Suitability of brachiaria grass as a trap crop for management ofChilo partellus

Abstract

The cereal stemborer Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) is a major insect pest of sorghum (Sorghum bicolor L. Moench) and maize (Zea mays L.) in Africa. Trap cropping systems have been shown to be a valuable tool in management of this pest. To optimize trap cropping strategies, an understanding of host‐plant preference for moth oviposition and host suitability for larval survival on potential trap plants is a prerequisite. Therefore, we assessed seven brachiaria accessions (Poaceae) for preference by C. partellus moths and subsequent larval performance. In two‐choice tests with a local open‐pollinated maize variety (cv. Nyamula), significantly higher numbers of eggs were deposited on brachiaria accessions Marandu, Piata, and Xaraes than on maize, whereas fewer eggs were recorded on plants of Mulato II, Mulato I, and Cayman. There was a significant and negative correlation between the trichome density on plant leaves and C. partellus oviposition preference for brachiaria. In addition to poor larval performance on brachiaria, there was no clear ranking in the accessions regarding larval orientation, settling, arrest, and food ingestion and assimilation. First instars did not consume leaf tissues of brachiaria plants but consumed those of maize, which also suffered more stem damage than brachiaria plants. No larvae survived on brachiaria plant tissue for longer than 5 days, whereas 79.2% of the larvae survived on maize. This study highlights the preferential oviposition of C. partellus on brachiaria plants over maize and the negative effects that these accessions have on subsequent larval survival and development. Our findings support the use of brachiaria as a trap crop for management of C. partellus through a push‐pull technology.

Plant Selection for the Establishment of Push–Pull Strategies for Zea mays–Spodoptera frugiperda Pathosystem in Morelos, Mexico

“…Mulato II and B. brizantha ( Table S2 ). The values found for these species are lower than those reported by Cheruiyot et al [ 61 ]. Except for Mombasa, the trichome density decreased from the leaf base to the leaf apex, as reported by Rendón-Carmona et al [ 38 ].…”

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

“…Samples were obtained from the intermediate position between leaf margin and midrib of the leaf lamina and halfway between proximal end and base of the leaf, from the leaves 6 and 7 of three weeks old plants. Trichomes were counted with a stereo microscope (Stemi 508 Carl Zeiss; Jena, Germany) with a magnification of 25×, moistening slightly the leaf cut [ 49 ].…”

Responses of stemborer Chilo partellus to volatiles emitted by maize landraces exposed to signal grass (Brachiaria brizantha)

“…Plant to plant communication is known to be a mechanism of pest control through herbivore-induced plant volatiles (HIPVs) (Khan et al 2001;Cook et al 2007;Heil 2008;Tamiru et al 2012;Magara et al 2015;Mutyambai et al 2016). Studies have shown that B. brizantha is preferred to maize for oviposition by gravid C. partellus (Midega et al 2011;Cheruiyot et al 2018). This is as a result of B. Brizantha leaves emitting more green-leaf volatiles signals ((Z)-3-hexenyl acetate) which are the responsible cues for attracting gravid females of C. partellus to the grass to deposit eggs compared to maize (Bruce et al 2010;Magara et al 2015;Tolosa et al 2019).…”