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

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

Screening for Sarawak Paddy Landraces with Resistance to Yellow Rice Stem Borer, Scirpophaga incertulas (Walker) (Lepidoptera: Crambidae)

The yellow rice stem borer, Scirpophaga incertulas (Walker) is a prevalent pest in paddy fields worldwide. In Sarawak, a survey on pest of paddy carried out from 2009 to 2011 covering 166 paddy fields revealed that rice stem borers caused 11.4% of total paddy damage. In order to reduce the damage, identifying resistance paddy variety is crucial. The objective of this study was to screen Sarawak paddy landraces with resistance to S. incertulas. Twelve Sarawak paddy landraces were selected randomly for this study. Antixenosis resistance screening was performed in aquariums (60 x 28 x 33 cm). Three replications of one-month-old seedlings were randomly arranged in aquarium and exposed to adult S. incertulas. The number and position of egg mass on each plant were recorded. Egg mass abnormalities were also observed. For antibiosis, rice culms of two-month old seedlings from each landrace were infested with larvae. The length of surviving larvae from five rice culms was measured. The experiment revealed variations in landrace of preference for ovipositing. Among the twelve Sarawak paddy landraces, Kanowit was more preferred by S. incertulas for ovipositing in comparison to other paddy landraces suggesting susceptibility towards the pest. Abaxial leaf surface was the preferred oviposition site. There was no clear antibiosis response of the paddy landraces towards S. incertulas larvae in this study.

Biochemical Analysis for Rice Germplasm Lines for Combat against Yellow Stem Borer, Scirpophaga incertulas: Implication for Varietal Selection of Rice in India

Seven germplasm lines (IC No. 381538, 450535, 463380, 464140, 464186, 574807 and 578388) were categorised as best entries with resistance/ moderately resistant reaction at both vegetative (dead hearts) and reproductive (white ears) stages of the rice crop through field screening trials for two successive seasons i.e., kharif, 2016 and kharif, 2017. Complex factors like behavioural, metabolic processes of the insects and biochemical constituents of the host plants are involved in resistance to rice stem borers. Exploiting the mechanism of induced resistance in rice through abiotic elicitors is the need of the hour. Keeping in view the damage of yellow stem borer and its influence on rice yield the promising seven entries were selected for biochemical analysis. The analysis revealed that entries with low sugars and low free amino acids and high total phenols, proteins, proline and silica content may confer resistance to rice yellow stem borer and can be subjugated in the breeding programme to develop resistant varieties.

Study of Paddy Stem Borers Population Dynamics and Influencing Environmental Factors through Light Trap

Rice crop is affected by many insect pests like White Stem Borer, Yellow Stem Borer and Pink Stem Borer. Rice stem borers are main pests affecting rice crop from nursery to physiological maturity including them in key pests. These studies had been carried out to discover the encouraging and antagonistic boundaries of weather parameters for the rice stem borers. As per result of studies, the population was recorded higher from mid-March to 1st week of May and then it escalated again from 2nd week of August to a maximum in September in case of Yellow Stem Borer (Scirpophaga incertulus) and White Stem Borer (Scirpophaga innotata) of rice during the both years 2017-2018; while in case of Pink Stem Borer population recorded from mid-September to the last week of April in 2017 and lasted till 4th week of May 2018. On evaluating the weather conditions specially temperature and relative humidity, it was detected that insect trap catches noted inside a certain range of temperature that varies from 18-35°C in case of White Stem Borer and 17-34°C for Yellow stem borer of rice. Extreme catches were documented in April and September inside a temperature range of 26-32°C considering it ideal series of temperature for insect light trap catches and activity of yellow and white stem borer. However, in case of pink stem borer above 32°C no catch was observed.

Farmers’ Perceptions of Rice Production Constraints and Stem Borers Management Practices in Tanzania

Rice farmers in Tanzania continue to experience losses due to stem borers. However, the information on farmers’ knowledge and perceptions of rice stem borers is limited and farmers’ efforts on managing this insect have been ineffective. The aim of this study was to investigate constraints affecting rice production and farmers’ approaches of stem borer management in irrigated low land rice ecosystems in Tanzania. Research method: A focus group discussion with farmers using a semi-structured questionnaire was used for data collection. The information collected included: farmers’ socio-economic profiles, farm characteristics, knowledge and perceptions of stem borers and their management practices.Farmers reported insect pests such as stem borers, white flies, leaf rollers and grasshoppers as major constraints of rice production. Other constraints reported were such as diseases, damage by birds, drought, weeds and lack of access to credit for purchasing inputs. Most of the farmers apply chemical insecticides against rice insect pests particularly stem-borers where number of health hazards have been reported. Very few farmers use cultural methods including crop residue disposal and split application of nitrogenous fertilizers for reduction of stem borer damages. The study revealed that, most farmers have limited knowledge on the recommended stem borer management practices and suggests that environmentally friendly pest management methods to be designed and implemented to minimize losses associated with rice stem borers.

BUDIDAYA PADI DI LAHAN RAWA PASANG SURUT DAN PENGARUHNYA TERHADAP PENGGEREK BATANG PADI

<p>Rice cultivation in tidal swampland of South Kalimantan has been practiced by farmers in the long period and influences the population of rice stem borer. This paper describes rice cultivation in tidal swampland of South Kalimantan and its impact on injury level caused by rice stem borer. Land preparation by slashing and spinning the rest of rice crop and then left it to rot, can thwart rice stem borer larvae to become imago (adult). Seeding by transplanting several times can kill stem borer larvae, while cutting the leaves of rice seedlings before planting can reduce egg population of the pest. Rice husk ash application is also able to reduce plant damage caused by stem borer. Another factor that contributes to the decreasing level of plant damage due to the pest is the presence of “purun tikus” (Eleocharis dulcis) weeds. Rice stem borers are more interested in laying eggs in the weed than that in rice plant resulted in low damage of rice planted adjacent to “purun tikus” area. Abundant population of natural enemy in “purun tikus” area also effectively suppresses the development of rice stem borer.</p><p>Keywords: Rice, cultivation, rice stem borer, tidal swampland</p><p align="center"><strong><br /></strong></p><p align="center"><strong>ABSTRAK</strong></p><p>Budi daya padi di lahan pasang surut Kalimantan Selatan sudah sejak lama dilakukan petani dan berpengaruh terhadap penurunan populasi dan tingkat serangan hama penggerek batang padi. Makalah ini menguraikan budi daya padi di lahan rawa pasang surut Kalimantan Selatan dan pengaruhnya terhadap tingkat kerusakan tanaman akibat penggerek batang padi. Penyiapan lahan dengan menebas sisa tanaman padi dan memintalnya kemudian membiarkannya membusuk dapat menggagalkan larva penggerek batang padi menjadi imago (dewasa). Pembibitan dengan cara tanam pindah yang dilakukan beberapa kali juga dapat mematikan larva penggerek batang padi. Sementara pemotongan daun bibit padi sebelum ditanam dapat mengurangi populasi kelompok telur hama tersebut. Pemberian abu sekam juga dapat menurunkan kerusakan tanaman akibat serangan hama tersebut. Faktor lain yang berkontribusi terhadap pengurangan tingkat kerusakan tanaman padi adalah keberadaan gulma purun tikus. Penggerek batang padi lebih tertarik meletakkan telurnya pada gulma tersebut dibandingkan pada padi sehingga kerusakan padi yang ditanam berdekatan dengan area purun tikus lebih rendah. Populasi musuh alami yang melimpah pada area purun tikus efektif menekan perkembangan hama penggerek batang padi.</p><p>Kata kunci: Padi, budi daya, penggerek batang padi, lahan rawa pasang surut<br /><br /></p>