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Resistance of sugarcane hybrids to internode borer Chilo sacchariphagus indicus (Lepidoptera: Crambidae)
- P. Mahesh, B. Singaravelu, J. Srikanth, K. P. Salin, K. Chandran, R. Nirmala
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- Journal:
- Experimental Agriculture / Volume 60 / 2024
- Published online by Cambridge University Press:
- 21 February 2024, e6
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A four-year field study (2013–2016) was conducted to screen Indian sugarcane hybrids together with two susceptible checks against internode borer Chilo sacchariphagus indicus (Kapur) (Lepidoptera: Crambidae) in endemic locations of Tamil Nadu State, India. Each year, borer incidence on cane basis and intensity on internode basis were assessed at harvest to eliminate susceptible entries. Of the total 535 hybrids screened, only Co 293 emerged as resistant at the end of fourth year trial which was confirmed in tests under controlled conditions with artificial infestation. A modified relative resistance ratio computed using incidence and intensity also confirmed its resistance to the borer. In laboratory oviposition choice tests with excised leaves of the resistant Co 293 and susceptible hybrids Co 86032 and Co 1060, percent of leaf bits oviposited, egg masses laid, and egg numbers deposited were significantly lowest in Co 293. Also, an oviposition preference index computed for both egg mass number and egg number was significantly lowest for Co 293 which suggested antixenosis. Larval survival was significantly lowest in Co 293 with 5 to 10-fold higher neonate mortality than in the two susceptible hybrids. Prolonged larval development period and lower fecundity were observed when the borer was reared on Co 293 which indicated antibiosis. A relative suitability ratio developed from larval and pupal durations also indicated lower suitability of Co 293. Among the plant morphological characters examined, leaf length and cane thickness positively influenced borer incidence; loose sheath-clasp was associated with higher borer incidence. Among 12 shoot phenolics quantified, eight were present in higher quantities in Co 293 suggesting their role in antibiosis. Co 293 identified as resistant hybrid in the present study has the potential to be used as a parent in breeding programs for C. sacchariphagus indicus resistance.
OCCURRENCE, DAMAGE PATTERN AND STATUS OF THE RICE LEAF FOLDER CNAPHALOCROCIS RURALIS WALKER (LEPIDOPTERA: CRAMBIDAE) IN ERIANTHUS SPP. IN INDIA
- P. MAHESH, J. SRIKANTH, K. CHANDRAN, B. SINGARAVELU, K. P. SALIN, C. JAYABOSE, S. BALAN
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- Journal:
- Experimental Agriculture / Volume 55 / Issue 3 / June 2019
- Published online by Cambridge University Press:
- 02 April 2018, pp. 471-483
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We investigated the occurrence and status of the leaf folder Cnaphalocrocis ruralis (Walker) (Lepidoptera: Crambidae) in accessions of Erianthus spp. maintained as a part of the world germplasm collection at the Research Center of ICAR-Sugarcane Breeding Institute, Kannur, Kerala State, India. The nature, pattern, extent and year-to-year variation in damage were examined and accessions categorized based on relative incidence. The larvae of C. ruralis caused characteristic injury by feeding on chlorophyll bearing tissues leading to the formation of white and transparent streaks on the leaf blade. The grown-up larvae folded the leaf longitudinally with the adaxial surface inside the fold and exposing the abaxial surface, the edges being held in place by bands of silk thread at regular intervals. The length of leaf folds varied from 2.6 to 27.0 cm with a mean of 9.1 cm, which roughly constituted 7.3% of the mean length of the leaf blade. Leaf length, leaf width and leaf area were not correlated with either the leaf fold length or the number of webs. However, the leaf fold length was positively correlated with the number of webs. Attack rates (infestation rate) on cane basis (up to 69.0%) were generally higher than the damage rates (intensity) on leaf basis (up to 50.0%); infestation index ranged between 0.0 and 13.7%. Correlations between infestation rate and intensity varied among the three study years. Non-parametric analysis indicated significant differences among the three years for percent of infested canes and infestation index but not percent of damaged leaves. All accessions showed C. ruralis incidence in at least one experimental year, indicating that none of the accessions tested was immune to its attack. When all 74 accessions were considered on the basis of infestation index, 85.1% were placed in low and moderate categories and only 14.9% in high incidence category. Within the accessions of Erianthus spp., leaf area was not related to infestation rate of cane or damage rate of leaves but positively related to infestation index. The dynamics of the leaf folder in the predominantly paddy ecosystem were discussed in the light of its first occurrence in Erianthus spp. accessions in India and the world.
RESISTANCE OF SACCHARUM SPP. AGAINST CHILO SACCHARIPHAGUS INDICUS (KAPUR) (LEPIDOPTERA: CRAMBIDAE) IN INDIA
- P. MAHESH, J. SRIKANTH, K. CHANDRAN, B. SINGARAVELU
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- Journal:
- Experimental Agriculture / Volume 54 / Issue 1 / February 2018
- Published online by Cambridge University Press:
- 28 October 2016, pp. 83-95
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Accessions of four Saccharum spp. from the world collection of sugarcane germplasm maintained at the ICAR-Sugarcane Breeding Institute Research Center, Kannur, Kerala State, India, were screened against Chilo sacchariphagus indicus (Kapur) (Lepidoptera: Crambidae), commonly known as internode borer. Observations on the progression of borer attack in the most susceptible Saccharum officinarum indicated that the incidence began in the first fortnight of July, increased in the next 2 months and reached its peak in September. Thereafter, the incidence decreased in the next 2 months but reached its overall peak in December. Simple correlation coefficients between mean monthly weather parameters and borer incidence were not significant. Percent of canes attacked was significantly lower in 2011 than in 2012 for S. officinarum, Saccharum barberi and Saccharum sinense but did not differ between the years for Saccharum robustum. Amongst the four Saccharum spp., S. robustum showed the lowest borer incidence whereas S. officinarum recorded the lowest attack intensity. Whilst infestation index showed the same trend as percent canes attacked, percent deadhearts did not differ amongst the four Saccharum spp. Considering the 171 accessions evaluated, 29 (16.9%) accessions were resistant, 39 (22.8%) moderately resistant and 103 (60.2%) susceptible to internode borer. Out of the 39 accessions of S. officinarum, none occupied the resistant category whereas 17.9% were in the moderately resistant category. In S. robustum, whilst nearly half (44.5%) the accessions emerged as resistant, a considerable number occupied the moderately resistant category. In S. barberi, no accession was resistant to the borer. In S. sinense, only one accession each represented resistant and moderately resistant categories. Plant morphological characters, yield and quality parameters did not show clear-cut relationship with the three infestation parameters.