论文部分内容阅读
Abstract In order to make clear the effects of rain shelter cultivation on the incidence of diseases and pests of grape in Shandong Province， with Summer Black as the material， the diseases and pests of grape under rain shelter cultivation and open field cultivation in Tai’an and Jining were investigated. The results showed that under the rain shelter cultivation condition， the phenological period of grape delayed 5-8 d. The types of grape diseases and pests under the rain shelter cultivation were the same as those in the open filed cultivation. The most serious pests were Apolygus lucorum， followed by Lycorma delicatula， Erythreura apicalis and Thrips tabaci. The most serious leaf disease was downy mildew， and the most serious disease of grape berries was grape sour rot. Compared with the open field cultivation， the rain shelter cultivation could effectively reduce the incidence of pests and diseases in grape leaves and fruit. At the end of May 2018 and 2019， the occurrence rate of grape pests under the rain shelter cultivation in Tai’an reduced by 57.69% and 60.47%， respectively， and those in Jining reduced by 72.22% and 62.50%， respectively. In the middle of July of 2018 and 2019， the incidence of grape fruit diseases under the rain shelter cultivation in Tai’an reduced by 62.49% and 50.07%， respectively， and that in Jining reduced by 49.96% and 100%， respectively.
Key words Shandong Province; Grape; Rain shelter cultivation; Open field cultivation; Phenological period; Diseases and pests
Received： February 23， 2021 Accepted： April 28， 2021
Supported by Key Research and Development Program of Linyi City （2020ZX010）; Agricultural Improved Variety Project of Shandong Province （2020LZGC008）; Agricultural Science and Technology Innovation Project of Shandong Academy of Agricultural Sciences （CXGC2021A11）.
Xiujie LI （1980-）， female， P. R. China， research assistant， master， devoted to research about viticulture physiology and breeding.
*Corresponding author. E-mail： sdtanlibo@163.com.
The grape cultivation area of Shandong Province is 38 000 hm which plays an important role in the poverty alleviation of farmers and the adjustment of industrial structure. The ripening period of grapes in Shandong Province coincides with the same season of rain and heat， and a little careless management will cause serious diseases and pests and difficult control of fruit cracking and rotten fruit. At present， agrochemicals are used in large doses and multiple batches in production， causing food safety hazards and soaring production costs. As people pay more and more attention to food safety， the research and development of green cultivation methods for reducing the occurrence of pests and diseases from sources has always been the focus of scientific and technical personnel. Rain shelter cultivation is a simple facility cultivation method in which plastic film is covered on the facilities above the top of canopies during the grape growing season to prevent rainfall from affecting the growth and fruiting of grape， thereby ensuring the normal maturity of grapes[1-3]. Rain shelter cultivation can avoid rain splashing and flowing， reduce the temperature and humidity of the grape leaf curtain layer， and theoretically reduce the incidence of moisture-loving diseases. In recent years， rain shelter cultivation has gradually emerged in southern China[4]， and the promotion of this technology has turned the sub-suitable areas for grape planting in the south into efficient areas. Drawing on the experience of rain-shelter cultivation of grapes in the south， Shandong Institute of Pomology introduced rain shelter cultivation techniques into the main growing areas of table grapes such as Jinan， Tai’an， Jining， Liaocheng， etc.， in 2010. They conducted a systematic study on the rain shelter cultivation mode， construction cost， and the effects of rain shelter cultivation on the growth and development， fruit quality and micro-environment of grape[5-9]， and initially formulated the grape rain shelter cultivation technical regulations suitable for Shandong Province. Studies in Guangxi and other places have shown that rain shelter cultivation has a certain effect on the prevention and control of grape downy mildew[10-12]， gray mold[13] and white rot[14]. The occurrence of plant diseases and pests has regional characteristics. The occurrence time and types of plant diseases and pests in different regions are different. However， as of now， there is no report on the effect of rain shelter cultivation on the occurrence of diseases and pests in the cultivation of edible grapes in Shandong Province. For this reason， for two consecutive years from 2018 to 2019 in the main edible grape production areas in Shandong Province， the occurrence of grape diseases and pests under the two cultivation methods of sheltered and open fields was investigated， aiming to provide guidance for the prevention and control of diseases and pests of grape cultivated in sheltered areas and further improve the technical system of rain shelter cultivation of grape in Shandong Province.
Materials and Methods
Experimental materials
The grape variety was Summer Black.
Experimental methods
Experimental design
From 2018 to 2019， in the main table grape producing area of central Shandong Province represented by Tai’an and the main table grape producing area of southwest Shandong represented by Jining for 2 consecutive years， the occurrence of grape diseases and pests under the two cultivation methods of sheltered and open fields was investigated. Specifically， the Tai’an pilot project was selected at the Jinniu Mountain Experimental Demonstration Base of Shandong Institute of Pomology， Daiyue District， Tai’an City， Shandong Province. The grape vines were planted in 2014， with a north-south direction， a row spacing of 2 m×6 m， and shaped with T-shaped frames. The Jining pilot project was selected in Jining Qufu Nishanhong Ecological Agriculture Co.， Ltd. The grape vines were planted in 2016， and the planting method and frame type were the same as the Tai’an pilot. In the same pilot， a comparative experiment design was adopted， and two methods of rain shelter cultivation and open field cultivation （CK） were set up. The rain shelter facilities were simple multi-span rain shelters with a height of 2.6 m and a span of 6 m， and the top was covered all year round. The two pilots were all irrigated by drip irrigation， and had good drainage and irrigation conditions and a high level of grape management. Incidence rate of fruit cluster diseases
The investigation results for 2 consecutive years （Table 6） showed that the rain shelter cultivation could effectively reduce the incidence of grape cluster diseases. As the fruit matured， the incidence of fruit cluster diseases of grape grown in open fields was on the rise. When the fruit began to mature in mid July 2018 and 2019， the incidence of fruit cluster diseases of open-field grape in Tai’an area was 13.33% and 6.67%， respectively， and the incidence of fruit cluster diseases of open-field grape in Jining area was 13.33% and 5.00%， respectively; and under the rain shelter cultivation， the incidence of grape cluster diseases in Tai’an area （5.00% and 3.33%， respectively） decreased by 62.49% and 50.07%， respectively， and the incidence of grape cluster diseases in Jining area （6.67% and 0， respectively） decreased by 49.96% and 100%， respectively. In mid August， that is， the fruit was hung on the trees for one month after maturity， compared with the open field cultivation， the incidence of fruit cluster diseases of grape cultivated under rain shelters in Tai’an area was reduced by 69.24% and 78.27%， respectively， and the incidence of fruit cluster diseases of grape cultivated under rain shelters in Jining area was reduced by 70.58% and 75.01%， respectively.
Conclusions and Discussion
From 2018 to 2019， the investigation results in Tai’an and Jining regions of Shandong Province for 2 consecutive years showed that the types and periods of occurrence of leaf and fruit diseases and pests in grape cultivated in sheltered and open fields were basically the same. Pests caused greater damage to the leaves of grape in the early growth stage than in the middle and late growth stages. The main pests were A. lucorum， L. delicatula and E. apicalis， among which A. lucorum was the most harmful pest to the leaves in the early stage of grape growth. Studies have found that since 2017， the population of A. lucorum has increased sharply and has become the main pest in the early stage of grape growth. Improper control can cause the damage rate of grape plants up to 70%[16]. In Tai’an area， without implementing any prevention and control measures， the damage rate of A. lucorum to grape leaves is as high as 80%. A. lucorum depends on the piercing and sucking mouthparts of adults and nymphs to injure the buds and young leaves of grape， and because the wound is small， they are usually found only after a few days when the damage has already formed， which not only affects the normal growth and development of grapes， but also seriously affects the commercial value of grapes due to the scars on the fruit. The adults of A. lucorum hide in the base of the tip leaves after feeding， and quickly escape after being slightly touched， so it is difficult to control them. The investigation found that the rain shelter cultivation could effectively reduce the occurrence of grape leaf pests， and compared with the open field cultivation， the incidence of leaf pests was reduced by 57%-72%. It might be related to the rain shelters or roof shed films that prevented the jumping and migration of pests. The damage to grape leaves in Tai’an area was greater than that in Jining area. The reason might be that there were overgrown trees on the slopes around the test site in Tai’an area， and there were apple， peach and other fruit trees in the orchards， which provided a place for the eggs to live through the winter， so as the temperature rose in spring， the pests migrated to the grape leaves to damage them. Therefore， attention should be paid to site selection when constructing orchards， and we should try to avoid mountainous areas with lush trees and choose plots far away from the woods， and should not interplant host fruit trees and seedlings in orchards. The investigation results for 2 consecutive years showed that the rain shelter cultivation delayed the phenological period of grape， and the fruit ripening period was 5-8 d later than that of open field cultivation. Although the types and time of occurrence of diseases in grape in the rain shelter cultivation mode were basically the same as those in the open field cultivation， the incidence of leaf diseases could be reduced by up to 60% compared with the open field cultivation. Leaf diseases mainly occurred in the later stages of growth， especially downy mildew that occurred from August to October. Sour rot was most harmful to grape fruit， followed by white rot， but in many cases the two occur at the same time. The incidence of fruit cluster diseases of grape cultivated in sheltered areas could be reduced by 50%-78%.
In summary， compared with the open field cultivation， the types of pests and diseases that occurred in grape cultivated in the rain shelter mode did not changed much， but the incidence of pests and diseases was significantly reduced， which in turn could reduce the use frequency and quantity of agrochemicals. As a green method of preventing and controlling diseases and pests， rain shelter cultivation not only reduces the production investment， but also helps to improve the safety of products and the environmental friendliness of the production system. Therefore， in Shandong Province， which is wet and rainy in summer， grape cultivation under rain shelters has a good promotion value.
References
[1] LIU TS， LI GF. Advances in research on physiology of grape protected cultivation[J]. Acta Horticulturae Sinica， 200 29（S1）： 24-28. （in Chinese）
[2] LIU HN， ZHU JQ. Feeding effect of buffer in fattening beef cattle diet[J]. Hubei Agricultural Sciences， 2001（4）： 70-72. （in Chinese）
[3] WANG ZH， ZHANG W， GUAN LP， et al. Effect of rain shelter cultivation on microenvironment and fruit quality of Zexiang grape[J]. Sino-Overseas Grapevine & Wine， 2015（3）： 14-17. （in Chinese）
[4] CAO M， GUO JN， GAO DT， et al. Feeding effect of buffer in fattening beef cattle diet[J]. Journal of Henan Agricultural Sciences， 2016， 45（1）： 15-19. （in Chinese）
[5] HAN Z， LI XJ， ZHANG QT， et al. Effects of rain-shelter cultivation on light intensity in canopy， cost and benefit[J]. Shandong Agricultural Sciences， 2018， 50（11）： 52-54. （in Chinese）
[6] HAN Z， LI XJ， ZHANG QT， et al. Effects of rain shelter cultivation on the microclimate and cost[J]. Journal of Anhui Agricultural Sciences， 2018， 46（34）： 184-185， 189. （in Chinese） [7] LI B， LI XJ， HAN Z， et al. Effects of shading on shoot growth and fruit quality of Summer Black grape[J]. Shandong Agricultural Sciences， 2017， 49（8）： 45-48. （in Chinese）
[8] LI B， ZHAO XQ， LI XJ， et al. Effect of shading on the endogenous hormones in the shoots during the differentiation of grape flower buds[J]. Jiangsu Agricultural Sciences， 2017， 45（13）： 104-107. （in Chinese）
[9] LI B， LI C， LI XJ， et al. Effect of shading on the microenvironment， leaf quality and fruit quality of ‘Xiahei’ grape[J]. China Fruits， 2017（5）： 45-48. （in Chinese）
[10] GONG HJ， JIANG QS， YE KY， et al. Field investigation of downy mildew （Plasmapara viticola） of the main grape cultivars with rain shelter cultivation in Guangxi[J]. Southern Horticulture， 2016， 27（5）： 17-19. （in Chinese）
[11] YU SY， LIU CY， FU JF， et al. Spatial distribution pattern and sampling technique for grapevine downy mildew in grape seedlings under open and rain-shelter cultivations [J]. Journal of Fruit Science， 2015， 32（4）： 720-726. （in Chinese）
[12] XIA YM. Control effects of different rain shelter cultivation patterns on main grape diseases and their effects on plant canopy temperature and humidity[J]. South China Agriculture， 2014（21）： 25， 27. （in Chinese）
[13] HUANG XD， HU WL， ZHU SS， et al. Research and application of disease control techniques for sheltered grape planting[J]. China Plant Protection， 201 32（10）： 25-27. （in Chinese）
[14] JIA TK， WANG LK. Investigation of effects on fruit quality and controlling main diseases of rainproof cultivation grape[J]. Shanxi Fruits， 2018（5）： 4-5， 9. （in Chinese）
[15] FU F， FAN K， QU JL. Investigation on the main pests and diseases of grape in the mountainous area of central Shandong[J]. Deciduous Fruits， 2019， 51（5）： 40-43. （in Chinese）
[16] ZHAO QF， LI QL， LI J， et al. Grape Apolygus lucorum in China： Occurrence trend and prevention and control strategies[J]. Chinese Agricultural Science Bulletin， 2019， 35 （36）： 138-142. （in Chinese）
Key words Shandong Province; Grape; Rain shelter cultivation; Open field cultivation; Phenological period; Diseases and pests
Received： February 23， 2021 Accepted： April 28， 2021
Supported by Key Research and Development Program of Linyi City （2020ZX010）; Agricultural Improved Variety Project of Shandong Province （2020LZGC008）; Agricultural Science and Technology Innovation Project of Shandong Academy of Agricultural Sciences （CXGC2021A11）.
Xiujie LI （1980-）， female， P. R. China， research assistant， master， devoted to research about viticulture physiology and breeding.
*Corresponding author. E-mail： sdtanlibo@163.com.
The grape cultivation area of Shandong Province is 38 000 hm which plays an important role in the poverty alleviation of farmers and the adjustment of industrial structure. The ripening period of grapes in Shandong Province coincides with the same season of rain and heat， and a little careless management will cause serious diseases and pests and difficult control of fruit cracking and rotten fruit. At present， agrochemicals are used in large doses and multiple batches in production， causing food safety hazards and soaring production costs. As people pay more and more attention to food safety， the research and development of green cultivation methods for reducing the occurrence of pests and diseases from sources has always been the focus of scientific and technical personnel. Rain shelter cultivation is a simple facility cultivation method in which plastic film is covered on the facilities above the top of canopies during the grape growing season to prevent rainfall from affecting the growth and fruiting of grape， thereby ensuring the normal maturity of grapes[1-3]. Rain shelter cultivation can avoid rain splashing and flowing， reduce the temperature and humidity of the grape leaf curtain layer， and theoretically reduce the incidence of moisture-loving diseases. In recent years， rain shelter cultivation has gradually emerged in southern China[4]， and the promotion of this technology has turned the sub-suitable areas for grape planting in the south into efficient areas. Drawing on the experience of rain-shelter cultivation of grapes in the south， Shandong Institute of Pomology introduced rain shelter cultivation techniques into the main growing areas of table grapes such as Jinan， Tai’an， Jining， Liaocheng， etc.， in 2010. They conducted a systematic study on the rain shelter cultivation mode， construction cost， and the effects of rain shelter cultivation on the growth and development， fruit quality and micro-environment of grape[5-9]， and initially formulated the grape rain shelter cultivation technical regulations suitable for Shandong Province. Studies in Guangxi and other places have shown that rain shelter cultivation has a certain effect on the prevention and control of grape downy mildew[10-12]， gray mold[13] and white rot[14]. The occurrence of plant diseases and pests has regional characteristics. The occurrence time and types of plant diseases and pests in different regions are different. However， as of now， there is no report on the effect of rain shelter cultivation on the occurrence of diseases and pests in the cultivation of edible grapes in Shandong Province. For this reason， for two consecutive years from 2018 to 2019 in the main edible grape production areas in Shandong Province， the occurrence of grape diseases and pests under the two cultivation methods of sheltered and open fields was investigated， aiming to provide guidance for the prevention and control of diseases and pests of grape cultivated in sheltered areas and further improve the technical system of rain shelter cultivation of grape in Shandong Province.
Materials and Methods
Experimental materials
The grape variety was Summer Black.
Experimental methods
Experimental design
From 2018 to 2019， in the main table grape producing area of central Shandong Province represented by Tai’an and the main table grape producing area of southwest Shandong represented by Jining for 2 consecutive years， the occurrence of grape diseases and pests under the two cultivation methods of sheltered and open fields was investigated. Specifically， the Tai’an pilot project was selected at the Jinniu Mountain Experimental Demonstration Base of Shandong Institute of Pomology， Daiyue District， Tai’an City， Shandong Province. The grape vines were planted in 2014， with a north-south direction， a row spacing of 2 m×6 m， and shaped with T-shaped frames. The Jining pilot project was selected in Jining Qufu Nishanhong Ecological Agriculture Co.， Ltd. The grape vines were planted in 2016， and the planting method and frame type were the same as the Tai’an pilot. In the same pilot， a comparative experiment design was adopted， and two methods of rain shelter cultivation and open field cultivation （CK） were set up. The rain shelter facilities were simple multi-span rain shelters with a height of 2.6 m and a span of 6 m， and the top was covered all year round. The two pilots were all irrigated by drip irrigation， and had good drainage and irrigation conditions and a high level of grape management. Incidence rate of fruit cluster diseases
The investigation results for 2 consecutive years （Table 6） showed that the rain shelter cultivation could effectively reduce the incidence of grape cluster diseases. As the fruit matured， the incidence of fruit cluster diseases of grape grown in open fields was on the rise. When the fruit began to mature in mid July 2018 and 2019， the incidence of fruit cluster diseases of open-field grape in Tai’an area was 13.33% and 6.67%， respectively， and the incidence of fruit cluster diseases of open-field grape in Jining area was 13.33% and 5.00%， respectively; and under the rain shelter cultivation， the incidence of grape cluster diseases in Tai’an area （5.00% and 3.33%， respectively） decreased by 62.49% and 50.07%， respectively， and the incidence of grape cluster diseases in Jining area （6.67% and 0， respectively） decreased by 49.96% and 100%， respectively. In mid August， that is， the fruit was hung on the trees for one month after maturity， compared with the open field cultivation， the incidence of fruit cluster diseases of grape cultivated under rain shelters in Tai’an area was reduced by 69.24% and 78.27%， respectively， and the incidence of fruit cluster diseases of grape cultivated under rain shelters in Jining area was reduced by 70.58% and 75.01%， respectively.
Conclusions and Discussion
From 2018 to 2019， the investigation results in Tai’an and Jining regions of Shandong Province for 2 consecutive years showed that the types and periods of occurrence of leaf and fruit diseases and pests in grape cultivated in sheltered and open fields were basically the same. Pests caused greater damage to the leaves of grape in the early growth stage than in the middle and late growth stages. The main pests were A. lucorum， L. delicatula and E. apicalis， among which A. lucorum was the most harmful pest to the leaves in the early stage of grape growth. Studies have found that since 2017， the population of A. lucorum has increased sharply and has become the main pest in the early stage of grape growth. Improper control can cause the damage rate of grape plants up to 70%[16]. In Tai’an area， without implementing any prevention and control measures， the damage rate of A. lucorum to grape leaves is as high as 80%. A. lucorum depends on the piercing and sucking mouthparts of adults and nymphs to injure the buds and young leaves of grape， and because the wound is small， they are usually found only after a few days when the damage has already formed， which not only affects the normal growth and development of grapes， but also seriously affects the commercial value of grapes due to the scars on the fruit. The adults of A. lucorum hide in the base of the tip leaves after feeding， and quickly escape after being slightly touched， so it is difficult to control them. The investigation found that the rain shelter cultivation could effectively reduce the occurrence of grape leaf pests， and compared with the open field cultivation， the incidence of leaf pests was reduced by 57%-72%. It might be related to the rain shelters or roof shed films that prevented the jumping and migration of pests. The damage to grape leaves in Tai’an area was greater than that in Jining area. The reason might be that there were overgrown trees on the slopes around the test site in Tai’an area， and there were apple， peach and other fruit trees in the orchards， which provided a place for the eggs to live through the winter， so as the temperature rose in spring， the pests migrated to the grape leaves to damage them. Therefore， attention should be paid to site selection when constructing orchards， and we should try to avoid mountainous areas with lush trees and choose plots far away from the woods， and should not interplant host fruit trees and seedlings in orchards. The investigation results for 2 consecutive years showed that the rain shelter cultivation delayed the phenological period of grape， and the fruit ripening period was 5-8 d later than that of open field cultivation. Although the types and time of occurrence of diseases in grape in the rain shelter cultivation mode were basically the same as those in the open field cultivation， the incidence of leaf diseases could be reduced by up to 60% compared with the open field cultivation. Leaf diseases mainly occurred in the later stages of growth， especially downy mildew that occurred from August to October. Sour rot was most harmful to grape fruit， followed by white rot， but in many cases the two occur at the same time. The incidence of fruit cluster diseases of grape cultivated in sheltered areas could be reduced by 50%-78%.
In summary， compared with the open field cultivation， the types of pests and diseases that occurred in grape cultivated in the rain shelter mode did not changed much， but the incidence of pests and diseases was significantly reduced， which in turn could reduce the use frequency and quantity of agrochemicals. As a green method of preventing and controlling diseases and pests， rain shelter cultivation not only reduces the production investment， but also helps to improve the safety of products and the environmental friendliness of the production system. Therefore， in Shandong Province， which is wet and rainy in summer， grape cultivation under rain shelters has a good promotion value.
References
[1] LIU TS， LI GF. Advances in research on physiology of grape protected cultivation[J]. Acta Horticulturae Sinica， 200 29（S1）： 24-28. （in Chinese）
[2] LIU HN， ZHU JQ. Feeding effect of buffer in fattening beef cattle diet[J]. Hubei Agricultural Sciences， 2001（4）： 70-72. （in Chinese）
[3] WANG ZH， ZHANG W， GUAN LP， et al. Effect of rain shelter cultivation on microenvironment and fruit quality of Zexiang grape[J]. Sino-Overseas Grapevine & Wine， 2015（3）： 14-17. （in Chinese）
[4] CAO M， GUO JN， GAO DT， et al. Feeding effect of buffer in fattening beef cattle diet[J]. Journal of Henan Agricultural Sciences， 2016， 45（1）： 15-19. （in Chinese）
[5] HAN Z， LI XJ， ZHANG QT， et al. Effects of rain-shelter cultivation on light intensity in canopy， cost and benefit[J]. Shandong Agricultural Sciences， 2018， 50（11）： 52-54. （in Chinese）
[6] HAN Z， LI XJ， ZHANG QT， et al. Effects of rain shelter cultivation on the microclimate and cost[J]. Journal of Anhui Agricultural Sciences， 2018， 46（34）： 184-185， 189. （in Chinese） [7] LI B， LI XJ， HAN Z， et al. Effects of shading on shoot growth and fruit quality of Summer Black grape[J]. Shandong Agricultural Sciences， 2017， 49（8）： 45-48. （in Chinese）
[8] LI B， ZHAO XQ， LI XJ， et al. Effect of shading on the endogenous hormones in the shoots during the differentiation of grape flower buds[J]. Jiangsu Agricultural Sciences， 2017， 45（13）： 104-107. （in Chinese）
[9] LI B， LI C， LI XJ， et al. Effect of shading on the microenvironment， leaf quality and fruit quality of ‘Xiahei’ grape[J]. China Fruits， 2017（5）： 45-48. （in Chinese）
[10] GONG HJ， JIANG QS， YE KY， et al. Field investigation of downy mildew （Plasmapara viticola） of the main grape cultivars with rain shelter cultivation in Guangxi[J]. Southern Horticulture， 2016， 27（5）： 17-19. （in Chinese）
[11] YU SY， LIU CY， FU JF， et al. Spatial distribution pattern and sampling technique for grapevine downy mildew in grape seedlings under open and rain-shelter cultivations [J]. Journal of Fruit Science， 2015， 32（4）： 720-726. （in Chinese）
[12] XIA YM. Control effects of different rain shelter cultivation patterns on main grape diseases and their effects on plant canopy temperature and humidity[J]. South China Agriculture， 2014（21）： 25， 27. （in Chinese）
[13] HUANG XD， HU WL， ZHU SS， et al. Research and application of disease control techniques for sheltered grape planting[J]. China Plant Protection， 201 32（10）： 25-27. （in Chinese）
[14] JIA TK， WANG LK. Investigation of effects on fruit quality and controlling main diseases of rainproof cultivation grape[J]. Shanxi Fruits， 2018（5）： 4-5， 9. （in Chinese）
[15] FU F， FAN K， QU JL. Investigation on the main pests and diseases of grape in the mountainous area of central Shandong[J]. Deciduous Fruits， 2019， 51（5）： 40-43. （in Chinese）
[16] ZHAO QF， LI QL， LI J， et al. Grape Apolygus lucorum in China： Occurrence trend and prevention and control strategies[J]. Chinese Agricultural Science Bulletin， 2019， 35 （36）： 138-142. （in Chinese）