Abstract Based on investigation and research， according to the current actual production of sugarcane， the occurrence dynamics and outbreak causes of important pests and diseases that seriously affect sugarcane production were summarized， and accurate and efficient green prevention and control technology was put forward according to the occurrence and damage characteristics of important pests and diseases， such as strengthening sugarcane introduction and quarantine， breeding and selecting varieties resistant to diseases and pests， promoting the use of detoxified healthy seedlings vigorously， applying lamp trapping technology on a large scale， scientifically guiding and promoting biological prevention and control technology， practically promoting the precise and efficient application of slow??release long??acting and low toxic pesticides， strengthening field management， spraying pesticides in time at the early stage of a disease， and doing a good job of monitoring and emergency prevention and control of sudden pests.
　　Key words Sugarcane areas of Yunnan； Sugarcane； Pests and diseases； Epidemic dynamics； Accurate prevention and control
　　Grain， cotton， oil and sugar are the main agricultural products and national strategic materials in China. The development of sugar is related to national food safety and increase in farmers?? income. Yunnan is the second largest sugar base in China. During the ?°Twelfth Five??Year Plan?± period， the planting area of sugarcane in Yunnan Province has exceeded 0.33 million hm2， and the yield of sugar has reached more than 2.3 million tons. The planting area of sugarcane and the yield of sugar accounted for about 20% of those of China. Sugar industry has become an important regional economic pillar industry in Yunnan and an important channel for farmers in the border areas to increase their income. In the province， ten autonomous prefectures and cities and 49 counties produce sugar， and more than 1.5 million peasant households and more than 6 million sugarcane farmers plant sugarcane. Sugarcane are mostly planted in ethnic minority areas along the border. Among them， there are 34 national poverty counties and 21 counties along the border. Sugar industry plays an important role in promoting economic development in the border areas， increasing farmers?? income and local fiscal revenue[1].
　　Yunnan has a long history of sugarcane cultivation， and sugarcane is widely distributed in the province. It is planted between 29??-29??15?? N， 97??39??-106??12??E. Most sugarcane areas belong to the tropics and subtropics， and the climate and environment are complex and variable[1]. Especially in recent years， with the adjustment of industrial structure， the expansion of plating area of sugarcane， the change of planting methods， long??term continuous cropping and single species have resulted in the accumulation of sugarcane pests and diseases. Moreover， a variety of pests and diseases have happened at the same time and have spread quickly. Meanwhile， they damage sugarcane seriously， and the rate of potential loss caused by harmful organisms is up to 15%-30%[2]. How to effectively prevent and control sugarcane pests and diseases has become an important task in the development of sugarcane industry. In this paper， based on an investigation and research， as well as the current actual production of sugarcane， the occurrence dynamics and causes of outbreaks of important sugarcane pests and diseases were analyzed and discussed， and corresponding prevention and control strategies and accurate prevention and control integration technology were proposed according to their occurrence characteristics. 　　Occurrence and Epidemic Dynamics of Important Pests and Diseases That Seriously Affect Sugarcane Production
　　Sugarcane borers
　　Borers are the most common and most serious pests in the sugarcane areas of Yunnan. They are typical boring pests and easy to spread with introduction. The main species include Sesamia inferens Walker， Chilo infuscatellus Snellen， Chilo auricilia Dudgeon， Argyroploce schistaceana （Snellen）， Proceras venosatus （Walker） and Tryporyza intacta Snellen[2-4]. S. inferens Walker mainly damages paddy sugarcane. C. infuscatellus Snellen mainly damages dry land sugarcane. A. schistaceana （Snellen） is distributed widely and has a great impact on stubble sugarcane. The populations of P. venosatus （Walker） and T. intacta Snellen increase and extend fast， so the damage becomes increasingly serious. At present， the damage caused by a variety of sugarcane borers in the sugarcane areas of Yunnan is serious. At the seedling stage， the dead heart rate of sugarcane damaged by borers is 8.33%-65.82%. In the middle and later period， the proportion of sugarcane plants damaged by borers is 26.67%-96.67%， and the proportion of sugarcane joints damaged by borers is 4.43%-27.91%. The loss rate of sugarcane yield is 25.92% on average and 44.53% at most. The juice yield of sugarcane reduces 2.4% on average and 3.74% at most. The sugar content of sugarcane decreases 2.16% on average and 5.69% at most[2-4]. In recent years， in Yunnan with a particularly rainy and humid climate， the populations of exotic new insects P. venosatus （Walker） and T. intacta Snellen has grown too fast， and the outbreak trend is obvious. Especially in the middle and late period， the 4th and 5th generation of the populations are large， and the per unit area yield of sugarcane has reduced by more than 30%， while sugar content in sugarcane has decreased by 4.19 Brix， so they should be mainly monitored， prevented and controlled[2-4].
　　Underground pests damaging sugarcane
　　Underground pests are important pests that seriously damage sugarcane production in Yunnan， mainly including sugarcane beetles[Exolontha serrulata （Gyllenhal）， Alissonotum impressicolle Arrow and Alissonotum pauper （Burmeister）][2，5]， sugarcane elephant insects （Trochorhopalus humeralis Chevrolat and Diocalandra sp）[2，6-7]， and sugarcane termites[Odontotermes formosanus （Shiraki） and Macrotermes barneyi Light][2]. Among them， the occurrence of sugarcane beetles and sugarcane elephant insects are the most common， and their damage is the most serious[2，8]. In recent years， with the adjustment of planting structure and the diversification of crop layout， the damage has been increasing. In some fields， the density of sugarcane beetles has been up to 40 heads/m2， and the density of sugarcane elephant insects has been as high as 93 heads/m2. The yield of the damaged sugarcane has reduced by 30%-50% or 100%， and sugar content in sugarcane has decreased by 3%-5%. Perennial roots have been reserved for one year， and the direct economic loss has been up to one billion yuan， so that the cost of sugarcane planting has increased by 20%-40%， which severely damps the enthusiasm of farmers for sugarcane planting[2，8]. 　　Ceratovacuna lanigera Zehntner
　　C. lanigera Zehntner is the main pest that appears most commonly and damages sugarcane seriously in the sugarcane areas of Yunnan， and the affecting area accounts for more than 80% of the planting area[2，9]. In particular， due to the implementation of autumn planting or winter planting in recent years， C. lanigera Zehntner can obtain sufficient food and transfer the damaged plants. Successive years of drought is conducive to its rapid reproduction and population development， and their damage has increased year by year. As a result， the yield of the damaged sugarcane has reduced by 18%-35.3% or above 45% at most. Sugar content in sugarcane has decreased by 5.48%-8.16%. The emergence rate of sugarcane seedlings developed from the damaged sugarcane has reduced by 19.7%-41.6%. In the fields with serous damage， the germination rate of perennial roots has declined by 57.7%-93.6%， and the decrease in sugarcane yield is more serious[9]. The occurrence， growth and decline of C. lanigera Zehntner can be divided into four stages： from June to July， winged adults move into a sugarcane field to form a central insect plant that becomes the base point of the occurrence in the same year； they spread rapidly to the whole field from July to August； they rampantly harm sugarcane from September to October； after mid??to??late November， a large number of winged aphids migrate to other plants such as wild sugarcane， reeds and weeds to overwinter[2].
　　Mythimna separata （Walker）
　　M. separata （Walker） is widely distributed in the sugarcane areas of Yunnan Province. It appears commonly and is an important pest that eats sugarcane leaves[2]. In the past， M. separata （Walker） rarely harmed sugarcane. In recent years， its frequency of occurrence has increased， and the damage has also increased. From June to August， it often damages sugarcane， corn， rice and other crops. The larvae bite sugarcane leaves， which seriously affects the growth of sugarcane plants and brings great loss to sugarcane production. When it is severely rampant， the larvae migrate in groups and eat all sugarcane， resulting in a large area of decrease in sugarcane yield or no harvest. M. separata （Walker） likes humidity and is afraid of high temperature and drought. In summer and autumn， it is rainy， and the humidity is high， while the climate is cool， which is beneficial to the occurrence of M. separata （Walker）. It often appears and damages plants， so the sugarcane areas should strengthen monitoring， prevention and control of M. separata （Walker）[2]. 　　Dry top rot of sugarcane
　　The pathogen of the dry top rot is Gibberella moniliformis （Sheldon） Wineland at the sexual stage and Fusarium moniliforme Sheldon at the asexual stage[2，10]. The disease was first discovered in Java in 1890. In 1921， with the breeding and promotion of POJ2878， the disease was widespread around the world[2，10]. At present， the disease is distributed in the sugarcane areas of Yunnan. It occurred sporadically before the 1980s and did not pose a threat to sugarcane production. Since 2000， with the widespread application of Xintaitang No. 1， Xintaitnag No. 25， Yuetang 93??159 and other susceptible varieties， the disease has occurred frequently and has become more and more serious， and it has become an important disease in the growth period of sugarcane. Especially in recent years， it is rainy and humid， and a large area of susceptible varieties such as Yuetang 93??159， ROC25 and ROC1 and Chuantang 79??15 have been planted. As a result， the disease has occurred in a large area in Lincang， Yuxi， Honghe， Banna， Pu??er and other sugarcane areas， and sugarcane yield and sugar content have decreased obviously. Sugarcane production is facing an increasingly serious disaster threat. Susceptible varieties were severely affected by the disease， and it often make a large number of sugarcane stems die. The average rate of diseased plants is 81.1% and even up to 100%. The average yield loss of sugarcane is 38.42% and even up to 48.5%. Sugar content in sugarcane decreases by 3.14% and even 4.21%[2]. The disease is an epidemic disease that appears in a rainy and highly wet season， and the spread is very rapid. High temperature and high humidity， poor ventilation and partial application of nitrogen fertilizer are favorable for the occurrence of this disease， and it is very easy to occur from July to October.
　　Sugarcane brown streak
　　Brown streak is the most common epidemic disease that can damage sugarcane leaves. The pathogenic bacterium is Cochliobolus stenospilus?¨Drech.??Mat. and Yam. at the sexual stage and Helminthosporium stenospilum Drechsler at the asexual stage[2，10]. The disease was first discovered in Cuba in 1924[10]. It is widely distributed in the sugarcane areas of Yunnan. It used to be sporadic and had little threat to sugarcane production. In recent years， the global climate is abnormal， and the disease has been widely prevalent in the sugarcane areas such as Lincang， Xinping， Banna， Pu??er and Honghe， which has caused widespread damage to sugarcane. The fields where Yuetang 93??159 and ROC25， Yunyin No. 3， and perennial roots are affected by the disease seriously. In the fields withe serious damage， sugarcane yield decreases by 18%-35% and even above 40%； sugar content reduces by 15%-30%. Brown streak is a disease that should be monitored and controlled in various sugarcane areas during the growth period of sugarcane. It occurs mostly in sugarcane areas with poor soil or lack of phosphorus and potassium， more rain （long??term rainy days） and high humidity. In recent years， the area where it appears is wider， and its occurrence is frequent. It is the frequentest from August to October. Yuetang 93??159 and ROC25， Yunyin No. 3， Yuetang 00??236， Liucheng 03??1137， Guitang 02??761， Yunzhe 03??194， Funong 0335， etc. are susceptible to the disease[2]. 　　Sugarcane rust
　　Sugarcane rust is epidemic in a rainy and humid season and is one of the most important diseases that harm sugarcane leaves. Brown rust is caused by Puccina. melanocephala H.Sydow ?? P.Sydow， and yellow rust is induced by Puccinia kuehnii （Kruger） Butler[2，10]. Sugarcane rust was first discovered in Java in 1890. After the 1970s， it has occurred extensively in countries and regions where sugarcane is planted and has been repeatedly epidemic[10]. In 1982， it occurred sporadically local sugarcane areas such as Changning and Gengma in Yunnan， and then it was reported in sugarcane areas in Fujian， Guangdong， Guangxi and Hainan[2，11]. It occurs mostly in the humid sugarcane areas of Yunnan and Guangxi， and it is easy to be epidemic under the conditions of heavy rain， heavy dew and high humidity. Yuetang 60， Dezhe 03??83， Funong 1110， Liucheng 03??1137， Yunzhe 06??407 and Guitang 46 are susceptible to the disease. In the fields withe serious damage， sugarcane yield decreases by 15%-30% and even above 40%； sugar content reduces by 10%-36%. During 2015-2017， the rainy season in the sugarcane areas of Yunnan came early and lasted for a long time， with more rainy days， less sunshine and high humidity. Due to the continuous cropping of highly susceptible varieties Yuetang 60 and Liucheng 03??1137， sugarcane rust appeared and was epidemic in the sugarcane areas of Yunnan such as Banna， Pu??er， Lincang and Dehong， and the damage tended to be serious day by day[2]. Sugarcane rust should be mainly monitored， prevented and controlled in humid sugarcane areas of Yunnan and Guangxi at present and in future.
　　Ratoon stunting disease of sugarcane
　　Ratoon stunting disease （RSD） of sugarcane， an important disease commonly occurring in various sugarcane areas in the world， is caused by Leifsonia xyli subsp.xyli （Lxx） that parasitizes in the vascular bundle of sugarcane plants[2，10]. It was confirmed that RSD appeared in Yunnan in 2004. Afterwards， the sugarcane areas were surveyed， and the results showed that RSD was present in the sugarcane areas. The detection rate of RSD in cultivars reached 100%， and RSD was detected in 21 main sugarcane areas. The positive detection rate was 65.5%-88%， and the average infection rate of sugarcane plants was 74.7%， and the susceptibility rate was 100% in case of drought and water shortage[13-14]. Due to RSD， sugarcane yield decreases by 10%-30%. The damage is more serious in case of drought and deficiency of elements， and sugarcane yield reduces by more than 60%. In recent years， the main varieties such as Yuetang 93??159， Mintang 69??421 and Yuetang 00??236 that have been widely planted in the sugarcane areas of Yunnan have been highly infected with RSD， so they have been degraded year by year， which seriously restricts the development of sugar industry[2，12-13]. 　　Agricultural Biotechnology 2018Strategies to Prevent and Control Important Diseases and Pests and Accurate Prevention and Control Technology
　　Prevention and control strategies
　　It is necessary to adhere to the policy of "putting stress on prevention and implementing comprehensive prevention and control"， mainly control important pests and diseases， control secondary pests and diseases at the same time， and establish the concept of "scientific plant protection， public plant protection， and green plant protection". It is needed to focus on pest and disease monitoring， strengthen technical guidance， and enhance the ability to prevent and control diseases and pests. Meanwhile， it is necessary to pay attention to the selection of disease??resistant varieties， vigorously promote detoxified healthy seedlings， speed up the transformation of methods of preventing and controlling diseases and pests， vigorously promote scientific use of pesticide， green prevention and control and unified control， and build a resource??saving and environment??friendly sustainable system to prevent and control diseases and pests， and achieve accurate prevention and control of sugarcane diseases and pests， reduction of pesticides used to control pests， and the increases of sugarcane in quality and efficiency.
　　Prevention and control technology
　　Strengthening sugarcane introduction and quarantine Quarantine can effectively prevent the spread of dangerous pests. In the work of introduction， and breeding， a good job should be done in quarantine. Firstly， it is needed to master and understand the occurrence of pests and diseases in sugarcane areas， avoid introduction from occurrence areas， and prevent the introduction of dangerous pests and diseases. Secondly， the introduced species of sugarcane should be bred at the same time， and the monitoring of pests and diseases should be strengthened. Once dangerous pests and diseases are found， they should be disposed or destroyed in time to control their spread. Thirdly， the residue of the cut sugarcane should be carefully removed and burned. Meanwhile， the cut sugarcane should be soaked in the mixture of 50% carbendazol wettable powder and 40% chlorantraniliprole?¤thiazide water dispersible granule solution diluted by 1 000 times and 20% Sushate Awei?¤fenitrothion emulsifiable concentrate diluted by 600 times for 10 min， and it can be disposed in warm water at 50 ?? with detoxification equipment for 2 h to avoid the spread of dangerous pests and diseases[2]. 　　Breeding and selecting varieties resistant to diseases and pests
　　The most economical and effective measure to control sugarcane pests and diseases is to breed varieties resistant to diseases and pests. At present， sugarcane pests and diseases are common in the sugarcane areas of Yunnan， and the damage is increasingly serious. To solve this problem， the most economical and effective way is to breed new varieties resistant to main diseases and pests in sugarcane areas. In addition， in the introduction of a sugarcane area， the resistance of varieties to pests and diseases should be understood to introduce varieties resistant to diseases and pests as much as possible according to the occurrence of pests and diseases in the sugarcane area. At the same time， the observation of the performance of pests and diseases should be strengthened， varieties susceptible to diseases and pests should be eliminated as soon as possible， so as to fundamentally control the occurrence and epidemic of pests and diseases in sugarcane areas.
　　Promoting the use of detoxified healthy seedlings vigorously
　　Promoting the use of detoxified healthy seedlings is the most economical and effective measure to prevent and control seed??borne diseases. At present， there are 22 sugar factories in Yunnan that have established 22 rooms with warm water detoxification equipment， and they have the capacity to produce more than 20 000 tons of detoxified seedlings per year， which lays a good foundation for the comprehensive promotion and application of detoxified seedlings. It is necessary to give full play to the advantages of warm water detoxification technology， establish a standardized system for the production and reproduction of detoxified seedlings， and vigorously promote the use of detoxified seedlings. To accelerate the promotion of detoxified seedlings， at first， it is needed to support the establishment of standardized breeding bases and planting demonstration zones for sugarcane detoxified seedlings； secondly， it is needed to establish a demonstration system for detoxified seedlings， and standardize and strengthen the demonstration of standardized technology for detoxified seedling production.
　　Applying lamp trapping technology on a large scale Based on the strong phototaxis of adults of sugarcane borers， beetles and termites， the adults can be killed with solar frequency trembler grid lamps， which can reduce the base of insect population， protect sugarcane seedlings and reduce damage. The specific method is as follows： in the full incidence period of the adults from March to July， one lamp （the radiation radius of the lamp is 100-120 m） is installed every 2-4 hm2， and the height is 1.0-1.5 m （the distance from the mouth receiving insects to the ground）. All lamps are turned on from 20：00 to 22：00 when the activity of the adults reaches a peak[2]. 　　Scientifically guiding and promoting biological prevention and control technology In the full incidence period of borer adults from March to July， 3-6 new moth traps as sex pheromone of borers are set per hectare to lure and kill the adults. The lures are replaced once every 15-20 d， and the traps are cleaned at the right time. In the egg hatching period of the first and second generation of borers in March and April， 1.8 kg/hm2 of 0.05% avermectin?¤10 billion living spores/g Bacillus thuringiensis （Bt） wettable powder， 1.5 L/hm2 of 200 g/L tebufenozide suspending agent or 4.5 kg/hm2 of 46% monosultap?¤B. thuringiensis （Bt） wettable powder is diluted with 900 kg of water and evenly sprayed on sugarcane plants.
　　Practically promoting the precise and efficient application of slow??release long??acting and low toxic pesticides In combination with sugarcane planting management， 900 kg/hm2 of 3.6% bisultap granular （75 kg/hm2 of 8% chlorpyrifos?¤phoxim granules） + 600 g/hm2 of 70% thiamethoxam dispersible powder or 450 kg/hm2 of 10% monosultap?¤thiamethoxam granules are mixed with fertilizer and evenly spread around sugarcane plants[2].
　　Strengthening field management After sugarcane is harvested， diseased or infected plants and residual leaves should be destroyed in time. If pests are serious， perennial roots should not be reserved， and the field should be deeply ploughed after sugarcane is harvested. Healthy sugarcane without diseases and pests， preferably newly planted sugarcane， should be chosen as seedlings. It is needed to conduct rational fertilization， apply organic fertilizer， apply more phosphorus and potassium fertilizer， and avoid heavy dressing of nitrogen fertilizer to enhance the ability of sugarcane plants to resist pests and diseases. A good irrigation and drainage system should be built to prevent water accumulation and reduce field humidity. It is necessary to remove diseased plants， severely diseased leaves and old leaves in time. It is needed to control weeds in time， make sugarcane fields ventilate and reduce field humidity， artificially kill pests to reduce the damage to plants and reduce the quantity of insects in a field， strengthen the rotation with non??sensitive crops such as rice， corn， sweet potato， peanuts， soybeans or intercropping with vegetables， green manure， etc.， improve soil structure， enhancing soil fertility， promote normal growth of sugarcane， and enhance its ability to resist pests and diseases.
　　Spraying pesticides in time at the early stage of a disease 　　Sugarcane diseases generally occur in the rainy season. It is necessary to strengthen the monitoring of the diseases in the areas where they often appear， and pesticides should be sprayed in time at the early stage of a disease. 1 500 g/hm2 of 75% chlorothalonil wettable powder+1 500 g/hm2 of 50% carbendazim wettable powder+ 24 000 g/hm2 of potassium dihydrogen phosphate+300 ml/hm2 of agricultural synergist can be used to control dry top rot and brown streak of sugarcane. 1 500 g/hm2 of 75% chlorothalonil wettable powder+1 500 g/hm2 of 80% mancozebwettable powder+24 000 g/hm2 of potassium dihydrogen phosphate+300 ml/hm2 of agricultural synergist can be used to control sugarcane rust. These pesticides are diluted with 900 kg/hm2 of water and sprayed on sugarcane leaves once every 7-10 d， and spraying is continued 2 times， which can effectively control the spread of diseases.
　　Doing a good job of monitoring and emergency prevention and control of sudden pests From June to August， M. separata （Walker） often damages sugarcane， so monitoring should be strengthened to control the young larvae in time. To control it， 20% Sushate Awei?¤fenitrothion emulsifiable concentrate diluted by 600 times+40% Daosan?¤high chlorine and fluorine emulsifiable concentrate diluted by 1 500 times， 4.5% beta??cypermethrin emulsifiable concentrate diluted by 1 500 times （5% esfenvalerate emulsifiable concentrate diluted by 1 500 times）+90% trichlorfon crystal diluted by 1 000 times （50% phoxim emulsifiable concentrate diluted by 1 000 times） are evenly sprayed， and the effect is good from 16：00 to 17：00.
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