Sesamia Inferens Research Articles

Impact of Gliricidia sepium and Cassia spectabilis hedgerows on weeds and insect pests of upland rice

Double hedgerows of two leguminous multipurpose trees Gliricidia sepium (Jacq.) Walp. and Cassia spectabilis DC. were established in highly eroded, low organic matter, acid uplands in northern Mindanao, Philippines. Alleyways were grown with upland rice Oryza sativa L. and fertilised with G. sepium green manure or C. spectabilis mulch (or in combination) and assessed for weed and insect pest suppression. Mulch reduced weed biomass which was mostly composed of grasses on infertile soil. Green manure favoured broadleaf weeds and increased weed biomass reducing the effect of mulching. Greater weed suppression may be achieved. Improvement in soil fertility increased the crops’ competitiveness against weeds by concentrating it to crop furrows. Greater crop nutrition from hedgerow biomass resulted in increases of rice seedling maggot Atherigona oryzae Malloch and stem borer (mainly Sesamia inferens (Walker)) damage and white grub (mainly Holotrichia mindanaoana Brenske and Leucopholis irrorata (Chevrolat)) larval densities over the control. Terrace formation reduced white grub densities the first year. The trend reversed in the second year as shade from the hedgerows and mulch probably favoured survival of white grub larvae by reducing soil temperature and increasing soil moisture. Despite higher insect pest densities, the moderate tillering UPLRi5 tolerated weeds and insect pest damage to produce higher yields in the biomass treatments than the control. But hedgerows may increase the incidence of rice blast Pyricularia oryzae Cav. by decreasing air movement. As purchased fertilisers provide limited crop response on depleted soils, alley cropping provides an economical means to overcome that constraint in small-scale tropical agriculture.

Fungal growth and fusarium mycotoxin content in isogenic traditional maize and genetically modified maize grown in France and Spain.

Fungi of the genus Fusarium are common fungal contaminants of maize and are also known to produce mycotoxins. Maize that has been genetically modified to express a Bt endotoxin has been used to study the effect of insect resistance on fungal infection of maize grains by Fusarium species and their related mycotoxins. Maize grain from Bt hybrids and near-isogenic traditional hybrids was collected in France and Spain from the 1999 crop, which was grown under natural conditions. According to the ergosterol level, the fungal biomass formed on Bt maize grain was 4-18 times lower than that on isogenic maize. Fumonisin B(1) grain concentrations ranged from 0.05 to 0.3 ppm for Bt maize and from 0.4 to 9 ppm for isogenic maize. Moderate to low concentrations of trichothecenes and zearalenone were measured on transgenic as well as on non-transgenic maize. Nevertheless, significant differences were obtained in certain regions. The protection of maize plants against insect damage (European corn borer and pink stem borer) through the use of Bt technology seems to be a way to reduce the contamination of maize by Fusarium species and the resultant fumonisins in maize grain grown in France and Spain.

Biocontrol of the maize borer Sesamia cretica Led. (Lepidoptera: Noctuidae) in Egypt using a granulovirus

Three field experiments were conducted under natural infestation levels from 1997 to 1999 in the Nile Delta in Egypt to evaluate the feasibility of controlling populations of the maize pink borer Sesamia cretica Lederer (Lepidoptera: Noctuidae) using a granulovirus (SecrGV) recently isolated from the species. The experimental design was a randomized complete-block. Spraying was done twice, at thinning and 2 weeks subsequently, in the first two experiments and only once at thinning in the last experiment. The first experiment compared the untreated control with the recommended systemic insecticide, methomyl, and with three highly purified suspensions of virus in water, at concentrations of 300 g granules ha -1 (i.e. 3.7 2 10 16 granules ha -1 ), 120 and 60 g granules ha -1, respectively. This trial showed that SecrGV was as efficient as the insecticide in reducing borer populations. The second experiment compared the control with three reduced virus concentrations: 10, 1.0 and 0.10 g granules ha -1 . All virus concentrations enabled effective control of S. cretica, with some gradation in impact on the pest. This gradation was, however, no more noticeable in yields: only the control had a significantly reduced yield. In 1999, the control was compared with the concentrations: 0.10 g, 1 mg and 10 w g granules ha -1 . The first concentration confirmed the good results of the previous year on borer populations and on yield. The other two concentrations were not as effective and did not enable an increase in yield. It is concluded that SecrGV is an efficient biocontrol agent of the pink borer, and a concentration 0.1 g granules ha -1 (i.e. 1.2 2 10 13 granules ha -1 ) is recommended.

Developing habitat management systems for gramineous stemborers in South Africa

The stemborers Busseola fusca (Lepidoptera: Noctuidae) and Chilo partellus (Lepidoptera: Crambidae) are important pests of maize and sorghum in South Africa. A habitat management system for these pests is being developed in the Northern Province of South Africa. This management system is similar to the one used in eastern Africa, where host and non-host plants of stemborers are used to repel moths away from the main crop and attract them to highly attractive trap plants. To identify possible trap crops, a survey of wild host plants of stemborers was undertaken in the Northern Province of South Africa and several new host plants were recorded. As a possible trap crop for stemborers, various Napier grass (Pennisetum purpureum) varieties were evaluated for oviposition preference by Ch. partellus moths and subsequent larval survival on those varieties. Few larvae survived longer than 15 days after inoculation onto Napier grass plants. A survey was conducted of farming practices that would affect the adoption of habitat management strategies. The high usage of tractors for ploughing may have a negative effect on adoption of perennial intercrops in a habitat management system. The common practice of free grazing animals also reduced the fodder value and benefit of trap crops. The value of Napier grass does not only lie in its use as trap crop but also as a measure to limit soil erosion and as animal feed.

Distribution of cereal stemborers in Zambia and release of Cotesia flavipes Cameron, an exotic natural enemy of Chilo partellus (Swinhoe)

Surveys of the cereal stemborers and their natural enemies in Zambia were initiated in 1997. The surveys verified the presence of three stemborer species on maize, sorghum and pearl millet. These were the maize stalk borer, Busseola fusca Fuller (Lepidoptera: Noctuidae), the spotted stemborer, Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) and the African pink borer, Sesamia calamistis Hampson (Lepidoptera: Noctuidae). Occasionally, the sugarcane borer, Eldana saccharina Walker (Lepidoptera: Pyralidae) was also recovered especially around areas near the sugarcane plantation at Mazabuka, Southern province. Chilo partellus was the predominant stemborer in region I (areas with less than 600 mm of rainfall per annum). Three ‘hot spot’ areas, namely Luangwa, Buleya Malima and Kalobolelwa, were identified based on the abundance of Ch. partellus. The exotic parasitoid, Cotesia flavipes Cameron (Hymenoptera: Braconidae) was released in the three areas for the control of Ch. partellus. However, post-release surveys in these areas have not revealed any recoveries of Co. flavipes. Three indigenous natural enemies, namely Cotesia sp., Dentichasmias sp. and Dolichogenidea sp. emerged from the field-collected larvae.

Comparative Studies on the Fecundity, Egg Survival, Larval Feeding, and Development of <I>Chilo partellus</I> and <I>Chilo orichalcociliellus</I> (Lepidoptera: Crambidae) on Five Grasses

Chilo partellus (Swinhoe) and Chilo orichalcociliellus Strand (Lepidoptera: Crambidae) are gramineous stem borers that occur sympatrically in the southern coastal area of Kenya. Evidence over a 30-yr period indicates that the indigenous stem borer, C. orichalcociliellus, is being gradually displaced by the exotic stem borer, C. partellus. Comparative laboratory studies were conducted in several large-stemmed grasses to examine factors that may be involved in the displacement of C. orichalcociliellus, and to examine other possible effects of the invasion of C. partellus into Kenya. C. partellus had a higher fecundity than C. orichalcociliellus at 25 and 28°C, but not at 31°C. In addition, more C. partellus than C. orichalcociliellus eggs survived to the first instar. C. partellus larvae developed faster than C. orichalcociliellus in maize and sorghum. In this shorter developmental time, C. partellus consumed more maize than C. orichalcociliellus, but both species consumed equal amounts of sorghum. On a daily basis, C. partellus consumed more maize and sorghum than C. orichalcociliellus. A few C. orichalcociliellus survived to the pupal stage in napier and guinea grasses, whereas no C. partellus survived. The shorter developmental period of C. partellus may give this species a competitive advantage over the slower developing C. orichalcociliellus. However, the ability of C. orichalcociliellus to complete development in two native grasses in which C. partellus did not survive may provide a refuge that has allowed C. orichalcociliellus to escape extirpation from the coastal area of Kenya.

Evaluation of rice for resistance to pink stem borer ( Sesamianonagrioides Lefebre)

The pink stem borer ( Sesamia nonagrioides Lefebre) is one of the most important rice pests in the Mediterranean area. The objective of this study was to identify rices resistant to pink stem borer and to determine plant characteristics associated with resistance. A total of 257 rice lines was evaluated in the field under natural infestation conditions during 1997 and 1998. The comparison between years was based on nine rice cultivars (Baldo 363, Koral, Ariete, Loto, Senia, Thaibonnet, Cigalon, Makedonia and Dion) which were common in the experimentation of both years and were used as control. A randomized complete block design with two replications was used for evaluation. The number of stems and panicles with infestation symptoms by the pink stem borer was measured at maturity. The infestation percentage of the plants varied from 0 to 89%, and on the average, it was higher in 1998 compared to 1997. The lines exhibited considerable variation in heading day (HD, 50–110 days), plant height (HT, 50–170 cm) and stem diameter (SD, 3–8 mm). The infestation was significantly correlated with HD, HT and SD. The ratio of plants with stem damage to those with panicle damage varied from 0.2 (Harra) to 11 (CT-13) but in the majority of lines it was less than 3. Eleven resistant lines (CI 1992K15, YRL-196, Colina, Frances, Niva, SB 1086, SB 428, SBSS 82, Lampo, IR-28, and IR-30), with infestation percentage less than 10%, were identified. These might be useful sources of resistance for rice breeding programmes in Mediterranean countries.

Relative abundance of rice stem borer species in Tamil Nadu

Three species of rice stem borers occurred in Tamil Nadu, of which yellow stem borer (YSB), Scirpophaga incertulas (Walker) was more predominant than pink stem borer (PSB). Sesamia inferens, (Walker) dark-headed borer (DSB), Chilo polychrysus (Meyrick) in both Kar (June-September) and Pishanum (Oct-Jan) seasons. The PSB was second most numerous (35.21%) in Kar and was relatively as abundant as YSB in Pishanum (48.43%). The DSB was less common during either season (4.29-7.18%). Varieties had variable compostion of stem borer infestation. The YSB infestation was more from early tillering to maximum tillering stage, decreasing gradually with increasing PSB infestation from flowering stage. YSB was the most common species in all districts. PSB was more abundant than DSB in Coimbatore, Tanjore, Tuticorin, Madurai and Dharmapuri districts, whereas DSB was more numerous in Tirunelveli, Kanyakumari and Vellore districts.

Transgenic rice plants with a synthetic cry1Ab gene from Bacillus thuringiensis were highly resistant to eight lepidopteran rice pest species.

To fully explore the resistance potential of transgenic rice produced by Agrobacterium-mediated transformation, an elite line KMD1 was assessed for its resistance to eight lepidopteran rice pest species. KMD1 contained a synthetic cry1Ab gene from Bacillus thuringiensis under the control of a maize ubiquitin promoter. It was derived from a commercial japonica Chinese rice variety Xiushui 11, and bred true for both agronomic traits and a cry1Ab gene when the bioassays were done in 1998 in the R5 generation. The eight lepidopteran pest species were: four Pyralidae species: Chilo suppressalis (striped stem borer, SSB), Scirpophaga incertulas (yellow stem borer, YSB), Cnaphalocrocis medinalis (leaf folder), Herpitogramma licarisalis; two Noctuidae: Sesamia inferens (pink stem borer, PSB) and Naranga anescens; one Stayridae: Mycalesis gotama; and one Hesperiidae, Parnara guttata. In laboratory bioassays, 100% mortality was observed in all insect species when their newly hatched or third-instar larvae were fed KMD1 leaf tissues, whereas only 9.65% of the neonates and none of the third-instar larvae died when fed the leaf tissues of non-transgenic control. Moreover, the leaf area of control tissues consumed in four days by stem borers was 20 to 40 times higher than that of KMD1 tissues, and the area of control tissues eaten by leaf-feeding species was 120 to 180 times greater than that of the transgenic tissues. Under natural infestation, no KMD1 plant was visibly damaged by the SSB, YSB and leaf folder in field evaluation. On the other hand, 80, 9.3 and 88.7% of control plants were injured by SSB, YSB, and leaf folder, respectively. These data disclosed that the transgenic line was highly resistant to a broad spectrum of lepidopteran insect species and could be useful in insect resistance breeding programs.

Ear Feeding Resistance of Sweet Corn Inbreds to Pink Stem Borer

Pink stem borer (Sesamia nonagrioides Lef.) is one of the most important insect pests of corn (Zea mays L.) in southern Europe. The objectives of this work were to determine the level of resistance in different sweet corn inbreds and to identify sources of resistance to ear feeding by the pink stem borer. Twenty-eight sweet corn (su1 and su1se1) inbreds and four resistant field corn (Su1Se1) inbreds were evaluated for ear resistance at different sowing dates, under two methods of artificial infestation. There were significant differences between infestation methods for ears with damaged grain, husks, cobs, and shanks. The inbred×infestation method interaction was significant for general appearance of the ear. The most resistant inbreds were identified by using mean comparisons and principal component analysis of ear damage traits. All inbreds were damaged. Hence, resistance was incomplete and in need of improvement. EP59, H3, I5125, IL767b, and V7726 were the most resistant sweet corn inbreds, which did not differ significantly from A635, the most resistant field corn inbred. General appearance of the ear appears to be a good indicator of pink stem borer resistance and can be used in preliminary evaluation. Variability exists in the resistance of these sweet inbreds to the pink stem borer and the use of field corn inbreds may not be necessary in the improvement of resistance, although further research is needed to determine if the sources differ in the pertinent genes conferring resistance.

Suitability of new and old association hosts for the development of selected microgastrine parasitoids of gramineous stemborers

The present study examined the acceptability and suitability of Old World stemborers (Chilo partellus and C. orichalcociliellus) for the development of New World parasitoids (Apanteles deplanatus and A. minator) and New World stemborers (Diatraea saccharalis and D. grandiosella) for the development of Old World parasitoids (Cotesia sesamiae, C. flavipes and C. chilonis). Results revealed that acceptance and suitability were high in old associations. In new associations, parasitoids accepted about 60% of the new association hosts. In addition, 10 out of 17 new associations were successful. Apanteles species appeared to be more physiologically host specific than Cotesia species. For example, two of four new association hosts were accepted by A. deplanatus and only one (D. saccharalis) was partially suitable for progeny development. Among the Cotesia species, Cotesia flavipes appeared to have a wider host range than the two other species. It attacked all hosts offered and successfully parasitized all but one (D. grandiosella). Diatraea saccharalis was accepted and was a suitable host for the development of all parasitoid species tested, whereas D. grandiosella was unsuitable for the development of four out of five parasitoid species tested. No clear pattern was observed as behavioral acceptance did not always agree with the pattern of physiological suitability. Implications of these findings for importation biological control of stemborers are discussed.

Resistance of Maize Inbreds to Pink Stem Borer

The most important insect pest of maize (Zea mays L.) in southern Europe is the pink stem borer (Sesamia nonagrioides Lef.). The objective of this work was to identify sources of resistance to stem and ear damage by the pink stem borer. One hundred twenty‐one inbreds from seven germplasm groups (American, Argentine, European, Lancaster, Northern Flint, Reid, and Other), divided according to their maturity grouping (very early, early, midscason, and late), were evaluated for several years under artificial infestation at Pontevedra (northwestern Spain). Twelve traits were recorded to measure stem and ear damage. Stem and ear damage resistance traits were not correlated, therefore simultaneous selection for the two types of resistance within the same population should be carried out. Eight very early, two early, seven midseason, and four late inbreds were resistant to stem‐damage. The Reid germplasm group was more resistant to stem attack than the other groups. Therefore, the best Reid inbreds could be used to form a stem‐damage resistant Reid synthetic, which could be a source of new stem‐damage resistant varieties. Simultaneously, the best non‐Reid inbreds could be used for making a non‐Reid stem‐damage resistant synthetic. Thirteen very early, 10 early, two midseason, and three late inbreds performed better than the others against ear attack. Only seven inbreds (A509, A635, CO125, EA2024, EP39, Oh43, and PB130) were resistant to both stem and ear damage. These inbreds could be used as sources of resistance to pink stem borer in a breeding program.

Seasonal changes in infestation level of sugarcane by the pink borer, Sesamia inferens (Lepidoptera : Noctuidae), in relation to a parasitoid, Cotesia flavipes (Hymenoptera : Braconidae), on Okinawa Island

Infestation of sugarcane by the pink borer, Sesamia inferens (Walker) (Lepidoptera : Noctuidae), parasitism of the pink borer by Cotesia flavipes (Cameron) (Hymenoptera : Braconidae) and host-parasitoid relationships were examined on Okinawa Island over a period of 4 years. Bimonthly surveys indicated that infestation by the pink borer had two peaks, one in April/May (20.5 to 29.3%) and the other, in August (22.2 to 29.5%), whereas parasitism of the pink borer had only one peak in August (61.2 to 80.1%). The density of C. flavipes at time t depended most strongly on the density of the pink borer at time t (r=0.77 to 0.84), whereas, the density of the pink borer depended most strongly on the density of C. flavipes at time t-3, i.e., 1.5 months earlier (r= -0.29 to -0.44). It was notable that the mean number of parasitoids that emerged from a single host varied seasonally, being smallest in February (17.6 to 26.8) and largest in August (48.8 to 59.2). A positive correlation between the mean number of emerged parasitoids and the mean temperature in each month (r=0.87) suggested that the number of eggs oviposited by a female per host was influenced by temperature.

Defense Mechanisms of Maize against Pink Stem Borer

The pink stem borer (Sesamia nonagrioides Lef.) is the most important pest of maize (Zea mays L.) in northwestern Spain. The objective of this work was to evaluate defense mechanisms against Sesamia in 10 inbred lines and the 10‐parent diallel among these inbreds. Hybrids and inbred lines were tested over 2 yr in northwesternSpain under natural and artificial infestations. Yield of infested and non infested plants per plot were computed to calculate yield loss caused by the pink stem borer attack. Principal component analyses for stem damage traits and for ear damage traits were made for each infestation condition. From the principal component analysis, an index was computed to measure stem damage and ear damage. Damage index under artificial infestation was used to evaluate antibiosis while antixenosis was detected when damage index of each genotype was compared under artificial and natural infestation. The regressions of yield loss on the damage index were used to separate the genotypes into four groups according to the possession of antibiosis and/or tolerance mechanisms. A509, A661, EP31, F7, PB60, and Z77016 showed stem antibiosis. A637, A661, EP31, F7, and PB60 exhibited stem tolerance. A509, A661, and EP31 stood out by their ear antibiosis. A637, A661, F7, and PB60 were tolerant to ear damage. We conclude that the three mechanisms of defense to the pink stem borer attack (antixenosis, antibiosis, and tolerance) were found among inbred lines and hybrids. A multitrait selection scheme using damage traits and yield could improve the defense level against pink stem borer.

5723756 Bacillus thuringiensis strains and their genes encoding insecticidal toxins

Transgenic rice to control stem borer damage is under development in China. To assess the potential of Bacillus thuringiensis (Bt) transgenes in stem borer control, the toxicity of five Bt protoxins (Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ba and Cry1Ca) against two rice stem borers, Sesamia inferens (pink stem borer) and Chilo suppressalis (striped stem borer), was evaluated in the laboratory by feeding neonate larvae on artificial diets containing Bt protoxins. The results indicated that Cry1Ca exhibited the highest level of toxicity to both stem borers, with an LC50 of 0.24 and 0.30 μg/g for C. suppressalis and S. inferens, respectively. However, S. inferens was 4-fold lower in susceptibility to Cry1Aa, and 6- and 47-fold less susceptible to Cry1Ab and Cry1Ba, respectively, compared to C. suppressalis. To evaluate interactions among Bt protoxins in stem borer larvae, toxicity assays were performed with mixtures of Cry1Aa/Cry1Ab, Cry1Aa/Cry1Ca, Cry1Ac/Cry1Ca, Cry1Ac/Cry1Ba, Cry1Ab/Cry1Ac, Cry1Ab/Cry1Ba, and Cry1Ab/Cry1Ca at 1:1 (w/w) ratios. All protoxin mixtures demonstrated significant synergistic toxicity activity against C. suppressalis, with values of 1.6- to 11-fold higher toxicity than the theoretical additive effect. Surprisingly, all but one of the Bt protoxin mixtures were antagonistic in toxicity to S. inferens. In mortality-time response experiments, S. inferens demonstrated increased tolerance to Cry1Ab and Cry1Ac compared to C. suppressalis when treated with low or high protoxin concentrations. The data indicate the utility of Cry1Ca protoxin and a Cry1Ac/Cry1Ca mixture to control both stem borer populations.

Ecology and management of tropical gramineous stemborers

Ecology and management of tropical gramineous stemborers

Progeny Production and Sex Ratios of Field Populations of the Parasitoids Cotesia Flavipes and Cotesia Sesamiae Reared from Gramineous Stemborers in Coastal Kenya

Progeny production and sex ratios of the parasitoids Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae) and its exotic congener Cotesia flavipes Cameron (Hymenoptera: Braconidae) emerging from three species of field-collected stemborers were compared. There were no significant differences in numbers of progeny of the two parasitoids from the African stemborers, Chilo orichalcociliellus (Strand) (Lepidoptera: Pyralidae) and Sesamia calamistis Hampson (Lepidoptera: Noctuidae). Cotesia flavipes produced more progeny than C. sesamiae on large larvae of its coevolved Asian host, Chilo partellus (Swinhoe). No significant differences in the number of parasitoid progeny were observed for different-sized Ch. orichalcociliellus or S. calamistis larvae. These data suggest that under field conditions, Co. flavipes may be superior to Co. sesamiae as a parasitoid of its co-evolved host, Ch. partellus.

Suitability of West African Gramineous Stemborers for the Development of Cotesia Species

The palaeotropical, gregarious, endoparasitic braconids Cotesia sesamiae, Cotesia flavipes and Cotesia chilonis were recently imported into Benin as candidates for biological control of stem and cob borers of maize. Host acceptability and host suitability of six gramineous borers occurring in western Africa, namely the noctuids Sesamia calamistis, Sesamia poephaga, Busseola fusca and the pyralids Coniesta ignefusalis, Eldana saccharina and Mussidia nigrivenella , to these candidate parasitoids was evaluated in order to gain insight into the physiological suitability of the natural and factitious hosts. All hosts were accepted by all Cotesia spp., except M. nigrivenella which was not attacked by Co. chilonis. Parasitoid progeny development was successful in S. calamistis, S. poephaga and Con. ignefusalis. Sesamia calamistis was the most suitable host for Cotesia spp. development, in terms of duration of developmental time, brood size and mortality of parasitoid progeny.

Ecology and Management of Tropical Gramineous Stemborers

Ecology and Management of Tropical Gramineous Stemborers

Pathogenicity of Three Entomogenous Fungi against Insect Pests of Sugarcane

Pathogenicity of three entomogenous fungi, Beauveria bassiana , Fusarium oxysporum and Metarhizium anisopliae var. anisopliae were conducted against eleven different insect pests of sugarcane in the laboratory. Of these, B. bassiana was found most pathogenic to larvae of Chilo auricilius , Chilo infuscatellus and Sesamia inferens ; nymphs and adults of Cavelerius sweeti , adults of Phytoscaphus sp. and Astychus lateralis , and grubs of Holotrichia consanguinea . Metarhizium anisopliae was found pathogenic to larvae of C. auricilius , C. infuscatellus and S. inferens ; adults of Phytoscaphus sp. and A. lateralis , and adults and nymphs of Pyrilla perpusilla . Fusarium oxysporum was found effective against larvae of C. auricilius , C. infuscatellus and S. inferens ; and adults and nymphs of P. perpusilla .