Incidence and relative abundance of rice stem borers in three selected rice fields in Lagos and Ogun States, Nigeria

Abstract

This study was conducted to investigate the incidence of rice stem borer infestations and the species composition present in the selected rice fields. Data were collected between April 2017 and November 2018 across three locations, which include the upland rice field in Agbajege, Ogun state, rainfed lowland in Itoikin and Mangrove swamp in Igbogun, Lagos state, respectively. The incidence of rice stem borers was indicated by dead heart and white heads symptoms, while tillers were excised for rice stem borer identification and population. Results showed a high and low incidence of rice stem borers with no significant difference(p>0.05) at p= 0.29 and 0.37 between the early and late planting seasons in the rainfed lowland and upland rice fields respectively. Planting seasons were significant in the incidence of rice stem borers in mangrove swamp rice fields at p<0.05, p=0.01). This study showed that the predominant species of rice stem borers present in the three study sites were Chilo zacconius and Sesamia calamistis. C. zacconius was the most abundant species at 89% while S. calamistis was 11%. Rice stem borer populations were significantly higher at (p<0.05, p=0.000) in flooded zones while the highest rice stem borer populations were observed at the reproductive phase of the rice plants. Thisstudy showed that the planting seasons coincided with the peak period of the development of rice stem borers. Hence, conservation of natural enemies, monitoring and surveillance should be adopted in insect pest management in rice agroecosystems

The Structure of Rice Stemborer Assemblages: A Review of Species’ Distributions, Host Ranges, and Interspecific Interactions

“…Early instars feed on leaf sheaths before entering the stem; late instars located in upper internodes [38] Chilo zacconius Bleszynski Primary species [49] Mainly affects mid-to late tillering plants, some resistance as plants age [50] Table 1. Cont.…”

“…Sesamia calamistis (Hampson) Secondary species [49,51] Occurs at the onset of flowering towards harvest [47] Sesamia nonagrioides (Lefèbvre) Primary species in southern Europe [52]; maize is the main crop host…”

“…Elasmopalpus lignosellus (Zeller) Primary species in upland rice [93] Eggs are deposited below the soil surface, larvae bore into the stem and tunnel upwards [93,94]; can attack and kill seedlings before tillering [93] 1 : Status in rice is based on reports of prominence; for details on occasional species see Table S1 and associated references [9,10,22,23,30,[33][34][35]40,41,[45][46][47]49,51,52,[57][58][59]61,69,70,72,77,78,82,83,; for information on occurrence in other crops see Table S2. 2 : Sesamia nonagrioides botanephaga Tams and Bowden is considered a subspecies.…”

Life Cycle of Chilo zacconius Blensynski (Lepidoptera: Crambidae) on Artificial Diet in The Laboratory

“…The disruption of nutrient supply within the tillers as a result of the feeding activities by C. zacconius may occur at any stage in the reproductive cycle, including heading/panicle initiation, leading to abortion of emerging panicles or during grain filling, impeding the milk filling in seeds (Dale, 1994;Ogah and Nwilene, 2017). The damage by C. zacconius at the reproductive phase is completely irreversible and cannot be compensated for by the rice plants, this impacts the paddy yield negatively during harvest (Adewoye et al, 2021). Unfortunately, there are no physical early warning signs for prompt control as symptoms are seen when the damage has been done.…”