Methyl Jasmonate Affects Population Densities of Phytophagous and Entomophagous Insects in Wheat

Abstract

Abstract. Methyl jasmonate (MEJA), a well-known herbivore-induced plant volatile, promotes plant defences against various stress factors. The aim of this study was to investigate the effects of different doses of exogenously applied MEJA on the population densities of wheat insect pests and their natural enemies by employing three sampling methods (direct visual sampling, sweep net, sticky traps) in 2012 and 2013 under semi-arid conditions. MEJA treatments had repellent effects on aphids (Hemiptera: Aphididae), phytophagous thrips species (Thysanoptera: Phlaeothripidae and Thripidae) and hoverfly species (Diptera: Syrphidae), whereas it was attractive to wheat stem sawflies (Hymenoptera: Cephidae), lady beetle species (Coleoptera: Coccinellidae) and Collyria coxator (Hymenoptera: Ichneumonidae). MEJA treatments had no effect on aphid parasitoids abundances (Hymenoptera: Braconidae). The experimental outcomes varied, depending on plant phenology and sampling method. MEJA treatment also led to reductions in wheat yield and plant height. MEJA treatment could be beneficial as a natural pest control tool when certain species are targeted.

Methyl Jasmonate – A Multifunctional Molecule Throughout the Whole Plant Life

“…MJ can induce expression of wound-inducible proteinase inhibitors (PIs), which could be useful in induced defense against insects [Howe 2004]. Overall, the results of MJ achieved on insects may vary depend-ing mainly on plant phenology and sampling method, but generally, MJ treatment contributes to plant defense by attracting natural enemies of pests being the natural pest control method for the precisely characterized goal [Bayram and Tonğa 2018].…”

“…MJ had repellent effects on leaf folders [Senthil-Nathan 2019], aphids, phytophagous thrips species and hoverfly species, the phloem feeder, the potato aphid Macrosiphum euphorbiae [Brunissen et al 2010], the soybean aphid Aphis glycines and the soybean thrips Neohydatothrips variabilis [Selig et al 2016]. What is important, with reduced number of the stink bug, Oebalus pugnax, also grains per panicle in rice elevated under MJ (2 and 5 mM) treatment [Stella de Freitas et al 2019], but MJ application also led to reductions in Triticum aestivum yield and plant height [Bayram and Tonğa 2018]. Simultaneously, MJ was attractive to wheat stem sawflies, lady beetle species [Bayram and Tonğa 2018], small-flower bug Orius spp.…”

“…What is important, with reduced number of the stink bug, Oebalus pugnax, also grains per panicle in rice elevated under MJ (2 and 5 mM) treatment [Stella de Freitas et al 2019], but MJ application also led to reductions in Triticum aestivum yield and plant height [Bayram and Tonğa 2018]. Simultaneously, MJ was attractive to wheat stem sawflies, lady beetle species [Bayram and Tonğa 2018], small-flower bug Orius spp. in cotton fields [Yu et al 2018], and lady beetle Chilocorus kuwanae on Diospyros kaki plants [Zhang et al 2009].…”

JA-Ile-Macrolactone 5b Induces Tea Plant (Camellia sinensis) Resistance to Both Herbivore Ectropis obliqua and Pathogen Colletotrichum camelliae

“…Numerous chemical elicitors have been found to trigger direct or indirect plant-induced defense responses against herbivores in the laboratory, such as methyl jasmonate (MeJA), coronalon, laminarin, and so on [12][13][14][15]. Moreover, 2, 4-dichlorophenoxyacetic acid [16], JA, and cis-jasmone [17] have been verified to elevate the plant defense capability against herbivores in the field, which is an attractive prospect for pest controlling [18,19]. Unfortunately, no any chemical elicitor has been used commercially in pest control until now.…”

Cotton treatment with methyl jasmonate at different growth stages reduces the population of sucking insect pests and marginally increases their associated predators

“…Plants, upon herbivore attack, release herbivore-induced plant volatiles (HIPVs), which play two main roles in plant defense: (1) repelling conspecifics of the herbivores, and (2) attracting their natural enemies (Dicke & van Loon, 2000). Such defense mechanisms can be triggered by exogenous treatments of synthetic elicitors such as methyl jasmonate (MEJA) (Williams et al, 2017;Bayram & Tonğa, 2018a). Compared with other jasmonate derivatives, MEJA is more active and volatile, especially when used exogenously (Beltrano et al, 1998;Horbowicz et al, 2009).…”