| Author | Hataichanok Sakornsinthu |
| Call Number | AIT Diss. no.AS-97-08 |
| Subject(s) | Pests--Integrated control--Thailand Tak
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| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Technical Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | Pesticides play an important role in modem agriculture. But the impact of chemical pesticides on human health and environment caused controversy to the Thai people. Due to this controversy, consumer buying behavior for agricultural products has created markets for organic, pesticide free or low residue products. An integrated pest management strategy based on biological methods of pest control was developed to evaluate the comparative efficacy of different biological control methods against major leafy vegetables insect pests. A field experiment was undertaken in Chong kab sub¬-district, Phop Phra district, Tak province. The area was chosen because it is one of the major area that produce leafy vegetables for the Bangkok metropolitan area due to the agro-climatic conditions. The treatments selected for the experiments were the commercial preparation of neem extract (Azadirecta indica, Juss), Bt (Bacillus thuringiensis, Aizawai) and entomopathogenic nematodes. A net house was constructed as one of the treatments using 32 holes per square inch net and local wood. The leafy vegetables under the experiments were Chinese kale (Brassica alboglabra), Chinese cabbage (Brassica pekinensis), spinach (Spinacia oleracea), and chrysanthemum (Chrysanthemum coronarium Linn.). The experiments were undertaken in three period according to the seasons in one year. The first experiment was in the summer season, the second was in the rainy season, and the third was in the cool dry season. Throughout the treatments, it was found that the yield of Chinese kale, Chinese cabbage, spinach, and chrysanthemum obtained from the net house were significantly higher than that of other treatments. The results of harvest of marketable leaves of the treated vegetables showed that Centari and Florbac showed no significant difference between each other. Nematodes in general showed significantly lower yield than other treatments. The major pests monitored in the field were diamondback moth (Plutella xylostelles), cabbage webworm (Hellula undalis), cutworm (Spodoptera litura), cabbage semilooper (Trichoplusia ni) and flea beetle (Phyttotreta spp.). The total of 20% of the farmers in the Chong kab sub-district were monitored throughout the experiment with interview through questionnaires. The findings were complete listing of outputs and inputs associated with the farm enterprise. Based on the Economic Analysis the selected biological methods in the study were found to be more economical to practice than spraying the chemical insecticides used by the farmers. The Dominance Analysis had confirmed that the Net treatment gave highest net return followed by Centari and Florbac. Therefore, Bt-products (Centari and Florbac) can be considered positive for insect control or good protection agent for pesticides-free vegetable production. In the case that there were not enough capital for net house construction, farmers can prefer to adopt the Bt-products which was affordable and environmentally friendly method. From the findings, it was concluded that the consistent performance of the 6 treatments tested in the field condition through three crop seasons in a year and in four kinds of vegetables have confirmed the effectiveness of Net and Bt-products for pesticides-free vegetable production. |
| Year | 1997 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Aquatic Systems(AS) |
| Chairperson(s) | Apisit Eiumnoh; |
| Examination Committee(s) | Boonjit Titapiwatanakun;Tinsley, Richard L.;Sunantar Setboonsarng;Hofsvang, Tron; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 1997 |