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Moonjun R.,University of Twente | Udomsri S.,Ministry of Agriculture and Cooperative | Taiyarom A.,Development of Mineral Resources
33rd Asian Conference on Remote Sensing 2012, ACRS 2012 | Year: 2012

New approach of soil survey methods is known as "digital soil mapping(DSM)", requires new techniques such as geo-information system and remote sensing techniques to produce accurate soil map. Airborne gamma-ray imagery (AGRI) is taken into an account for the very important source of information for soil study at regional scale. The ratio of eTh and K concentrations as representing soil component and chemical concentration during the rock weathering process. Digital terrain modelling (DTM) is representing topographic feature, explaining the landform pattern as the most important soil forming factor. Aim of this study was to combine ratio of gamma-ray and CTI as a covariable using statistical modeling as local predicting approach. Geographically Weight Regression (GWR) was tested to predict percent of top-soil clay CTI, using GWR method can therefore be possible to map of top-soil pH and percent clay. Source

Two local and three imported entomopathogenic nematodes (EPNs) were tested for control of the American cockroach (Periplaneta americana) and the German cockroach (Blattella germanica). Only two Steinernematidae caused substantial cockroach mortality; one was a local strain of Steinernema sp. (strain T1), and the other was an imported strain of S. carpocapsae. A homemade bait that contained cat food and attapulgite clay at a ratio of 3:7 (W:W, 10 g total per bait) and 1x10 6 Steinernema sp. (T1) per bait resulted in 48.0 ± 4.7% mortality of the American cockroach and 57.7 ± 8.0% mortality of the German cockroach. A similar bait containing S. carpocapsae caused 40.0 ± 3.3% mortality of the American cockroach and 86.7 ± 4.7% mortality of the German cockroach. The optimal concentration of Steinernema sp. (T1) and S. carpocapsae to control the American and German cockroach was 1x10 6 EPNs and 5.4x10 4 EPNs per bait, respectively. The most susceptible stage of the American cockroach to both EPNs was the last instar, but susceptibility of the German cockroach to both EPNs did not differ among cockroach stages. Source

Maketon M.,Kasetsart University | Somsook V.,Ministry of Agriculture and Cooperative | Rattanakorn P.,Kasetsart University | Hotaka D.,Kasetsart University
Nematropica | Year: 2011

An isolate of the entomopathogenic nematode Heterorhabditis indica, designated "T2," was collected in Kanchanaburi Province, Thailand. The life cycle of T2 in Galleria mellonella larvae required 10 days and two generations at 25°C. The first generation was hermaphroditic and the second was amphimictic. Survival of infective-stage juveniles in water-filled sponges at 15°C was 81% after 1 month. In the laboratory, T2 was able to penetrate and kill Aphis gossypii, Spodoptera exigua, Sitophilus zeamais, Tenebrio molitor, Bactrocera correcta, and Coptotermis gestroi but reproduced poorly in all of these hosts except S. exigua. In G. mellonella, T2 reproduced best at 25°C, and the optimum soil moisture for infection was 7 to 9%. Isolate T2 reared on yeast salt broth caused 84% mortality 2 days after inoculation of diamondback moth (Plutella xylostella L.) third-instar larvae. The best artificial medium for mass-rearing H. indica T2 was modified yeast salt broth containing 2.0% soluble starch, 1.5% yeast extract, 2.5% nutrient broth, 1.0% lard, and 2.0% MgCl2 • 6H2O. Source

Singh K.,University of Prince Edward Island | Dey M.M.,University of Arkansas at Pine Bluff | Laowapong A.,Ministry of Agriculture and Cooperative | Bastola U.,Washington State University
Aquaculture Economics and Management | Year: 2015

We have examined the presence of price transmission asymmetry along the value chain, and the price transmission across four main aquaculture species in Thai fish market using monthly data from January 2001 to October 2010. This is an attempt to contribute to the literature on horizontal and vertical price transmission in the seafood markets including the price transmission asymmetry in the developing countries. We did not find any evidence of asymmetric price transmission in walking catfish (except in long-run), vannamei shrimp and tilapia; however, it is evident in Thai Asian sea bass market; wholesalers exercising some market power. In general, price of one species is not found to significantly affect price of the other species at the same level of value chain. © 2015, Taylor & Francis Group, LLC. Source

Lertmongkol S.,Kasetsart University | Sarobol E.,Kasetsart University | Premasthira C.-U.,Ministry of Agriculture and Cooperative
Kasetsart Journal - Natural Science | Year: 2011

Mungbean contains allelochemicals that can either inhibit or promote the growth and yield of subsequent crops in certain cropping systems. To examine the role of mungbean in a cropping system, the allelopathic effects of mungbean on the seed germination and plant growth of subsequent crops were evaluated in laboratory and pot experiments. In the laboratory experiment, the allelochemicals in mungbean inhibited the germination and root length of lettuce, whereas it had no negative effect on Echinochloa crus-galli seed germination. The pot experiment revealed that allelochemicals from decomposed mungbean in soil reduced the seed germination and plant height of subsequent crops especially in soybean (Glycine max) and lettuce (Lactuca sativa). The seed germination of soybean and lettuce was severely inhibited while the plant height of Echinochloa crus-galli was reduced. A high performance liquid chromatogram of the allelochemical compounds from the mungbean root and stem was composed of one major peak that had a retention time identical to that of thioglycerol and four other different peaks with one of these peaks having a retention time similar to that of aglycone. Source

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