Plant-associated microbes may induce plant defenses against herbivores. Plants, in turn, can attract natural enemies, such as predators, using herbivore-induced plant volatiles. Intricate communication occurs between microorganisms, plants, and insects. Given that many aspects related to mechanisms involved in this symbiotic system remain unknown, we evaluated how beneficial soil-borne microorganisms can affect the interactions between plants, herbivores, and natural enemies. For this study, we established a multitrophic system composed of the predatory earwig Doru luteipes (Dermaptera: Forficulidae), arugula (Eruca sativa, Brassicaceae) as the host plant, Plutella xylostella (Lepidoptera: Plutellidae) larvae as a specialist herbivore, Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae as a generalist herbivore, and Bacillus amyloliquefaciens as the plant growth-promoting rhizobacteria (PGPR), in a series of nocturnal olfactometry experiments. By assessing earwig preference towards herbivore-induced and PGPR-inoculated plants in different combinations, we showed that the interaction between rhizobacteria, plants, and herbivores can affect the predatory earwig’s behavior. Furthermore, we observed a synergistic effect in which earwigs were attracted by plants that presented as PGPR inoculated and herbivore damaged, for both specialist and generalist herbivores. Our findings help fill the important knowledge gap regarding multitrophic interactions and should provide useful guidelines for their application to agricultural fields.

Fall armyworm (FAW) Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) was recorded for the first time in 2016 attacking maize fields in central and west Africa. Soon after, several other regions and countries have reported the pest in almost the entire sub-Saharan Africa. In the present study, we assumed that (i) a variety of alternative plant species host FAW, especially during maize off-season, (ii) a wide range of local parasitoids have adapted to FAW and (iii) parasitoid species composition and abundance vary across seasons. During a two-year survey (from June 2018 to January 2020), parasitoids and alternative host plants were identified from maize and vegetable production sites, along streams and lowlands, on garbage dumps and old maize fields in southern and partly in the central part of Benin during both maize growing- and off-season. A total of eleven new host plant species were reported for the first time, including Cymbopogon citratus (de Candolle) Stapf (cultivated lemon grass), Bulbostylis coleotricha (A. Richard) Clarke and Pennisetum macrourum von Trinius (wild). The survey revealed seven parasitoid species belonging to four families, namely Platygastridae, Braconidae, Ichneumonidae, and Tachinidae associated with FAW on maize and alternative host plants. The most abundant parasitoid species across seasons was the egg parasitoid Telenomus remus (Nixon) (Hymenoptera: Platygastridae). These findings demonstrate FAW capability to be active during the maize off-season in the selected agro-ecologies and provide baseline information for classical and augmentative biocontrol efforts.

Several important vegetable crops grown outdoors in temperate climates in Europe can be damaged by the root-feeding larvae of Diptera (Delia radicum, Delia floralis, Chamaepsila rosae, Delia platura, Delia florilega, Delia antiqua). Knowledge of pest insect phenology is a key component of any Integrated Pest Management (IPM) strategy, and this review considers the methods used to monitor and forecast the occurrence of root-feeding flies as a basis for decision-making by growers and the ways that such information can be applied. It has highlighted some current management approaches where such information is very useful for decision support, for example, the management of C. rosae with insecticidal sprays and the management of all of these pests using crop covers. There are other approaches, particularly those that need to be applied at sowing or transplanting, where knowledge of pest phenology and abundance is less necessary. Going forward, it is likely that the number of insecticidal control options available to European vegetable growers will diminish and they will need to move from a strategy which often involves using a single ‘silver bullet’ to a combination of approaches/tools with partial effects (applied within an IPM framework). For the less-effective, combined methods, accurate information about pest phenology and abundance and reliable decision support are likely to be extremely important.

The natural occurrence of entomopathogenic fungal endophytes in sugarcane (Saccharum officinarum) and in soil samples from sugarcane fields was evaluated in Chikwawa District, southern Malawi. Fungi from soil were isolated by baiting using Galleria mellonella larva. Fungal endophytes were isolated from surface-sterilized plant tissue sections. Forty-seven isolates resembled the genus Beauveria, 9 isolates were Metarhizium, and 20 isolates were Isaria. There was no significant difference in the number and type of fungal isolates collected from soil and from plant tissue. There was, however, a significant difference in the part of the plant where fungal species were isolated, which fungal species were isolated, and the number of fungal species isolated at each location. Phylogenetic analysis of 47 Beauveria isolates based on DNA sequencing of the Bloc intergenic region indicated that these isolates all belonged to B. bassiana and aligned with sequences of B. bassiana isolates of African and Neotropical origin. The Malawian B. bassiana isolates formed a distinct clade. No larvae died from infestation by multiple fungi. To the best of our knowledge, this is the first report of B. bassiana and Isaria spp. occurring naturally as endophytes in sugarcane. Further, it is the first report of B. bassiana, Isaria spp., and Metarhizium spp. in the soil of sugarcane fields in Africa.

Sugarcane is one of the most valuable crops in the world. Native and exotic Lepidopteran stemborers significantly limit sugarcane production. However, the identity and genetic diversity of stemborers infesting sugarcane in Malawi is unknown. The main objectives for this study were to identify and determine genetic diversity in stemborers infesting sugarcane in Malawi. We conducted field surveys between June 2016 and March 2017 in the Lower Shire Valley district of Chikwawa and Nsanje, southern Malawi. Molecular identification was based amplification the partial cytochrome oxidase subunit I (COI) gene region. Phylogenetic trees for sequences were generated and published GenBank accessions for each species were constructed. We found that Malawi Busseola fusca (Lepidoptera: Noctuidae) specimens belonged to clade II, Spodoptera frugiperda sp. 1 (Lepidoptera: Noctuidae) and Chilo partellus (Lepidoptera: Crambidae) were infesting sugarcane. Interspecific divergence ranged from 8.7% to 15.3%. Intraspecific divergence was highest for B. fusca, 3.6%. There were eight haplotypes for B. fusca, three for S. frugiperda and three for C. partellus. The importance of accurate species identification and genetic diversity on stemborer management is presented.