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Thai National AGRIS Centre was established in March 13, 1980 by General National FAO Committee, Ministry of Agriculture and Cooperatives cooperated with Food and Agriculture Organization of the United Nations. Collects information related to agricultural sciences and technologies produced/printed in Thailand including those of agricultural information about Thailand produced/printed in abroad Technical management of agricultural information system: indexing, cataloging, creating Thai Agricultural Database Care and preservation of valuable agric [...]

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Journal Article

Journal Article

Spatial dispersion and optimum sample size for cotton bollworm, Helicoverpa armigera (Hubner) (Lepidoptera:Noctuidae) larvae on cotton  [2002]

Khaing, Ohnmar(Kasetsart University. Bangkhen Campus, Bangkok (Thailand). Faculty of Agriculture. Department of Entomology); Praparat Hormchan(Kasetsart University. Bangkhen Campus, Bangkok (Thailand). Faculty of Agriculture. Department of Entomology); Surachart Jamornmarn(Kasetsart University. Bangkhen Campus, Bangkok (Thailand). Faculty of Agriculture. Department of Entomology); Ngarmchuen Ratanadilok(Kasetsart University. Kamphaeng Saen Campus, Nakhon Pathom (Thailand). Faculty of Agriculture. Department of Agronomy); et al.

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Field experiments were conducted in the irrigated and the rain-fed crops of 2000 and 2001 at Suwan Farm, Pak Chong, Nakon Ratchasima, Northeastern Thailand to determine the spatial dispersion of cotton bollworm, Helicoverpa armigera (Hubner) larvae on four cotton varieties/lines, namely, AP1 and AP2, the mutant lines, SR60 (Sri Samrong 60) and SD1 (Sarid 1), the recommended varieties. RCB was used with four replicates for both crops. Spatial dispersion was analyzed using the variance-to-mean ratio (s **(2)/x mean), Morisita Index (I delta) and the negative binomial parameter (k). Although cotton bollworm larvae exhibited mainly clumped distribution, sometimes it was found to be randomly disperse during the sampling periods of both crops. In general, H. armigera larvae were at high aggregation (k=0.10) on the irrigated crop and low aggregation (k=3.92) on the rain-fed crop. Dispersion information was used to select an optimum sample size at the 0.05 probability. Optimum sample size of 15 and 30 plants per 140 square m were needed to monitor low and high aggregation levels of H. armigera larvae, respectively.
From the journal
Witthayasan Kasetsart (Sakha Witthayasat)
ISSN : 0075-5192

Bibliographic information

Language:
English
Type:
Summary
In AGRIS since:
2006
Start Page:
235
End Page:
241
All titles:
"Spatial dispersion and optimum sample size for cotton bollworm, Helicoverpa armigera (Hubner) (Lepidoptera:Noctuidae) larvae on cotton"@eng
Other:
"Summary (En)"
"3 ill., 3 tables"
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Bibliographic information

Language:
English
Type:
Summary
In AGRIS since:
2006
Start Page:
235
End Page:
241
All titles:
"Spatial dispersion and optimum sample size for cotton bollworm, Helicoverpa armigera (Hubner) (Lepidoptera:Noctuidae) larvae on cotton"@eng
Other:
"Summary (En)"
"3 ill., 3 tables"