Wireworms (Coleoptera: Elateridae), the larval stage of several economic click beetle species, have become major cereal crop pests in key agricultural regions of Canada and the United States. In recent trials following minimum tillage practices (Alberta), we determined that isocycloseram, the initial isoxazoline agricultural seed treatment developed, provided exceptional control of cereal crop damage, and significantly reduced neonate and resident wireworm populations of the sugarbeet wireworm, Limonius californicus (Mannerheim). Herein we evaluated isocycloseram in cultivated wheat plots (British Columbia) for control of the dusky wireworm, Agriotes obscurus L., and collectively these studies determined that isocycloseram applied at 5.0 to 7.5 g AI/100 kg seed protected crop stand and yield from these species equal to all currently registered wireworm seed-treatment insecticides (ie, neonicotinoids, diamides, and meta-diamides), and significantly reduced resident and neonate wireworms equal to levels expected from the former industry standard lindane. Abiotic and biotic conditions negatively influencing insecticide performance and ways to mitigate them were also identified. These conditions include soil fertility, moisture, and compaction, and planting after most wireworm feeding in the spring has occurred.

Fall armyworm (Spodoptera frugiperda (J.E. Smith)) (FAW) impacts maize (Zea mays L.) production. No maize genotype is completely resistant to FAW. This experiment was conducted in Calabar, Cross River State, with twenty maize genotypes using a randomized complete block design with three replications. These maize genotypes varied in responses to FAW scores, plant height, leaf count, plant standability and performance, days to 50% anthesis and silking, anthesis-silking interval, fresh and de-husked cob weight and length, husk proportion, ear rating, grains per cob, 100-seed weight, and grain yield. FAW score perfectly correlated with plant and ear ratings. Grain yield is strongly associated with cobs per plant and grains per cob. The study of this genetic variability showed that while seedling emergence, days to 50% anthesis, and 50% silking showed moderate genetic gain, all other traits showed high genetic gain. This suggests that under FAW pressure, it might be possible to choose maize genotypes that have these traits. FAW score, plant standability and performance, and ear rating were all found to be in the same cluster in the principal component and genotype-by-traits biplot analyses. This proved that they were useful for the identification of maize genotypes that are tolerant to FAW pressure. In one cluster were cobs per plant, husk covering, cob length, and grains per cob with grain yield. This further confirmed the importance of these traits in selecting maize genotypes with high yield potential under FAW pressure. Despite FAW pressure, maize genotypes AS2001-20, AS2001-24, M1628-8, AS2106-63, and FAW 2212 demonstrated high grain yields considerable for inclusion in further FAW-related studies.

In production of cereals like maize ( Zea mays L.) and barley ( Hordeum vulgare L.), seeds are often treated with pesticides and/or commercial products of plant beneficial microorganisms (PBM) to reduce possible root damage from insect pests and soil borne root diseases. In a field experiment with maize and barley under conservation agriculture, we examined how such seed treatments affected the resident root and soil microbiota. The seed treatments included a pesticide mixture and different commercial products of common PBM based on the biocontrol agents (BCA) Trichoderma harzianum and Metarhizium anisopliae alone and in combination and a mix of plant growth promoting rhizobacteria (PGPR), which were compared to a negative control without seed treatment. Soil and root samples were taken at two and three sampling times during the crop cycles for barley and maize, respectively, to measure root biomass, root colonization with mycorrhizal fungi and pathogens, soil microbial communities at a general taxonomic level using biomarker fatty acids, and ecological guilds of soil nematodes. Root health was monitored with observations of the presence of insect feeding larvae and root disease symptoms, which in general showed healthy roots during the full crop cycle. Overall, most of the root and soil biota variables measured changed during the crop cycle. However, for both crops, the seed treatments had no effects on the soil and root microbiota measured, except in the case of barley root infection with Polymyxa sp., which was reduced by all treatments. In conclusion, the pesticide and PBM seed treatments evaluated in the present study for maize and barley under conservation agriculture, in general, had limited effects on the resident root and soil microbiota. However, future studies should include complementary high-resolution sequencing methods when examining non-target effects of pesticides and microbial inoculants on the root and soil microbiota.

Most crop species are cultivated in nutrient-deficient soils, in combination with other challenging constraints that are exacerbated by the current climate changes. The significance of micronutrient shortage in stress management is often underappreciated, although their deficiency restricts both plant growth and resistance to abiotic stresses and diseases. While the application of nutrients to growing plants is a potential strategy to improve plant resistance to abiotic stresses, seed nutrient status may also play a role in crop stress tolerance as a storage and accumulation site of nutrients. To avoid hidden hunger problems, developing countries need to increase domestic cereal production, enhance their resilience to extreme weather events, and improve their nutritional status and quality. Here, we analyze the accumulated knowledge about the effects of nutri-priming in cereal crop species with a focus on mechanisms of application and stress tolerance, keeping in mind the risk of crop damage mostly caused by global climate change, which is driving an alarming increase in the frequency and intensity of abiotic stresses. We also propose new approaches to food production, which may be promising solutions for global warming, emerging diseases, and geopolitical conflicts recognized as major drivers of food insecurity.