Incidence of Groundnut Leafminer (GLM), Aproaerema modicella (Deventer) (Lepidoptera: Gelechiidae) and its Parasitic Fauna on Alternate Leguminous Hosts in Tamil Nadu, India

Background: The groundnut leafminer (GLM), Aproaerema modicella is an important pest of several legume crops which causes 50 to 100 per cent yield loss in India. The exploration of indigenous natural enemies is crucial to the success of every biological control strategy. Besides, alternative host plants act as a source of both herbivorous pests and their natural enemies. In this view, occurrence of GLM and their parasitic fauna on groundnut, alternate leguminous hosts viz., redgram and babchi were recorded. Methods: Survey on damage potential of GLM and their parasitic fauna were recorded on groundnut at Sivagangai and Coimbatore districts of Tamil Nadu, India during 2016 to 2018. Survey was also conducted to find the damage potential of A. modicella on alternate leguminous hosts viz., redgram, babchi and their parasitic fauna at Coimbatore district. The damage potential of A. modicella, per cent parasitization and parasitoid emergence were assessed from A. modicella infested groundnut, redgram and babchi leaves. Result: Severe incidence of A. modicella was recorded as 98.10% (2016 to 2017) and 98.45% (2017 to 2018) at Sivagangai district. The parasitization of GLM was also found higher at Sivagangai recording 46.67% in both the years which was positively related with the pest population. 13 hymenopteran parasitoids belonging to eight families were recorded. Among them, Avga choaspes Nixon recorded high per cent parasitoid emergence (20.00%). Furthermore, GLM incidence on redgram and babchi indicated the highest damage potential of 38.20 and 34.50 per cent and parasitization of 33.33 and 20.00 per cent, respectively during 2017 to 2018.

Augmentative biological control in greenhouses in Japan.

In Japan, augmentative biological control is mainly implemented in greenhouses using arthropod natural enemies. Two imported natural enemy species, Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) against spider mites and Encarsia formosa Gahan (Hymenoptera: Aphelinidae) against the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae), were first commercialised in greenhouses in 1995, followed by the commercialisation of other exotic species. Exotic arthropod natural enemies are used to control both exotic and indigenous pests in greenhouses. Currently, the most popular exotic natural enemy species are predatory mites such as P. persimilis and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae). Recently, there has been a shift from using exotic to using indigenous natural enemies in greenhouses. Currently, the importation of generalist predators for augmentative biological control is very difficult in Japan. Several collaborative studies have been conducted in Japan to develop biological control using indigenous natural enemies. These studies developed innovative technologies, such as new banker plant systems based on combinations of two natural enemies or flightless Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae). Indigenous natural enemies have been commercialised following the registration of Orius strigicollis (Poppius) (Hemiptera: Anthocoridae). Biological control can be achieved using an indigenous strain of Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) with a banker plant system, on which the bug can reproduce without alternative prey. Research and development of biological control using indigenous natural enemies should be continued in Japan.

Biodiversity in and around Greenhouses: Benefits and Potential Risks for Pest Management

One of the ecosystem services of biodiversity is the contribution to pest control through conservation and stimulation of natural enemies. However, whether plant diversity around greenhouses is beneficial or a potential risk is heavily debated. In this review, we argue that most greenhouse pests in temperate climates are of exotic origin and infest greenhouses mainly through transportation of plant material. For indigenous pests, we discuss the potential ways in which plant diversity around greenhouses can facilitate or prevent pest migrations into greenhouses. As shown in several studies, an important benefit of increased plant diversity around greenhouses is the stimulation of indigenous natural enemies that migrate to greenhouses, where they suppress both indigenous and exotic pests. How this influx can be supported by specific plant communities, plant characteristics, and habitats while minimising risks of increasing greenhouse pest densities, virus transmission, or hyperparasitism needs further studies. It also requires a better understanding of the underlying processes that link biodiversity with pest management. Inside greenhouses, plant biodiversity can also support biological control. We summarise general methods that growers can use to enhance pest control with functional biodiversity and suggest that it is particularly important to study how biodiversity inside and outside greenhouses can be linked to enhancement of biological pest control with both released and naturally occurring species of natural enemies.

Natural Enemies of Fall Armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) in Different Agro-Ecologies

Fall armyworm (FAW) Spodoptera frugiperda (J.E. Smith) and southern armyworm (SAW) Spodoptera eridania (Stoll) have become major threats to crops in Africa since 2016. African governments adopted emergency actions around chemical insecticides, with limited efforts to assess the richness or roles of indigenous natural enemies. Field surveys and laboratory studies were conducted to identify and assess the performance of parasitoids associated with spodopterans in Cameroon. FAW was the most abundant spodopteran pest. Telenomus remus (Nixon), Trichogramma chilonis (Ishi), Charops sp. (Szépligeti), Coccygidium luteum (Cameron), Cotesia icipe (Fernandez & Fiaboe), and Cotesia sesamiae (Cameron) are the first records in the country on spodopterans. Telenomus remus, T. chilonis, C. icipe, and Charops sp. were obtained from both FAW and SAW; C. luteum and C. sesamiae from FAW. The distribution of spodopterans, their endoparasitoids, and parasitism rates varied with host, season and location. In the laboratory, T. remus showed significantly higher parasitism on FAW than SAW, and significant differences in the development parameters between the two host eggs, with shorter development time on FAW. It induced significant non-reproductive mortality on FAW but not on SAW. Developmental parameters showed that C. icipe has a shorter development time compared to other larval parasitoids. Implications for conservative and augmentative biocontrol are discussed.

Erionota acroleucus (palm redeye).

Although E. acroleucus has been found to be a relatively common minor pest on rattan palms (Steiner, 2001b), and is reported from a variety of crop and ornamental palms (Cock, 2015), no economic impact has been reported. It is likely that this is a species that is kept under control by its indigenous natural enemies, but could become an outbreak pest if this natural control were disrupted, e.g. by the use of insecticides, or if it were introduced into new areas and thereby freed of its natural enemies.

Mononychellus tanajoa (cassava green mite).

The cassava green mite, M. tanajoa, is of Neotropical origin but was accidentally introduced to Africa in 1971 (Nyiira, 1972). By 1985, the pest had spread throughout the cassava belt of Africa (Yaninek and Heren, 1988). M. tanajoa affects the important annual crop cassava (Manihot esculenta) and can cause a reduction of about 50% in leaf weight, and up to 80% tuber yield loss (Shukla, 1976; Gutierrez et al., 1988; Pallangyo et al., 2004). M. tanajoa is mainly dispersed by human activity, whereby infested plant materials and contaminated media are transported over long distances. Natural dispersion by wind and water may also spread the cassava green mite. In areas where both the pest and host plant are exotic, there is no evidence that indigenous natural enemies are significant factors in limiting the mite population growth rates. M. tanajoa can feed and reproduce on other plant species (Moraes et al., 1995) and is reported as a quarantine pest (Delalibera et al., 1992; EPPO, 2009).

First Report on Megaselia scalaris Loew (Diptera: Phoridae) Infestation of the Invasive Pest Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in China

The invasive pest Spodoptera frugiperda first emerged in China in January 2019 and has, to date, migrated to 29 provinces and municipalities in China, causing heavy crop damage in large areas. As a response to this invasive species from the environment, some indigenous natural enemies have been discovered and reported after S. frugiperda invasion. In this paper, parasitic flies were collected and identified from S. frugiperda collected in the Yunnan, Guangxi, and Henan provinces and the Chongqing municipality in China. By using both conventional and molecular approaches, we were able to show that all the parasitic flies of S. frugiperda identified in the four regions were Megaselia. scalaris, and that they attacked the pest larvae and pupae. This is the first report on an indigenous Chinese Megaselia species that has parasitic ability against the invasive pest S. frugiperda, potentially providing new ideas for pest control in China.

Integrated pest management options for the fall armyworm Spodoptera frugiperda in West Africa: Challenges and opportunities. A review

Introduction. The fall armyworm Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) is a voracious and generalist insect pest native to America. It was first detected in West Africa in 2016 and rapidly spread across the continent. The indiscriminate use of chemical insecticides poses risks to human health and threatens the few natural enemies present in these environments. Despite the existence of alternative control measures in America (e.g. genetically modified maize), efforts are needed to develop environmentally friendly approaches that are affordable for smallholder farmers and compatible with the African context. Literature. In this literature review, we describe the potential of the available alternative controls methods which include cultural, physical, biological and semiochemical strategies. The potential of their association is discussed considering their cost-benefice balance and local economic and agricultural context. Conclusions. Several affordable mitigation options could be implemented rapidly, pending proper communication efforts, including (i) the promotion of indigenous natural enemies by promoting refuges and training smallholder farmers on their identification; (ii) cultural methods, mainly by planting directly after the main rainfalls, as well as performing intercropping and crop rotation; and (iii) the use of microbial biopesticides, and avoiding some of the already identified ineffective chemical insecticides.

Biological control of Drosophila suzukii.

Drosophila suzukii (Matsumura) is native to East Asia but has widely established in the Americas and Europe, where it is a devastating pest of soft-skinned fruits. It has a wide host range and these non-crop habitats harbor the fly which then repeatedly reinvades crop fields. Biological control in non-crop habitats could be the cornerstone for sustainable management at the landscape level. Toward this goal, researchers have developed or investigated biological control tactics. We review over 100 studies, conducted in the Americas, Asia and Europe on natural enemies of D. suzukii. Two previous reviews provided an overview of potential natural enemies and detailed accounts on foreign explorations. Here, we provide an up-to-date list of known or evaluated parasitoids, predators and entomopathogens (pathogenic fungi, bacteria, nematodes, and viruses) and summarize research progress to date. We emphasize a systematic approach toward the development of biological control strategies that can stand alone or be combined with more conventional control tools. Finally, we propose a framework for the integrated use of biological control tools, from classical biological control with host-specific Asian parasitoids, to augmentative and conservation biological control with indigenous natural enemies, to the use of entomopathogens. This review provides a roadmap to foster the use of biological control tools in more sustainable D. suzukii control programs.