cm × 10 cm jute bags containing 50 g of millet grains, 30 g of millet flour, 25 Corcyra cephalonica larvae and two mated H. hebetor females are the most effective option for on-farm delivery of the parasitoid. The parasitoid progeny started emerging from the bags eight days after confinement and 57–71 parasitoid adults emerged from each bag. Using the methods we developed, over 90 % parasitism of MHM larvae was achieved in millet farms. The implications of these findings for a large extension of MHM biocontrol program are discussed.

Estimating effect of augmentative biological control on grain yields from individual pearl millet heads

AbstractPearl millet is the principal staple food crop in large portions of Western Sub‐Sahelian Africa and the millet head miner (Heliocheilus albipunctella) is one of its most devastating insect pests. Since 2006, augmentative mass releases of the larval ectoparasitoid, Habrobracon hebetor, have been conducted in Mali, Burkina Faso and Niger as part of minimizing pearl millet grain losses imposed by millet head miners. These ongoing mass releases are based on low‐cost mass‐rearing of both host larvae and parasitoids. A release of parasitoids consists of placing jute bags containing pearl millet grain and flour and parasitized host larvae near pearl millet fields. The total production costs of a single jute bag with parasitized rice moth larvae are US$ 3–4. Based on a study of 6634 individual pearl millet heads collected at harvest in 12 farmers' fields in southern Niger in 2010, we demonstrated (i) a strong negative correlation between pearl millet head damage (mining) and grain yield and (ii) that parasitism by H. hebetor reduced grain losses by, on average, 34% (comparison of infested millet heads with/without parasitism) within the given growing season. Additional benefits may include reduction in millet head miners in subsequent generations. Data from 900 pearl millet heads collected in nine farmers' fields in 2011 were used to confirm data trends observed in the 2010 data and to characterize the dispersal of parasitoids in upwind and downwind directions from a release site. This study provided a quantitative description of the negative impact of millet head miner infestations on pearl millet grain yields and of benefits on grain yield of parasitism by H. hebetor. Our findings strongly support (i) intensification of mass‐rearing of H. hebetor, (ii) expansion of educational activities to increase local empowerment and understanding of the potential of augmentative biological control and (iii) optimization of H. hebetor mass release programmes among smallholders in Sub‐Sahelian Africa.