scholarly journals Effects of Organic Farming of Rice Plants on Population Density of Leafhoppers and Planthoppers. I. Population Density and Reproductive Rate.

1993 ◽  
Vol 37 (3) ◽  
pp. 137-144 ◽  
Author(s):  
Tatsuto KAJIMURA ◽  
Yousuke MAEOKA ◽  
I Nyoman WIDIARTA ◽  
Takeshi SUDO ◽  
Kazuya HIDAKA ◽  
...  
Keyword(s):  
Population Density ◽  
Organic Farming ◽  
Reproductive Rate ◽  
Rice Plants

scholarly journals The effect of population density upon rate of reproduction with special reference to insects

1932 ◽  
Vol 111 (773) ◽  
pp. 437-454 ◽  
Keyword(s):  
Population Density ◽  
Death Rate ◽  
Human Population ◽  
Previous Investigation ◽  
Reproductive Rate ◽  
Small Cell ◽  
Harvard University ◽  
Population Increase ◽  
Modern Biology ◽  
The Individual

As the result of a previous investigation, involving the analysis of environmental factors controlling population increase in nature, it became apparent to the writer that population density constituted an environmental factor which had been comparatively neglected, doubtless on account of its obscurity, but whose effects were nevertheless of greater significance than generally realised. It seemed desirable, therefore, that this relatively obscure phenomenon should be investigated, and the writer commenced work at the Laboratory of General Physiology, Harvard University, U. S. A. It has long been known that crowding of animals produces definite and peculiar effects on the various vital processes, and even the morphology of the individual. For instance, as far back as 1854, Hogg produced evidence to show that a snail kept in a small cell would only grow to such a size as would enable it to move about freely. Later, Semper (1874) came to the conclusion that there was a relationship between volume and the ultimate size of the individual. As regards the effect of crowding upon reproductive rate the first observation appears to have been made by Balbiani (1860), who reported that Paramecium must be placed in not less than 2-3 c. c. of medium to bring about maximum productivity. Again, Farr (1843) showed that there existed a definite relationship between the density of the human population and the death-rate, and anticipated the trend of modern biology to the extent of elaborating a mathematical formula which conformed to his findings.

scholarly journals UJI ADAPTASI VARIETAS UNGGUL BARU TERHADAP WERENG HIJAU DAN PENYAKIT TUNGRO DI KABUPATEN MERAUKE, PROVINSI PAPUA

Agric ◽  
2017 ◽  
Vol 29 (1) ◽  
pp. 1
Author(s):  
Sudarsono Sudarsono ◽  
Dini Yuliani
Keyword(s):  
Population Density ◽  
Yield Components ◽  
Block Design ◽  
Rice Tungro Bacilliform Virus ◽  
Rice Plants ◽  
Average Population Density ◽  
Average Population ◽  
Randomized Block Design ◽  
Effect On Yield ◽  
1000 Grain Weight

<p><em><span class="fontstyle0">Tungro is one of the important diseases in rice plants caused by two types of viruses were rod virus (rice tungro bacilliform virus) and spherical virus (rice tungro spherical virus) that was transmitted by the green leafhopper (GLH) Nephotettix virescens. The purpose of this study to determine the adaptation of new improved varieties against GLH and tungro disease in Merauke, Papua Province. Research conducted at Tanah Miring District, Merauke, Papua Province between February and June 2010. The study was a randomized block design with three replications. The treatment consisted of 11 varieties, namely Inpari 1, Inpari 2, Inpari 3, Inpari 4, Inpari 5 Merawu, Inpari 6 Jete, Inpari 7 Lanrang, Inpari 8, Inpari 9 Elo, Inpari 10 Laeya, and Ciherang. Observations included the intensity of tungro and GLH population density at the age of rice plants of 1, 2, 3, and 4 weeks after planting (WAP). In addition, it was observed also the yield components of rice. The results showed that the GLH population density and the intensity of tungro disease was not significantly different at the 11 varieties tested. GLH attack had been found in 1 WAP with an average population density of 4.18 individual/20 single swing. GLH increases with the age of the rice crop with an average population density in 2 WAP (20 individual), 3 WAP (103.27 individual), and 4 WAP (154.15 individual) per 20 single swing. Tungro disease intensity in 11 varieties began were found in 3 WAP on average by 0.16% and increased at 4 WAP on average by 0.28%. Varieties significant effect on yield components such as plant height, panicle length, number of total grain/panicle, percentage of filled grain, 1000 grain weight and productivity except the number of panicles/clump. </span></em><span class="fontstyle2"><strong><span><br /> <!--[if !supportLineBreakNewLine]--><br /> <!--[endif]--></span></strong></span></p>

SERANGAN DAN POPULASI Scotinophara sp. PADA TANAMAN PADI SAWAH DI KABUPATEN BOLAANG MONGONDOW TIMUR

EUGENIA ◽  
2019 ◽  
Vol 22 (3) ◽  
Author(s):  
Alex Hendra Kila ◽  
Ch. L. Salaki ◽  
Elisabeth R.M. Meray
Keyword(s):  
Population Density ◽  
Rice Plant ◽  
Survey Methods ◽  
Test Site ◽  
Rice Cultivation ◽  
Plant Age ◽  
Vegetative Stage ◽  
Rice Plants ◽  
Generative Phase

ABSTRACT   The research aimed to find out the attacks and pest populations Scotinophara sp. in rice crops have been carried out in EastBolaang Mongondow from July to October 2014. The study used survey methods at several centers of rice cultivation in East Bolaang Mongondow, then set three districts as a test site where sampling. Sampling using Method Diagonal slices then select ten clump of rice plants in each sub-sample plots. Samples were taken at vegetative stage and generative phase. Things were observed in this study is the percentage of infected plants and pest populations. The results showed that the highest percentage of infected rice plants in the age of the plants 8 weeks after plants are found in Sub Tutuyan amounted to 66.66 percent and the lowest sequentially the District Nuangan and the District Kotabunan namely 39.33 percent and 11.13 percent.The highest Scotinophara sp. population density was found based on the location is district Tutuyan 10,11 tail and the lowest sequentially District Nuangan and the District Kotabunan is 1.82 and 0.96 tail. The density of the population by age of the plant, the highest in the plant age 8 mst 12.75 and the lowest sequentially 6, 4 and 2 mst is4.38, 0.06 and 0 tail. Keywords : attack, population, Scotinophara sp., rice plant

When vector control and organic farming intersect: Pesticide residues on rice plants from aerial mosquito sprays

2021 ◽  
Vol 773 ◽  
pp. 144708
Author(s):  
Junlang Qiu ◽  
Sarah S. Wheeler ◽  
Marcia Reed ◽  
Gary W. Goodman ◽  
Yaxin Xiong ◽  
...  
Keyword(s):  
Vector Control ◽  
Organic Farming ◽  
Pesticide Residues ◽  
Rice Plants

scholarly journals SERANGAN DAN POPULASI Scotinophara sp. PADA TANAMAN PADI SAWAH DI KABUPATEN BOLAANG MONGONDOW TIMUR

EUGENIA ◽  
2019 ◽  
Vol 22 (3) ◽  
Author(s):  
Alex Hendra Kila ◽  
Ch. L. Salaki ◽  
E. R.M. Meray
Keyword(s):  
Population Density ◽  
Rice Plant ◽  
Survey Methods ◽  
Test Site ◽  
Rice Cultivation ◽  
Plant Age ◽  
Vegetative Stage ◽  
Rice Plants ◽  
Generative Phase

ABSTRACT The research aimed to find out the attacks and pest populations Scotinophara sp. in rice crops have been carried out in EastBolaang Mongondow from July to October 2014. The study used survey methods at several centers of rice cultivation in East Bolaang Mongondow, then set three districts as a test site where sampling. Sampling using Method Diagonal slices then select ten clump of rice plants in each sub-sample plots. Samples were taken at vegetative stage and generative phase. Things were observed in this study is the percentage of infected plants and pest populations. The results showed that the highest percentage of infected rice plants in the age of the plants 8 weeks after plants are found in Sub Tutuyan amounted to 66.66 percent and the lowest sequentially the District Nuangan and the District Kotabunan namely 39.33 percent and 11.13 percent.The highest Scotinophara sp. population density was found based on the location is district Tutuyan 10,11 tail and the lowest sequentially District Nuangan and the District Kotabunan is 1.82 and 0.96 tail. The density of the population by age of the plant, the highest in the plant age 8 mst 12.75 and the lowest sequentially 6, 4 and 2 mst is4.38, 0.06 and 0 tail.Keywords : attack, population, Scotinophara sp., rice plant

Population dynamics of Meloidogyne graminicola and Hirschmanniella oryzae in a double rice-cropping sequence in the lowlands of Myanmar

Nematology ◽  
2013 ◽  
Vol 15 (7) ◽  
pp. 795-807 ◽  
Author(s):  
Pa Pa Win ◽  
Pyone Pyone Kyi ◽  
Zin Thu Zar Maung ◽  
Dirk De Waele
Keyword(s):  
Population Density ◽  
Growing Season ◽  
Lowland Rice ◽  
Population Densities ◽  
Rice Varieties ◽  
Meloidogyne Graminicola ◽  
Rice Plants ◽  
Double Rice ◽  
Heading Stage ◽  
Rice Growing Season

The rice root-knot nematode, Meloidogyne graminicola, and the rice root nematode, Hirschmanniella oryzae, are considered potentially important nematode pathogens in lowland rice. A study was undertaken from December 2009 until December 2010 in the Ayeyarwady River Delta, the major lowland rice-producing area of Myanmar, to monitor the population dynamics of M. graminicola and H. oryzae in a naturally infested field. Root samples of the two rice varieties Yatanartoe and Taungpyan that are commonly cultivated in double rice-cropping sequences in Myanmar and represent irrigated and rainfed lowland rice varieties, respectively, were obtained for nematode analysis. During the summer-irrigated rice-growing season the root population density of second-stage juveniles (J2) of M. graminicola showed two distinct peaks – at the maximum tillering stage of the rice plants in January and at the heading stage of the rice plants in March 2010. With the onset of the monsoon rains, the J2 population densities in the roots of ratoon rice plants gradually decreased in May. During the rainfed monsoon rice-growing season, very low population densities of M. graminicola J2 were detected in the roots of rice plants, while the root population density of H. oryzae juveniles and adults showed two distinct peaks – at the maximum tillering stage of the rice plants in August and at the heading stage of the rice plants in October 2010. With the onset of the dry season, population density of H. oryzae in the roots reached the lowest density at harvest in November. Root galling caused by M. graminicola followed the same trend as the J2 population densities throughout the irrigated season. No root galls were observed during the monsoon season. Our results can be used for practical purposes aimed at a better management of both M. graminicola and H. oryzae.

scholarly journals Economy and Social Development of Rural Sikkim

2016 ◽  
Vol 4 (2) ◽  
pp. 61 ◽  
Author(s):  
Sushmita Chakraborty ◽  
Namita Chakma
Keyword(s):  
Ethnic Identity ◽  
Population Density ◽  
Social Development ◽  
Organic Farming ◽  
Rural Areas ◽  
Field Survey ◽  
Farming System ◽  
Sources Of Information ◽  
Secondary Sources ◽  
Organic Farming System

The tiny Himalayan state of Sikkim is well known for its multi-cultural and multi-ethnic identity. There is a political and historical debate regarding the identity of communities in Sikkim. Lepchas are considered as original inhabitants of Sikkim. Currently, Lepcha, Bhutia and Limbu are recognised as minor communities and have Schedule Tribes (ST) status in the state. Individual community concentration is mainly found in North and West Sikkim. Lepcha-Bhutias are found mainly in North Sikkim whereas Limbus are concentrated in West Sikkim. Community concentration is profound in rural areas. Gyalshing sub-division of West Sikkim has been selected for the present study. Purpose of this study is to investigate the Gram Panchayat Unit (GPU) level economy and social development of the rural areas based mainly on secondary sources of information. A field survey was also conducted to interact with the local people. Findings suggest that education and population density are the key determinants for GPU level disparity in social development of the study area. It has been found that the economy is primarily agriculture based and fully organised by organic farming system. Recently, homestay (eco)tourism business has been started here like other parts of Sikkim.

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