STEM BORERS

Chapter 13 

STEM BORERS 

Wu Junxiang 

Li Yiping 

Junxw@nwsuaf.edu.cn 

lyp2003@126.com

Chapter 13 STEM BORERS 

Lecture Outline 

‣ Corn borers 

‣ Rice borers 

‣ Other stem borers 

‣ Monitoring and Management

Corn Borers 

Chinese byname is 玉米钻心虫 or 箭杆虫 , 

belong to Lepidoptera, Pyralidae. 2 species 

recorded in China: 

• Asian corn borer Ostrinia furnacalis 

• Europe corn borer O. nubilalis 

Asian corn borer is predominant in China.

1. Distribution 

• Asian corn borer: Asia and Oceania; 

Nationwide distribution in China; 

• Europe corn borer: Europe, Northwestern 

Africa, Western Asia and Northern America; 

Predominant species in Yili, Xinjiang; 

• Occasionally found in Ningxia, Inner 

Mongolia and Hebei, but Asian corn borer is 

more predominant

2. Damage 

Polyphagous pests, more than 200 host 

plants recorded. 

Mainly cause damage through boring 

plants as larvae. During seedling stage of corn 

or sorghum, bore leaves to produce “ 花叶 ”. 

During seedling stage of millet, bore young 

leaves to produce “ 枯心 ”. After rice shooting 

and heading stages, larval damage influences 

nutrient transportation in plants, causing 

plants to produce non-rich grains. Also, larval 

damaged plants are easily pushed down by 

strong winds.

3. Life Cycle 

1-6 generations/year in China. 2-3 in 

Northeast and mid-downstream of Yellow 

River; 3-4 in mid-downstream of Yangtsz 

River; 5-6 in Huanan area. 

Overwinter as grown larvae in stems, ear 

centers and root stubbles of corns.

3. Behavior 

Adults: 

Activity at night; hide in crops or weeds 

during daytime; 

Good at flying with phototaxis; 

Eggs laid at back of leaves near central 

veins in masses of scales; 20-30 eggs a 

mass and 300-600 eggs per female adult; 

Prefer not to lay on plants lower than 

50cm.

Larvae 

‣ Newly hatched larvae crawl quickly to 

spread out or spin silk to move to other 

plants; 

‣ Prefer sugar and moisture, but don’t like 

light; 

3. Behavior

3. Behavior 

Larvae 

‣During the late seedling period, newly 

hatched larvae feed on the mesophyll of 

young un-spread leaves or bore into curled 

young leaves to produce consecutive spots or 

holes when the leaves are unfurled. The 

situation of consecutive holes, caused by the 

insects boring through un-spread leaves’ 

layers is often called “ 花叶或链珠孔 ”. 

在玉米心叶期 , 初孵幼虫取食未展开的心叶叶肉 , 或将纵卷的心叶 

蛀穿 , 到心叶伸展后 , 叶面呈现半透明斑点 , 孔洞呈横列排孔 , 通称 

“ 花叶或链珠孔 ”。

3. Behavior 

Before the male flower appears, most 

larvae either bore into the stems of male 

flowers to break the male flowers, or bore 

into plant stems above female ears. 

在雄穗出现前 , 幼虫大多蛀入雄穗柄内 , 造成折雄 , 或蛀入雌 

穗以上节内。

3. Behavior 

During the female ear period, most younger larvae 

in male flowers bore into the stem at its points of 

connection with female ears and into its upper and 

lower stem segments. This damage severely 

influences plant nutrient transportation and 

female ear growth, even causing stems to break. A 

stem break below the female ears can cause a 

severe reduction of plant harvest. 

玉米抽丝时 , 原在雄穗上一些较小的幼虫 , 大多自雌穗节及上下 

茎节蛀入 , 严重破坏养分输送和影响雌穗的发育 , 甚至遇风造成折茎 

而减产 , 尤以穗下折茎影响产量最重。

3. Factors influencing population 

1) Climate conditions 

‣ Prefer middle temperatures and high humidity; 

optimal temp.15-30℃ and RH +60%; 

‣ Precipitation and humidity would influence the 

overwintered larvae to pupate, adults to oviposit 

and eggs to hatch. At the same time, also influence 

the parasitoid wasp’s population. 

‣ facultative diapause insect


2) Culture 

Prefer summer sowing to spring sowing; 

avoid mixture of both sowing seasons. 

3) Natural enemy 

Over 70 predators and parasitoids found 

in China, such as pine caterpillar 

trichogrammatids, corn borer 

trichogrammatids and white 

muscardine fungi.


4) Host plants 

Adults prefer to choose plants sown early, that are 

growing well, with very green leaves to oviposit; 

Variety resistance: Corn contains certain 

substances, called anti-borertin ( 抗螟素 ), resistant to 

insects. These include: anti-borertins A, B and C. Of 

which, anti-borertin A and anti-borertin C, called 

“Dimboa”, are the most effective in resistance.

Rice Stalk Borers 

• Striped rice borer, Asian rice borer 

Chilo suppressalis ( 二化螟 ) 

• Tryporyza incertulas ( 三化螟 ) 

Lepidoptera, Pyralidae

Striped rice borer 

Asian rice borer 

Chilo suppressalis 

( 二化螟 )

Striped rice borer, Asian rice borer 

Chilo suppressalis ( 二化螟 )

Tryporyza incertulas ( 三化螟 )

1. Distribution 

Chilo suppressalis: Continents of both Asia 

and Europe and all the countries of Southeast 

Asia; Nationwide distribution in China; 

Tryporyza incertulas: Tropical to subtropical 

areas of Asia; The valley of Yangtse 

River and southern areas in China, most 

severe damage found in plains along seas and 

rivers.

2. Damage 

Chilo suppressalis is polyphagous; rice, 

wheat, corn, sorghum, water bamboo ( 茭白 ), 

sugarcane, millet, horsebean ( 蚕豆 ), etc; 

Tryporyza incertulas is monophagous; 

rice and wild rice;

2. Damage 

Newly hatched larvae aggregate, burrow into leaf 

sheathes, and cause leaf sheathes to become dry ( 枯 

鞘 ). Larvae at and/or beyond their second instar do 

different damage at different plant stages. During 

the tillering stage, they burrow into stems and cause 

the seedlings to dry up or die ( 枯心苗 ); during the 

booting stage, the bootings to die ( 死孕穗 ); during 

the heading stage, heads to become white ( 白穗 ); 

during the mature stage, the plants to be damaged 

( 虫伤株 ).

2. Damage 

枯心团 

白穗 

Rice borer damage

3. Life Cycle 

1) Chilo suppressalis ( 二化螟 ) 

1-5 generations a year; 2 in the region 

from 32° to 36°N latitude. (Southern 

Shaanxi, Henan, Anhui, Hubei); 3-4 between 

26° and 32°N latitude. (valley of Yangtse 

River); 5 south of 20°N latitude. (islands of 

Hainan) .

3. Life Cycle 

Overwinter as 4 th to 6 th instar larvae in rice 

stakes ( 稻桩 ), straws ( 稻草 ), water bamboo ( 茭白 ) 

and other places around paddy fields. 

Overwintered nonmature larvae (4 th or 5 th instar) 

come out to feed on wheat, horsebean and rape.

3. Life Cycle 

2. Tryporyza incertulas ( 三化螟 ) 

2-7 generations/year; 3-4 in middownstream 

paddy areas of Yangtse River; 

4-7 in areas south of Yangtse River. 

Overwinter as grown larvae in rice stems. 

Overwintered larvae pupate and emerge 

as weather becomes warm (over 16℃)

4. Behavior 

Adults: 

• Fallow during daytime and active at night; 

• Strong phototaxis; 

• Prefer ovipositing eggs on 

green and healthy plants; 

• Eggs laid in masses on faces 

of leaves

4. Behavior 

Larvae: 

• Newly hatched larvae crawl along rice leaves down 

or spin to spread; intrude rice stems from sheath 

gaps ( 叶鞘 ). 

• Tryporyza incertulas Larvae prefer white tissue of, 

and rarely feed on, green parts of sheathes. After 

burrowing into a stem, they eat the vascular 

bundles at the horizontal level they entered at, 

leaving the sheath and stem outerside ( 断环 ), and 

then eat upward. Each individual larva follows this 

same eating pattern upon entering a new plant.

5. Relationship with environment 

1) Climate conditions 

Chilo suppressalis favors lower temp.; most 

found in hill and mountain areas. Tryporyza 

incertulas prefers warm conditions, causes severe 

damage in plain rice areas.


2) Culture 

Rice borers occur more severely in mixed paddy 

areas consisting of single cropping rice ( 单季稻 ) and 

double cropping rice ( 双季稻 ) due to more consistent 

rice growth periods. Generally, young larval 

hatching periods do not coincide well with rice 

growths suited for larval intruder, but in areas of 

single cropping rice or double cropping rice 

continuous planting, there is a longer period of rice 

growth suitable for rice borer’s intrusion.


3) Natural enemies 

Egg parasitoid wasps are most important. 

Maximum parasite rate is 80-90%. 

4) Host plants 

Cross rice is more suitable to growth and 

development than common rice. 

Rice is the only host of Tryporyza 

incertulas.

Other Stem Borers 

( 其它蛀茎害虫 )

1. Common Species 

• Meromyza saltatrix ( 麦秆蝇 ) 

• Melanagromyza sojae( 豆秆黑潜蝇 ) 

• Chilo venosatus ( 高梁条螟 ) 

• Chilo infuscatellus ( 粟灰螟 ) 

• Sesamia inferens ( 大螟 ) 

• Apophylia flavoviens ( 玉米旋心虫 ) 

• Chlorops oryzae ( 稻秆蝇 ) 

• Ceuthorrhynchus asper ( 油菜茎象甲 ) 

• Janus pire ( 梨茎蜂 )

2. Meromyza saltatrix ( 麦秆蝇 ) 

‣ Called also 麦钻心虫 or 麦蝇 ; 

‣ Diptera, Chloropidae ( 黄潜蝇科 ); 

‣ Distributed in northern spring wheat areas 

and winter wheat areas of Huabei Plain; 

‣ Host plants include wheat, barley and rye 

( 黑麦 ); 

‣ Newly hatched larvae intrude stem from 

sheath, feed down in a twisting motion and 

cause seedlings to die ( 枯心 ), ears become 

white ( 白穗 ) or rot ( 烂穗 ).

3-44 generations/year in 

winter wheat areas; 

Overwinter as larvae in 

wheat seedling or weeds; 

Larvae of overwintered 

and 1st generation damage 

wheat; 

Most severe damage 

caused from April to May.

3. Melanagromyza sojae ( 豆秆黑潜蝇 ) 

‣ Called also 豆秆蝇 , 豆秆穿 

心虫 or 豆秆蛇潜蝇 ; 

‣Diptera, 

‣Agromyzidae ( 潜蝇科 ); 

‣Distributed in soybean 

planting area of valleys 

of Yellow River and 

Huai River.


4-13 generations a year; 

Overwinter as pupa in root stubbles and 

stalks; 

Eggs laid under epidemics of lead-back 

near main vein on the mid-lower parts of 

plants; 

Main control measures include destroying 

overwinter hosts and spraying insecticides 

when and after adults emerge.

4. Chilo infuscatellus ( 粟灰螟 ) 

Chinese byname is 谷子钻心虫 or 二点螟 ; 

Lepidoptera, Pyralidae; 

Distributed in most provinces in China; 

Prefers feeding on millet; also often feeds 

on corn and sorghum but does not cause as 

much damage to these plants;


Larvae burrow into and feed on stem 

bases, causing seedlings to become dry 

and/or die. Also, this basis damage makes it 

easy for strong winds to push the seedlings 

down. If a seedling is pushed down, it makes 

it unlikely that it will grow well and offer a 

good harvest.


4-13 generations a year; 

Overwinter as pupa in root stubbles and 

stalks; 

Eggs laid under epidemics of lead-back 

near main vein on the mid-lower parts of 

plants; 

Main control measures include destroying 

overwinter hosts and spraying insecticides 

when and after adults emerge.

4. Chilo infuscatellus ( 粟灰螟 )


2-3 generations per year; 

Overwinter as grown larvae in millet 

stubbles or stems; 

Adults move about and oviposit at night, 

eggs laid on back of leaves; 

Newly hatched larvae feed in sheath; 

intrude stem after 1-3 days; transfer to feed 

after 3 rd instar. 

Grown larvae pupate in stems.

4. Chilo infuscatellus ( 粟灰螟 )

Chilo venosatus ( 高梁条螟 )

栗秆蝇

5. Chlorops oryzae ( 稻秆潜蝇 ) 

Chinese byname is 稻秆蝇 , 稻钻心虫 or 

双尾虫 ; 

Diptera; 

Chloropidae ( 秆蝇科 , 黄潜蝇科 ); 

Larvae intrude rice stems to feed on 

newly sprouted leaf ( 心叶 ), top of the plant 

( 生长点 ) and young ears.

Chlorops oryzae ( 稻秆潜蝇 )

稻秆蝇为害幼穗造成 “ 花白穗 ” 

稻秆蝇为害心叶造成裂口

Ceutorrhynchus asper ( 油菜茎象甲 ) 

Called also 靛蓝龟象甲 ; 

Coleoptera, Cucurlidae ( 象甲科 ); 

Mainly distributed in Northwest; 

Severely damages rape, also feed on many 

kinds of cruciferous vegetables; 

Larvae intrude into stems to cause 

distortion and swelling of stems; adults feed 

leaves and young stems.

Janus pire ( 梨茎蜂 ) 

梨茎蜂又名梨梢茎蜂、梨茎锯 

蜂、折梢虫、截芽虫

Janus pire ( 梨茎蜂 )

Monitoring and Management

1. Survey Methods 

1) Survey on corn borer 

‣ Survey on overwintering larval # 

‣ Survey on pupating and emerging 

schedules 

‣ Survey on adults 

Light trapping 

Sexual lure trapping 

‣ Survey on # of eggs

1. Survey Methods 

2) Survey on rice borer 

‣ Survey on pupating schedule each 

generation 

‣ Survey on larval # per generation

2. Control Measures 

1) Cultural control 

Destroy overwintered hosts 

Plant the early-sowing trapping crops 

Use resistant varieties, such as Bt corn 

Adjust the planting system

2. Biological Control 

1) Releasing trichogrammatids 

(1) To control the corn borers: releasing wasps 

2-3 times at the initial ovipositing period, the 

beginning peak and peak of ovipositing respectively. 

10000-20000 wasps are released in 3-5 different plots 

each time in 667m2. This number can be increased 

during the egg peak. The wasp cards are about 1m 

from the ground. Keep the wasp cards from rain 

and sunlight.

2. Biological Control 

1) Releasing trichogrammatids 

(2) To control the rice borers: use 50000 

wasps, releasing wasps three times at the 

amount of a third of 50000 each time. Release 

wasps at the very beginning of adult 

emergence with a 4-5 day space between each 

release.

2) Spray white muscardine fungi ( 白僵菌 ) 

(1)Use the white muscardine fungi to control 

corn borers during the late seedling period. Mix one 

part fungus powder containing of 5-10 billion spores 

in one gram with 10-20 parts of granule carrier. 

Then put this mixture on the top of corn plants, 

about 1-2 grams per plant, during the late seedling 

period. 

(1) 心叶期施用白僵菌 GR 防治玉 

米螟 : 以每克含孢子 50-100 亿的菌粉 

一份 , 载体颗粒 10-20 份 , 于春、夏玉 

米心叶中期施入心叶丛中 .

2) Spray white muscardine fungi ( 白僵菌 ) 

(2) To control corn borers with white 

muscardine fungi: Cover corn stem piles with 

fungi during early spring. Use about 100g 

fungus powder, made by original methods, 

per each 1 m3 of corn stems. 

(2) 早春用白僵菌封垛防治玉米螟 : 

按每 m 3 秸秆用土法生产的白僵菌粉 100g 左 

右 , 每 m 3 面积上用喷粉器喷一个点 , 到 

垛面飞扬出白僵菌粉的 “ 白烟 ” 即可。

3) Use B.t. formulation 

10.5kg/hm 2 of Bt GR used during late 

seedling. 

4) Sexual semichemicals 

30-45 sexual lure/hm2。 

5) Protect natural enemies

2. Control Measure 

3) Physical and mechanical control 

Light trapping: black light, High 

pressure mercury light, double color light. 

Destroy any egg masses, withered 

seedlings or white ears immediately.


4) Chemical control 

Corn borer: 

To control corn borers during the late seedling 

period: Use 1.5g of insecticides such as 1% GR 

phoxim ( 辛硫磷 ), 3% GR carbofuran ( 呋喃丹 ), 

or 0.1% GR lambda-cyhalothrin ( 功夫 ) per plant. 

Or, mix 5% EC phoxim with soil on the basis of a 

1:100 proportion. Then put the mixture on corn 

plant tops, about 1-2 per plant. 

玉米心叶期防治 : 1% 辛硫磷 GR,3% 呋喃丹 GR。0.1% 和 0.15% 功 

夫 GR, 每株 1.5g; 用 5% 的辛硫磷 EC 按 1:100 配成毒土 , 每株心叶施 

入 1-2g。


To control the corn borers during the ear 

period: spread GR insecticide on the following 4 

axils listed and one top, top meaning the filament 

of ear top. Axils: 1 axil of ear, 2 axils of the upper 

leaves and 1 axil of the lower leaves, upper 

meaning above ears, lower meaning below ears. 

This method is called “4 axils and 1 top control”. A 

greater amount of insecticides is used during the 

ear period than during the late seedling period. 

穗期防治 : “ 四腋一顶 ”GR 防治。在玉米抽丝盛期利用上述 GR 撒 

于雌穗着生节的叶腋及其上两叶和下一叶的叶腋及穗顶花丝上 , 用量 

比心叶期适当增大。


Rice borer: 

Periods: peak of egg hatching to 1st 

instar larvae; 

Note: Keep 3-5cm 3 

water layer in paddy 

field after initial spraying insecticides, it is 

especially important to spray insecticide in 

early morning or evening during high temp. 

seasons.

STEM BORERS

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