Shoot Borer Infestation Research Articles

Biology of shoot and fruit borer, Earias vittella Fabricius (Noctuidae: Lepidoptera) on okra

The biology of fruit and shoot borer (Earias vittella F.) was studied under the natural conditions in the instructional farm of Uttar Banga Krishi Viswavidyalay in pre-kharif, kharif and post-kharif on okra. The study revealed that the egg incubation in pre-kharif, kharif and post-kharif revealed that the egg incubation were 3.18±0.40, 3.61±0.70 and 4.25±0.67 and larval period were 11.00±0.88, 11.00±0.82 and 13.01±1.81 during corresponding seasons respectively. The pupal period in pre-kharif, kharif and postkharif were 13.01±1.81; 11.00±0.82; 10.97±2.15 days respectively. The adult male longevities observed were 3.64±0.67, 5.60±0.70 and 7.33±0.97 during pre-kharif, kharif and post-kharif. On the other hand female longevities observed were about 7.45±1.57b; 8.87±1.10; 9.41±1.51 days in corresponding seasons respectively. The female fecundity during pre-kharif, kharif and post-kharif were 91.55±10.93, 117.55b±10.60 and 132.04±5.83 eggs in their lifetime. The pre-oviposition during pre-kharif, kharif and post-kharif were 1.64±0.50, 1.52±0.53 and 1.88±0.57 and the oviposition periods in corresponding seasons were 2.73±0.47, 3.22±0.79 and 4.32±0.52. While post-oviposition periods in pre-kharif, kharif and post-kharif were 3.09±0.70, 4.14±0.63 and 3.23±0.92 respectively. Its total life-cycle was completed in 27.45±1.57, 31.60±1.90 and 41.35±2.55 days during pre-kharif, kharif and post-kharif respectively. Higher fecundity may lead to faster population growth that may surpass the economic threshold level (ETL), even though the shoot and fruit borer’s life cycle is longer in Kharif and post-kharif. Thus, it may be said that the kharif and poskharif seasons are the most susceptible to shoot fruit and shoot borer infestation.

Studies on Genetic Variability and Associations of Fruit and Shoot Borer Infestation for Yield Attributing Traits in Transgressive Segregating Populations of Brinjal (Solanum melongena L.)

Studies on Genetic Variability and Associations of Fruit and Shoot Borer Infestation for Yield Attributing Traits in Transgressive Segregating Populations of Brinjal (Solanum melongena L.)

Evaluation of Purple Segmented Brinjal (Solanum melongena L.) Genotypes for Growth and Yield Contributing Characters under Coimbatore Condition

Aim: Brinjal (Solanum melongena L.) is one of the most important vegetable crops which is grown in India and throughout the world which belongs to Solanaceae family with chromosome number 2n =24. This investigation is mainly aimed to evaluate the brinjal genotypes and identify the superior genotypes with high yield, good quality and tolerance to shoot and fruit borer.
 Study Design: The experimental materials consisted of twenty-one genotypes and two check were laid out in Randomized Block Design (RBD) with two replications.
 Place and Duration of Research: The study was carried out at Horticulture orchard, Department of Vegetable Science, Horticulture College and research Institute, Tamil Nadu Agricultural University, Coimbatore during 2022-2023.
 Methodology: In this study, twenty-one genotypes along with two checks were collected from various part of Tamil Nadu. Plants were raised in portrays and 30 days old plants were transplanted to main field at 60 X 60 cm spacing. Growth and yield parameters were observed and recorded.
 Results: Based on per se performances CBE-SM-006 found to be superior genotype since, it recorded highest marketable fruit yield, number of flowers per cluster, number of fruits per cluster and minimum fruit and shoot borer infestation followed by CBE-SM-108. Hence, CBE-SM-006 and CBE-SM-108 are the promising genotypes which can be used for further breeding programme. 
 Conclusion: The study will provide detail knowledge on selecting the superior genotypes for further crop improvement in brinjal.

Seasonal incidence and effect of abiotic factors on population dynamics of major insect pests on Brinjal crop

Experiment was carried out on Seasonal incidence and effect of abiotic factors on population dynamics of major insect pests on Brinjal (Solanum melongena L.) at College Farm, N. M. College of Agriculture, Navsari Agricultural University, Navsari during summer-2020. The results revealed that incidence of shoot borer infestation on shoot was commenced from second week of March (11th SMW) to third week of May (21st SMW) while, infestation of fruit damage was noticed at first picking of the brinjal fruit in the first week of April (14th SMW) with maximum in fourth week of May (21st SMW). Shoot and fruit borer infestation exhibited significant and positive correlation with maximum temperature (r= 0.8129) and minimum temperature (r= 0.8444) and wind velocity (r= 0.5871), respectively. Whitefly population was started from second week of February (9th SMW) with 0.93 whitefly per leaf, increased gradually to reach its peak in the last week of April, i.e.17th SMW (15.95 whiteflies/leaf) and positively and significantly correlated with and maximum temperature (r= 0.8062). The jassid infestation started from first week of March, i.e. 10th SMW (0.34 jassids/ leaf), initially increased slowly and reached to its peak level (11.89 jassids/leaf) at last week of April (17th SMW) and positively and significantly correlated with maximum (r= 0.7202) and minimum (r= 0.5712) temperatures. Aphid population started from the first week of March (10th SMW) with a minimum level of 0.60 aphids/leaf, increased slowly and reached to its peak level (5.04 aphids/leaf) at third week of April (16th SMW) and exhibited positive and significant correlation with maximum temperature (r= 0.7849).

Evaluation and Selection of Brinjal (Solanum melongena L.) Genotypes for High Yield with Fruit and Shoot Borer Tolerance

Aim: Brinjal (Solanum melongena L.) is a vital crop of India which belongs to the family Solanaceae with a chromosome number of 2n=24.This study is aimed to evaluate brinjal genotypes and identify superior types with desirable qualities, high yield with fruit and shoot borer tolerance.
 Study Design: The experimental materials consisted of fifteen genotypes and two checks which were laid out in a Randomized Block Design (RBD) with three replications.
 Place and Duration of Research: The investigation was carried at Horticultural College orchard, Department of Vegetable Science, Horticultural College and Research Institute Tamil Nadu Agricultural University, Coimbatore during 2021-2022.
 Methodology: Fifteen local types of brinjal and two checks were collected from several districts of Tamil Nadu and various other sources. Seeds were sown in portrays and then transplanted to main field at the age of 30 days. Growth and yield parameters were observed and recorded.
 Results: Based on the per se performance of the genotypes, CBE SM-006 was adjudged as the best one since, it has recorded superior performance for the characters studied viz., number of branches, fruit weight, number of fruits per plant, fruit yield per plant. Also, CBE–SM-006 found to have minimum fruit borer infestation and shoot borer infestation hence providing maximum marketable yield per plant. The genotype CBE-SM-105 also performed the best for most of the desirable characters. Thus, CBE-SM-006 could be a promising genotype for further breeding programme.
 Conclusion: Thus, the study will provide comprehensive knowledge on evolving and selecting superior genotypes which is indispensable to aim at rational improvement in crop plant.

Phenotypic Stability for Fruit yield and its Components of Brinjal

The present study was carried out at Vegetable Research Station, ARI, Rajendranagar, Hyderabad, Telangana State, India during kharif (June–October, 2014), rabi (October–February, 2014–15) and Summer (February–May, 2015) to assess the performance of genotypes in terms of yield as well as quality across seasons under wide range of environments through phenotypic stability studies. Thirty brinjal genotypes were evaluated for yield and quality parameters under three environments comprising of three different seasons. The portioning of environments + (genotypes × environments) mean squares showed that environments (linear) differed significantly and were quite diverse with regards to their effect on the performance of the genotypes for fruit yield and quality traits. A perusal of stability parameters indicated two genotypes C3 and P6 showed stable performance for earliness, C3 for days to first fruit harvest and C3, C10, C16, C21, P1 for days to last fruit harvest hence these genotypes were adapted to all types of environments. Among the stable hybrids, five hybrids C3, C11, C13, C16 and C21 were significantly more yield plant-1 and more number of marketable fruits plant -1 over the best check Chhaya. Whereas, for ascorbic acid content 5 hybrids i.e C2, C4, C11, C14 and C18 to be stable over the check Utkarsha. C3 was showed stable performance over best check Chhaya for the trait fruit and shoot borer infestation on shoots and four hybrids C3, C11, C13 and C21 were found to be stable for the trait fruit and shoot borer infetstation on fruits over the best check Chhaya.

G × E interaction, biochemical characterization and SSR marker analysis of eggplant (Solanum melongena) for shoot and fruit borer resistance

Brinjal or Aubergine or Eggplant, one of the top ten growing vegetables incurs serious crop losses due to shoot and fruit borer from season to season especially under high humidity leading to population buildup reducing the crop yield up to 60–70%. This present investigation was carried out during 2018–19 at Annamalai University, Tamil Nadu, India using 36 genotypes and landraces to identify stable genotypes of eggplant with high yield and resistance to shoot and fruit borer. The genotypes were also characterized using eleven SSR markers, where three were not amplified. The AMMI and GGE biplot analyses have shown the significant contribution of genotypic variation over the environments and their interaction. AMMI and GGE analysis revealed that ICO361838 was the most stable genotype for fruit yield per plant, whereas ICO-354749 and ICO-427008 were stable for the trait shoot borer infestation. The resistant lines had the highest total phenol, polyphenol oxidase and ascorbic acid content but total sugar content was lowest in these lines. The identified genotypes can be further utilized in breeding for resistance and the selection can also be done on the basis of these biochemical parameters. However, the SSR markers utilized were not informative enough and for marker assisted selection a greater number of primers should be added.

Overview of Insecticides against Shoot and Fruit borer [Earias vittella (Fabricius)] of Okra

Okra Abelmoschus esculentus (L), a Malvaceous vegetable which is cultivated throughout the tropical and warm temperate regions of the world and India and different states of India too. Many of the pests occurring on cotton are found to ravage okra crop Okra shoot and fruit borer, Earias vittella (Fabricius) have emerged as a major pest of okra from last decades. Fruit infestation started at the beginning of fruiting, increased progressively up to harvesting and reached a peak. Further, it was noticed that the population of Earias spp. increased slowly up to mid-September and rapidly thereafter. Minimum temperature and relative humidity had a significant negative correlation with shoot borer infestation.

Study of combining ability for yield contributing traits in brinjal (Solanum melongena L.)

The combining ability analysis of 8×8 half diallel set of crosses in brinjal was undertaken for fruit yield and its attributing characters. Eight parents, twenty eight hybrids and two standard checks were evaluated during late kharif/rabi 2018-19 for the present study in randomized block design for two replications. The analysis of variance revealed presence of considerable variability among genotypes for all the characters under study. Combining ability analysis revealed important of both additive and non additive variances in expression of various traits. Among the parental genotypes, parent SBJH-631 and Sep-034 were good general combiners for fruit length, fruit cluster per plant, number of fruits per plant, fruit yield, number of leaves per plant, shoot borer infestation and fruit borer infestation. Followed by Utkal Keshari and IBH-2 for days to 50% flowering, fruit weight, fruit diameter, fruit cluster per plant, number of fruits per cluster and fruit borer infestation. In respect to estimates of specific combining ability effects, cross IBH-2 x SBJH-631 was good for number of branches per plant, number of fruits per plant, number of fruits per cluster and fruit yield and SBJH-631 x Sep-034 was shown best specific combining ability for number of leaves per plant, number of flowers per plant, number of fruits per plant, total yield and fruit borer infestation characters. The additive gene components were observed to be predominant for all characters except number of branches per plant, number of leaves per plant and shoot borer infestation.

Correlation studies on yield and yield components in brinjal (Solanum melongena L.)

An experiment on correlation analysis involving brinjal (Solanum melongena L.) was carried during rabi 2018 at college orchard, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India. Genotypic correlation coefficient was similar in nature and higher in magnitude than the corresponding phenotypic correlation coefficient for most of the characters. Total yield per plant exhibited highly significant and positive relationship with length of the fruit and the number of fruits per plant is significantly but negatively correlated with shoot borer infestation. Thus, the yield per plant can be enhanced by making selection of these traits during the yield improvement programme.

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.

Effect of nitrogen and potash on Early shoot borer (Chilo infuscatellus Snellen) incidence in differently maturing varieties of sugarcane

It has been argued that fertilization may influence the susceptibility of insect pests, and thus, can increase the crop production by lowering the incidence of insect-pest. Here, the present investigation was carried out to study the influence of nitrogen and potash levels on the incidence of early shoot borer, Chilo infuscatellus Snellen in sugarcane varieties at Regional Research Station CCSHAU Uchani farm, Karnal. The experiment was laid out in split-split plot design with three differently maturing varieties viz., Co 0238, CoH 119 and CoH 150 as main plot, three doses of nitrogen viz., 150, 200 and 250 kg per hectare (kg/ha) as sub plot and two doses of potash viz., 0 and 50 (kg/ha) as sub-sub plot. The early shoot borer mean per cent incidence recorded in April, May and June, 2015 was highest (7.68, 12.19 and 6.35, respectively) in Co 0238 while, lowest (5.16, 8.51 and 5.40, respectively) in CoH 119 followed by CoH 150 (6.29, 8.79 and 5.43, respectively). In relation to nitrogen application, maximum mean per cent incidence (7.12, 11.19 and 6.48, respectively) in April, May and June, 2015 of early shoot borer was recorded at 250 kg N/ha and the minimum (5.68, 8.57 and 5.23, respectively) at 150 kg N/ha. Application of potassium significantly reduced the shoot borer infestation with mean per cent incidence lower at 50 kg K2O/ha (5.90, 9.24 and 5.33, respectively) in April, May and June, 2015 compared to control i.e., no application of potassium (6.85, 10.42 and 6.12, respectively). Results revealed that application of potassium with optimum dose of nitrogenous fertilizer along with selection of suitable variety acted as preventive measures to avoid shoot borer infestation.

Association of Fruit and Shoot Borer Infestation in Eggplant with Morphological, Yield, Quality and External Weather Variables

The association of the fruit and shoot borer (Leucinodes orbonalis Guen) Infestation in eggplant with morphological, yield, quality and weather variables was studied at Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India, during the spring–summer (February–June) of 2012–2013 and 2013–2014 and autumn–winter (September–March) of 2013–2014 and 2014–2015. Earlier infestation occurred on the plants during the spring–summer, while late infestation of the pest was observed during the autumn–winter. The Number of infested shoots per plant, per cent shoot infestation, number of infested fruits per plant, per cent fruit infestation and larvae per fruit were greater during the spring–summer months than during the autumn–winter months. The fruit infestation had a significant negative association with fruit yield per plant. The number of infested fruits per plant was positively and significantly associated with primary branches per plant, fruits per plant and fruit yield per plant. A significant negative correlation was observed between spines on stem and number of infested shoots per plant, and the correlation of number of infested fruits per plant with the spines on the stem, petiole and pigmentation on leaf lamina was positively significant. Genotypes with purple colour flowers and fruits had greater eggplant fruit and shoot borer (EFSB) infestation. The long slender fruit shape and clustered fruiting habit promoted the EFSB infestation. The TSS and anthocyanin in peel were found as the phagostimulants, while the high total phenols content and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging capacity were the feeding deterrents. The per cent of infested fruits per plant exhibited a positive correlation with maximum (Tmax), average (Tavg) and day temperatures. Larvae per fruit had a positive association with maximum temperature (Tmax), day temperature and helio-thermal units.

Mean performance ofbrinjal (Solanum melongena L.) genotypes under Tamil Nadu condition

Thirteen genotypes of brinjal were collected from various places of Tamil Nadu and other states and evaluated during September 2017- January 2018. Among these, the plant height of the genotypes ranged between 72.93cm (Utkal Anushree) to 95.84 cm (Bhavani Gold), Number of branches was found be highest in IC 3749281 (7.75), ABSR 2 recorded the least number of days to first flowering (43.15 days), Karur Local showed the least value of 64.46 days for days to first harvest among the genotypes, Thevur Local recorded the maximum fruit length of 12.95 cm, Mattu Gulla showed the highest value of fruit girth (17.44 cm) and individual fruit weight (88.67 g). The maximum number of fruits was recorded in ABSR 2 (39.75), the shoot borer infestation was found to least in IC 374928-1 (11.28 %) and least value for fruit borer infestation was observed in Karur Local (14.16 %) and ABSR 2 (14.87 %). Among the genotypes evaluated, the highest marketable yield was recorded in Karur Local (2.60 kg) followed by Bhavani Gold (2.15 kg).

Screening of Sugarcane clones for resistance to Early shoot borer and Internode borer

Field trials were to identify the resistant sources for early stem borer, inter node borer and to evaluate the breeding pipelines for their resistance/susceptibility. To screening of IVT early accessions, planting of ten entries with two checks were periodically assessed for the pest incidence and damage levels were recorded for the major pests early shoot borer and internode borer. Among the two entries, Co 05081 and 05101 recorded lower levels of early shoot borer. With regards to the inrternode borer, three accessions viz., Co 05081, Co 05101 and Co Si (Sc) had lower levels of damage which had the intensity of 12, 15 and 18%, respectively. Screening of sugarcane accessions in main crop, all the 30 clones, were recorded lower levels of early shoot borer infestation. With regard to the internode borer, 22 accessions viz., Co-07-001, Co-03134, MS 0681, Co 06023, Co 06010, Co 06014, Co-06013, PI 07131, Co 07004, Co 07005, Co 07007, Co 07009, Co 07020, CoV 07061, con 07073, CoM 07083, CoSnk 07103, CoSnk 07104, CoSnk 07105, Co 06012 CoSnk 06101 and Si 2000–02 had lower level of damage and 8 accessions viz., Ms 07081, Co 06022, Co 06022, Co 06001, Co 07006, CoJn 07093, CoJn 070940 and PI 06131 were medium level of damage. In first ratoon crop, all the 30 clones, were recorded lower levels of early shoot borer infestation. With regard to the internode borer, 22 accessions viz., Co 07001, Co 03134, MS 0681, Co 06023, Co 06010, Co 06014, Co 06013, PI 07–131, Co 07004, Co 07005, Co 07007, Co 07009, Co 07020, CoV 07061, CoN 07073, CoM 07083, CoSnk 07103, CoSnk 07104, CoSnk 07105, Co 06012, CoSnk 06101 and Si 2000–02 had lower level of damage and 8 accessions viz. Ms 07081, Co 06022, Co 06022, Co 06001, Co 07006, CoJn 07093, CoJn 070940 and PI 06131 were medium level of damage.

English

Heterosis has been amply exploited in developing hybrids in brinjal. In India, only 17.8% area of brinjal cultivation is under hybrid seed due to lack of appropriate hybrids for specific area and purpose. In the present investigation, 14 parents were selected on the basis of divergence and mated in line (L) × tester (T) design hybrids and parents were raised to measure heterosis for different yield attributes. 40 hybrids resulting from a L × T mating design comprised of 10 lines (female) and 4 testers (males) were studied to determine the magnitude of heterosis and genotypic correlation between yield and yield characters. Expression of superiority over the commercial check occurred in 7 crosses, which ranged from -56.36 (L3 × T4) to 34.07% (L7 × T2). The hybrid (L7 × T2) had good heterosis values for growth and yield and is recommended as the most promising combination for developing high yielding hybrid eggplant varieties. Most crosses involving T2 as tester parent had significant positive heterosis over the mid-parent and standard variety. There were strong correlations between fruit yield and numbers of branches per plant, average fruit weight and number of fruit per plant. Path analysis indicated that plant height, number of branches per plant, fruit length, fruit pedicel length, number of fruit per plant, average fruit weight and little leaf incidence had direct and positive effects on yield per plant, but negative and direct effects occurred for days to first flowering, fruit circumference, calyx length, shoot borer infestation, fruit borer infestation, ascorbic acid content and total phenol content. Simple selection would be effective for improvement of fruit yield.   Key words: Solanum melongena, association analysis, hybrid vigour.

Out breeding for yield and horticultural attributes in indigenous eggplant germplasm

Heterotic effects and genetic components of variation for qualitative and quantitative characters were estimated in eggplant (Solanum melongena L.). Forty hybrids generated by crossing four testers (males) with ten lines (females) were studied along with parents for studying heterosis and gene action for calyx length, fruit pedicel length, shoot borer infestation, fruit borer infestation, little leaf incidence, ascorbic acid content, total phenols content, number of fruit per plant and fruit yield per plant during rainy season of 2010-2011. The crosses obtained by L × T method possessed variation in terms of growth, yield and quality traits. Mean fruit yield per plant ranged from 2.85 to 1.04 kg. Among the 40 hybrids, the ones obtained from the cross 'Alagarkovil Local' × 'Annamalai' (L4 × T1), 'Palamedu Local' × 'Punjab Sadabahar' (L5 × T3), 'Palamedu Local' × 'EP 65' (L5 × T4) and 'Keerikai Local' × 'KKM 1' (L7 × T2) were suitable for heterosis breeding. Average performance of parents indicated that lines 'Alavayal local' (L1), 'Sedapatty local' (Green) (L2) and the tester 'Annamalai' (T1) were good parents for further breeding to exploit high yield and low pest and disease incidences. Performance of these hybrids needs to be further evaluated in multiple locations or on farm trial prior to commercial use. Key words: Hybrid vigour, brinjal germplasm, selection, yield attributes.

Gene action and combining ability of yield and its components for late kharif season in okra (Abelmoschus esculentus (L.) Moench)

Knowledge on the genetic system controlling the quantitative traits is important for devising an efficient selection program through the use of a suitable mating design. Forty five F 1s were generated by crossing 10 germplasm lines of okra (Abelmoschus esculentus (L.) Moench) namely P1(IC282248), P2(IC27826-A), P3(IC29119-B), P4(IC31398-A), P5(IC45732), P6(IC89819), P7(IC89976), P8(IC90107), P9(IC99716), and P10(IC111443) during summer 2009. Forty five F 1s along with their 10 parents were evaluated in a randomized block design with three replicates during late kharif (AugustNovember) 2009 at Vegetable Research Station, Hyderabad, Andhra Pradesh, India, for studying gene action and combining ability of yield and its components. Significant general combining ability and specific combining ability variances were obtained in majority of the traits except fruit and shoot borer infestation on fruits and shoots; implying that both the additive and non-additive gene effects operated in the genetic expression of the traits. The relative magnitude of general and specific combining ability variances indicated preponderance of non-additive gene action for majority of the characters studied except number of branches per plant and fruit width. Combining ability analysis of parents revealed that the parental lines P5(IC45732), P6(IC89819) and P7(IC89976) were superior general combiners for total and marketable yield per plant and other traits. The crosses C23(IC29119-B × IC99716), C17(IC27826-A × IC111443), C42(IC89976 × IC111443) and C43(IC90107 × IC111443) were superior specific combiners for total as well as marketable yield per plant with the potential of being commercially exploited for the production of F1 hybrids. The crosses C17 (IC27826-A × IC111443) and C42(IC89976 × IC111443) involving one or both of the parents with positively significant general combining ability effects for marketable yield per plant could be utilized in recombination breeding.

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.

Influence of spray fluid volume and purity on the effectiveness of a granulosis virus infecting sugarcane shoot borer,Chilo infuscatellusSnellen

Abstract Two field experiments were conducted with a granulosis virus infecting sugarcane shoot borer, Chilo infuscatellus Snellen. In both the experiments, application of the virus significantly reduced the borer infestation compared to untreated control. The first experiment was carried out to determine the effectiveness of the virus applied as high and low volume sprays. When virus was applied at 5.5 x 1012 IB/ha as high volume (500 I/ha), 70.2% of the plants were protected from shoot borer infestation compared to 53.6% in low volume spray (150 I/ha). Significant reduction (P> 0.01) in shoot borer infestation was observed in plots treated with high compared to low volume spray. In the second experiment the effectiveness of the virus applied as crude and purified preparations was assessed. Both crude and purified preparations significantly (P > 0.01) reduced the borer infestation compared to untreated check. No significant differences (P < 0.05) were observed between plots treated with crude and purifie...