Background.Population growth has led to the need to increase global food production. Pesticides are an important tool used in efforts to control insect pests. About 20–30% of agricultural produce is lost annually due to insect pests, diseases, weeds and rodents. While pesticides are effective against pest populations, if used injudiciously, they may pose health hazards to humans, domestic animals, natural enemies of crop pests and other forms of life through unwanted contamination of food, feed, water bodies and the environment.Objectives.The aim of the present study was to examine farmers' level of knowledge and awareness of environmental pollution due to unsafe use of pesticides for controlling rice pests and to explore ways of reducing their usage.Methods.The research population consisted of 120 rice farmers: 40 farmers randomly selected from each of the three rice growing districts of Bangladesh; Mymensingh, Tangail and Jamalpur. Data was collected through group discussions, direct observations and personal interviews during March 2013 to May 2014.Results.Farmers mainly sought advice on pesticide use from pesticide dealers or retailers and a very few farmers contacted government extension workers for this purpose. Most of the farmers had an understanding of natural enemies of rice pests and that the application of synthetic insecticides in the field can reduce their population. A few farmers followed integrated pest management (IPM) practices with little understanding of the adverse effects of insecticides on the environment and ecosystem. The majority of farmers understood the harmful effects of pesticides on health of human and animals, beneficial species, fish, insect resistance, soil and food. It was also found that education on pest management, information through television, more contact with extension personnel and farmers' awareness of IPM were critical factors for improving rice farmers' understanding of the ecological hazards caused by overuse of pesticides. Most of the farmers suggested that timely removal of weeds, appropriate timing for pesticide application, balanced doses of fertilizers, pest monitoring, correct dose of appropriate pesticides, pest tolerant varieties, increasing technical knowledge and skills and creating social awareness of environmental pollution among farmers were necessary to reduce the quantity of pesticides and minimize environmental hazards.Conclusions.The present study identified a need to intensify farmers' awareness and knowledge of integrated pest management and environmental pollution through extension organizations which could help promote sustainable agricultural development and improve the currently endangered bio-diversity of Bangladesh.Participant Consent.ObtainedEthical Approval.This study was approved by the PhD Supervisory Committee assigned by the Department of Entomology of Bangladesh Agricultural University.Competing Interests.The authors declare no competing financial interests

The relative abundance of different stem borer species and their natural enemies with interaction effects were studied at three growth stages of irrigated Boro rice at Madhupur under the district of Tangail, Bangladesh during January to April, 2013. Five stem borer species viz; Yellow stem borer (Scirpophaga incertulas), Pink stem borer (Sesamia inferens), Dark headed stem borer (Chilo polyhcrysus), Stripped stem borer (Chilo suppressalis), White stem borer (Scirpophaga innotata), and nine different natural enemies were collected from the rice fields and recorded. The population of stem borers and natural enemies was highest in tillering stage and lowest in seedling stage. The relative abundance of stem borer species under investigation showed ranking order; yellow stem borer >dark headed stem borer>pink borer>white borer>stripped stem borer and natural enemies as ladybird beetle >long jawed spider>wolf spider>damselfly>carabid beetle>green mirid bug>lynx spider>dragon fly>ear wig. Populations of all five stem borers were positively correlated with ladybird beetle, wolf spider, long jawed spider, lynx spider, damsel fly, dragon fly, green mirid bug and negatively correlated with carabid beetle and earwig.

The resistance of commercial rice (Oryza sativa L.) varieties widely grown in Louisiana was assessed against the rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), the major insect pest of rice in the United States, in a 5-yr field study that included conventional inbred, herbicide-tolerant, and hybrid varieties. Resistance was evaluated by comparing densities of immature rice water weevils (larvae and pupae) in root-soil core samples taken at two time points after flooding. Randomized block experiments were conducted in two different locations to enable identification of potentially resistant varieties over diverse environments. There were small but significant differences in the resistance of commercial varieties over the 5-yr field study. The variety 'Jefferson' was found to support larval densities 6-70% lower than other varieties, while 'Jupiter' often supported higher larval densities. Greenhouse experiments evaluated adult preference for oviposition and survivorship of larvae on different varieties. Females exhibited limited ovipositional preference for varieties: numbers of weevil eggs per plant differed significantly among varieties in choice tests but not in no-choice tests, while first instar densities in both choice and no-choice tests showed no significant differences among varieties. Analysis of data from both choice and no-choice tests showed that numbers of late instars and pupae differed significantly among varieties, suggesting presence of antibiosis in some cultivars. Our results suggest that none of the varieties tested possess high levels of resistance to rice water weevil infestation, although 'Jupiter' appears to be more susceptible than other varieties and 'Jefferson' appears to be somewhat more resistant.

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