Received: 9 May 2012, Reviewed: 23 May 2012, Revised: 24 May 2012, Accepted: 27 May 2012 The Effective Factors on the Adoption of Biological Control in Farmers' Field School by Rice Producers: The Case of Babol Township 1 Hadi Moumeni Helali and 2 Amir Ahmadpour 1 Member of Young Researchers Club and M.Sc student of Agricultural Extension and Education, Sari Branch, Islamic Azad University, Sari, Iran 2 Assistant Professor Agricultural Extension and Education Department, Sari Branch, Islamic Azad University, Sari, Iran The main purpose of this research is to determine the effective factors in adopting biological control in the Farmer Field School approach. The method used in this research is descriptive-correlation and comparative, which has been done by survey. The rice farmers of the township of Babol, Mazandaran, Iran were selected as the sample population of this research. The statistical sample of the research was 472 which included 92 rice farmers who attended the Farmer Field School and 380 people who did not participate in this course The designed questionnaire, after some modifications according to the corresponding experts’ opinion, was distributed between the two groups of rice farmers. At last, 433 collected questionnaires were analyzed by SPSS software (81 of the rice farmers who participated and 352 of them that did not participate). The findings show that the independent variables of rice farmer's attitude toward to biological control, use of information sources and knowledge of biological control determine 85.5% of the changes in the dependent variable of adopting biological control. [H, Moumeni Helali and A, Ahmadpour. The Effective Factors on the Adoption of Biological Control in Farmers' Field School by Rice Producers: The Case of Babol Township International Journal of Agricultural Science, Research and Technology, 2011; 1(4):201-206]. Key words: Farmer Field School, Adoption, Biological Control, Rice Farmers 1. Introduction The increasing needs to expand agricultural production and achieve a more appropriate level of food security lead to the uncontrolled use of chemical fertilizers and pesticides in 1950s. However, during the 1960s it became clear that the overuse of chemical pesticides not only has caused resistance in pests and the development of their new generations, but also has endangered the stability of the environment and human health. Therefore, using nonchemical control, like integrated pest management method, was gradually considered at the international level. And, for the first time in 1970, it was carried out in developing countries, But contrary to what was expected, the implementation of integrated pest management in developing countries was not successful. Researchers found the reason in the method of training the concepts of integrated pest management to the illiterate and less literate farmers of these areas. Because the methods which were used until then followed “Central” and “Top to Bottom” extension approach consequently due to lack of farmers’ participation in the learning process the content of training courses in some cases was even and incomprehensible for farmer (Osko et al, 2007). Since human resource development and technology transfer and in line with it the change from the traditional methods of production to new methods based on scientific principles, one of the most important factors to achieve is Agricultural development that this will be obtained with researchers, extension agents and farmers’ cooperation (Kalantari et al, 2005). One of the most suitable approaches in this case is the Farmer Field School approach that in 1998 the Food and Agriculture Organization and the office of comprehensive facilities of integrated pest management of this organization, the regional workshop of Biological control of plant pests in its summary in Near East, in Babolsar Township, Mazandaran, Iran, introduced the best way of public adoption of this innovation in the participation of all villagers in an educational environment without a wall, called Farmer Field School(Osko et al, 2007). originally the FFS were developed in Asia, where there are some 200 million rice farmers (Braun et al, 2000).The Farmer Field School extension method was introduced in Central Java in Indonesia at 1989, International Journal of Agricultural Science, Research and Technology Available online on: www.ijasrt.com Abstract