Agricultural pesticide use and food safety:California's model

Pesticides have been an essential part of agriculture to protect crops and livestock from pest infestations and yield reduction for many decades. Despite their usefulness, pesticides could pose potential risks to food safety and the environment as well as human health. This paper reviews the positive benefits of agricultural pesticide use as well as some potential negative impacts on the environment and food safety. In addition, using the case of California, we discuss the need for both residue monitoring and effective pest management to promote food safety. Twenty years＇ pesticide residue data from California＇s pesticide residue monitoring program were analyzed. Results showed that more than 95% of food samples were in compliance with US pesticide residue standards （tolerances）. However, certain commodities from certain sources had high percentages of residues above tolerance levels. Even when residues above tolerance levels were detected, most were at levels well below 1 mg kg^-1, and most posed negligible acute health risk. However, a few detected residues had the potential to cause health effects. Therefore, establishing an effective food residue monitoring program is important to ensure food quality throughout the marketplace.

The impact of Bt cotton adoption on the stability of pesticide use

Even though the impact of Bacillus thuringiensis （Bt） cotton on pesticide use has been well documented, all previous stud- ies focus on the mean value of pesticide use. Using seven unique waves of panel data collected between 1999 and 2012 in China, we show that Bt cotton adoption has not only caused a reduction of the mean value of pasticide use, but also a reduction of the standard deviation of pesticide use. We conclude that Bt technology adoption has also contributed to the stability of pesticide use in cotton production. We believe that this contribution is theoretically and practically relevant because of the long length of our unique dataset.

Farmer's Knowledge on GM Technology and Pesticide Use:Evidence from Papaya Production in China

Genetically modified （GM） technology can significantly reduce pesticide use and increase yield in crop production. However, the benefit from reducing pesticide use varies substantially among farmers. The overall goal of this paper is to understand the relationship between farmers＇ knowledge of GM technology and pesticide use in genetically modified papaya （GMP） production. Based on a survey of 223 farms in three main papaya production provinces in 2010, the data show that almost all papaya planted in 2009 was genetically modified. However, only 28% of papaya farmers knew that they planted GMP, and 55% of them did not know GMP is resistant to papaya ringspot virus （PRSV）. Further analyses using the general least squares （GLS） method show that farmers＇ knowledge of GMP significantly affects their pesticide use, and potential gain from GM technology is far below its full potential. The paper concludes with policy implications.

Rules of Pesticide Use for Food Crop Diseases and Pests: A Concise Diagram Based on Correspondence Analysis

In order to ensure food security, the selection of pesticide must take into account the controlling effect and economy in the chemical control of food crop diseases and pests. Although China has registered a large number of pesticides and fungicides on food crops, traditional statistical methods cannot treat the complex relationships between crops, pests and diseases, as well as pesticides. To this end, the correspondence analysis was used to mine the data of pesticides being registered after January 1, 2010 for the prevention and control of pests and diseases on wheat, corn, and rice in China, in order to reveal the general rules of pesticide use for the prevention and control of grain crop pests and diseases and to provide scientifically recommended pesticide regimens.(1) Recommended pesticides for wheat diseases and pests: For underground pest control, phoxim, diazinon or clothianidin is recommended;imidacloprid is recommended for aphid control;avermectin is recommended for mite control;chlorpyrifos is recommended for midge control;the pesticides for rust control could be selected according to the order of epoxiconazole>flutriafol>kresoxim-methyl>cyproconazole≈hexaconazole;tebuconazole is recommended for the prevention and control of smut;difenoconazole is recommended for the simultaneous occurrence of take-all, smut and sheath blight;it is recommended to use carbendazim or thiophanate-methyl for the control of scab;and triazolone or pyraclostrobin is recommended for the control of powdery mildew.(2) Recommended pesticides for corn diseases and pests: For the control of underground pests, fipronil, carbosulfan or chlorpyrifos are recommended;thiamethoxam is recommended for control of planthoppers and corn aphids;Bacillus thuringiensis or phoxim is recommended for control of corn borers;pyraclostrobin is recommended for the control of northern leaf blight;tebuconazole is recommended for the control of head smut;and fludioxonil+metalaxyl-M is recommended for the control of corn stalk rot.(3) Recommended pesticides for rice diseases and pests: It is recommended to use triazophos, avermectin analogs or methoxyfenozide for the control of borers;for rice planthoppers, the pesticides could be selected in order of pymetrozine>imidacloprid>thiamethoxam>thiazide>nitenpyram;avermectin analogs are recommended for the control of rice leaf rollers;tebuconazole is recommended for the control of rice false smut;prochloraz and its manganese salts are recommended for the control of bakanae disease;hymexazol is recommended for the control of wilt disease;thifluzamide or hexaconazole is recommended for the control of sheath blight;and the pesticides for the control of rice blast are in order of tricyclazole>kasugamycin>fenoxanil>isoprothiolane>Bacillus subtilis. In addition, potential applications of correspondence analysis in other fields of plant protection are discussed.

Impact of insect-resistant GM rice on pesticide use and farmers' health in China

The economic benefits of insect-resistant genetically modified(GM) crops have been well documented, but the impact of such crops and the consequent reduction in pesticide use on farmers' health remains largely unknown. Through the analysis of the data collected from the physical examination from farmers in China, we show that GM rice significantly reduces pesticide use and the resultant not only visible but also invisible adverse effects on farmers' neurological, hematological, and electrolyte system. Hence, the commercialization of GM rice is expected to improve the health of farmers in developing countries, where pesticide application is necessary to mitigate crop loss.

Do large-scale farmers use more pesticides? Empirical evidence from rice farmers in five Chinese provinces

It is of great theoretical and practical significance to understand the rules of the differences in pesticide use behaviors between large-scale and small-scale farmers,so as to regulate the behavior of farmers differently and improve the quality and safety of rice.The overall pesticide use behavior of large-scale farmers was characterized by large doses and high application frequency,while that of small-scale farmers was characterized by small doses and low application frequency.The econometric test showed that(i)the proportion of staple food ration has a significant negative impact on the single dose exceeding the standard and pesticide application frequency of small-scale farmers,and the increase of the proportion of staple food ration will reduce the demand among small-scale farmers for pesticides;(ii)yield effect has a greater impact on the frequency of pesticide application by large-scale farmers,and the large yield effect will increase the frequency of pesticide application among large-scale farmers.Therefore,in pesticide use behaviors,large-scale farmers should reduce pesticide quantity and increase efficiency,while small-scale farmers improve the level of plant protection.

An index method to evaluate growers' pesticide use for identifying on-farm innovations and effective alternative pest management strategies:a case study of winegrape in Madera County,California

Winegrape is an important perennial crop in California,USA.Each year California winegrape farming consumes about 20 million kilograms of pesticides that have been a pollutant source to the fresh water systems of the state.The variation of pesticide use among winegrape growers has been significant.It has been observed that some growers have developed effective ways to reduce pesticide use,yet control pests efficiently to ensure harvest.Iden-tification of the growers with low and high pesticide use is very helpful to extension programs that aim on reducing pesticide environmental risk.In this study,an index approach is proposed to quantitatively measure pesticide use intensity at grower level.An integrated pesticide use index is developed by taking pesticide quantity and toxicity into account.An additive formula and a multiplying formula were used to calculate the pesticide use index,i.e.,PUI and PUIM.It was found that both PUI and PUIM were capable of identifying the low and high pesticide users while PUI was slightly more conservative than PUIM.All pesticides used in California winegrape farming were taken into account for calculating the indices.Madera County,one of the largest winegrape producers in California,was taken as an example to test the proposed approach.In year 2000,among the total 208 winegrape growers,28 with PUI≤10 and 34 with 10<PUI≤20 were identified as low pesticide users who were characterized with both low quantity and low toxicity of pesticide use.Most of the growers had small-sized vineyards,i.e.,one field and small planted areas.Furthermore,they had very low pesticide use intensity,used only 1-2 types of pesticides(mainly fungicides) ,applied few pesticides(1-3 only) ,and emphasized the use of low toxicity compounds.Meanwhile,19 growers with PUI>60,identified as high pesticide users,had large-sized vineyards,i.e.,more fields and large planted areas.They used all types of pesticides and many compounds,which indicated that their pest controls heavily depended on pesticides rather than on-farm management.Through the case study,the proposed approach proved to be useful for analyzing the growers'pesticide use intensities and interpreting their pesticide use behaviors,which led to a new start point for further investigation of searching ways to reduce pesticide environmental risk.

Operating pesticide use reduction within the boundary of food security in peri-urban settings

Pesticide use in peri-urban areas afects the urban enviroment and public health,and reducing the use may present food security isues for urban dwellers.In this study,we explore how a muiallyadopted goal of a 20%reduetion in pesticide use could be achieved,along with local food security and environmental implica-tions,for Shanghai located in the densely populated East China.A regional Shanghai Agricultural Sector Model inorporating district-and technology-varying crop budgets,was developed to simulate the efects of pesticide reduction policy.Here we find that achieving the reduction goal had the largest implications in districts with high pesticide use totals and intensities,potentially reducing pesticide non point source pollution in the Yangtze River Estuary and Dianshan Lake;the production levels of rice and leafy vegetables would be most afected;and adopting machinery that allows more precise pesticide application modulates these results.Moreover,imposing the requlrements at the district-level caused more severe local food security concerns,and less environmental benefits.Furthermore,a closed Shanghai's agricultural economy would subtantally enlarge the regional het-erogeneity in the above-mentioaned outcomes.Exploring the ffects of a quantity control policy on current-use pesticides at diferent aggregation levels has important implications for regulating the use of agrochemicals.

Pesticide Contamination in Land Reform Settlements in Brazil： Empirical Evidences from Caiaponia, Goias State

Brazil is the largest consumer of pesticides worldwide. Public health studies in Brazil show that inadequate use of pesticides increases the incidence of accidents and contamination of poor rural communities. This study sought to identify factors that determine the occurrence of problems with pesticides in a typical Brazilian land reform settlement. The study was carried out in Caiaponia, Goias state. In the empirical analysis, the econometric model pro bit was used. The dependent variable was the existence of health problems in the family setting that are caused by pesticides. The independent variables were the family size; the attendance to any church, whether Catholic or Protestant; if farmers received any technical assistance; the current health condition of the family, and if there are exacerbated erosion problems on the farm. Data from 28 farmers were collected through a structured questionnaire. Among the main findings, larger families have a higher probability of accidents involving pesticides. The current healthy conditions of family and the problems of soiled gradation in the farm imply are duction in the likelihood of contamination with pesticides. These two results indicate that rural households that have good health condition and have experienced environmental degradation on their farm have higher environmental awareness.

Case Control Study of Impulsivity,Aggression,Pesticide Exposure and Suicide Attempts Using Pesticides among Farmers

A case-control study was conducted to investigate associations between organophosphate pesticide（OP）exposure,aggression,impulsivity,and attempted suicide.Questionnaires were used to collect information;impulsivity and aggression were measured by the Barratt Impulsivity Scale（BIS）and the Aggression Inventory（AI）.

Development and Application of Green Pest Control Technology in Tea Garden

A discussion on the necessity of green control of tea pests in tea gardens was conducted on the basis of the development process from traditional control, chemical control to green and ecological control. The connotation of green control in tea gardens was analyzed, and physical control and chemo-ecological control, biological control and agricultural control respectively were introduced. Besides, the rational selection and precise use of pesticides were proposed and current problems in the green control of tea gardens in China were introduced.

Design and test of a six-rotor unmanned aerial vehicle(UAV)electrostatic spraying system for crop protection

In recent years,multi-rotor unmanned aerial vehicle(UAV)crop protection operations have experienced tremendous growth.Compared with manual operations,they have advantages such as high operational efficiency,small pesticide dosage,and low pesticide hazards for humans.However,the tiny droplets produced during UAV spraying for crop protection are affected by the rotor air flow and will drift in all directions in an uncontrollable manner,severely affecting the pesticide deposition pattern and resulting in pesticide waste.To improve pesticide use efficiency during multi-rotor UAV spraying,an electrostatic spray system was designed based on electrostatic spray technology and a six-rotor UAV.The proper operation parameters for the UAV electrostatic spray were determined by test,which were spray altitude of 50 cm above the crop,spray pressure of 0.3 MPa and charging voltage of 9 kV.Field test was performed based on these parameters.The results showed that compared with non-electrostatic spray,the electrostatic spray improved by 13.6%in the average deposition density above the sampling device and 32.6%in the middle.The research can provide a reference for designing multi-rotor UAV electrostatic spray devices.