Integrated pest management (IPM) is the ideal method to reduce pesticide use and protect the environment from pollution, helping to ensure food safety and human health [12]. Pest management is achieved directly using a variety of tools, including pesticides, and indirectly through a number of other farming practices; this integrated approach has a positive effect on plant health in general as well as helps to reduce the pesticides needed for the plants [13]. In Gia Lam district, alternative pest and crop protection methods focusing on agroecosystems and integrated pest management had been prioritized for application in vegetable production by farmers in the two surveyed communes (Table 4).

1) Field sanitation: That is an important tactics in IPM which mean cleaning up crop residues and eliminating weeds thoroughly. This helps to reduce the appearance of pests and diseases, thus minimizing early-season spraying. The survey results showed that more than 90% of the farmers in the two surveyed communes thoroughly cleaned the fields at the beginning of each croppingng season.

2) Taking advantage of natural enemies and parasites: Farmers use Eocanthecona

Source: Survey result (2021).

furcellata bugs, parasitic wasps, and beetles, etc. (these species are natural enemies of pests such as green planthoppers, leafhoppers, butterflies and young caterpillars of stem borers, and greenworms, etc.) to eliminate pests, thereby helping to reduce the amount of pesticides used in farming and limiting the risks of pesticides. More than 30% of the interviewees used natural enemies and parasites in their production to reduce the use of pesticides.

3) Crop rotation: Farmers have formed the habit of diversifying vegetable varietiess, alternating crop varieties throughout the years, thereby limiting the proliferation of pests, thus limiting the use of pesticides. This is a relatively important measure in preventing pests and diseases of the farmers in the study area, with about 43.33% to 46.67% of the interviewed households in each commune applying this method as a solution. reduce the use of pesticides.

4) Choosing proper plant varieties: People have paid attention to choose the varieties that are disease-free, resistant to pests and diseases, and certified by the seed quality testing agency. This helps to reduce the amount of pesticides used on crops in the area quite effectively. The rate of applying plant variety orientation in the two surveyed communes was about 40% of the interviewed households (mainly and with cabbage and cucumber).

5) Applying technical advances into production: There were 60% of households in Van Duc commune and 53.33% of households in Dang Xa commune that implemented models of technical advances including Methyl Eugentol bait traps to eliminate fruit flies, yellow sticky traps to trap silkworms, green sticky traps to trap thrips, and sweet and sour bait traps to kill insects, etc. to prevent and control pests and diseases, especially putting the Passlite coating model into testing to minimize the use of pesticides.

Biological pesticides, in general, have many advantages over conventional pesticides [14] [15]. Biological pesticides are becoming more and more popular around the world by being a safer tactic in the management of pests and diseases for the crops whilst having significantly lower risks to not only humans but also the environment [16]. Using biological pesticides and pesticide products with low toxicity and high efficiency in pest control but safer for humans and the environment is one of the important risk reduction measures.

The survey results show that the proportion of biological pesticides in the pesticide structure used in Van Duc commune was 67.63%, this rate in Dang Xa commune was 63.56% (higher than the rate of chemical pesticides) (Table 2). In which, the most popular were pesticides of Group III (accounting for more than 50% of the structure of pesticides). This is the result of the careful guidance from technical staff specialized in plant protection, cooperative staff and thanks to active participation in the farmer groups.

Most common biological pesticides applied in vegetable cultivation in the two communes were those containing active ingredients such as Bacillus Thuringiensis, Emamectin benzoate, Diafenthiuron, Matrine, Azadirachtin, Cytokinin (Zeatin), and Bacillus subtilis, etc. All of these pesticides were included in the list allowed to be used by the Vietnam’s Ministry of Agriculture and Rural Development as well as the list of pesticides recommended for use prepared by the Plantation and Plant Protection Station of Gia Lam district and sold in pesticide stores in the study area.

The application of pesticides, especially of the improper pesticides and improper doses applied, poses a dominant threat to the farmers who apply the pesticides on the fields [17]. Pesticide use principle is important since pesticide risks can be avoided or reduced if farmers understand and practice the principle well. The 4-right principles in the use of pesticides was officially legalized in Vietnam in 2015. It is one of the most important principles in plant protection and quarantine activities in Vietnam [18].

In the two surveyed communes, the majority of farmers understood and practiced quite well in accordance with the 4-right principle: When pests and diseases have reached the threshold, farmers use pesticides in compliance with the instructions of specialized agencies, using pesticides according to the 4-right principles: “RIGHT pesticides for the right crop, RIGHT dose and concentration, RIGHT time of application and RIGHT methods of application”.

Specifically, according to the survey results with the Plantation and Plant Protection Station of Gia Lam district on the practice of using pesticides on vegetables of farmers in 2 Van Duc commune and Dang Xa, there were about 86.67% of the farming households in Van Duc commune and 83.33% of households in Dang Xa commune practiced spraying according to the 4-right principle. People chose the right pesticides according to the type of pests and diseases, did not use pesticides of unknown origin, choose pesticides on the list of pesticides allowed to use, mainly on the list of recommended pesticides prepared by the District Plantation and Plant Protection Station and the cooperatives in the locality. Thanks to the guidance and timely advice of technical staff, most farmers in the study area sprayed at the time when the pest was easily destroyed, reached the threshold, sprayed when it was cool and windless. The spraying process of households followed the instructions on the labels, within the recommended dosage and concentration range. Pesticides were also mixed according to the instructions of the technicians, it was very rare for farmers to arbitrarily mix them.

Besides that, about 60% of households have paid attention to alternating pesticides in use, thereby limiting the phenomenon of pesticide resistance and resistance of pests and diseases. This was possible thanks to the timely advice of technical staff as well as the owners of local drug stores. Every year, at the beginning of each cropping season, the staff of the District Cultivation and Plant Protection Station make a list of pesticides recommended for use in production for each crop for the farmers, which is shown by visual images and distributed to each commune, each cooperative to promptly advise and provide recommendations to people.

Protective equipment is again an important solution to pesticide risk reduction [19]. Using labour protection when spraying contributed to the minimization of the exposure to pesticides during use, thereby minimizing the risks of pesticides for direct users, the farmers.

The survey results at Van Duc commune and Dang Xa showed that most the majority of farmers were aware of and habitually using protective equipment during spraying (Table 5). Specifically, over 83% of people regularly used labor protection while spraying. Over 96% used masks, over 60% used gloves, over 73% wore boots, over 96% of people wear hats/caps, over 46% wore eyeglasses, only about 10% - 16.67% of people used a raincoat while spraying (Table 5).

Survey results show that the majority of farmers in Van Duc and Dang Xa communes in Gia Lam district consciously collected bottles and packages of pesticides after using them to the right places as regulated. Rarely the farmers threw away pesticide bottles and packages at the yards at the banks of the fields, or rivers, streams and ponds, causing water pollution, soil and air pollution. Table 6 shows that about 80% of households in Van Duc and Dang Xa communes collected drug bottles and packages to the storage tanks in accordance with regulations (summarizing results of interviews with the officials of the Cultivation and Plant Protection Station of Gia Lam district, 2021). Most farmers understood and formed the habit of not burning pesticide containers, but collecting them to the dumping tanks according to regulations.

Two communes, Van Duc and Dang Xa, important safe vegetable granaries of Hanoi city, have also invested in building a system of cement tanks containing pesticide packaging in 5 safe vegetable production areas to create favorable conditions for the farmer households to fulfill the commitment of keeping the field clean implemented by the District People’s Committee and the cooperatives.

Source: Survey data (2021).

Source: Survey result (2021).

In addition, the farmers of the two surveyed communes also formed a habit of cleaning spraying tools after spraying—washing the pesticide spray tanks both inside and outside with soap, disassembling each set part separately, opening the nozzle, draining the water and letting the tanks dry off, and storing them in a warehouse separate from houses and barns. The proportion of farmers cleaning the pesticide spray tanks after spraying at Van Duc and Dang Xa communes reached 100% of the surveyed households. The percentages of households that kept spray tools away from houses and barns in Van Duc and Dang Xa communes were 73.33% and 80%, respectively (Table 6).

For the excess pesticides after spraying, most farmers poured them into the containers in accordance with regulations. This percentage of surveyed households pouring excess pesticides to the regulated places reached 50% and 56.67% in Van Duc and Dang Xa communes, respectively. There was no case that farmers dumped the excess pesticides in the ditches or near water sources.

After spraying pesticides, most of the surveyed farmers practiced personal hygiene measures such as rinsing the mouth (85% of the interviewed households), using eye drops (58% of the interviewed households) and keeping the spraying clothes separate from other clothes (90% of the interviewed households).

It can be seen that, in general, farmers in the two surveyed communes performed the treatment measures after spraying relatively well as a solution to reduce the risks of pesticides in their production.