Shoot Borer Chilo Infuscatellus Research Articles

Ultrastructure of the sensilla on the larval antennae and mouthparts of Chilo infuscatellus (Snellen, 1890) (Lepidoptera: Crambidae)

The sugarcane shoot borer Chilo infuscatellus (Snellen, 1890) is a major sugarcane pest in Lepidoptera, but little information is available on its larval ultrastructure. Here, the sensilla of the antennae and mouthparts of the mature larva of C. infuscatellus were investigated using scanning electron microscopy. The antenna is three-segmented and possesses two types of sensilla, as well as three sensilla basiconica and two sensilla chaetica on the apical surface of the middle pedicel; three sensilla basiconica on the apex of the distal flagellum. The mandibulate mouthparts consist of a labrum, a pair of mandibles, a pair of maxillae, a labium, and a hypopharynx. The labrum possesses six pairs of sensilla chaetica; the membranous epipharynx bears three pairs of flattened sensilla chaetica, three pairs of epipharyngeal sensilla, and a pair of oval sensilla digitiformia. The mandible is equipped with two sensilla chaetica on the posterolateral surface. The maxillae are well developed, each formed by a cardo, a stipes, a galea and a two-segmented maxillary palp. Each galea carries six sensilla basiconica and two large sensilla styloconica. The maxillary palp is furnished with 9 sensilla basiconica, one sensillum digitiformium and one sensillum placodeum on the distal segment. On the labium, each labial palp has a sensillum chaeticum with apical bifurcation and a thick sensillum styloconicum. This paper briefly discusses the possible function of sensilla on antennae and mouthparts.

Novel approaches to circumvent the devastating effects of pests on sugarcane

Sugarcane (Saccharum officinarum L.) is a cash crop grown commercially for its higher amounts of sucrose, stored within the mature internodes of the stem. Numerous studies have been done for the resistance development against biotic and abiotic stresses to save the sucrose yields. Quality and yield of sugarcane production is always threatened by the damages of cane borers and weeds. In current study two problems were better addressed through the genetic modification of sugarcane for provision of resistance against insects and weedicide via the expression of two modified cane borer resistant CEMB-Cry1Ac (1.8 kb), CEMB-Cry2A (1.9 kb) and one glyphosate tolerant CEMB-GTGene (1.4 kb) genes, driven by maize Ubiquitin Promoter and nos terminator. Insect Bio-toxicity assays were carried out for the assessment of Cry proteins through mortality percent of shoot borer Chilo infuscatellus at 2nd instar larvae stage. During V0, V1 and V2 generations young leaves from the transgenic sugarcane plants were collected at plant age of 20, 40, 60, 80 days and fed to the Chilo infuscatellus larvae. Up to 100% mortality of Chilo infuscatellus from 80 days old transgenic plants of V2 generation indicated that these transgenic plants were highly resistant against shoot borer and the gene expression level is sufficient to provide complete resistance against target pests. Glyphosate spray assay was carried out for complete removal of weeds. In V1-generation, 70–76% transgenic sugarcane plants were found tolerant against glyphosate spray (3000 mL/ha) under field conditions. While in V2-generation, the replicates of five selected lines 4L/2, 5L/5, 6L/5, L8/4, and L9/6 were found 100% tolerant against 3000 mL/ha glyphosate spray. It is evident from current study that CEMB-GTGene, CEMB-Cry1Ac and CEMB-Cry2A genes expression in sugarcane variety CPF-246 showed an efficient resistance against cane borers (Chilo infuscatellus) and was also highly tolerant against glyphosate spray. The selected transgenic sugarcane lines showed sustainable resistance against cane borer and glyphosate spray can be further exploited at farmer’s field level after fulfilling the biosafety requirements to boost the sugarcane production in the country.

The reappearance of the early shoot borer Chilo infuscatellus in Java’s sugarcane

Chilo infuscatellus is one of the earliest identified and reported borer species from Java’s sugarcane. The study aimed to describe the composition and distribution of the shoot borer species attacking young sugarcane plants. Field surveys were conducted in 19 sampling sites in the sugarcane fields in Malang, Kediri and Pati. The plant samples with dead heart symptoms were taken from fields to the laboratory to be observed the borer’s attacks and identified the species. The finding of C. infuscatellus in all field samples confirmed that this species did not disappear from the sugarcane crop in Java. Along with this borer, other borer species had been discovered, namely C. sacchariphagus, C. auricilius, Tetramoera schistaceana, Scirpophaga excerptalis and Sesamia inferens. Further study needs to be done to investigate the borer distribution across sugarcane producing regions along with its potential loss due to the borer infestation.

INFESTATION LEVELS OF SUGARCANE SHOOT BORER CHILO INFUSCATELLUS IN CAUVERY DELTA ZONE OF TAMIL NADU, INDIA

Status of sugarcane shoot borer Chilo infuscatellus Snellen (Lepidoptera: Pyralidae) in the sugarcane command area of Pudukottai and Thanjavur districts lying in the Cauvery delta zone of Tamil Nadu, India, was assessed in May and October during 2013-2015. Infestation levels of the borer varied among eight divisions of the command area, two seasons and three years. In May, mean infestation rate was the highest in Vallathirakottai division (44.32%) and lowest in Andakulam division (37.86%). In October, the highest mean infestation rate was observed in Avanam (37.99%) and the lowest in Andakulam (25.49%). Repeated measures ANOVA analysis indicated that mean shoot borer infestation rate was significantly higher (40.84%) in May than in October (31.24%). Also, mean infestation rate was significantly lower in 2013 than in 2015. The possible factors responsible for the observed variation are discussed.

Molecular cloning, characterization, and expression profiling analysis of Cry toxin receptor genes from sugarcane shoot borer Chilo infuscatellus (Snellen)

The sugarcane shoot borer Chilo infuscatellus (Snellen) is known for causing severe damage to sugarcane yield in China. Methods have been developed to control this pest, including Cry toxin pesticide and transgenic Bt plants. In order to investigate the molecular mechanism of the Cry toxin binding process and provide a basis for understanding the insect's resistance mechanism, we used a high throughput sequencing platform to perform a de novo transcriptome assembly across different larval developmental stages and analyzed Cry toxin receptors based on our assembled transcripts. We cloned twelve Cry toxin receptor genes including 1 cadherin (Cad), 7 aminopeptidase-Ns (APNs), 3 alkaline phosphatases (ALPs), and 1 ATP-binding cassette transporter subfamily C2 (ABCC2), and three of them with full length. The sublethal dosage of Cry1Ac toxin was applied to sugarcane shoot borer and identified some Cry toxin receptor genes that were significantly induced after 48 h of exposure. Furthermore, quantitative RT-PCR was conducted to detect the expression profiles of these genes. Our transcriptome sequence data provided a valuable molecular resource for further study and the identified Cry toxin receptor data gave insights for improved research into the mechanism of Bt resistance.

Field reaction of selected sugarcane hybrids and Erianthus arundinaceus genotypes against shoot borer, Chilo infuscatellus snellen

Investigations were carried out to screen the different groups of sugarcane genotypes against early shoot borer Chilo infuscatellus from 2013–14 to 2016–17. A total of 18 exotic clones, 23 Erianthus arundinaceous and 38 sugarcane hybrids were selected for the study and the genotypes were graded based on cumulative % incidence of shoot borer. In all three years, none of the exotic clones escaped shoot borer attack and the infestation ranged from 3.0 to 47.8%. Among the exotic clones CL 44–223, F 31–450 and M 76–39 were recorded as resistant. Similarly, shoot borer incidence varied from 0.0 to 15.9% among E. arundinaceous genotypes. Shoot borer attack was absolutely nil (0.0%) in the genotypes IK 76–84 and IJ 76–370. Among the 23 E. arundinaceous genotypes tested under field conditions 16 genotypes were graded as resistant. In the 38 hybrids evaluated, five genotypes viz., Co 84028, Co 98013, Co 99016, 84A 146 and Co 97008 were not damaged by shoot borer over the study period which identified as highly resistant genotypes. However, highest shoot borer incidence was recorded in 9 entries viz., Co 62174, CoSnk 0754, Co 99004, Co 99008, ISH 153, Co 97015, CoC 671, Co 94005 and Co 99006 and categorized as highly susceptible with incidence levels ranging from 20.7 to 50%.

An Improved Bioassay Method for Entomopathogenic Fungi of Sugarcane Pests and Its Evaluation in Studies of Virulence in Subcultures

An improved bioassay method was developed for evaluating entomopathogenic fungi (EPF) using pests and fungi from sugarcane crop system. Third instar larvae of white grub Holotrichia serrata F. (Coleoptera: Scarabaeidae) and shoot borer Chilo infuscatellus Snellen (Lepidoptera: Crambidae) surface-contaminated with suspensions (108 spores/ml) of Beauveria brongniartii (Sacc.) Petch and Beauveria bassiana (Balsamo-Criv.) Vuill., respectively were subjected to starvation and feeding regimes. Holotrichia serrata grubs maintained in starvation regime showed lower overall mortality and higher LT50 values than those kept in feeding regime in one test; the trend was, however, opposite in the second test. On the other hand, C. infuscatellus larvae in starvation regime produced higher mortality and lower LT50 values than those in feeding regime in both tests. Further, spore output per C. infuscatellus larval cadaver was equal in both regimes. In degeneration studies, spore output of Metarhizium anisopliae Metch. maintained on nutrient broth for 15 continuous subcultures showed overlapping differences and a decreasing trend after the first six subcultures. In virulence studies with M. anisopliae from eight subcultures against diet-reared C. infuscatellus, third instar larvae treated with the fungus and maintained under starvation regime showed two peaks of LC50 and LT50 values. In comparative studies with field-collected C. infuscatellus, third instar larvae treated with 108 spores/ml of the fungus from 15 subcultures and fed with sugarcane shoots showed indistinct peaks in per cent mortality which reached significantly lowest value in the 15th subculture. The advantages of the modified bioassay method in virulence tests and the importance of degeneration studies for candidate EPF such as B. brongniartii are discussed.

Genetic transformation and pyramiding of aprotinin-expressing sugarcane with cry1Ab for shoot borer (Chilo infuscatellus) resistance

We evaluated the insecticidal toxicity of Cry1Aa, Cry1Ab and Cry1Ac toxins against neonate larvae of sugarcane shoot borer Chilo infuscatellus Snellen (Lepidoptera: Crambidae) in vitro on diet surface. With the lowest LC(50) value, Cry1Ab emerged as the most effective among the three toxins. Sugarcane cultivars Co 86032 and CoJ 64 were transformed with cry1Ab gene driven by maize ubiquitin promoter through particle bombardment and Agrobacterium-mediated transformation systems. Gene pyramiding was also attempted by retransforming sugarcane plants carrying bovine pancreatic trypsin inhibitor (aprotinin) gene, with cry1Ab. Southern analysis confirmed multiple integration of the transgene in case of particle bombardment and single site integration in Agrobacterium-mediated transformants. The expression of cry1Ab was demonstrated through Western analysis and the toxin was quantified using ELISA. The amount of Cry1Ab protein in different events varied from 0.007 to 1.73% of the total soluble leaf protein; the events transformed by Agrobacterium method showed significantly higher values. In in vivo bioassay with neonate larvae of shoot borer, transgenics produced considerably lower percentage of deadhearts despite suffering feeding damage by the borer compared with the untransformed control plants. Expressed Cry1Ab content was negatively related to deadheart damage. Aprotinin-expressing sugarcane pyramided with cry1Ab also showed reduction in damage. The potential of producing sugarcane transgenics with cry1Ab and aprotinin genes resistant to early shoot borer was discussed in the light of the results obtained.

Assessment of the tachinid Sturmiopsis inferens as a natural and applied biological control agent of sugarcane shoot borer (Chilo infuscatellus) in southern India

In field studies during 2000–2005, seasonal dynamics of sugarcane shoot borer Chilo infuscatellus Snellen (Lepidoptera: Crambidae) and its parasitoid Sturmiopsis inferens Tns. (Diptera: Tachinidae) were examined and augmentative releases of the parasitoid against the borer were evaluated at Coimbatore, India. The borer was active throughout the study period with the overall range of 0.3–28.6% fortnightly deadheart incidence. With considerable year-to-year variation, the borer peaked during July–August in high incidence years but showed indistinct peak activity periods in low attack years. Sturmiopsis inferens was found in all the study years with zero activity in some fortnights and overall maximum parasitism rates of 23.3 and 21.0% in 2000 and 2001, respectively; parasitoid activity dropped drastically in 2002 and the decline continued thereafter. The high parasitism years witnessed distinct peak activity in March and somewhat higher activity in July–August. Simple and multiple correlation analyses showed inconsistent influence of weather parameters on borer and parasitoid activity. Shoot borer activity was weakly related to St. inferens activity either in individual years or in the entire five-year period. Augmentative releases of St. inferens gravid females at dosages of 25–95 females/ha enhanced parasitism rates and reduced borer incidence in some trials but produced variable effects in some other trials. Dosage of parasitoid was not related to post-release parasitism rates in release plots. The results of the field trials and their implications are discussed.

Evaluation of Different Strains of Trichogramma chilonis Ishii for the Suppression of Sugarcane Early Shoot Borer, Chilo infuscatellus Snellen

The efficacy of high temperature tolerant (PDBC strain) and Ludhiana (Punjab) strain of Trichogramma chilouis Ishii against early shoot borer Chilo infuscatellus Snellen was evaluated in farmers' field during 2004 and 2005. The PDBC strain was released from April to June @ 50000, 40000 and 30000 parasitoids/ha. and the Ludhiana strain @ 50000 parasitoids/ha. Nine releases of PDBC strain and Ludhiana strain @ 50000 parasitoids/ha were as effective as application of cartap hydrochloride (Padan 4G) @ 25 kg/ha in reducing the incidence of C. infuscatellus by 52.7 and 50.5% over untreated control, respectively. At lower two doses, the reduction was 29.03 and 34.7 per cent over untreated control and was significantly better as compared to untreated control and mechanical control (removal of dead hearts). The maximum parasitoid recovery (10.71% parasitization) was recorded with PDBC strain @ 50,000 parasitoids/ha and was on par with Ludhiana strain (9.88% parasitization) and significantly higher than that with lower doses of PDBC strain and control. Based on reduced pest incidence, higher parasitism and yield, the releases of T. chilonis (PDBC strain/Ludhiana) @ 50000 parasitoids/ha at 10 days interval from April to June can be successfully used for the suppression of early shoot borer.

Infectivity of entomopathogenic nematodesHeterorhabditis andSteinernema spp. to sugarcane shoot borer (Chilo infuscatellus snellen) at different temperatures

Infectivity of twenty nine entomopathogenic nematode (EPN) isolates belonging to the families of Heterorhabditidae and Steinernematidae to sugarcane shoot borerChilo infuscatellus Snellen was investigated at 18 and 27°C under laboratory conditions. Although all the EPN isolates tested caused mortality of shoot borer larvae, there were differences in the level of mortality. Among the EPN isolates tested at 27°C, 120 h after inoculationHeterorhabditis indica (LN2),H. bacteriophora (German isolate) andSteinernema glaseri (Australian isolate) caused 100 per cent mortality of shoot borer larvae. Average time taken to kill shoot borer larvae was least (22.8 h) in case ofH. indica (LN2) followed byS. glaseri (26.5 h) andH. bacteriophora (German isolate) (28.4 h). Mortality percentage for other isolates ranged from 39.9 to 86.6. At 18°C,S. glaseri (Australian isolate) andH. bacteriophora (German isolate) caused 100 per cent mortality 120 h after nematode inoculation; with an average time taken to kill shoot borer larvae of 41.2 and 42.6 h respectively. All the EPN isolates took less time to cause mortality of shoot borer larvae at 27 than at 18°C. The multiplication of EPN in shoot borer larvae infected at 27°C was comparatively more than those infected at 18°C.

Evaluation of different formulations ofbacillus thuringiensis against sugarcane early shoot borerchilo infuscatellus snellen

FiveBacillus thuringiensis Berliner formulations,viz., Delfin, Biobit, Halt, Dipel (Bt. ssp.kurstaki and Spicturin (Bt. ssp.galleriae) were evaluated in two field trials in Tamil Nadu, India, against sugarcane early shoot borerChilo infuscatellus Snellen. Shoot borer infestation in bothBt. formulations and Sevidol treated plots decreased significantly by 42.59 to 62.41 per cent in the first experiment and 29.42 to 50.12 per cent in the second field experiment over untreated control. The number of millable canes (NMC) per plot at harvest was significantly high in Delfin (413.0) followed by Biobit (411.0), Dipel (396.3), Halt (390.0) and Spicturin (385.7) as compared to Sevidol (388.0) and untreated control (352.3) in the first experiment. A more or less similar trend was noticed in the second experiment. Cane yield, commercial cane sugar (CCS) per cent and sugar yield significantly increased due toBt treatments compared to control. In both the experiments, the order of efficacy ofBt formulations was Delfin> Biobit > Dipel > Halt > Spicturin. The currently recommended insecticide Sevidol was less effective compared to Delfin, Biobit and Dipel.

Incidence of sugarcane shoot borer under different levels of weed competition, crop geometry, intercropping and nutrient supply systems

The effect of selected agronomic practices on the incidence of sugarcane shoot borerChilo infuscatellus Snellen (Lepidoptera: Crambidae) was examined. In an experiment on critical periods of crop-weed competition, wherein sugarcane crop was maintained with different weed regimes, the incidence of borer was significantly lower in weedy crop than in weed-free crop. The study suggested that crop-weed vegetational diversity maintained up to 75DAP may reduce shoot borer populations. In the experiment on crop geometry - intercrop combinations with three planting patterns and four intercrops, shoot borer incidence showed non-significant differences. Similarly, in the trial on nutrient supply systems that included combinations of organic manure, green manure, sugarcane trash, biofertilizer and chemical fertilizer as sources of nutrients, shoot borer incidence showed non-significant differences.

Patterns of Laboratory Parasitisation Rates of Cotesia flavipes Cameron (Hymenoptera: Braconidae) in Borers of Sugarcane and Sorghum

Laboratory parasitisation rates of a native (Indian) and an exotic (Indonesian) population of the gregarious larval endoparasitoid Cotesia flavipes Cameron (Hymenoptera: Braconidae), mass reared by the group-exposure method in glass chimneys, were examined during 1990–1994 on three hosts, namely the sugarcane shoot borer Chilo infuscatellus Snellen, sugarcane internode borer Chilo sacchariphagus indicus (Kapur) and spotted stemborer Chilo partellus (Swinhoe) (Lepidoptera: Crambidae). Parasitisation rates of both the Indian and Indonesian populations in individual rearing batches showed considerable variation. Correlation and multiple regression analysis of parasitisation rates in rearing batches and three rearing parameters, viz. percent males, number of larvae and number of larvae per female parasitoid, indicated variable influence of the rearing parameters. Parasitisation rates of the Indian population were positively related to percent males and negatively related to number of larvae and number of larvae per female parasitoid in some hosts. The parasitisation rates of the Indonesian population were negatively related to percent males only in Ch. partellus. Mean monthly parasitisation rates of both populations during the study period fluctuated considerably in different hosts. The role of rearing parameters as well as rearing history of host and parasitoid cultures in parasitisation rates is discussed.

Borer and predator incidence in sugarcane intercropped with pulses

The effect of pulse intercrops on some borer pests of sugarcane and general predators was examined in two field studies. In a replicated experiment with black gram, cowpea, green gram and soybean as intecrops, the incidence of shoot borerChilo infuscatellus Snellen (Leptidoptera : Crambidae) did not differ significantly amongst the different combinations and control. The incidence of top borerScirpophaga excerptalis Wlk. (Lepidoptera : Pyralidae) was negligible in all combinations. Counts of predators, comprising spiders and coccinellids, showed marginal differences. In the second study at farmers’ fields, shoot borer incidence was significantly higher in 25 days and 65 days old sugarcane-soybean diculture plots than in sugarcane monocrop plots of corresponding age; the differences were not significant in a 30 days old crop. Mean predator numbers did not differ significantly between intercrop and monocrop in these three plots. The importance of factors such as crop combination, temporal and spatial patterns of planting, agronomic suitability, etc. in sugarcane-based ploycultures for sugarcane pest management is discussed.

Pathogenicity and Host Range of Beauveria nr. bassiana , a Fungal Pathogen of Chilo infuscatellus Snellen

Second and third Instar larvae of the shoot borer Chilo infuscatellus Snell., were more susceptible (51.47 to 65.2 %) to the fungus, Beauveria nr. bassiana even at a low dosage (10 5 or 10 6 spores/ml), At 10 7 spores/ml, the mortality observed was 68.53-75.93 %. Mortality of the larvae decreased with increase in larval age or decrease in the concentration of the fungus. The fungus took less time to cause mortality in second instar larvae and the incubation period Increased with Increase in the age of the larvae or decrease in the dosage. All the six species of phytophagous insects tested Viz ., Chilo sacchariphagus indicus (Kapur), C. partellus Swinhoe, Scirpophaga excerptalis Walker, Sesamia inferens Walker, Heliothis arniigera Hubner and Spodoptera litura Fabricius were susceptible to the fungal Infection. The mean mortailty of third Instar larvae varied from 50.0 to 65.0 per cent in the different species. The fungus was not infective to Sturmiopsis inferens Tns. the principal larval parasite of the shoot borer.

Survey of granulosis virus infection in sugarcane borers,Chilo infuscatellusSnellen andC. sacchariphagus indicus(Kapur) in India

Abstract A survey was undertaken to observe the pevalence of granulosis viruses infecting sugarcane shoot borer Chilo infuscatellus Snellen and internode borer C. sacchariphagus indicus (Kapur) in Tamil Nadu State and Union Territory of Pondicherry in India. Nine districts in Tamil Nadu and Pondicherry had the occurrence of shoot borer granulosis virus in all the locations surveyed ranging from 2.6 to 14.6%. In internode borerthe mortality varied from 3.8 to 31.5% in the eight districts of Tamil Nadu and Pondicherry.