An Indirect Defence Trait Mediated through Egg-Induced Maize Volatiles from Neighbouring Plants.

Attack of plants by herbivorous arthropods may result in considerable changes to the plant's chemical phenotype with respect to emission of herbivore-induced plant volatiles (HIPVs). These HIPVs have been shown to act as repellents to the attacking insects as well as attractants for the insects antagonistic to these herbivores. Plants can also respond to HIPV signals from other plants that warn them of impending attack. Recent investigations have shown that certain maize varieties are able to emit volatiles following stemborer egg deposition. These volatiles attract the herbivore's parasitoids and directly deter further oviposition. However, it was not known whether these oviposition-induced maize (Zea mays, L.) volatiles can mediate chemical phenotypic changes in neighbouring unattacked maize plants. Therefore, this study sought to investigate the effect of oviposition-induced maize volatiles on intact neighbouring maize plants in 'Nyamula', a landrace known to respond to oviposition, and a standard commercial hybrid, HB515, that did not. Headspace volatile samples were collected from maize plants exposed to Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) egg deposition and unoviposited neighbouring plants as well as from control plants kept away from the volatile emitting ones. Behavioural bioassays were carried out in a four-arm olfactometer using egg (Trichogramma bournieri Pintureau & Babault (Hymenoptera: Trichogrammatidae)) and larval (Cotesia sesamiae Cameron (Hymenoptera: Braconidae)) parasitoids. Coupled Gas Chromatography-Mass Spectrometry (GC-MS) was used for volatile analysis. For the 'Nyamula' landrace, GC-MS analysis revealed HIPV production not only in the oviposited plants but also in neighbouring plants not exposed to insect eggs. Higher amounts of EAG-active biogenic volatiles such as (E)-4,8-dimethyl-1,3,7-nonatriene were emitted from these plants compared to control plants. Subsequent behavioural assays with female T. bournieri and C. sesamiae parasitic wasps indicated that these parasitoids preferred volatiles from oviposited and neighbouring landrace plants compared to those from the control plants. This effect was absent in the standard commercial hybrid we tested. There was no HIPV induction and no difference in parasitoid attraction in neighbouring and control hybrid maize plants. These results show plant-plant signalling: 'Nyamula' maize plants emitting oviposition-induced volatiles attractive to the herbivore's natural enemies can induce this indirect defence trait in conspecific neighbouring undamaged maize plants. Maize plants growing in a field may thus benefit from this indirect defence through airborne signalling which may enhance the fitness of the volatile-emitting plant by increasing predation pressure on herbivores

A maize landrace that emits defense volatiles in response to herbivore eggs possesses a strongly inducible terpene synthase gene.

Maize (Zea mays) emits volatile terpenes in response to insect feeding and egg deposition to defend itself against harmful pests. However, maize cultivars differ strongly in their ability to produce the defense signal. To further understand the agroecological role and underlying genetic mechanisms for variation in terpene emission among maize cultivars, we studied the production of an important signaling component (E)-caryophyllene in a South American maize landrace Braz1006 possessing stemborer Chilo partellus egg inducible defense trait, in comparison with the European maize line Delprim and North American inbred line B73. The (E)-caryophyllene production level and transcript abundance of TPS23, terpene synthase responsible for (E)-caryophyllene formation, were compared between Braz1006, Delprim, and B73 after mimicked herbivory. Braz1006-TPS23 was heterologously expressed in E. coli, and amino acid sequences were determined. Furthermore, electrophysiological and behavioral responses of a key parasitic wasp Cotesia sesamiae to C. partellus egg-induced Braz1006 volatiles were determined using coupled gas chromatography electroantennography and olfactometer bioassay studies. After elicitor treatment, Braz1006 released eightfold higher (E)-caryophyllene than Delprim, whereas no (E)-caryophyllene was detected in B73. The superior (E)-caryophyllene production by Braz1006 was positively correlated with high transcript levels of TPS23 in the landrace compared to Delprim. TPS23 alleles from Braz1006 showed dissimilarities at different sequence positions with Delprim and B73 and encodes an active enzyme. Cotesia sesamiae was attracted to egg-induced volatiles from Braz1006 and synthetic (E)-caryophyllene. The variation in (E)-caryophyllene emission between Braz1006 and Delprim is positively correlated with induced levels of TPS23 transcripts. The enhanced TPS23 activity and corresponding (E)-caryophyllene production by the maize landrace could be attributed to the differences in amino acid sequence with the other maize lines. This study suggested that the same analogous genes could have contrasting expression patterns in different maize genetic backgrounds. The current findings provide valuable insight not only into genetic mechanisms underlying variation in defense signal production but also the prospect of introgressing the novel defense traits into elite maize varieties for effective and ecologically sound protection of crops against damaging insect pests

Evaluation of African Maize Cultivars for Resistance to Fall Armyworm Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) Larvae

The fall armyworm (FAW) has recently invaded and become an important pest of maize in Africa causing yield losses reaching up to a third of maize annual production. The present study evaluated different aspects of resistance of six maize cultivars, cropped by farmers in Kenya, to FAW larvae feeding under laboratory and field conditions. We assessed the arrestment and feeding of FAW neonate larvae in no-choice and choice experiments, development of larvae-pupae, food assimilation under laboratory conditions and plant damage in a field experiment. We did not find complete resistance to FAW feeding in the evaluated maize cultivars, but we detected differences in acceptance and preference when FAW larvae were given a choice between certain cultivars. Moreover, the smallest pupal weight and the lowest growth index were found on ’SC Duma 43′ leaves, which suggests an effect of antibiosis of this maize hybrid against FAW larvae. In contrast, the highest growth index was recorded on ‘Rachar’ and the greatest pupal weight was found on ‘Nyamula’ and ‘Rachar’. The density of trichomes on the leaves of these maize cultivars seems not to be directly related to the preference of neonates for feeding. Plant damage scores were not statistically different between cultivars in the field neither under natural nor artificial infestation. However, plant damage scores in ‘Nyamula’ and ‘Jowi’ tended to be lower in the two last samplings of the season compared to the two initial samplings under artificial infestation. Our study provides insight into FAW larval preferences and performance on some African maize cultivars, showing that there are differences between cultivars in these variables; but high levels of resistance to larvae feeding were not found

Bioactive Volatiles From Push-Pull Companion Crops Repel Fall Armyworm and Attract Its Parasitoids

Fall armyworm, Spodoptera frugiperda, is a serious invasive pest in Africa but "Push-Pull" companion cropping can substantially reduce infestation. Here, we elucidate the underpinning chemical ecology mechanisms. We hypothesized that companion crop volatiles repel herbivores (push) while attracting natural enemies (pull). Headspace volatiles collected from companion plants (Desmodium intortum, Desmodium uncinatum, Brachiaria Mulato II) were used in bioassays and electrophysiological recordings with S. frugiperda and parasitoid wasps. Insect populations, plant damage and herbivore parasitism were assessed in field plots. Coupled GC-electroantennogram (GC-EAG) recordings showed robust responses to certain aromatic and terpenoid volatile compounds. In wind tunnel bioassays, maize volatiles mixed with Desmodium volatiles were less attractive to moths than maize alone. In oviposition bioassays, S. frugiperda laid significantly fewer eggs on maize when Desmodium volatiles were present. Conversely, in an olfactometer bioassay, parasitoid wasps were attracted to the scent of both Desmodium spp. (intercrop) and the Brachiaria border crop. Our data provide evidence of the mechanisms underpinning reduced S. frugiperda infestation in the Push-Pull companion cropping system, i.e., volatiles from companion crops repel S. frugiperda while attracting its parasitoid natural enemies. These findings explain why Push-Pull field plots had fewer S. frugiperda larvae and lower crop damage than monocropped maize

Orange jasmine as a trap crop to control Diaphorina citri

[EN] Novel, suitable and sustainable alternative control tactics that have the potential to reduce migration of Diaphorina citri into commercial citrus orchards are essential to improve management of huanglongbing (HLB). In this study, the effect of orange jasmine (Murraya paniculata) as a border trap crop on psyllid settlement and dispersal was assessed in citrus orchards. Furthermore, volatile emission profiles and relative attractiveness of both orange jasmine and sweet orange (Citrus¿×¿aurantium L., syn. Citrus sinensis (L.) Osbeck) nursery flushes to D. citri were investigated. In newly established citrus orchards, the trap crop reduced the capture of psyllids in yellow sticky traps and the number of psyllids that settled on citrus trees compared to fallow mowed grass fields by 40% and 83%, respectively. Psyllids were attracted and killed by thiamethoxam-treated orange jasmine suggesting that the trap crop could act as a `sink¿ for D. citri. Additionally, the presence of the trap crop reduced HLB incidence by 43%. Olfactometer experiments showed that orange jasmine plays an attractive role on psyllid behavior and that this attractiveness may be associated with differences in the volatile profiles emitted by orange jasmine in comparison with sweet orange. Results indicated that insecticide-treated M. paniculata may act as a trap crop to attract and kill D. citri before they settled on the edges of citrus orchards, which significantly contributes to the reduction of HLB primary spread.This work was supported by Fund for Citrus Protection (Fundecitrus) and by Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) (Proc. 2015/07011-3). We thank Moacir Celio Vizone, Felipe Marinho Martini and Joao Pedro Ancoma Lopes for technical support with experiments. Furthermore, we thank Cambuhy Agricola Ltda. and University of Araraquara (Uniara) for providing the areas in which the field experiments were performed. Second author received scholarship from National Council for Scientific and Technological Development (CNPq)/Brazil (Proc. 300153/2011-2).Tomaseto, AF.; Marques, RN.; Fereres, A.; Zanardi, OZ.; Volpe, HXL.; Alquézar-García, B.; Peña, L.... (2019). Orange jasmine as a trap crop to control Diaphorina citri. Scientific Reports. 9:1-11. https://doi.org/10.1038/s41598-019-38597-5S1119Bové, J. M. Huanglongbing: a destructive, newly-emerging, century-old disease of citrus. J Plant Pathol. 88, 7–37 (2006).Alvarez, S., Rohrig, E., Solís, D. & Thomas, M. H. Citrus greening disease (Huanglongbing) in Florida: economic impact, management and the potential for biological control. Agric. Res. 5, 109–118 (2016).Belasque, J. Jr. et al. Lessons from huanglongbing management in São Paulo state, Brazil. J. Plant Pathol. 92, 285–302 (2010).Boina, D. R., Meyer, W. L., Onagbola, E. O. & Stelinski, L. L. Quantifying dispersal of Diaphorina citri (Hemiptera: Psyllidae) by immunomarking and potential impact of unmanaged groves on commercial citrus management. Environ. Entomol. 38, 1250–8 (2009).Lewis-Rosenblum, H., Martini, X., Tiwari, S. & Stelinski, L. L. Seasonal movement patterns and long-range dispersal of Asian citrus psyllid in Florida citrus. J. Econ. Entomol. 108, 3–10 (2015).Hall, D. G. & Hentz, M. G. Seasonal flight activity by the Asian citrus psyllid in east central Florida. Entomol. Exp. Appl. 139, 75–85 (2011).Tomaseto, A. F., Krugner, R. & Lopes, J. R. S. Effect of plant barriers and citrus leaf age on dispersal of Diaphorina citri (Hemiptera: Liviidae). J. Appl. Entomol. 140, 91–102 (2016).Gottwald, T. R. Current epidemiological understanding of citrus huanglongbing. Annu. Rev. Phytopathol. 48, 119–139 (2010).Bassanezi, R. B. et al. Efficacy of area-wide inoculum reduction and vector control on temporal progress of huanglongbing in young sweet orange plantings. Plant Dis. 97, 789–796 (2013).Sétamou, M. & Bartels, D. W. Living on the edges: spatial niche occupation of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), in citrus groves. PLoS One 10, 1–21 (2015).Gottwald, T., Irey, M., Gast, T. & Parnell, S. Spatio-temporal analysis of an HLB epidemic in Florida and implications for spread. In Proceedings of the 17 th Conference of International Organization of Citrus Virologists, IOCV, University of California, Riverside, CA, 84–97 (2010).Shelton, A. M. & Badenes-Perez, F. R. Concepts and applications of trap cropping in pest management. Annu. Rev. Entomol 51, 285–308 (2006).Hokkanen, H. M. T. Trap cropping in pest management. Annu. Rev. Entomol. 36, 119–138 (1991).Stern, V. M., Mueller, A., Sevacherian, V. & Way, M. Lygus bug control in cotton through alfalfa interplanting. Calif. Agric. 8–10 (1969).Godfrey, L. D. & Leigh, T. F. Alfalfa harvest strategy effect on lygus bug (Hemiptera: Miridae) and insect predator population density: Implications for use as trap crop in cotton. Environ. Entomol. 23, 1106–1118 (1994).Gonsalves, D. & Ferreira, S. Transgenic papaya: a case for managing risks of Papaya ringspot virus in Hawaii. Plant Heal. Prog. 1–6, https://doi.org/10.1094/PHP-2003-1113-03-RV (2003)Aubert, B. Trioza erytheae del Guercio and Diaphorina citri Kuwayama (Homoptera: Psylloidea), the two vectors of citrus greening disease: biological aspects and possible control strategies. Fruits 42, 149–162 (1987).Leong, S. C. T., Fatimah, A., Beattie, A., Heng, R. K. J. & King, W. S. Influence of host plant species and flush growth stage on the Asian citrus psyllid, Diaphorina citri Kuwayama. Am. J. Agric. Biol. Sci. 6, 536–543 (2011).Patt, J. M. & Sétamou, M. Responses of the Asian citrus psyllid to volatiles emitted by the flushing shoots of its rutaceous host plants. Environ. Entomol. 39, 618–24 (2010).Damsteegt, V. D. et al. Murraya paniculata and related species as potential hosts and inoculum reservoirs of ‘Candidatus Liberibacter asiaticus’, causal agent of huanglongbing. Plant Dis. 94, 528–533 (2010).Lopes, S. A. et al. Liberibacters associated with orange jasmine in Brazil: Incidence in urban areas and relatedness to citrus liberibacters. Plant Pathol. 59, 1044–1053 (2010).Cifuentes-Arenas, J. C. Huanglongbing e Diaphorina citri: Estudos das relações patógeno-vetor-hospedeiro. Ph.D. Thesis. Faculdade de Ciências Agrárias e Veterinárias/Universidade Estadual Paulista (UNESP), Jaboticabal, SP, Brazil. 1–133 (2017).Morilla, G. et al. Pepper (Capsicum annuum) is a dead-end host for Tomato yellow leaf curl virus. Phytopathology 95, 1089–1097 (2005).Midega, C. A. O., Pittchar, J. O., Pickett, J. A., Hailu, G. W. & Khan, Z. R. A climate-adapted push-pull system effectively controls fall armyworm, Spodoptera frugiperda (J. E. Smith), in maize in East Africa. Crop Prot. 105, 10–15 (2018).Miranda, M. P. et al. Processed kaolin affects the probing and settling behavior of Diaphorina citri (Hemiptera: Liviidae). Pest Manag. Sci. 74, 1964–1972 (2018).Kobori, Y., Nakata, T., Ohto, Y. & Takasu, F. Dispersal of adult Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae), the vector of citrus greening disease, in artificial release experiments. Appl. Entomol. Zool. 46, 27–30 (2011).Sétamou, M. et al. Diurnal patterns of flight activity and effects of light on host finding behavior of the Asian citrus psyllid. J. Insect Behav. 25, 264–276 (2012).Wenninger, E. J., Stelinski, L. L. & Hall, D. G. Roles of olfactory cues, visual cues, and mating status in orientation of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) to four different host plants. Environ. Entomol. 38, 225–234 (2009).Miranda, M. P., Dos Santos, F. L., Felippe, M. R., Moreno, A. & Fereres, A. Effect of UV-blocking plastic films on take-off and host plant finding ability of Diaphorina citri (Hemiptera: Liviidae). J. Econ. Entomol. 108, 245–251 (2015).Visser, J. H. Host odor perception in phytophagous insects. Annu. Rev. Entomol. 31, 121–144 (1986).Robbins, P. S., Alessandro, R. T., Stelinski, L. L. & Lapointe, S. L. Volatile profiles of young leaves of Rutaceae spp. varying in susceptibility to the Asian citrus psyllid (Hemiptera: Psyllidae). Florida Entomol. 95, 774–776 (2012).Fancelli, M. et al. Attractiveness of host plant volatile extracts to the Asian citrus psyllid, Diaphorina citri, is reduced by terpenoids from the non-host cashew. J. Chem. Ecol. 44, 397–405 (2018).Alquézar, B. et al. β-caryophyllene emitted from a transgenic Arabidopsis or chemical dispenser repels Diaphorina citri, vector of Candidatus Liberibacters. Sci. Rep. 7, 5639 (2017).Jones, R. A. C. Effects of cereal borders, admixture with cereals and plant density on the spread of bean yellow mosaic potyvirus into narrow‐leafed lupins (Lupinus angustifolius). Ann. Appl. Biol. 122, 501–518 (1993).Beloti, V. H., Alves, G. R., Coletta-Filho, H. D. & Yamamoto, P. T. The Asian citrus psyllid host Murraya koenigii is immune to citrus huanglongbing pathogen ‘Candidatus Liberibacter asiaticus’. Phytopathology 108, 1089–1094 (2018).Walter, A. J., Duan, Y. & Hall, D. G. Titers of ‘Ca. Liberibacter asiaticus’ in Murraya paniculata and Murraya-reared Diaphorina citri are much lower than in Citrus and Citrus-reared psyllids. HortScience 47, 1449–1452 (2012).Walter, A. J., Hall, D. G. & Duan, Y. P. Low incidence of ‘Candidatus Liberibacter asiaticus’ in Murraya paniculata and associated Diaphorina citri. Plant Dis. 96, 827–832 (2012).Ammar, E.-D. D., Ramos, J. E., Hall, D. G., Dawson, W. O. & Shatters, R. G. Acquisition, replication and inoculation of Candidatus Liberibacter asiaticus following various acquisition periods on huanglongbing-infected citrus by nymphs and adults of the Asian citrus psyllid. PLoS One 11, e0159594 (2016).Inoue, H. et al. Enhanced proliferation and efficient transmission of Candidatus Liberibacter asiaticus by adult Diaphorina citri after acquisition feeding in the nymphal stage. Ann. Appl. Biol. 155, 29–36 (2009).Pelz-Stelinski, K. S., Brlansky, R. H., Ebert, T. A. & Rogers, M. E. Transmission parameters for Candidatus Liberibacter asiaticus by Asian citrus psyllid (Hemiptera: Psyllidae). J. Econ. Entomol. 103, 1531–1541 (2010).Canale, M. C. et al. Latency and persistence of ‘Candidatus Liberibacter asiaticus’ in its psyllid vector, Diaphorina citri (Hemiptera: Liviidae). Phytopathology 107, 264–272 (2017).Li, W., Hartung, J. S. & Levy, L. Quantitative real-time PCR for detection and identification of Candidatus Liberibacter species associated with citrus huanglongbing. J. Microbiol. Methods 66, 104–115 (2006).Nakata, T. Effectiveness of micronized fluorescent powder for marking citrus psyllid. Diaphorina citri. Appl. Entomol. Zool. 43, 33–36 (2008).Tomaseto, A. F. et al. Environmental conditions for Diaphorina citri Kuwayama (Hemiptera: Liviidae) take-off. J. Appl. Entomol. 142, 104–113 (2018).Paris, T. M., Croxton, S. D., Stansly, P. A. & Allan, S. A. Temporal response and attraction of Diaphorina citri to visual stimuli. Entomol. Exp. Appl. 155, 137–147 (2015).Zanardi, O. Z. et al. Putative sex pheromone of the Asian citrus psyllid, Diaphorina citri, breaks down into an attractant. Sci. Rep. 8, 455 (2018).Metsalu, T. & Vilo, J. ClustVis: A web tool for visualizing clustering of multivariate data using Principal Component Analysis and heatmap. Nucleic Acids Res. 43, W566–W570 (2015).Fournier, D. A. et al. AD Model Builder: using automatic differentiation for statistical inference of highly parameterized complex nonlinear models. Optim. Methods Softw. 27, 233–249 (2012).Bates, D., Mächler, M., Bolker, B. & Walker, S. Fitting linear mixed-effects models using lme4. J. Stat. Softw. 67, 1–48 (2015).Nelder, J. A. & Wedderburn, R. W. M. Generalized linear models. J. R. Stat. Soc. 135, 370–384 (1972).Demétrio, C. G. B., Hinde, J. & Moral, R. A. In Ecological Modelling Applied to Entomology (eds Ferreira, C. P. & Godoy, W. A. C.) 219–259 (Springer, 2014).Lenth, R. V. Least-Squares Means: the R package lsmeans. J. Stat. Softw. 69, (2016).R Core Team R: A language and environment for statistical computing. 2015. R Foundation for Statistical Computing, Vienna, Austria (2015). Available at, http://www.r-project.org/ . (Accessed: 20th July 2017)

Biodiversity and structure of spider communities along a metal pollution gradient

The objective of the study was to determine whether long-term metal pollution affects communities of epigeal spiders (Aranea), studied at three taxonomic levels: species, genera, and families. Biodiversity was defined by three indices: the Hierarchical Richness Index (HRI), Margalef index (DM) and Pielou evenness index (J). In different ways the indices describe taxa richness and the distribution of individuals among taxa. The dominance pattern of the communities was described with four measures: number of dominant species at a site, percentage of dominant species at a site, average dominant species abundance at a site, and the share of the most numerous species (Alopecosa cuneata) at a site. Spiders were collected along a metal pollution gradient in southern Poland, extending ca. 33 km from zinc and lead smelter to an uncontaminated area. The zinc concentration in soil was used as the pollution index.The study revealed a significant effect of metal pollution on spider biodiversity as described by HRI for species (p = 0.039), genera (p = 0.0041) and families (p = 0.0147), and by DM for genera (p = 0.0259) and families (p = 0.0028). HRI correlated negatively with pollution level, while DM correlated positively. This means that although broadly described HRI diversity decreased with increasing pollution level, species richness increased with increasing contamination. Mesophilic meadows were generally richer. Pielou (J) did not show any significant correlations. There were a few evidences for the intermediate disturbance hypothesis: certain indices reached their highest values at moderate pollution levels rather than at the cleanest or most polluted sites

Fall Armyworm (Spodoptera frugiperda)

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), originated from America but is reported recently from Africa and the Asia-Pacific. FAW has caused huge international concern since its outbreak in Africa since 2016 and in Asia since mid-2018. The chapter mainly reviews its global distribution, life cycle, identification characters, strains, host plants, nature of damage, economic damage, and integrated pest management strategies available. The pest completes its life cycle on maize in 30 days (in warm summer months); in cooler temperatures, it may extend up to 60–90 days. For effective management of fall armyworm, different tools, viz., cultural control, agronomic management, breeding for resistance, natural enemies, and eco-friendly insecticides, should be used in an integrated approach. As the insect is recently introduced to Africa and the Asia-Pacific, possible management strategies and future cases of action are discussed

Exploiting chemical ecology for developing novel integrated pest management strategies for Africa

Push-pull, a novel approach for integrated management of insect pests, weed and soil fertility, was developed through the exploitation of chemical ecology and agro-biodiversity to address agricultural constraints facing millions of resource-poor African farmers. The technology was developed by selecting appropriate plants that naturally emit signalling chemicals (semiochemicals) and influence plant-plant and insect-plant interactions. Plants highly attractive for egg laying by lepidopteran cereal stemborer pests were selected and employed as trap crops, to draw pests away from the main cereal crops. Among these, Pennisetum purpureum produced significantly higher levels of volatile cues (stimuli), used by gravid stem borer females to locate host plants, than maize (Zea mays) or sorghum (Sorghum bicolor). Despite its attractiveness to stemborer moths, P. purpureum supported minimal survival of the pests’ immature stages. Plants that repelled stem borer moths, notably Melinis minutiflora and forage legumes in the genus Desmodium, were selected as intercrops, which also attracted natural enemies of the pests through emission of (E)-β-ocimene and (E)-4,8-dimethyl-1,3,7-nonatriene. Desmodium intercrop suppressed parasitic weed, Striga hermonthica, through an allelopathic mechanism. Their root exudates contain novel flavonoid compounds which stimulate suicidal germination of S. hermonthica seeds and dramatically inhibit its attachment to the host roots. We identified and selected new drought- and temperature-tolerant trap [Brachiaria ( B. brizantha × B. ruziziensis ) cv. mulato] and intercrop plants (Desmodium, e.g. D. intortum) suitable for drier agroecologies. The new trap and intercrop plants also have appropriate chemistry in controlling stemborers, a new invasive pest, fall armyworms and parasitic striga weeds. Opportunities for semiochemical delivery by companion plants, including plant-plant signalling and early herbivory alert, are explored for developing future smart integrated pest management (IPM) strategies