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Abstract Sugarcane borers are the most common pests in Yunnan sugarcane areas， and their harm is the most serious presently. The damage caused by sugarcane borers has become the first important factor seriously influencing the sustainable and stable development of sugar industry in Yunnan. To scientifically and effectively prevent and control sugarcane borers to ensure the production safety of sugarcane， the characteristics of occurrence and damage of sugarcane borers in Yunnan sugarcane areas were systematically introduced， and corresponding comprehensive control measures and strategies were proposed according to the characteristics of its occurrence and damage and the actual production of sugarcane.
Key words Yunnan sugarcane areas； Sugarcane borers； Occurrence and damage； Control measures
Sugarcane industry is an important pillar of economic development in Yunnan and the main economic source of an increase in farmers income and occupies an important position and role in agricultural economy income[1]. However， in recent years， not implementing the strict quarantine of introduced sugarcane， the diversification of crop structure， the reform of tillage system， the management of stubble sugarcane and the unreasonable use of chemical pesticides have provided favorable conditions for the propagation， reproduction and survival of sugarcane borers， have led to an increase in the species quantity of borers harming sugarcane， a sharp increase in the dead heat rate of sugarcane caused by borders at the seedling stage and the proportion of sugarcane stems damaged by borders in the late period， and a drop of sugarcane yield and sugar content in Yunnan sugarcane areas， and have brought severe disaster threats to the safe production of sugarcane in Yunnan， so the damage to sugarcane caused by borders has become the primary factor affecting the sustainable and stable development of sugarcane industry in Yunnan[2-4]. In order to scientifically and effectively prevent and control sugarcane borers to ensure the production safety of sugarcane， the characteristics of occurrence and damage of sugarcane borers in sugarcane planting areas in Yunnan Province were systematically introduced， and corresponding comprehensive prevention and control measures and strategies were put forward according to the characteristics of its occurrence and damage and the actual production of sugarcane.
Occurrence and Damage of Sugarcane Borers
Sugarcane borers belonging to Lepidoptera are the most common pests， and their harm is the most serious in Yunnan sugarcane areas presently. Sugarcane borers in Yunnan sugarcane areas mainly include Sesamia inferens Walker， Chilo infuscatellus Snellen， Chilo auricilia Dudgeon， Argyroploce schistaceana （Snellen）， Proceras venosatus （Walker）， and Tryporyza intacta Snellen. At the seedling stage， sugarcane borers harm the growing point and then causes dead seedlings； at the middle and late growth stage， they drill sugarcane stems and damage sugarcane stem tissues， which can affect the jointing of sugarcane and result in a decline in sugarcane yield and sugar content. According to an investigation， the dead heat rate of sugarcane seedlings caused by borers in Yunnan sugarcane growing areas is generally 9.12%-19.58% and even up to 31.16%-61.82% presently； in the late period， the proportion of sugarcane stems damaged by borders ranges from 40.88% to 59.66% and even reaches more than 80.22%， which has resulted in a great decrease in sugarcane yield and sugar content[2-6]. Under normal conditions， sugarcane yield reduces by 2 625-7 950 kg/hm2 when the dead heat rate of sugarcane seedlings caused by borers is 5%-20%， decreasing by 3.2%-9.4%； as the dead heat rate is 25%-35%， sugarcane yield decreases by 9 960-13 537.5 kg/hm2， reducing by 11.7%-15.9%[2]. The feeding habits of S. inferens Walker are complex， and it mainly harms rice， sugarcane， corn， sorghum， wild rice， chestnut， barnyardgrass， and so on. The damage to sugarcane planted with wheat and after rice caused by S. inferens Walker is particularly serious. C. infuscatellus Snellen mainly appears upland sugarcane fields， and in addition to sugarcane， it endangers chestnut， millet， sorghum， barnyard grass， green bristlegrass， vetiver grass， and wild rice. C. auricilia Dudgeon mainly damages rice and also endanger sugarcane， corn， sorghum， and so forth. A. schistaceana （Snellen） is a monophagous pest and only harmful to sugarcane. Besides sugarcane， P. venosatus （Walker） harms corn， sorghum， pennisetum， grassiness and reed. According to a survey， T. intacta Snellen only endangers sugarcane[2].
The newly hatched larvae of S. inferens Walker have the habit of clustering inside of the leaf sheath to eat epidermis. The larvae begin to disperse at age 1 and mostly invade into the inside of sugarcane seedlings which is 1 cm away from the ground surface. They have the habit of endangering different plants and can damage 3-5 sugarcane seedlings in a lifetime. With the increase of sugarcane height， the damaged position will also increase. After age 3， their food intake increases greatly， and they are more destructive to sugarcane. The newly hatched larvae of C. infuscatellus Snellen crawl on the leaves or hang down by spun silk and blow in wind， disperse to nearby sugarcane plants， and invade from a space between leaf sheaths at the base of sugarcane seedlings. The larvae at age 1 have the habit of clustering inside of the leaf sheath， gradually disperse and invade into the inside of sugarcane seedlings after two years old. They often damage other plants. The damage to sugarcane caused by C. infuscatellus Snellen is great mainly at the seedling stage， and the damage to the seedlings caused by C. infuscatellus Snellen before the tillering or at the early tillering stage can lead to lack of plants. In the middle and late period， the damage to sugarcane stems is slight. The first and second generation of C. infuscatellus Snellen is the most harmful to sugarcane， and the first generation mainly damages mother stem seedlings， thereby often resulting in lack of plants and affecting the effective number of stems per hectare. The larvae of C. auricilia Dudgeon are lively， crawl on the leaves or hang down by spun silk and blow in wind after hatching. They invade into sugarcane plants from a space between leaf sheaths， and several larvae often eat the same plant. The tunnels dug by the larvae in sugarcane stems can span 2-4 joints， and there are irregular horizontal tunnels. They have the habit of endangering different plants. The larvae pierced more holes on the damaged stems， and most holes are generally rectangular or nearly square. The occurrence of C. infuscatellus Snellen is related to the cultivation system of rice. It mainly damages sugarcane planted with rice in Dehong sugarcane areas seasonally. It appears frequently in sugarcane fields from June to August， and its density is high in fields near paddy fields. The occurrence of this pest is related to field humidity， and it mainly happens on paddy sugarcane and in lowlands， while it rarely appears in sugarcane fields on dry slopes and hills. A. schistaceana （Snellen） likes a humid environment， and high temperature and drought are adverse to its occurrence， so it mainly occurs in paddy fields or more humid sugarcane fields. After the larvae hatch， they crawl downward， then invade into a space between leaf sheaths and eat the tender parts of sugarcane such as buds or roots finally. The larvae often invade into sugarcane seedlings and tillers from the parts under the surface of mud， and the dug tunnels are twisty. One larva often damages one sugarcane seedling. The newly hatched larvae of P. venosatus （Walker） have the habit of clustering and damaging heart leaves. After 2-3 d， a layer of transparent irregular eating marks or round holes can be seen on the extending harmed heart leaves， and this symptom is called "mosaic". The larvae at or over the age of 3 damage sugarcane stems， and several larvae often eat one stem， while there is frass left nearby. After sugarcane joints， sugarcane stems are damaged， and wormholes are large， while there is a large amount of frass inside or outside of the holes. The area around the holes is often dry yellow， and their esophagus is transverse. Tunnels dug in stems have many branches and stride across many joints， while upper continuous joints shrink obviously to become short and thin， so they are broken by wind easily， thereby leading to top drying even. The newly hatched larvae of T. intacta Snellen are lively and often hang down by spun silk. They invaded into sugarcane plants from the base of heat leaves which have not expanded and bore downward until reaching the growth point. After heat leaves expand， the wormholes are zonal， and the area around the holes is brown. After the larvae grow， they harm the growth point to form withered seedlings and broom sugarcane[2] （Fig.1-Fig.8）. Control Methods of Sugarcane Borers
Control strategies
There are a variety of borers damaging sugarcane， and several varieties of borers happen at the same time to harm sugarcane plants. To control borers damaging sugarcane， it is necessary to adhere to the principle of "prevention first and comprehensive control"， pay more attention to early warning and monitoring， and mainly control the first and second generation of borers to reduce borer population base based on agricultural control， physical control and biological control. Meanwhile， pesticides should be applied in key periods to decrease the quantity of borders effectively and rapidly and to control the occurrence of sugarcane borers effectively[2，7-8].
Physical control
In the peak period of sugarcane borers from March to July， based on the strong phototaxis of adults of sugarcane borers， one insecticidal lamp is installed in 2-4 hm2 of sugarcane fields to kill the adults （the radiation radius of a lamp is 100-120 m， and its height is 1-1.5 m）， which can reduce borer population base， protect sugarcane seedlings and decrease damage[2，9].
Biological control
Using sex pheromone Firstly， in the early emergence period of each generation of pupa， 30-45 tubs per hectare which are about 20 cm in diameter are put in a sugarcane field to kill male moths， and a lure is put over the water surface of each tub （the distance between them is around 1 cm）. Secondly， 3 000 plastic pipe lures per hectare containing sex pheromone are inserted evenly in the midrib of sugarcane leaves according to the area 1.8 m×1.8 m， and the lures are changed every 15-20 d to interfere with adult mating and reduce the number of borers[2，7].
Releasing Trichogramma Trichogramma is the parasitoid natural enemy of sugarcane borers at the egg stage and can be bred artificially. Releasing Trichogramma into sugarcane fields in the beginning and peak periods of borer spawning can control the growth of sugarcane borer population effectively. There are 75-120 releasing points per hectare， and the quantity of Trichogramma released into the fields is around 0.15 million each time， and Trichogramma is released 5-7 times every year. To prevent the survival activity of Trichogramma from being affected， pesticides should be applied in sugarcane fields 7-20 d after Trichogramma is released[2，7].
Protecting natural enemies A variety of parasitic natural enemies like Apanteles flavipes （Cameron） in sugarcane fields are dominant natural enemies of sugarcane borers and are distributed widely， while the natural parasite rate ranges from 15% to 35%[10-12]. Terbutaline， phorate and other high （drama） poisonous broad-spectrum pesticides are lethal to natural enemy insects. Hence， selective insecticides with low or middle toxicity such as bisultap and chlorpyrifos phoxim should be applied in sugarcane fields to control borers. Moreover， pesticides should be applied in soil around roots to reduce or prevent natural enemies of sugarcane borers from being killed and decrease the damage to sugarcane caused by borers. Agricultural control
Rational rotation of sugarcane with peanut， soybean and rice or planting sugarcane in the same filed with vegetables and green manure can change microclimate in the field， create an environment favorable for the survival and proliferation of natural enemies of sugarcane borers， and enhance the control of natural enemies to reduce the damage to sugarcane. Healthy seedlings chosen from new sugarcane fields should be planted to prevent the spread of sugarcane borers and then reduce the damage to sugarcane. Seeds should be sown in good time， and fertilization and soil cultivation should be conducted timely， while N， P and K fertilizer should be applied reasonably to promote the tillering of sugarcane seedlings and enhance the ability of sugarcane plants to resist pests. After sugarcane is harvested， it is necessary to clean sugarcane parks to kill overwintering sugarcane borers， decrease borer source base and then reduce the damage to sugarcane. When sugarcane is harvested， it is cut at a depth of 3-5 cm， which can eliminate the larvae and pupae of C. infuscatellus Snellen and A. schistaceana （Snellen） which overwinter on the surface of soil. In February and March， dead heart seedlings appearing sporadically can be cut off from their base artificially to kill the larvae inside of the dead heart seedlings and then reduce the damage to other plants and the quantity of next generation of borers.
Chemical control
In the hatching peak period of the first and second generation of borer eggs from March to April， 90% trichlorfon crystal diluted by 500 times is sprayed every 10-15 d to control the “mosaic” caused by sugarcane borers， and it is sprayed two times in total.
In the hatching peak period of the first and second generation of borer eggs from March to April， 600 ml/hm2 of 30% chlorantraniliprole·thiamethoxam （Duirui） suspending agent or 600 g/hm2 of 40% chlorantraniliprole·thiamethoxam （Fuge） water dispersible granule， 98% cartap （Badan） wettable powder solution diluted by 1 000 times， 25% bisultap aqueous solution diluted by 200 times， or 20% abamectin·fenitrothion emulsifiable concentrate diluted by 600 times or 95% monosultap powder solution diluted by 1 000 times can be sprayed on sugarcane leaves every 10-15 d to control C. infuscatellus Snellen， S. inferens Walker， A. schistaceana （Snellen）， P. venosatus （Walker）， and T. intacta Snellen. They are sprayed two times in total， and these pesticides should be sprayed alternately. In late February or early March and late May or early June， pesticides are applied two times according to the planting and management of sugarcane. After 45-90 kg/hm2 of 3.6% Kekewusun bisultap， 8% Kekewusun chlorpyrifos·phoxim or 5% carbosulfan， 15-18 kg/hm2 of 15% chlorpyrifos， 600 ml/hm2 of 30% chlorantraniliprole·thiamethoxam （Duirui） suspending agent or 600 g/hm2 of 40% chlorantraniliprole·thiamethoxam （Fuge） water dispersible granule is mixed with fertilizer， the mixture is applied in sugarcane ditches， sugarcane piles or the base of sugarcane plants and is covered with soil or film to control all kinds of borers； the efficacy of pesticides can last for about 40-60 d[13-15].
References
[1] ZHANG YB. Development technology of sugarcane industry in China[M]. Beijing： China Agricultural Press，2011.
[2] HUANG YK， LI WF. Modern coloured atlas of diseases and pests of sugarcane[M]. Beijing： China Agricultural Press，2011.
[3] LUO ZM， HUANG YK， LI WF， et al. The causes for rampage and countermeasures of sugarcane borers in ecological sugarcane area of plateau[J]. Zoological Research， 2009 （Zoological album）： 105-109.
[4] LI WF， SHAN HL， HUANG YK， et al. Occurrence dynamics and control strategies of major pests and diseases of sugarcane in Yunnan[J]. Sugar Crops of China， 2013（1）： 59-62.
[5] HUANG YK， LI WF. Pests of sugarcane and their natural enemy resources in Yunnan[J]. Sugarcane and Canesugar，1995（5）：15-17.
[6] HUANG YK， LI WF. Comprehensive prevention and control of pests and diseases of "double high sugarcane" in Yunnan[J]. Yunnan Agricultural Science and Technology，2004（4）：16-18.
[7] LU WJ， XU Hong， LI WF， et al. Control technology of sugarcane diseases and insect pests and application of efficient and low toxicity pesticides[J]. Sugar Crops of China， 2011（3）： 64-67.
[8] XU Hong， LU WJ， MAO YL， et al. Specialized prevention and control of sugarcane diseases and pests[J]. Sugar Crops of China， 2011（2）： 77-80.
[9] LI YR， YANG LT. New developments in sugarcane industry and technologies in china since the 1990s[J]. Southwest China Journal of Agricultural Sciences，2009，22（5）： 1469-1474.
[10] LI WF. Preliminary observation of Apanteles flavipes （Cameron）[J]. Natural Enemies of Insects 1995，17（3）：7-8.
[11] LI WF， HUANG YK. Natural enemies of sugarcane pest and their roles in natural control[J]. Natural Enemies of Insects， 2004，26（4）：156-162.
[12] HUANG YK， LI WF. Dominant natural enemies of sugarcane pests and their protection and utilization[J]. Natural Enemies of Insects，2006，28（2）：85-92.
[13] HUANG YK， LI WF， LUO ZM. Field efficacy trial of 15% chlorpyrifos granules against sugarcane pests[J]. Pesticides，2001，40（10）：26-27.
[14] HUANG YK， LI WF. Field efficacy trial of 5% carbosulfan granules against sugarcane pests [J]. Sugar Crops of China， 2006（4）： 34-35.
[15] LUO ZM， LI WF， HUANG YK， et al. Pesticide test of 3.6% bisultap granules on controlling sugarcane borers[J]. Pesticides， 2010， 49（5）： 383-385.
Key words Yunnan sugarcane areas； Sugarcane borers； Occurrence and damage； Control measures
Sugarcane industry is an important pillar of economic development in Yunnan and the main economic source of an increase in farmers income and occupies an important position and role in agricultural economy income[1]. However， in recent years， not implementing the strict quarantine of introduced sugarcane， the diversification of crop structure， the reform of tillage system， the management of stubble sugarcane and the unreasonable use of chemical pesticides have provided favorable conditions for the propagation， reproduction and survival of sugarcane borers， have led to an increase in the species quantity of borers harming sugarcane， a sharp increase in the dead heat rate of sugarcane caused by borders at the seedling stage and the proportion of sugarcane stems damaged by borders in the late period， and a drop of sugarcane yield and sugar content in Yunnan sugarcane areas， and have brought severe disaster threats to the safe production of sugarcane in Yunnan， so the damage to sugarcane caused by borders has become the primary factor affecting the sustainable and stable development of sugarcane industry in Yunnan[2-4]. In order to scientifically and effectively prevent and control sugarcane borers to ensure the production safety of sugarcane， the characteristics of occurrence and damage of sugarcane borers in sugarcane planting areas in Yunnan Province were systematically introduced， and corresponding comprehensive prevention and control measures and strategies were put forward according to the characteristics of its occurrence and damage and the actual production of sugarcane.
Occurrence and Damage of Sugarcane Borers
Sugarcane borers belonging to Lepidoptera are the most common pests， and their harm is the most serious in Yunnan sugarcane areas presently. Sugarcane borers in Yunnan sugarcane areas mainly include Sesamia inferens Walker， Chilo infuscatellus Snellen， Chilo auricilia Dudgeon， Argyroploce schistaceana （Snellen）， Proceras venosatus （Walker）， and Tryporyza intacta Snellen. At the seedling stage， sugarcane borers harm the growing point and then causes dead seedlings； at the middle and late growth stage， they drill sugarcane stems and damage sugarcane stem tissues， which can affect the jointing of sugarcane and result in a decline in sugarcane yield and sugar content. According to an investigation， the dead heat rate of sugarcane seedlings caused by borers in Yunnan sugarcane growing areas is generally 9.12%-19.58% and even up to 31.16%-61.82% presently； in the late period， the proportion of sugarcane stems damaged by borders ranges from 40.88% to 59.66% and even reaches more than 80.22%， which has resulted in a great decrease in sugarcane yield and sugar content[2-6]. Under normal conditions， sugarcane yield reduces by 2 625-7 950 kg/hm2 when the dead heat rate of sugarcane seedlings caused by borers is 5%-20%， decreasing by 3.2%-9.4%； as the dead heat rate is 25%-35%， sugarcane yield decreases by 9 960-13 537.5 kg/hm2， reducing by 11.7%-15.9%[2]. The feeding habits of S. inferens Walker are complex， and it mainly harms rice， sugarcane， corn， sorghum， wild rice， chestnut， barnyardgrass， and so on. The damage to sugarcane planted with wheat and after rice caused by S. inferens Walker is particularly serious. C. infuscatellus Snellen mainly appears upland sugarcane fields， and in addition to sugarcane， it endangers chestnut， millet， sorghum， barnyard grass， green bristlegrass， vetiver grass， and wild rice. C. auricilia Dudgeon mainly damages rice and also endanger sugarcane， corn， sorghum， and so forth. A. schistaceana （Snellen） is a monophagous pest and only harmful to sugarcane. Besides sugarcane， P. venosatus （Walker） harms corn， sorghum， pennisetum， grassiness and reed. According to a survey， T. intacta Snellen only endangers sugarcane[2].
The newly hatched larvae of S. inferens Walker have the habit of clustering inside of the leaf sheath to eat epidermis. The larvae begin to disperse at age 1 and mostly invade into the inside of sugarcane seedlings which is 1 cm away from the ground surface. They have the habit of endangering different plants and can damage 3-5 sugarcane seedlings in a lifetime. With the increase of sugarcane height， the damaged position will also increase. After age 3， their food intake increases greatly， and they are more destructive to sugarcane. The newly hatched larvae of C. infuscatellus Snellen crawl on the leaves or hang down by spun silk and blow in wind， disperse to nearby sugarcane plants， and invade from a space between leaf sheaths at the base of sugarcane seedlings. The larvae at age 1 have the habit of clustering inside of the leaf sheath， gradually disperse and invade into the inside of sugarcane seedlings after two years old. They often damage other plants. The damage to sugarcane caused by C. infuscatellus Snellen is great mainly at the seedling stage， and the damage to the seedlings caused by C. infuscatellus Snellen before the tillering or at the early tillering stage can lead to lack of plants. In the middle and late period， the damage to sugarcane stems is slight. The first and second generation of C. infuscatellus Snellen is the most harmful to sugarcane， and the first generation mainly damages mother stem seedlings， thereby often resulting in lack of plants and affecting the effective number of stems per hectare. The larvae of C. auricilia Dudgeon are lively， crawl on the leaves or hang down by spun silk and blow in wind after hatching. They invade into sugarcane plants from a space between leaf sheaths， and several larvae often eat the same plant. The tunnels dug by the larvae in sugarcane stems can span 2-4 joints， and there are irregular horizontal tunnels. They have the habit of endangering different plants. The larvae pierced more holes on the damaged stems， and most holes are generally rectangular or nearly square. The occurrence of C. infuscatellus Snellen is related to the cultivation system of rice. It mainly damages sugarcane planted with rice in Dehong sugarcane areas seasonally. It appears frequently in sugarcane fields from June to August， and its density is high in fields near paddy fields. The occurrence of this pest is related to field humidity， and it mainly happens on paddy sugarcane and in lowlands， while it rarely appears in sugarcane fields on dry slopes and hills. A. schistaceana （Snellen） likes a humid environment， and high temperature and drought are adverse to its occurrence， so it mainly occurs in paddy fields or more humid sugarcane fields. After the larvae hatch， they crawl downward， then invade into a space between leaf sheaths and eat the tender parts of sugarcane such as buds or roots finally. The larvae often invade into sugarcane seedlings and tillers from the parts under the surface of mud， and the dug tunnels are twisty. One larva often damages one sugarcane seedling. The newly hatched larvae of P. venosatus （Walker） have the habit of clustering and damaging heart leaves. After 2-3 d， a layer of transparent irregular eating marks or round holes can be seen on the extending harmed heart leaves， and this symptom is called "mosaic". The larvae at or over the age of 3 damage sugarcane stems， and several larvae often eat one stem， while there is frass left nearby. After sugarcane joints， sugarcane stems are damaged， and wormholes are large， while there is a large amount of frass inside or outside of the holes. The area around the holes is often dry yellow， and their esophagus is transverse. Tunnels dug in stems have many branches and stride across many joints， while upper continuous joints shrink obviously to become short and thin， so they are broken by wind easily， thereby leading to top drying even. The newly hatched larvae of T. intacta Snellen are lively and often hang down by spun silk. They invaded into sugarcane plants from the base of heat leaves which have not expanded and bore downward until reaching the growth point. After heat leaves expand， the wormholes are zonal， and the area around the holes is brown. After the larvae grow， they harm the growth point to form withered seedlings and broom sugarcane[2] （Fig.1-Fig.8）. Control Methods of Sugarcane Borers
Control strategies
There are a variety of borers damaging sugarcane， and several varieties of borers happen at the same time to harm sugarcane plants. To control borers damaging sugarcane， it is necessary to adhere to the principle of "prevention first and comprehensive control"， pay more attention to early warning and monitoring， and mainly control the first and second generation of borers to reduce borer population base based on agricultural control， physical control and biological control. Meanwhile， pesticides should be applied in key periods to decrease the quantity of borders effectively and rapidly and to control the occurrence of sugarcane borers effectively[2，7-8].
Physical control
In the peak period of sugarcane borers from March to July， based on the strong phototaxis of adults of sugarcane borers， one insecticidal lamp is installed in 2-4 hm2 of sugarcane fields to kill the adults （the radiation radius of a lamp is 100-120 m， and its height is 1-1.5 m）， which can reduce borer population base， protect sugarcane seedlings and decrease damage[2，9].
Biological control
Using sex pheromone Firstly， in the early emergence period of each generation of pupa， 30-45 tubs per hectare which are about 20 cm in diameter are put in a sugarcane field to kill male moths， and a lure is put over the water surface of each tub （the distance between them is around 1 cm）. Secondly， 3 000 plastic pipe lures per hectare containing sex pheromone are inserted evenly in the midrib of sugarcane leaves according to the area 1.8 m×1.8 m， and the lures are changed every 15-20 d to interfere with adult mating and reduce the number of borers[2，7].
Releasing Trichogramma Trichogramma is the parasitoid natural enemy of sugarcane borers at the egg stage and can be bred artificially. Releasing Trichogramma into sugarcane fields in the beginning and peak periods of borer spawning can control the growth of sugarcane borer population effectively. There are 75-120 releasing points per hectare， and the quantity of Trichogramma released into the fields is around 0.15 million each time， and Trichogramma is released 5-7 times every year. To prevent the survival activity of Trichogramma from being affected， pesticides should be applied in sugarcane fields 7-20 d after Trichogramma is released[2，7].
Protecting natural enemies A variety of parasitic natural enemies like Apanteles flavipes （Cameron） in sugarcane fields are dominant natural enemies of sugarcane borers and are distributed widely， while the natural parasite rate ranges from 15% to 35%[10-12]. Terbutaline， phorate and other high （drama） poisonous broad-spectrum pesticides are lethal to natural enemy insects. Hence， selective insecticides with low or middle toxicity such as bisultap and chlorpyrifos phoxim should be applied in sugarcane fields to control borers. Moreover， pesticides should be applied in soil around roots to reduce or prevent natural enemies of sugarcane borers from being killed and decrease the damage to sugarcane caused by borers. Agricultural control
Rational rotation of sugarcane with peanut， soybean and rice or planting sugarcane in the same filed with vegetables and green manure can change microclimate in the field， create an environment favorable for the survival and proliferation of natural enemies of sugarcane borers， and enhance the control of natural enemies to reduce the damage to sugarcane. Healthy seedlings chosen from new sugarcane fields should be planted to prevent the spread of sugarcane borers and then reduce the damage to sugarcane. Seeds should be sown in good time， and fertilization and soil cultivation should be conducted timely， while N， P and K fertilizer should be applied reasonably to promote the tillering of sugarcane seedlings and enhance the ability of sugarcane plants to resist pests. After sugarcane is harvested， it is necessary to clean sugarcane parks to kill overwintering sugarcane borers， decrease borer source base and then reduce the damage to sugarcane. When sugarcane is harvested， it is cut at a depth of 3-5 cm， which can eliminate the larvae and pupae of C. infuscatellus Snellen and A. schistaceana （Snellen） which overwinter on the surface of soil. In February and March， dead heart seedlings appearing sporadically can be cut off from their base artificially to kill the larvae inside of the dead heart seedlings and then reduce the damage to other plants and the quantity of next generation of borers.
Chemical control
In the hatching peak period of the first and second generation of borer eggs from March to April， 90% trichlorfon crystal diluted by 500 times is sprayed every 10-15 d to control the “mosaic” caused by sugarcane borers， and it is sprayed two times in total.
In the hatching peak period of the first and second generation of borer eggs from March to April， 600 ml/hm2 of 30% chlorantraniliprole·thiamethoxam （Duirui） suspending agent or 600 g/hm2 of 40% chlorantraniliprole·thiamethoxam （Fuge） water dispersible granule， 98% cartap （Badan） wettable powder solution diluted by 1 000 times， 25% bisultap aqueous solution diluted by 200 times， or 20% abamectin·fenitrothion emulsifiable concentrate diluted by 600 times or 95% monosultap powder solution diluted by 1 000 times can be sprayed on sugarcane leaves every 10-15 d to control C. infuscatellus Snellen， S. inferens Walker， A. schistaceana （Snellen）， P. venosatus （Walker）， and T. intacta Snellen. They are sprayed two times in total， and these pesticides should be sprayed alternately. In late February or early March and late May or early June， pesticides are applied two times according to the planting and management of sugarcane. After 45-90 kg/hm2 of 3.6% Kekewusun bisultap， 8% Kekewusun chlorpyrifos·phoxim or 5% carbosulfan， 15-18 kg/hm2 of 15% chlorpyrifos， 600 ml/hm2 of 30% chlorantraniliprole·thiamethoxam （Duirui） suspending agent or 600 g/hm2 of 40% chlorantraniliprole·thiamethoxam （Fuge） water dispersible granule is mixed with fertilizer， the mixture is applied in sugarcane ditches， sugarcane piles or the base of sugarcane plants and is covered with soil or film to control all kinds of borers； the efficacy of pesticides can last for about 40-60 d[13-15].
References
[1] ZHANG YB. Development technology of sugarcane industry in China[M]. Beijing： China Agricultural Press，2011.
[2] HUANG YK， LI WF. Modern coloured atlas of diseases and pests of sugarcane[M]. Beijing： China Agricultural Press，2011.
[3] LUO ZM， HUANG YK， LI WF， et al. The causes for rampage and countermeasures of sugarcane borers in ecological sugarcane area of plateau[J]. Zoological Research， 2009 （Zoological album）： 105-109.
[4] LI WF， SHAN HL， HUANG YK， et al. Occurrence dynamics and control strategies of major pests and diseases of sugarcane in Yunnan[J]. Sugar Crops of China， 2013（1）： 59-62.
[5] HUANG YK， LI WF. Pests of sugarcane and their natural enemy resources in Yunnan[J]. Sugarcane and Canesugar，1995（5）：15-17.
[6] HUANG YK， LI WF. Comprehensive prevention and control of pests and diseases of "double high sugarcane" in Yunnan[J]. Yunnan Agricultural Science and Technology，2004（4）：16-18.
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