Spatial dynamics of teak defoliator (Hyblaea puera Cramer) - Cochin ...

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away places. These populations seldom cause further outbreaks in the area and the local population declines to endemic level. This may be due to the reduction in food source since most of the leaves would be mature and not acceptable to the early larval instars. The graph in Fig 8.1. shows the temporal sequence of shifts in population density. At Nilambur the population density remains at endemic level during January and February (A). During late February or March, the initial epicentres occur causing an increase in population density (B). From April to July, the population remains at epidemic level, causing large outbreaks at different places (C). During August, the population reverts to endemic level (Az). During September - October further small-scale outbreaks occur (Bj) followed by a period of endemic population (A3) which extends to February, next year. At the local level a specific period can be identified during which control operations are feasible. Control of the epicentres and any new populations occurring during the build-up phase can theoretically prevent large-scale outbreaks. This would be an economical way of preventing outbreaks as compared to an attempt to control wide-spread outbreaks. The model also indicates that it will be impossible to prevent all outbreaks by this method of control since the outbreaks which occur during the final phase are independent from the sequence of outbreaks which occur during the early part of the year. But this study has shown that controlling the initial outbreaks can prevent outbreaks in nearly 78% of the total area under outbreaks. The model also indicates that since recolonization can occur from far away habitats, control operations have to be repeated every year. 94
REFERENCES Ahmed, M. (1987) Relati ve resistance of various clones of Tectona grandis to teak defoliator, Hyblaea puera Cram. (Lepidoptera, Hyblaeidae) in south India. Indian Forester. 113(4): 281-286. Anderson, H., Durston, B. H. and Poole, M. (1970) Thesis and assignment writing. Wiley Eastern Limited, New Delhi: 135 pp. Andrewartha, RG. and Birch, 1. C. (1954) The distribution and abundance of animals, xv+782 pp. Chicago. ARC/INFO (1995) Understanding GIS- The ARCIINFO method: version 7 for UNIX and open VMS. 3 rd edition. John Wiley & Sons Inc., New York, NY-I0158. 723 pp. Basu-Chowdhury, J. C. (1971) Interim report on Konny Aerial Spraying Project. Appendix 3 In: Vasudevan K.G., Working plan for Nilambur Forest Division, 1967-68 to 1976-77. Govt.ofKerala, pp.165-168. Beeson, C. F. C. (1928) The defoliation of teak. Indian Forester. 54(4): 204 215. Beeson, C. F. C. (1934) The biological control of teak defoliators. Indian forester. 60( 10):672-683. Beeson, C. F. C. (1941) The ecology and control of the forest insects ofIndia and neighbouring countries. Reprint 1961. Govt. of India publication, 767 pp. Berryman, A. A. (1986) Forest insects: Principles and practice of population management. Plenum Press, New York. 279 pp.
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SPATIAL DYNAMICS OF TEAK DEFOLIATOR
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CERTIFICATE This is to certify that
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Mr. Rajan James, Mr. A. Moosa, Mr.
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4.3.5. Correlation between outbreak
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CHAPTER I INTRODUCTION Insects are
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covering the entire plantations of
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Burma and recommended that providin
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In a two-year light trap study at J
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during 1983-94 and 1987-89 recorded
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area of 50 ha. A group of ten grids
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CHAPTER IV STUDIES ON THE SPATIAL D
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within these various spatially refe
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4.2.3. Correlation between outbreak
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4.3. 2. Outbreak pattern, 1993 The
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4.3.3. Outbreak pattern, 1994 Table
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_ 0 _ 1 0 2 _ 3 _ 4 _ 5
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_ 0 _ 1 0 1 _ 3
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Table 4.7. The relationship between
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Fig. 8. Location of first outbreak
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Table 4.9. Elevation and aspect oft
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aspect and outbreak frequency. The
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map. The methodology adopted for da
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The sixth outbreak occurred on 26 M
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Page 55 and 56: Fig.5.3. Map ofNilambur teak planta
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Page 67 and 68: Fig.5 .15. Map ofNilambur teak plan
Page 71 and 72: Fig.5.l9. Map ofNilambur teak plant
Page 73 and 74: Fig.5 .21. Map ofNilambur teak plan
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Page 78 and 79: 6.2. METHODS In this study, post em
Page 80 and 81: was observed at around 06.15 h on t
Page 82 and 83: Two moths (one male and one female)
Page 84 and 85: Aggregations of the moths were pred
Page 86 and 87: CHAPTER VII DEVELOPMENT OF OUTBREAK
Page 88 and 89: -.-.-._ --- _--. Black light tube -
Page 91 and 92: Table 7.1. Correspondence between l
Page 93 and 94: foliage. If folds are detected, obs
Page 95 and 96: study has considerable bearing on t
Page 97 and 98: maximum of 13 ha (see Section 5.2,
Page 99 and 100: c) Variation in plant quality I ava
Page 104 and 105: Berryman, A. A. (1987) The theory a
Page 106: Nair, K. S. S., Mohanadas, K and Su
Page 109: APPENDIX A ALGORITHM: FOR COMPUTATI
Page 112 and 113: Date *No. of Incidence Local Date *
Page 115: Date "No. of Incidence local Date "
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Spatial dynamics of teak defoliator (Hyblaea puera Cramer) - Cochin ...

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