Green Prevention and Control Technology against Main Diseases and Insect Pests of Facility Tomato

Hongping Tian,Fujun Li*,Guocai Lu,Chunhua Li

1.Weifang Academy of Agricultural Sciences,Weifang 261071,China;2.Shouguang Kenongyuan Fruit and Vegetable Professional Cooperative,Shouguang 262728,China

Abstract In recent years,with the increasing planting area of facility tomato,diseases and insect pests such as tomato grey mold(Botrytis cinerea),early blight(Alternaria solani),late blight(Phytophthora infestans),and whitefly(Trialeurodes uaporariorum)occur frequently,causing severe harms and difficulties in prevention and control.In order to ensure the normal production of facility tomato and improve the yield and quality of tomato,the corresponding prevention and control measures are put forward according to the regularity of the occurrence of diseases and insect pests and the characteristics of facility environment,which has certain guiding significance for agricultural production.

Keywords Facility tomato;Diseases and insect pests;Prevention and control

As a major vegetable production province,Shandong Province has been continuously expanding the cultivation area of facility vegetables.With the increase of the varieties of facility vegetables and the adjustment of industrial structure,the yield reduction of facility vegetables caused by diseases and insect pests is becoming more and more serious,with an annual reduction of about 20%[1].At present,pesticides and agricultural measures are mainly used to control diseases and insect pests of facility vegetables.In the process of pesticide control,problems such as excessive drug use,long-term use of a single pesticide and unscientific drug use methods often occur.These problems are not conducive to the prevention and control of diseases and insect pests of facility vegetables,and will bring about issues in food safety[2].

In order to improve the prevention and control effect of diseases and insect pests and the cultivation efficiency of facility vegetables,some scholars put forward ecological prevention and control measures.For example,Qiu[3]raised green prevention and control technology against diseases and insect pests of facility vegetables.The technology reduces the damage caused by diseases and insect pests to less than 10% and reduces the usage amount of chemical pesticides by 20%.With the increasing attention to the prevention and control of diseases and insect pests of facility vegetables,the author studied the diseases and insect pests of facility tomato,and established the integrated control system of main diseases and insect pests of facility tomato.

1 Investigation on Main Diseases and Insect Pests of Facility Tomato and Their Prevention and Control Status

From March 2019 to November 2020,the facility vegetable growing areas in Fangzi,Hanting,Qingzhou and Shouguang in Weifang City were investigated,to understand the occurrence and development of major diseases and insect pests in the main tomato producing areas and their control measures.The survey results showed that the main diseases affecting the quality of facility tomato were grey mold (Botrytis cinerea),early blight(Alternaria solani)and late blight(Phytophthora infestans),and the main insect pests were whitefly(Trialeurodes uaporariorum)and American vegetable leaf miner(Liriomyza sativae).

1.1 Tomato grey mold Tomato grey mold is a severe fungal disease in tomato production,which mainly infects tomato flowers,fruits and leaves.At present,chemical agent is the major prevention and control measure against tomato grey mold.In the past few decades,many botanical pesticides and biocontrol agents have been utilized to control tomato gray mold.Due to large sporulation quantity and fast growth of B.cinerea,fungicides are used frequently in the production to control the development of the disease,which brings about a series of negative effects such as the emergence of resistance.

1.2 Tomato early blight Tomato early blight,also known as ring rot,mainly damages leaves,stems and fruits of tomato plants,and typical annular lesions are often formed in the late incidence stage.Poor variety resistance,poor field drainage,dense planting or excessive plant growth will aggravate the disease.In the initial stage of incidence,there are brown spots on leaf surface,which then expand into a circle,with concentric rings.There are yellow haloes around,and the center is grey brown,or expands to large lesions in severe cases.

1.3 Tomato late blight In the early incidence stage,water-soaked lesions first appear at leaf apex or margin,and then leaves are chlorotic and yellowing.Afterwards,the lesions gradually change to yellowish-brown V-shaped lesions.Finally,all the leaves become yellow and dead,and exposure to the sun leads to sun burn of fruits.The prevalence of this disease is closely related to the annual precipitation.Generally,when there are much rainfall and mild climate,the prevalence is severe,otherwise it is lighter.

1.4 American vegetable leaf miner American vegetable leaf miner is a dangerous quarantine pest,with strong adaptability,fast reproduction rate and wide host range,causing great harms to facility tomato.Generally,the yield is reduced by 25%-80%,or even the field fails to harvest.

1.5 Whitefly The adults and nymphs of whitefly suck the sap of tomato plants,leading to chlorosis,yellowing and wilting leaves,or even the whole plant withers.Meantime,because of its strong reproduction,fast speed,and large population,it will seriously pollute leaves and fruits,depriving vegetables of their commercial value.

2 Green Prevention and Control Technology

2.1 Agricultural control

2.1.1 Selection of variety.The tomato varieties that are suitable for planting in this region with strong resistance,high quality and high yield are selected.

2.1.2 Cultivation of vigorous seedlings.Seedbed management is strengthened to cultivate disease-free,insect-free strong seedlings.

2.1.3 Soil treatment.On the one hand,the soil is sterilized to eliminate the residual pests,eggs and pathogens in the soil.The soil is disinfected by high temperature and ultraviolet rays of the sun to improve physical and chemical properties of soil and reduce the harms of soil-borne diseases.The fields are cleaned,to remove litters and weeds.

On the other hand,the prepared ozone water is directly irrigated by agricultural integrated control machine in the initial incidence stage of the disease.

2.1.4 Seed disinfection.Seeds are strictly treated before sowing,and are often disinfected by soaking.

2.1.5 Technique of fertilization.The fully decomposed organic fertilizer is applied as the main fertilizer.Base fertilizer is dominated,while topdressing is performed in the early stage as far as possible.

2.2 Physical control

2.2.1 Two-net coverage technology.In spring,30-mesh white insect nets are covered at the air inlet and entrance of the greenhouse.In summer,sunshade nets are covered,which can effectively block small insect pests such as tobacco whitefly and aphids,and reduce high temperature burns.

2.2.2 Insecticidal lamp trapping technology.During the peak occurrence period of insect pests in summer and autumn,black light lamps are used to kill many species of vegetable pests,such as Lepidoptera,Coleoptera and Orthoptera,receiving significant effort.

2.2.3 Colored sticky plate pest control technology.The tropism for special colors is used to trap some insect pests,so as to reduce the occurrence and harms of insect pests.Yellow sticky plates are installed in the field to kill alatae and tobacco whitefly.Silver grey films are laid or hanged to avoid aphids.Blue sticky plates are used to kill thrips and other pests.

2.3 Biological control Biological control takes advantage of the interrelationships between biological species to inhibit one or a group of organisms by another or another group of organisms.It is highlighted by no pollution to the environment,which is definitely superior to nonbiological pest control methods such as pesticides.For example,Encarsia formosa kills whiteflies by parasitising them.When the density of whitefly reaches 0.5-1.0 individuals/plant,E.formosa are released at the density of 5 individuals/plant for three times with an interval of 5-7 d.

2.4 Chemical control Chemical pesticides have many advantages in the prevention and control of vegetable diseases and insect pests,such as wide range of control objects, obvious control effect,quick effect and convenient utilization.However,long-term and single use of chemical pesticides often leads to the development of resistance in crops,and excessive use causes environmental pollution and poses a threat to human health.Therefore,chemical pesticides must be used in a scientific and reasonable manner.First,biological pesticides and biochemical preparations should be selected,and pesticides with high efficiency,low toxicity and low residue must be used to ensure the production safety.Second,according to different varieties of vegetables and differences in drug resistance at different growth stages,the application frequency,concentration,range and dose should be strictly controlled.According to the toxicity of pesticides and the occurrence of diseases and insect pests,pesticides are sprayed in combination with climate and seedling status,and the dosage and concentration of preparations should be strictly controlled.Different types of pesticides must be used alternatively and rationally.Third,pesticide safety regulations must be strictly implemented,and the safe interval must be followed to ensure the safety of vegetables.

3 Conclusions

In short,green prevention and control technology against main diseases and insect pests of facility tomato is a comprehensive process.According to the actual growth of facility tomato,the idea of"prevention first,comprehensive control"is implemented with"green prevention and control"as the basic principle,so as to minimize the adverse effects of diseases and insect pests on the quality and safety of tomato plants,and ensure that facility tomato can meet the national food safety needs.