Scirpophaga Innotata Research Articles

A Study of the African White Rice Stem Borer (Maliarpha separatella Rag.) Population Density Fluctuations at Mwea Irrigation Scheme in Central Kenya

The African white rice stem borer (Maliarpha separatella Ragonot) is a major pest of rice in Kenya. To understand and develop appropriate management packages, its population dynamics were studied at Mwea irrigation scheme in Central Kenya. This was for two wet and two dry periods. Farmer fields located in different parts of the scheme and outside the scheme were sampled every fortnight. Farms sampled represented five water provision schedules (System of Rice intensification (SRI), rain fed, flood irrigated, sporadic irrigation, and fallow period). Five planting regimes (on season, off season double cropping, ratoon, and late planting) and three management styles (controlled by National Irrigation Board (N.I.B), not controlled by N.I.B and out-growers) were studied. During each sampling, a 1mx1m quadrant was used randomly and pest counted on all the plants within the quadrant. Results showed that the number of M. separatella varied significantly (p<0.05) in the scheme. Pest densities were highest in off season planted rice (13.1). High numbers were also found in Non N.I.B controlled fields with sporadic irrigation (8.1) and the lowest in the N.I.B, fallow (2.5) and this was significant (p<0.05). There were no significant differences in pest infestations on the normal season crop (0.3) and the ratoon crop (0.6) p<0.05 and SRI and conventional irrigated fields (p<0.05). From the results it is recommended that off season planting of rice be discouraged and that efforts are made to ensure that farmers synchronize planting dates and other cultural practices for the crop, within the scheme and in rice farms outside the scheme.

Relative abundance of stem borer species and natural enemies in rice ecosystem at Madhupur, Tangail, Bangladesh

The relative abundance of different stem borer species and their natural enemies with interaction effects were studied at three growth stages of irrigated Boro rice at Madhupur under the district of Tangail, Bangladesh during January to April, 2013. Five stem borer species viz; Yellow stem borer (Scirpophaga incertulas), Pink stem borer (Sesamia inferens), Dark headed stem borer (Chilo polyhcrysus), Stripped stem borer (Chilo suppressalis), White stem borer (Scirpophaga innotata), and nine different natural enemies were collected from the rice fields and recorded. The population of stem borers and natural enemies was highest in tillering stage and lowest in seedling stage. The relative abundance of stem borer species under investigation showed ranking order; yellow stem borer &gt;dark headed stem borer&gt;pink borer&gt;white borer&gt;stripped stem borer and natural enemies as ladybird beetle &gt;long jawed spider&gt;wolf spider&gt;damselfly&gt;carabid beetle&gt;green mirid bug&gt;lynx spider&gt;dragon fly&gt;ear wig. Populations of all five stem borers were positively correlated with ladybird beetle, wolf spider, long jawed spider, lynx spider, damsel fly, dragon fly, green mirid bug and negatively correlated with carabid beetle and earwig.J. Bangladesh Agril. Univ. 12(2): 267-272, December 2014

Populasi Penggerek Batang Padi pada Ekosistem Sawah Organik dan Sawah Anorganik

Rice stem borer (RSB ) is a major pest for rice in Central Java in the past ten years as well as previous years . The presence of RSB occurs during the rice growing season with a high intensity , especially in the rainy season . RSB which is the main type, yellow RSB Scirpophaga incertulas Walker and white S. innonata. Walker . Other types are pink Sesamia inferens Walker , striped Chilo suppressalis Walker, headed black C. polychrysus Meyrick , and shiny C. auricilius Dudgeon. Organic farming in Central Java is still not widely applied so it is still very less information available, including information on the fluctuations in species diversity and population abundance of RSB. In this study examined the types and abundance fluctuations keenekaragaman RSB populations in rice field ecosystem organic and inorganic. Research will be conducted for one year (3 times transplanting rice) paddy ecosystems in organic and inorganic Bakalrejo Village, District Susukan, Semarang regency. The results showed that the dominant RSB is yellow S. incertulas. Yellow RSB found in every season paddy rice planting in both organic and inorganic rice. While the pink, shiny and white RSB, occasionally encountered. The RSB encountered seem to prefer the ecosystem tend rice paddy organic than inorganic . Keywords : rice stem borer ( RSB ) , organic rice ecosystem, inorganic rice ecosystem.

Intercropping of Rice Varieties Reduces Green Leafhopper and White Stem Borer Infestation

A system of crop management by intercropping of diverse rice varieties in the field provides an effective way to control rice disease, but its effectiveness to control rice pest insects is not well known. Our research evaluated the impact of four rice varieties planted by strip intercropping on populations of green leaf hopper Nephotettix virescens and incidence of rice white stem borer Scirpophaga innotata in Sulawesi, Indonesia. The average number of green leafhopper insects caught by five consecutive passes with a sweep net on Pulut putih, Lapang, Fatmawati, Ciliwung varieties planted by monoculture, between 30 and 58 days after planting in a Sidrap plantation was respectively 0.6 - 4.3, 1.0 - 6.0, 1.7 - 6.7 and 2.3 - 6.0 adults, while in rice grown in strip intercropping the catch was respectively 0.7 - 2.5, 0.4 - 2.7, 0.5 - 2.6, and 1.4 - 3.5 adults. The average incidence of white stem borer observed between 30 and 65 days after planting on the same varieties in Sidrap planted by monoculture was respectively 1.8 - 9.7, 5 - 40%, 10.0 - 23.2, and 0.0 - 28.5% and in the strip intercropping was respectively 1.5 - 11.6%, 8.0 - 27.5%, 4.2 - 12.8%, and 2.0 - 7.2%. The average incidence of white stem borer in the Wajo plantation using monoculture was respectively 22.5 - 35.4%, 30.2 - 60.5%, 24.0 - 35.0%, and 17.5 - 28.5% and in the rice planted by strip intercropping was respectively 26.0 - 36.1%, 28.1 - 57.0%, 24.0 - 35.0%, and 15.0 - 23.2%. These data demonstrate that intercropping of rice varieties results in a reduction of rice pest infestation.

KEANEKARAGAMAN, DOMINASI, PERSEBARAN SPESIES PENGGEREK BATANG PADI DAN SERANGANNYA PADA BERBAGAI TIPOLOGI LAHAN DI PROVINSI JAMBI

Diversity, domination, and distribution of rice stem borer species and its damage in various land typologies in Jambi Province. The research was conducted to analyze the diversity, domination, species distribution of rice stem borers (RSB) and its damage on various land typologies in Jambi Province. The research was carried out using survey method, from December 2010 until June 2011. Samples of RSB were collected from tidal swamp in Tanjung Jabung Timur District, swampy area in Muaro Jambi District, rainfed lowland in Sarolangun District, irrigated lowland in Merangin District, and irrigated upland in Kerinci District and Sungai Penuh District. The results showed that there were five spesies of RSB found in Jambi Province. Scirpophaga incertulas Walker (yellow stem borer) was the most dominant of RSB, followed by Sesamia inferens Walker (pink stem borer), Chilo suppressalis Walker (striped stem borer), Chilo polychrysus Meyrick (dark-headed stem borer), and Scirpophaga innotata Walker (white stem borer). The distribution of S. incertulas, S. inferens, C. suppressalis and C. polychrysus were in all of rice field in Jambi Province, but that of S. innotata was limited over tidal swamp and rainfield lowland area. The RSB damage rate was lower than economic thereshold.

Shapes of mandibles of white stemborer Scirpophaga innotata (Walker, 1863)larvae associated with different rice varieties

Rice stem borers are considered the most serious insect pest of rice in Asia. The white stem borer Scirpophaga innotata (Walker, 1863) is the most prevalent among the different species that exist in the Philippines. This pest uses its strong mandibles to penetrate and feed on its plant host. Rice varieties of various level of resistance were deployed in different geographical locations in the Philippines but infestations were still observed and have contributed to economic losses to the farmers. Although differences in the resistance level among rice varieties makes an important factor in the control of the pest, no rice variety has been reported to be completely resistant against rice stem borer attacks. Several reports have indicated however that the level of damage caused by rice stem borer attacks differs. Thus it was the major objective of this study to determine if populations of white stem borer showed intraspecific variation between different geographical locations and between rice varieties. Since the mandible of the larvae is used in penetrating the plant, this morphological part of the insect larvae was investigated. Outline-based geometric morphometric analysis was used to test the hypothesis that the mandible shape of white stem borer differ with respect to different rice varieties and geographical location. Results of the principal component analysis showed variation in the shape of the mandible among populations of white stem borer taken from different rice varieties but not in the same variety collected from different geographical locations. Results of this study further confirm the general argument that host plant resistance play an important role in the evolution of pests.

Rice white stemborer Scirpophaga innotata (Walker) in southern Mindanao, Philippines. II. Synchrony of planting and natural enemies

Although the rice white stemborer (WSB) Scirpophaga innotata (Walker) has been an epidemic pest in other locations in the Philippines and Indonesia, its population has remained at chronic pest levels in Koronadal, southern Mindanao, Philippines. Field studies were undertaken to determine the role of egg parasitoids and general predators in suppressing WSB numbers. The results revealed greater mortality levels on WSB than in any other location where beneficials have been assessed. Four hymenopteran parasitoids (Tetrasticus schoenobii Ferriere [Eulophidae], Telenomus rowani (Gahan) [Scelionidae], Telenomus dignus (Gahan), and Trichogramma japonicum Ashmead [Trichogrammatidae]) combined to parasitise 65% of eggs in the second 1990 – 1991 rice crop. Multiple parasitism occurred in 61% of parasitised egg masses. Egg predation averaged 44% principally by the tettigoniids Conocephalus longipennis (de Haan) and C. maculatus (Leth.). Generalist predators steadily built up over the rice crop. A contributing factor to the high success of natural enemies could be related to the special situation of two irrigation systems interspersed among each other. Communal systems fed by artesian wells resulted in asynchronous planting areas where farmers can plant five crops in 2 years juxtaposed to a larger river diversion system typified by highly synchronous double rice cropping. The heterogeneous habitat created by the two irrigation systems could favour the density-dependent T. schoenobii, the keystone parasitoid in the rice ecosystem, which acts as both a parasitoid and predator.

Rice white stemborer Scirpophaga innotata (Walker) in southern Mindanao, Philippines. I. Supplantation of yellow stemborer S. incertulas (Walker) and pest status

The rice white stemborer (WSB) Scirpophaga innotata (Walker) supplanted the closely related rice yellow stemborer (YSB) S. incertulas (Walker) in irrigated, double-rice culture in both Koronadal, South Cotabato, Philippines and Java, Indonesia. In Java, WSB became a serious pest but not in Koronadal where damage levels remained unchanged. The species shift and subsequent outbreaks are seen as independent events. The former occurred just after the El Niño droughts in 1982 – 1983 which suggests that climatic factors triggered the demise of YSB which does not aestivate. A contributing factor may have also been the crop failures from pest outbreaks that occurred during the same period creating long fallows which would have allowed WSB larvae selectively to survive. WSB larvae have been known to diapause for up to 10 – 12 months and consequently is able to survive climatically driven long fallows. Diapause is terminated by rainfall >10 mm after larvae have rested for a minimum of 4 months. Supportive evidence in favour of climate as the causal agent of change is that the distribution of WSB in Asia and Oceania overlaps that of the Intertropical Convergence Zone of the Southern Oscillation. YSB on the other hand is more adapted to a monsoon climate. It is also hypothesised that WSB, normally associated with single-crop, rainfed-rice culture, was able to adapt to double-cropped, irrigated culture due to the introduction of early maturing rices. From what is known about rice stemborer ecology, five cultural practices and natural events were postulated as the reasons keeping WSB densities in check in Koronadal: (1) medium maturing varieties to reduce the dry season fallow, (2) low inorganic N levels, (3) natural enemies, (4) destruction of crop residue harbouring larvae and pupae during land preparation, and (5) rainfall in the dry season causing suicide flights. Control strategies for areas where WSB is a pest should be based on: (1) reducing the fallow period by growing longer maturing varieties and (2) undertaking early ploughing for the wet season crop.

SHJ NOTES: Occurrence of White Stem Borer in Agusan del Norte Lowland Ricefields

The occurrence of white stem borer (Scirpophaga innotata Walker) in relation with other insect pest and natural enemies in the irrigated and rainfed lowland ricefields in Agusan del Norte was studied for two cropping seasons. Seasonal abunance of the white stem borer and associated arthropods were determined through sweep net, quadrat, and pan sampling in 12 individual harvest. There were three generations of white stem borer recorded during the survey as shown by the occurence of egg masses althought overlapping of generations was also noted. However, its population fluctuated as the crop matured.

Some factors affecting white stem borer Scirpophaga innotata (Walker) (Lepidoptera: Pyralidae) injury to rice

The amount of injury to rice caused by white stem borer Scirpophaga innotata depends on cultivar, and stage of plant and insect development, as well as insect abundance. Of the cultivars tested, IR64, IR42, Cisadane and Ketan, IR64 were the most susceptible and Ketan the least susceptible to feeding damage. Third and fourth instars consumed more stem dry matter than other stages, although yield reduction depended on the number of tillers injured. On the wider stemmed Ketan, fewer tillers were injured than the narrower IR64. Larvae are more likely to move among tillers in the third instar stage, which tends to coincide with maximum tillering and may result in more tillers injured and in yield reduction. Later instar larvae burrow downwards to the internode where they pupate. Larvae appear to move less among tillers in ‘resistant’ cultivars. Management strategies should target this pest at third instar and when its abundance in the field warrants control. Fewer than 10% of the neonates establish successfully on stems, and this mortality needs to be taken into account when deciding on control, as does the ability of rice plants to compensate for injury.

White stem borer damage and grain yield in irrigated rice in West Java, Indonesia

Factors influencing the relationship between whiteheads caused by the white stem borer Scirpophaga innotata (Walker) and grain yield were investigated. We determined the effect of different numbers of whiteheads on grain yield using different cultivars, nitrogen application, and at different field locations in Cilamaya, West Java. At the same number of panicles and whiteheads per plant, yield reduction is greater in Cisadane than in IR64. With increasing nitrogen application, the range in panicle height increased. Except for Ketan, more whiteheads were recorded in shorter panicles. Two locations planted to the same cultivar showed different relationships between whiteheads and grain yield. The relationship between whiteheads and grain yield depends on the distribution of whiteheads in the field. Unless these factors have been taken into consideration, it may be difficult to make a damage prediction of white stem borer in the field.

Farmers' perceptions of the white stem borer Scirpophaga innotata (Walker), in Cilamaya, West Java, Indonesia

In connection with the white stem borer outbreak, reported during the 1989–1990 wet season in the northern part of West Java, field surveys were conducted to determine the importance of this pest to farmers, to assess their knowledge of it and to determine current control practices. The largest percentage (85%) of farmers perceived the white stem borer as important and difficult to control (22%). When farmers observe white stem borers in their fields most believe that moths migrated from other rice fields. Many farmers were uncertain that an outbreak will occur the next season, mainly because of the lack of understanding of the population dynamics of the pest and the factors causing white stem borer outbreaks. The majority of the farmers use insecticides against white stem borers including those banned by the government with the implementation of the IPM policy in 1986. An account of farmers reliance on pesticide use against white stem borers is discussed.

Noxiousness of the african white stem borer, Maliarpha separatella Rag (Pyralidae: Phycitinae) in irrigated paddy fields at lake Alaotra (Madagascar)

A study of the noxiousness of the African white rice stem borer, Maliarpha separatella Rag carried out under controlled field conditions has revealed that the impact of this pest on the yield and its components is assessable. For mean infestation rates up to 68% during the period of highest sensitivity of a paddy rice culture (second half of tillering to panicle initiation), no significant decrease could be observed in the number of panicles, nor any significant increase in the number of white heads and the number of empty grains per hill. However, with increasing infestation rates, the number of immature panicles increased and the number and weight of filled grains per hill decreased. An explorative analysis of the infestation rate-yield loss relationship, showed that a sigmoid model describes this interdependence appropriately. The proposed economic injury level (EIL), is here considered more the result of an approach, which had as its goal the re-definition of the status of the pest than as an instrument of a chemical control programme with treatments based on an action threshold.

Sex pheromone of female african white rice stem borer,Maliarpha separatella (Lepidoptera: Pyralidae) from Sierra Leone: Identification and field testing

Analysis of ovipositor washings of femaleMaliarpha separatella from Sierra Leone by high-resolution gas chromatography (GC) linked to a male electroantennograph (EAG) indicated the presence of three electrophysiologically active compounds. The GC retention times of these compounds were consistent with those of (Z)-9-tetradecen-1-ol, (Z,E)-9,12-tetradecadien-1-ol, and (E,E)-10,12-tetradecadien-1-ol. Analysis by El and CI mass spectrometry of ovipositor washings confirmed these identifications and also indicated the presence of the saturated analog, tetradecan-1-ol. There was no evidence, from these analyses, of the corresponding aldehydes or acetates. The EAG-active compounds were present in the ovipositor washings in a ratio of approximately 2∶3.5∶1, with the major component constituting approximately 0.4 ng per ovipositor. GC-MS analysis of entrained female effluvia confirmed that the EAG-active compounds were released by virgin females. Field testing of the EAG-active compounds indicated that (Z,E)-9,12-tetradecadien-1-ol and (E,E)10,12-tetradecadien-1-ol were attractive to male moths in ratios of between 9:1 and 39:1, while (Z)-9-tetradecen-1-ol was found to reduce trap catch when added to blends of the other two compounds.

Status and control of Chilo spp., their distribution, host range and economic importance in Oceania

From the literature review and available information on Chilo in the seven Oceanian countries, only six species of Chilo have been recorded as pests of graminaceous crops. C. terrenellus Pag. is one of major sugar-cane pests, in Papua New Guinea and a minor sugar-cane pest on Saibai, Torres Strait Islands, Australia, respectively. In the former country, the damage assessment, host plants, life cycle, phenology and natural enemies of the stem borer have been studied. Since 1981, two larval parasites, Apanteles flavipes Cam. (Indian strain) and Bracon chinensis (Szep.), have been introduced against the stem borer from India, propagated and released but have failed to become established. The search for additional parasites continues. C. influscatellus Sn. is a minor sugar-cane pest also in Papua New Guinea; C. suppressalis (Walk.), C. polychrysa (Meyr.), C. auricilia Dudg. and Chilo sp. are minor pests of rice in Papua New Guinea; the former two species are also minor rice pests in the Northern Territory, Australia where integration of cultural, chemical and biological control measures have been applied against the major white rice borer, Scirpophaga innotata (Walk.), in conjunction with C. suppressalis and C. polychrysa.