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Abstract In recent years， with the adjustment of agricultural structure， the change of planting system， the continuous cropping phenomenon and the abnormal climate and environment have provided favorable conditions for the spread， reproduction and survival of sugarcane pests. The pest species that are harmful to sugarcane have increased， which pose potential threats to sugar cane production. Therefore， the occurrence dynamics and control of 6 sugarcane pests with potential threats were studied in order to prospectively grasp the dynamics of sugarcane pests， scientifically and effectively prevent and control sugarcane pests， and ensure the safety of sugarcane production.
Key words Sugarcane； Potential threat； Pests； Occurrence dynamics； Control measures
Sugarcane is the main sugar-yielding crop in China， which occupies an important position in the agricultural economy. Each year， pest damage can cause the yield loss of several to over 10 percent or even more. With the expansion of sugarcane planting area， the reform of the agricultural farming system， the frequent introduction， the abuse of chemical pesticides， and the complex and changeable climate and environment in the sugarcane-producing regions in China， new changes have occurred to the dynamic relations between crops and pests， pests and natural enemies. The number of pest species has increased， the degree of occurrence has become increasingly serious， the number of natural enemies has continued to decrease， and prevention and control work have become more passive. According to incomplete statistics， there are more than 360 species of sugarcane pests in China， of which the major ones that affect the growth of sugarcane and often cause disasters are： the sugarcane borer （Diatraea saccharalis）， the cane beetle， the turnip moth， the African armyworm， leaf-cutting ants， termites， spittlebugs， and the beetle Migdolus fryanus[1-4]. In this paper， the occurrence dynamics and control of 6 sugarcane pests with potential threats were studied in order to prospectively grasp the dynamics of sugarcane pests， scientifically and effectively prevent and control sugarcane pests， and ensure the safety of sugarcane production.
Macrotermes barneyi Light
Occurrence and damage
M. barneyi Light is a member of termites belonging to the genus Macrotermes in the family of Termitidae. It is distributed in the sugarcane-planting provinces （districts） like Guangdong， Guangxi， Fujian， Taiwan， Yunnan， Sichuan， Hainan， Guizhou， Zhejiang， Hunan， Jiangxi in China. In addition to damaging sugarcane， it also does harms to sorghum， corn， peanuts， soybeans， sweet potatoes， cassava， fruit trees， forest trees and so on. In the drylands in hilly and arid areas， sugarcane is often severely damaged， especially in the newly-reclaimed land. Damaged sugarcane species are often invaded from both ends of the incision， and then the pest feeds on the stem tissue， forming a tunnel filled with dirt and their secretions. In severe cases， only a very thin layer of epidermis remains， causing the seedlings to fail to germinate. In the severely damaged sugarcane planting areas， the damage rate reaches as high as 30%-60%， resulting in a large area of lack of seedlings and ridges， or even crop failure. In the middle and late growth stages of sugarcane， the pests bore through the underground cane stalks， making the stem hollow inside， leaves yellow or dried， and the plants are easy to break or beat down， wither， leading to considerable loss. Shape recognition
The soldiers of M. barneyi Light are divided into two kinds： big ones and small ones. The head of the big one is particularly large， approximately rectangular of yellow-brown. The shape of the small one is similar to that of the big one， but much smaller in size. Soldiers can secrete a yellow-brown liquid when they encounter an enemy. The alate queen has dark reddish-brown head of broadly ovate shape， and the body is brownish-brown while yellowish brown in wings.
Living habits and occurrence rules
For M. barneyi Light， as in most other termites， the colony consists of many individuals， divided into several levels of the king and queen， workers and soldiers. Among them， the workers are the largest in the colony and are the ones do direct harm to sugarcane. Sugarcane can be harmed by termites during the whole growing period from sowing to harvesting， but the most severe damage occurs during the germination period after sowing， while the damage during the seedling period is lighter. However， the damage becomes more serious during the elongation period， and the second damage peak often occurs during the middle and late stages of growth. The occurrence is the most frequent and the damage is the most severe in the hilly mountainous areas. The sugarcane plants around the house and near the bamboo gardens are also often damaged by termites. In early spring， when the climate is arid and warm， and the soil moisture is low， the seedlings are often severely damaged by termites before germination. On the contrary， the damage is light when there are many spring rains with low temperatures， and the soil remains wet for a long time. During the middle and late periods， rains after long-term drought can make the soil wet， and the damage of termites often greatly increases. The varieties with hard stalk， fast germination， developed roots and strong tillering capacity always suffer less from the damage.
Control measures
Agricultural control Before planting， it can deeply plough the land to improve the soil and destroy the nest， thereby wiping out the termites before the planting. It can also set up trapping pits using the favorite plants of termites， such as pine twigs， gum tree barks， sugarcane residues， when a large number of termites are trapped in the pits， available chemical medications such as mirex， chlorpyrifos， phoxim， can be sprayed to kill them.
Physical control In the swarming season， Jiaduo frequency-vibration insecticidal lamp can be used to trap the alate queen. Chemical control The workers and soldiers are most active and mindless when building the swarming holes， which is the best time to spray Mirex powder directly on the termite body. If proper， the whole colony can be wiped out. Before planting， the seedling plants can be soaked for 1 min in the 300-400 times diluted liquid of the mixture of 50% phoxim， 20% Carbosulfan， 48% chlorpyrifos， 10% Uranus emulsifiable concentrate or 5% fipronil suspension agent. The seedlings can be planted together with the spring canes， ratooned and fertilized with stubble canes from February to May. On the other hand， a full stand of seedlings can be kept for 2 months by soil sealing or film mulching in sugarcane ditches， sugarcane stubbles after evenly spraying the fully mixed 60-90 kg of 8% chlorpyrifos phoxim， 3.6% broad-spectral biultap， 5% carbosulfan， 5% monosultap chlorpyrifos， 5% isopropyl terbufos or 15-18 kg of 15% chlorpyrifos granules in the fertilizing amount of each hectare.
Hypomeces squamosus Fabricius
Occurrence and damage
H. squamosus Fabricius is a member of Hypomeces in the subfamily of Entiminae of family Curculionidae in Coleoptera. It is distributed in Jiangxi， Hunan， Sichuan， Fujian， Taiwan， Guangdong， Hainan， Guangxi， Yunnan and other provinces （regions） in China. With miscellaneous eating habits， in addition to harming sugar cane， it also damages cotton， wheat， peach， guava， mulberry， large leafhopper， tea， citrus fruit trees and so on. In the field， H. squamosus usually occurs accompanied with Trochorhopalus humeralis， Diocalandra Sp. and other sugarcane weevil species， and their population accounts for about 15%. In recent years， H. squamosus has frequently done damages to the sugarcane plating areas in Guangxi and Menglian， Bohai， Mengzi of Yunnan with the occurrences ranging from hundreds of to thousands of hectares. In the field with severe damage， the population density reaches 1-2 per plant， and a large number of sugarcane leaves are eaten with only veins left， which greatly affects the growth of sugarcane plants and causes significant losses to sugarcane production.
Shape recognition
Adults have a body length of 12.8-15.1 mm and a body width of 4.8-6.0 mm. The body is hypertrophic and slightly flat. The body walls are black and densely covered with uniform golden blue-green scales （the same scales are blue or green due to their different angles）. The back of the head and gills is flattened， with a wide， deep mid-ditch in the middle， reaching up to the top of the head. There are two shallow grooves on each side， either curved or straight. Each end of the elytra wing shrinks to 2 sharp protrusions at the top and bottom， and the top one is larger. The feet are black densely covered with blue-green scales but no teeth inside the tibia. Living habits and occurrence rules
There is only 1 generation occurrence in 1 year， and the adults and larvae go through the winter in soil. The overwintering adults begin to come up out of the earth in early March and become the most active from June to July， then become rare in early October. Not quite active， the adults have the features of gregariousness and death-feigning， and they are afraid of light and most active in the morning and evening.
Control measures
Agricultural control From May to June when the sugarcane plants are not high and the adults begin to be more active in morning and evening in groups， the adults can be caught and killed artificially to reduce the pest population and relieve the damage. Since H. squamosus is particularly like to eat Artemisia halodendron， Rudbeckia laciniata， these plant species can be planted around the ridges， and timely spraying when there are large number of weevils clustering to feed can obtain a multiplier effect.
Chemical control During the high occurrence period of adults in June-July， broad-spectrum agents can be sprayed to effectively control the adults in accordance with the control of Ceratovacuna lanigera as follows： 800-1 000 times diluted solution of 90% dipterex crystal， 20% Carbosulfan EC， 1 000-2 000 times diluted 48% chlorpyrifos EC or 50% phoxim EC， 1 000-1 500 times diluted 5% fipronil SC. Weevils have more activities in the afternoon （especially at dusk）， so the control effect is much more significant when spraying in the afternoon. In view of the miscellaneous eating habits of weevils， uniform control of various crops should be adopted， and the effect would be better if the wild weeds and plants around the fields can be sprayed.
Hieroglyphus tonkinensis Bolivar
Occurrence and damage
H. tonkinensis Bolivar is a member of Acridoidea in Orthoptera. It occurs commonly in Guangdong， Guangxi， Yunnan， Fujian， Taiwan， Hunan， Hainan and other sugarcane-planting provinces （regions） in China. In addition to sugarcane， H. tonkinensis also does harm to rice， wheat， corn， peanuts， sweet potatoes， beans， bamboo， wild weeds and so on. Adults and nymphs are used to feed on sugarcane leaves. In severe cases， a large number of sugarcane leaves are foraged and only veins are left， affecting the growth of sugarcane and reducing production.
Shape recognition
Male adults are 30-40 mm in length and female adults are 40-52 mm in length with blue-green bodies. The head， frontal， cheek and rear lateral， outside the upper eyelids are blue-green， too， while the top of the head， the part above the back， compound eye are yellowish-brown. The pronotum and lateral plates are blue-green， with a dark brownish brown indentation on both sides of the back of tergum， followed by three dark brown indentations. The base of the forehead is pale green， and the end is yellowish-brown. Female adults are wedge shaped， while males are bifurcated. The nymph has a brown body with a yellow flower running through the prothorax to the end of the abdomen in the center of the back. There are black brown stripes on both sides of the flower. The wing bud and antennae increase with age. Living habits and occurrence rules
There is 1 generation each year， and the pest go through the winter in clusters of eggs， which begin the eclosion successively from mid-April of the following year. After 5-6 times of molting， they emerge from early June to early August and die after copulating and spawning. The nymphs are fond of feeding on tender leaves， while the adults and aged ones often feed on old leaves.
Control measures
Agricultural control It can strengthen field management， eradicate the weeds at the ridges and edges of fields and ditches， which can destroy the places for the growth and development of locusts， thereby reducing the source base number of the pest. It can also set up artificial trapping and killing during the nymph stage， which can kill the pest before damage.
Chemical control Before the dispersion of the locust nymphs， spraying the 90% trichlorphon crystals， 600-800 diluted solution of 80% dichlorvos EC； 50% phoxim EC， 48% chlorpyrifos EC or 1 000-1 500 times diluted 5% fipronil SC； 2.5% Cyhalothrin EC， 2.5% Deltamethrin EC or 1 500-3 000 times diluted solution of other pyrethroid pesticides can effectively kill the nymphs， thus reducing damage. When spraying， try to avoid spraying at time with high temperature at noon and windy days.
Melanotus caudex Lewis
Occurrence and damage
M. caudex Lewis is a member of family Elateridae of Coleoptera. Distributed in Guangdong， Guangxi， Fujian， Taiwan， Yunnan， Hainan， Sichuan， Guizhou， Hunan， Jiangxi and other sugarcane-planting provinces （regions） in China， it has frequent occurrences and severe damages. The wireworm has very miscellaneous feeding habits， and in addition to damaging sugarcane， it also does harms to wheat， corn， sorghum， soybeans， cotton， sweet potatoes， peppers， peanuts and other crops. Mainly active in the soil in larvae， it can bore through the underground stems， buds and roots. The occurrence during the seedling stage can result in dead heart seedlings， which resemble borer damage.
Wenfeng LI et al. Occurrence Dynamics and Control of 6 Sugarcane Pests with Potential Threats
Shape recognition
The adult body is about 9 mm long and about 2.7 mm wide， which is slender， dark brown and has grey short hair. The head is black of convex profile covered with thick punctures. The prothorax is black， where the punctures are smaller than those on the head， and the trail angle protrudes backward. The elytra are dark brown， about 2.5 times longer than the cephalothorax. There are nine vertical punctures. The tentacles are dark brown with a total of 11 joints， and the 2nd and 3rd joints are slightly spherical， while the 4th joint is slightly longer than the 2nd and 3rd ones. The feet are dark brown. The mature larvae have a body length of about 30 mm and a width of about 1.7 mm. They are slender， cylindrical and glossy dark brown. The 1st thoracic segment and 9th abdominal segment are red-brown. The head is flat and trapezoidal， with longitudinal grooves and small punctures. The back of the body has fine grooves and punctures. The 1st thoracic segment is long， while the 2nd-8th segments have dark brown crescent stripes on both sides at the leading edge before each segment. The telum is flat and long， with three small tubers at the tip and a sharp reddish-brown in the middle. There are two half-moon spots on the leading edge of the telum， and four vertical lines on the front and wrinkles on the second half， covered with thick and deep punctures. Living habits and occurrence rules
M. caudex has 3 years for a generation， and the generations are overlapped. The larva and adults can go through winter in soil. Occurrences can see to the adults from mid April to early November， with the peak in May-June. The adults have phototaxis and death-feigning capacity. Continuous rainy days are beneficial to their activities， especially in the event of rain in dry weather， when number of adults will increase sharply. Adults often inhabit in sugarcane leaves or cracked leaf sheaths in daytime， mostly mating at night. After mating， the females sneak into the soil to lay eggs. Each female can produce about 100 eggs. The eggs are sparsely scattered in the soil layer about 10 cm deep from the roots of the cane， but also in the rotten subterranean stems. Spawning period is from the end of May to the end of June， and the peak spawning season is mid-June. Without feeding， the adults die successively right after spawning. The larval stage is the longest and the larvae hatch from the early May of the 2nd year and pupate in the early October of the 4th year. The larvae live in the soil for a long time and damage the underground stem buds， roots and other parts of the sugarcane， which can greatly affect the germination of stubble cane production in the next season. After the emergence of the cane seedlings， the larvae often invade into the seedlings from the bottom of the soil under the cane seedlings， causing the cane seedlings withered， which quite resembles borer damage. The larva can do damage to different plants， which can happen all year round， especially in April-June， when the damage is the most severe. After sugarcane jointing， the larvae begin to damage the bud eyes of sugarcane sprouts， resulting in rotting buds. After July， the larvae stop doing harm and move deep into soil for over-summering. In autumn， the larvae return to the cultivating layer to harm the underground rhizomes of sugarcane. Because the larvae have a long duration and many instars， larvae of various instars can be found in the field at the same time. From early October to early November in the 4th year， the mature larvae begin the pupation.
Control measures
Agricultural control For the sugarcane field with severe damage but no stubbles， the tractor-suspended rotary cultivator can be used to deep plough the land to 12-20 cm after sugarcane harvest to break the head of the cane. Mechanical action and artificial picking can effectively remove adults， larvae and some pupae. For the field with sugarcane stubbles， adults， larvae and pupa that have been plucked from the soil should be collected and killed when ploughing and ripping. For the fields with a large number of withered seedlings， the withered seedlings can be removed from the base manually， and then killed the larvae to reduce the damaged plants and decrease the pest population of the next generation. For sugarcane fields that are seriously damaged， no sugarcane stubble should be left， and the crop rotation with rice shoud be strengthened to reduce the damage. Physical control During the peak period of adults （April-June）， 1 insecticidal lamp can be installed for every 2-4 hectare for trapping and killing. The daily light-on time is preferred from 20：00 to 22：00， the active peak period of adults.
Chemical control Severely infested plots can apply the mixture of 15-18 kg of 3.6% of broad-spectral dimehypo， 3.6% common dimehypo， 5% Carbosulfan， 5% monosultap·chlorpyrifos， 5% of isobutyl terbufos， 8% chlorpyrifos·Phoxim granules or 15-18 kg of 15% chlorpyrifos granules with 600 kg of dry fine soil or chemical fertilizer per hectare. The new-planting sugarcane should be planted in March-April， and the mixture is sprayed evenly to the sugarcane bases when the cane stubbles sprout or during the ridging in May-June， followed with timely earth covering.
Diptiloplatus sacchari Shin et Don
Occurrence and damage
D. sacchari Shin et Don is a member of family Rhyncaphytoptidae in Acarina of Archanoidea. Currently it has been found in the sugarcane planting areas in Guangxi， Yunnan in China. It mainly does damage to sugarcane， which is mostly found on the back of sugarcane leaves and sucking leaf juice with muzzle. The chlorophyll of the damaged leaves is destroyed， so the damaged leaves may have yellowish-white specks at the beginning， which gradually expand into russet patches. The damage gradually develops inward from the other leaf to the lobus cardiacus when affected. The damaged sugarcane plant leaves are scorched and their growth is obstructed， resulting in reduced yield and sugar production.
Shape recognition
The female adult is like worms with a body length of 0.27 mm， width of 0.07 mm， thickness of 0.06 mm， light yellow. The back scutum is triangular and the anterior lobule is clearly covered by the base of the iliac crest. There are 2 pairs of feet. The eggs are milky white， translucent， with a long diameter of about 0.05 mm and a short diameter of about 0.04 mm.
Living habits and occurrence rules
D. sacchari can be seen in Guangxi all year round. There are 2 occurrence peaks in a year. The first peak is during the high-temperature and dry period before the rainy season from May to June； the second peak is during the autumn drought period after the ending of rainy season from September to October. The damage is the most severe of the occurrence in dry years， while the damage is light in the rainy years. The adults and nymphs are found of inhabiting on the back of the sugarcane leaves to suck sugarcane leaf juice， especially fond of damaging the leaves in the middle parts of sugarcane plants.
Key words Sugarcane； Potential threat； Pests； Occurrence dynamics； Control measures
Sugarcane is the main sugar-yielding crop in China， which occupies an important position in the agricultural economy. Each year， pest damage can cause the yield loss of several to over 10 percent or even more. With the expansion of sugarcane planting area， the reform of the agricultural farming system， the frequent introduction， the abuse of chemical pesticides， and the complex and changeable climate and environment in the sugarcane-producing regions in China， new changes have occurred to the dynamic relations between crops and pests， pests and natural enemies. The number of pest species has increased， the degree of occurrence has become increasingly serious， the number of natural enemies has continued to decrease， and prevention and control work have become more passive. According to incomplete statistics， there are more than 360 species of sugarcane pests in China， of which the major ones that affect the growth of sugarcane and often cause disasters are： the sugarcane borer （Diatraea saccharalis）， the cane beetle， the turnip moth， the African armyworm， leaf-cutting ants， termites， spittlebugs， and the beetle Migdolus fryanus[1-4]. In this paper， the occurrence dynamics and control of 6 sugarcane pests with potential threats were studied in order to prospectively grasp the dynamics of sugarcane pests， scientifically and effectively prevent and control sugarcane pests， and ensure the safety of sugarcane production.
Macrotermes barneyi Light
Occurrence and damage
M. barneyi Light is a member of termites belonging to the genus Macrotermes in the family of Termitidae. It is distributed in the sugarcane-planting provinces （districts） like Guangdong， Guangxi， Fujian， Taiwan， Yunnan， Sichuan， Hainan， Guizhou， Zhejiang， Hunan， Jiangxi in China. In addition to damaging sugarcane， it also does harms to sorghum， corn， peanuts， soybeans， sweet potatoes， cassava， fruit trees， forest trees and so on. In the drylands in hilly and arid areas， sugarcane is often severely damaged， especially in the newly-reclaimed land. Damaged sugarcane species are often invaded from both ends of the incision， and then the pest feeds on the stem tissue， forming a tunnel filled with dirt and their secretions. In severe cases， only a very thin layer of epidermis remains， causing the seedlings to fail to germinate. In the severely damaged sugarcane planting areas， the damage rate reaches as high as 30%-60%， resulting in a large area of lack of seedlings and ridges， or even crop failure. In the middle and late growth stages of sugarcane， the pests bore through the underground cane stalks， making the stem hollow inside， leaves yellow or dried， and the plants are easy to break or beat down， wither， leading to considerable loss. Shape recognition
The soldiers of M. barneyi Light are divided into two kinds： big ones and small ones. The head of the big one is particularly large， approximately rectangular of yellow-brown. The shape of the small one is similar to that of the big one， but much smaller in size. Soldiers can secrete a yellow-brown liquid when they encounter an enemy. The alate queen has dark reddish-brown head of broadly ovate shape， and the body is brownish-brown while yellowish brown in wings.
Living habits and occurrence rules
For M. barneyi Light， as in most other termites， the colony consists of many individuals， divided into several levels of the king and queen， workers and soldiers. Among them， the workers are the largest in the colony and are the ones do direct harm to sugarcane. Sugarcane can be harmed by termites during the whole growing period from sowing to harvesting， but the most severe damage occurs during the germination period after sowing， while the damage during the seedling period is lighter. However， the damage becomes more serious during the elongation period， and the second damage peak often occurs during the middle and late stages of growth. The occurrence is the most frequent and the damage is the most severe in the hilly mountainous areas. The sugarcane plants around the house and near the bamboo gardens are also often damaged by termites. In early spring， when the climate is arid and warm， and the soil moisture is low， the seedlings are often severely damaged by termites before germination. On the contrary， the damage is light when there are many spring rains with low temperatures， and the soil remains wet for a long time. During the middle and late periods， rains after long-term drought can make the soil wet， and the damage of termites often greatly increases. The varieties with hard stalk， fast germination， developed roots and strong tillering capacity always suffer less from the damage.
Control measures
Agricultural control Before planting， it can deeply plough the land to improve the soil and destroy the nest， thereby wiping out the termites before the planting. It can also set up trapping pits using the favorite plants of termites， such as pine twigs， gum tree barks， sugarcane residues， when a large number of termites are trapped in the pits， available chemical medications such as mirex， chlorpyrifos， phoxim， can be sprayed to kill them.
Physical control In the swarming season， Jiaduo frequency-vibration insecticidal lamp can be used to trap the alate queen. Chemical control The workers and soldiers are most active and mindless when building the swarming holes， which is the best time to spray Mirex powder directly on the termite body. If proper， the whole colony can be wiped out. Before planting， the seedling plants can be soaked for 1 min in the 300-400 times diluted liquid of the mixture of 50% phoxim， 20% Carbosulfan， 48% chlorpyrifos， 10% Uranus emulsifiable concentrate or 5% fipronil suspension agent. The seedlings can be planted together with the spring canes， ratooned and fertilized with stubble canes from February to May. On the other hand， a full stand of seedlings can be kept for 2 months by soil sealing or film mulching in sugarcane ditches， sugarcane stubbles after evenly spraying the fully mixed 60-90 kg of 8% chlorpyrifos phoxim， 3.6% broad-spectral biultap， 5% carbosulfan， 5% monosultap chlorpyrifos， 5% isopropyl terbufos or 15-18 kg of 15% chlorpyrifos granules in the fertilizing amount of each hectare.
Hypomeces squamosus Fabricius
Occurrence and damage
H. squamosus Fabricius is a member of Hypomeces in the subfamily of Entiminae of family Curculionidae in Coleoptera. It is distributed in Jiangxi， Hunan， Sichuan， Fujian， Taiwan， Guangdong， Hainan， Guangxi， Yunnan and other provinces （regions） in China. With miscellaneous eating habits， in addition to harming sugar cane， it also damages cotton， wheat， peach， guava， mulberry， large leafhopper， tea， citrus fruit trees and so on. In the field， H. squamosus usually occurs accompanied with Trochorhopalus humeralis， Diocalandra Sp. and other sugarcane weevil species， and their population accounts for about 15%. In recent years， H. squamosus has frequently done damages to the sugarcane plating areas in Guangxi and Menglian， Bohai， Mengzi of Yunnan with the occurrences ranging from hundreds of to thousands of hectares. In the field with severe damage， the population density reaches 1-2 per plant， and a large number of sugarcane leaves are eaten with only veins left， which greatly affects the growth of sugarcane plants and causes significant losses to sugarcane production.
Shape recognition
Adults have a body length of 12.8-15.1 mm and a body width of 4.8-6.0 mm. The body is hypertrophic and slightly flat. The body walls are black and densely covered with uniform golden blue-green scales （the same scales are blue or green due to their different angles）. The back of the head and gills is flattened， with a wide， deep mid-ditch in the middle， reaching up to the top of the head. There are two shallow grooves on each side， either curved or straight. Each end of the elytra wing shrinks to 2 sharp protrusions at the top and bottom， and the top one is larger. The feet are black densely covered with blue-green scales but no teeth inside the tibia. Living habits and occurrence rules
There is only 1 generation occurrence in 1 year， and the adults and larvae go through the winter in soil. The overwintering adults begin to come up out of the earth in early March and become the most active from June to July， then become rare in early October. Not quite active， the adults have the features of gregariousness and death-feigning， and they are afraid of light and most active in the morning and evening.
Control measures
Agricultural control From May to June when the sugarcane plants are not high and the adults begin to be more active in morning and evening in groups， the adults can be caught and killed artificially to reduce the pest population and relieve the damage. Since H. squamosus is particularly like to eat Artemisia halodendron， Rudbeckia laciniata， these plant species can be planted around the ridges， and timely spraying when there are large number of weevils clustering to feed can obtain a multiplier effect.
Chemical control During the high occurrence period of adults in June-July， broad-spectrum agents can be sprayed to effectively control the adults in accordance with the control of Ceratovacuna lanigera as follows： 800-1 000 times diluted solution of 90% dipterex crystal， 20% Carbosulfan EC， 1 000-2 000 times diluted 48% chlorpyrifos EC or 50% phoxim EC， 1 000-1 500 times diluted 5% fipronil SC. Weevils have more activities in the afternoon （especially at dusk）， so the control effect is much more significant when spraying in the afternoon. In view of the miscellaneous eating habits of weevils， uniform control of various crops should be adopted， and the effect would be better if the wild weeds and plants around the fields can be sprayed.
Hieroglyphus tonkinensis Bolivar
Occurrence and damage
H. tonkinensis Bolivar is a member of Acridoidea in Orthoptera. It occurs commonly in Guangdong， Guangxi， Yunnan， Fujian， Taiwan， Hunan， Hainan and other sugarcane-planting provinces （regions） in China. In addition to sugarcane， H. tonkinensis also does harm to rice， wheat， corn， peanuts， sweet potatoes， beans， bamboo， wild weeds and so on. Adults and nymphs are used to feed on sugarcane leaves. In severe cases， a large number of sugarcane leaves are foraged and only veins are left， affecting the growth of sugarcane and reducing production.
Shape recognition
Male adults are 30-40 mm in length and female adults are 40-52 mm in length with blue-green bodies. The head， frontal， cheek and rear lateral， outside the upper eyelids are blue-green， too， while the top of the head， the part above the back， compound eye are yellowish-brown. The pronotum and lateral plates are blue-green， with a dark brownish brown indentation on both sides of the back of tergum， followed by three dark brown indentations. The base of the forehead is pale green， and the end is yellowish-brown. Female adults are wedge shaped， while males are bifurcated. The nymph has a brown body with a yellow flower running through the prothorax to the end of the abdomen in the center of the back. There are black brown stripes on both sides of the flower. The wing bud and antennae increase with age. Living habits and occurrence rules
There is 1 generation each year， and the pest go through the winter in clusters of eggs， which begin the eclosion successively from mid-April of the following year. After 5-6 times of molting， they emerge from early June to early August and die after copulating and spawning. The nymphs are fond of feeding on tender leaves， while the adults and aged ones often feed on old leaves.
Control measures
Agricultural control It can strengthen field management， eradicate the weeds at the ridges and edges of fields and ditches， which can destroy the places for the growth and development of locusts， thereby reducing the source base number of the pest. It can also set up artificial trapping and killing during the nymph stage， which can kill the pest before damage.
Chemical control Before the dispersion of the locust nymphs， spraying the 90% trichlorphon crystals， 600-800 diluted solution of 80% dichlorvos EC； 50% phoxim EC， 48% chlorpyrifos EC or 1 000-1 500 times diluted 5% fipronil SC； 2.5% Cyhalothrin EC， 2.5% Deltamethrin EC or 1 500-3 000 times diluted solution of other pyrethroid pesticides can effectively kill the nymphs， thus reducing damage. When spraying， try to avoid spraying at time with high temperature at noon and windy days.
Melanotus caudex Lewis
Occurrence and damage
M. caudex Lewis is a member of family Elateridae of Coleoptera. Distributed in Guangdong， Guangxi， Fujian， Taiwan， Yunnan， Hainan， Sichuan， Guizhou， Hunan， Jiangxi and other sugarcane-planting provinces （regions） in China， it has frequent occurrences and severe damages. The wireworm has very miscellaneous feeding habits， and in addition to damaging sugarcane， it also does harms to wheat， corn， sorghum， soybeans， cotton， sweet potatoes， peppers， peanuts and other crops. Mainly active in the soil in larvae， it can bore through the underground stems， buds and roots. The occurrence during the seedling stage can result in dead heart seedlings， which resemble borer damage.
Wenfeng LI et al. Occurrence Dynamics and Control of 6 Sugarcane Pests with Potential Threats
Shape recognition
The adult body is about 9 mm long and about 2.7 mm wide， which is slender， dark brown and has grey short hair. The head is black of convex profile covered with thick punctures. The prothorax is black， where the punctures are smaller than those on the head， and the trail angle protrudes backward. The elytra are dark brown， about 2.5 times longer than the cephalothorax. There are nine vertical punctures. The tentacles are dark brown with a total of 11 joints， and the 2nd and 3rd joints are slightly spherical， while the 4th joint is slightly longer than the 2nd and 3rd ones. The feet are dark brown. The mature larvae have a body length of about 30 mm and a width of about 1.7 mm. They are slender， cylindrical and glossy dark brown. The 1st thoracic segment and 9th abdominal segment are red-brown. The head is flat and trapezoidal， with longitudinal grooves and small punctures. The back of the body has fine grooves and punctures. The 1st thoracic segment is long， while the 2nd-8th segments have dark brown crescent stripes on both sides at the leading edge before each segment. The telum is flat and long， with three small tubers at the tip and a sharp reddish-brown in the middle. There are two half-moon spots on the leading edge of the telum， and four vertical lines on the front and wrinkles on the second half， covered with thick and deep punctures. Living habits and occurrence rules
M. caudex has 3 years for a generation， and the generations are overlapped. The larva and adults can go through winter in soil. Occurrences can see to the adults from mid April to early November， with the peak in May-June. The adults have phototaxis and death-feigning capacity. Continuous rainy days are beneficial to their activities， especially in the event of rain in dry weather， when number of adults will increase sharply. Adults often inhabit in sugarcane leaves or cracked leaf sheaths in daytime， mostly mating at night. After mating， the females sneak into the soil to lay eggs. Each female can produce about 100 eggs. The eggs are sparsely scattered in the soil layer about 10 cm deep from the roots of the cane， but also in the rotten subterranean stems. Spawning period is from the end of May to the end of June， and the peak spawning season is mid-June. Without feeding， the adults die successively right after spawning. The larval stage is the longest and the larvae hatch from the early May of the 2nd year and pupate in the early October of the 4th year. The larvae live in the soil for a long time and damage the underground stem buds， roots and other parts of the sugarcane， which can greatly affect the germination of stubble cane production in the next season. After the emergence of the cane seedlings， the larvae often invade into the seedlings from the bottom of the soil under the cane seedlings， causing the cane seedlings withered， which quite resembles borer damage. The larva can do damage to different plants， which can happen all year round， especially in April-June， when the damage is the most severe. After sugarcane jointing， the larvae begin to damage the bud eyes of sugarcane sprouts， resulting in rotting buds. After July， the larvae stop doing harm and move deep into soil for over-summering. In autumn， the larvae return to the cultivating layer to harm the underground rhizomes of sugarcane. Because the larvae have a long duration and many instars， larvae of various instars can be found in the field at the same time. From early October to early November in the 4th year， the mature larvae begin the pupation.
Control measures
Agricultural control For the sugarcane field with severe damage but no stubbles， the tractor-suspended rotary cultivator can be used to deep plough the land to 12-20 cm after sugarcane harvest to break the head of the cane. Mechanical action and artificial picking can effectively remove adults， larvae and some pupae. For the field with sugarcane stubbles， adults， larvae and pupa that have been plucked from the soil should be collected and killed when ploughing and ripping. For the fields with a large number of withered seedlings， the withered seedlings can be removed from the base manually， and then killed the larvae to reduce the damaged plants and decrease the pest population of the next generation. For sugarcane fields that are seriously damaged， no sugarcane stubble should be left， and the crop rotation with rice shoud be strengthened to reduce the damage. Physical control During the peak period of adults （April-June）， 1 insecticidal lamp can be installed for every 2-4 hectare for trapping and killing. The daily light-on time is preferred from 20：00 to 22：00， the active peak period of adults.
Chemical control Severely infested plots can apply the mixture of 15-18 kg of 3.6% of broad-spectral dimehypo， 3.6% common dimehypo， 5% Carbosulfan， 5% monosultap·chlorpyrifos， 5% of isobutyl terbufos， 8% chlorpyrifos·Phoxim granules or 15-18 kg of 15% chlorpyrifos granules with 600 kg of dry fine soil or chemical fertilizer per hectare. The new-planting sugarcane should be planted in March-April， and the mixture is sprayed evenly to the sugarcane bases when the cane stubbles sprout or during the ridging in May-June， followed with timely earth covering.
Diptiloplatus sacchari Shin et Don
Occurrence and damage
D. sacchari Shin et Don is a member of family Rhyncaphytoptidae in Acarina of Archanoidea. Currently it has been found in the sugarcane planting areas in Guangxi， Yunnan in China. It mainly does damage to sugarcane， which is mostly found on the back of sugarcane leaves and sucking leaf juice with muzzle. The chlorophyll of the damaged leaves is destroyed， so the damaged leaves may have yellowish-white specks at the beginning， which gradually expand into russet patches. The damage gradually develops inward from the other leaf to the lobus cardiacus when affected. The damaged sugarcane plant leaves are scorched and their growth is obstructed， resulting in reduced yield and sugar production.
Shape recognition
The female adult is like worms with a body length of 0.27 mm， width of 0.07 mm， thickness of 0.06 mm， light yellow. The back scutum is triangular and the anterior lobule is clearly covered by the base of the iliac crest. There are 2 pairs of feet. The eggs are milky white， translucent， with a long diameter of about 0.05 mm and a short diameter of about 0.04 mm.
Living habits and occurrence rules
D. sacchari can be seen in Guangxi all year round. There are 2 occurrence peaks in a year. The first peak is during the high-temperature and dry period before the rainy season from May to June； the second peak is during the autumn drought period after the ending of rainy season from September to October. The damage is the most severe of the occurrence in dry years， while the damage is light in the rainy years. The adults and nymphs are found of inhabiting on the back of the sugarcane leaves to suck sugarcane leaf juice， especially fond of damaging the leaves in the middle parts of sugarcane plants.