Stem Borer Management in Paddy Farming: Symptoms, Rice Damages, Natural, Organic, Chemical, and Biological Control

Welcome to our blog on the topic of stem borer in paddy farming. As a farmer, it’s essential to be aware of the pests that can affect your crops and the damage they can cause. Stem borers are a particularly destructive pest when it comes to paddy farming. In this blog, we’ll take a closer look at the characteristics of stem borers, the nature of the damage they can cause, and the symptoms to look out for. Stem borer in paddy fields, including its characteristics, the nature of the damage it causes, and management strategies.

Stem Borer Management in Paddy Farming

It will also discuss symptoms of infestation, identification, and control measures to minimize losses. We’ll also discuss effective management techniques that can help you protect your crops from these pests. Whether you’re a seasoned farmer or new to the field, this information will be valuable in ensuring the success of your paddy crop. So, let’s go in and learn more about stem borers and how to manage them.

Stem borer management in paddy farming

Paddy crop 

Paddy or Rice is one of the world’s oldest and most widely cultivated crops. It is grown in many environments and is a significant food source for more than half of the global population. Paddy is a hardy crop that can tolerate flooding and heavy rainfall, making it well-suited for growing in low-lying areas. It is a staple food for many countries, providing a significant food source, nutrition, and income.

Paddy is grown in a wide range of agro-ecological conditions. Paddy cultivation is widespread in Asia, Africa, and Latin America. The crop goes through several stages of growth, starting with the seedling stage and progressing to the vegetative and reproductive stages. The grain is the edible part of the paddy plant and is covered by a husk. Paddy farming is a labor-intensive process that requires careful management to ensure a successful harvest.

Major pests of paddy

Major pests of paddy include stem borers, leaf folder, stem gall midge, white-backed planthoppers, brown planthoppers, leafrollers, cutworms, rice weevils, and rice leafhoppers. Rice stem borers: These pests are the larvae of certain moths and beetles that feed on the stem and leaves of the paddy plant. They can cause significant damage and reduce yields.

  1. Rice planthoppers: These small insects feed on the sap of the paddy plant and can transmit viral diseases. Cause wilting, drying, and yellowing of the leaves and lead to significant yield losses.
  2. Rice gall midges: These pests are small flies that lay their eggs on the paddy plant. The larvae then feed on the stem and roots, causing galls to form. It weakens the plant and reduces yields.
  3. Rice leaf folder: These are the larvae of certain moths that feed on the leaves of the paddy plant. They can cause significant damage and reduce yields.
  4. Rice hoppers: these pests suck the sap from the paddy plant. These can cause discoloration and wilting of the leaves and cause significant yield losses.

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Stem Borer in Paddy Farming

These pests affect the yield and quality of the paddy crop. They need to be managed through integrated pest management programs. Cultural practices such as crop rotation, inter-cropping, and resistant varieties are essential components of an integrated pest management plan. Chemical control is also commonly used to control populations of paddy pests.

Stem borer of paddy (Scirpophaga)

Stem borer is one of the most dangerous pests of paddy crops. The stem borer of paddy, also known as Scirpophaga incertulas or the rice stem borer, or Rice Yellow Stem Borer, belongs to the family Crambidae, is a severe pest of rice plants in many countries, including India, Pakistan, Burma, and Sri Lanka, China, Japan, Formosa, Philippines, and Indonesia.

This moth’s larvae bore into the rice plant’s stem and feed on the inner tissues, causing the stem to weaken and eventually collapse. The adult moth does not cause damage to the plant, but multiple generations per year can lead to significant crop loss. This pest is commonly known as stem borer because the larvae bore into the stem. 

Lifecycle of paddy stem borer

The stem borer is a pest that affects rice plants and goes through four stages in its life cycle: egg, larva, pupa, and adult.

Oviposition and egg-laying

The male and female moths unite for sexual union and internally fertilize eggs. After three days, the female moths lay 400-600 eggs in 2-3 clusters on the upper surface of the leaves of the paddy plant, typically at night.

Larva

The second stage in the stem borer’s life cycle is the larval stage, which begins when the eggs hatch after 5-8 days. The newly hatched larvae, first-in-star larvae, are 1.5 mm long, pale white with dark brown heads. They move downward on the plant surface and may get blown off to other plants by hanging down on their silken thread.

They then enter the leaf casing or stem and feed on the green tissues for two or three days before boring into the stem, typically at the node region. As they bore into the stem, they are known as stem borers. They feed on the inner tissues of the stem and grow, eventually reaching a full-grown size after five molting stages and becoming 20 mm long. This whole larval period lasts 4-5 weeks. 

Pupation

The third stage in the stem borer’s life cycle is pupation, which occurs after the larvae reach full growth. The larvae make a thin silken case, or cocoon, around themselves inside the stem, which remains closed at the upper end by an operculum and is rounded and bag-like at the lower end. Pupae do not eat, and the pupa itself becomes dark brown. The pupation period usually lasts 6-10 days but can be prolonged to a month, depending on the climate.

Adult

The final stage in the stem borer’s life cycle is the adult stage. The adult moths emerge from the hole made in the stem during the pre-pupation period. They are inactive during the day and active in the evening, with strong flight power. However, they have a short lifespan and die two to three days after laying eggs.

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Stem Borer Issue in Paddy Farming

Overview of Life Cycle

The female moth lays eggs on the upper surface of the leaves, which hatch into larvae after 5-8 days. The larvae then move downward and enter the leaf casing or stem, feeding and boring into the stem. After 4-5 weeks, the larvae create a silken cocoon inside the stem, transforming into pupae for 6-10 days. Finally, the adult moths emerge from the hole in the stem and are active in the evening. They have strong flight power but are short-lived and die 2-3 days after laying eggs. This cycle repeats itself, with the moths laying new eggs to continue the life cycle.

Why is paddy stem borer important/ major pest of paddy?

Paddy stem borer infestation can have severe consequences on rice crop yields. Excessive boring through the sheath can destroy the crop and reduce the number of reproductive tillers. At later stages of infection, plants may develop whiteheads.

Yield loss can be significant, with yellow stemborer causing up to 80% loss in late-planted crops and white stemborer capable of destroying entire fields. Striped stemborer is considered one of Asia’s most damaging insect pests, with the potential for 100% yield loss in severe cases. Gold-fringed stemborer can also cause significant yield loss, up to 30%.

How does a stem borer attack a paddy crop?

A stem borer attacks a paddy crop by laying eggs on the upper surface of the leaves of the paddy plant, typically at night. The eggs hatch into larvae after 5-8 days; the newly hatched larvae move downward on the plant surface, and they may get blown off to other plants by hanging down on their silken thread. They then enter the leaf casing or stem and feed on the green tissues for two or three days before boring into the stem, typically at the node region. As they bore into the stem, they are known as stem borers.

They feed on the inner tissues of the stem and grow, eventually reaching a full-grown size after five molting stages and becoming 20 mm long. This whole process can cause damage to the plant by weakening the stem and reducing the plant’s ability to absorb nutrients and water, which can lead to decreased yields and even plant death if the infestation is severe.

Identification of paddy stem borer, pest characters, and damage symptoms

The Paddy Stem Borer, also known as the rice stem borer, is a pest that affects rice plants. The adult form of the insect is a brownish-gray moth with a wingspan of about 1.5 inches. The larvae, or caterpillars, are creamy-white with a brown head and can grow up to 20mm long. They bore into the stem of the rice plant and feed on the inner tissues, weakening the stem and reducing the plant’s ability to absorb nutrients and water.

  • Most Damaging Stage: The larval stage of the stem borer moth is the most dangerous because it feeds on the interior tissues of the paddy plant. Adult moths have no adverse effects on paddy plants and do not constitute a hazard to the plants.
  • Symptoms of Paddy Stem Borer infestation include wilting or yellowing of the leaves, lodging of the plant (i.e., the plant falling over), and the presence of small holes or frass (insect excrement) on the stem.
  • Nature of Damage: The stem borer is a pest that causes damage to young rice plants by eating away at the inner tissues of the stem of the young rice plant. In older rice plants, the larvae feed on the inner stem tissues, resulting in white, empty ear heads.

Damage caused by Paddy stem borer includes 

  • Yellowing of the leaves 
  • Wilting of the leaves 
  • Holes in the stem 
  • Lodging of the plant 
  • Decrease in grain filling 
  • Death of the plant 
  • Frass (insect excrement) on the stem.

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Stem Borer

A way to confirm infestation is by cutting the stem of the plant and checking for the presence of the larvae inside. Identifying and treating the infestation as early as possible is essential to prevent significant damage to the crop.

How to recognize stem borer?

Stem Borers lay their eggs in large groups of 15-80 on the upper surface of leaves. Young larvae use silk threads to move to other plants to feed, while mature ones bore into the plant’s sheath and tiller.

Why is stem borer a risk to paddy crops?

The stem borer is a risk to paddy crops because it is a type of insect that feeds on the stem of the plant, which can weaken or kill the plant. A stem borer is a dangerous pest that affects crops during the early stages, reducing crop quality and yield by 20-70%. Rice plants are particularly susceptible to this pest from the early stage to flowering.

It can lead to reduced yield and loss of the entire crop. Additionally, the larvae of the stem borer can tunnel into the stem, which can cause the plant to become hollow and brittle, making it more susceptible to disease and damage from wind and rain. 

Best management tips for the control of paddy stem borer

  1. Use resistant varieties: This is one of the most effective methods for controlling stem borers.
  2. Handpick and destroy egg masses: This should be done at the seedbed and transplanting stages.
  3. Raise the level of irrigation water: This is done periodically to submerge eggs in the lower parts of the plant.
  4. Apply nitrogen fertilizer in a split following the recommended rate and time of application.
  5. Scout fields regularly to detect an early infestation.
  6. Implement an integrated pest management approach combining chemiRice cuRiceal and biological control methods.

It is best to consult with local expRice orRiceicultural extension services to determine the most appropriate approach for a specific location.

Cultural measures for the management of paddy stem borer

  • Crop rotation: Growing non-host crops such as soybeans, groundnuts, and cotton before planting rice can help reduce the population of stem borer pests.
  • Early planting: Planting rice early can help to avoid the peak stem borer infestation period.
  • Remove weeds: Weeds can act as alternate hosts for stem borers, so keeping the field free of weeds is important.
  • Remove egg masses: Before transplanting, remove the egg masses of stem borers from the seedlings and burn them.
  • Field sanitation: Collect and destroy infested tillers, panicles, and straws after harvest to prevent the survival of stem borer larvae and pupae.
  • Selecting early maturity, high tillering varieties suitable for the specific growing season.
  • Applying a mixture of Pseudomonas flourescens/ PGPR consortia, Neem cake, and decomposed farmyard manure to the soil, depending on the pH level.
  • Treating the seeds with Pseudomonas florescens/ PGPR consortia.
  • Removing stem borer egg masses from seedlings before transplanting. 
  • Regularly scouting the field during vulnerable crop growth stages for early detection of pests and diseases.

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Stem Borer Problem in Paddy Farming

Biological control measures for the management of paddy stem borer

Biological control measures for managing paddy stem borer involve using natural predators, parasites, and pathogens to control the pest population. Some commonly used biological control agents include:

  1. Trichogramma wasps: These are small parasitic wasps that lay their eggs inside the eggs of stem borers, killing the developing larvae.
  2. Nephotettix virescens: This type of leafhopper feeds on the eggs and young larvae of stem borers.
  3. Microbial insecticides include viruses, bacteria, and fungi that infect and kill stem borer larvae.
  4. Predators: Birds like the Greater Coucal, Blue-tailed Bee-eater, and White-throated Kingfisher feed on stem borer larvae.
  5. Predators (ladybird beetle, tiger beetle, spider, year wig, microvelia, etc.) and parasitoids are augmented (Telenomus, tetrastichus, etc.).
  6. Trichogramma japonicum must be released thrice weekly beginning 28 days after transplanting, followed by Trichogramma chilonics release at 37, 44, and 51 DAT.

Organic/natural measures for the management of paddy stem borer

  1. Use of resistant varieties: Planting paddy varieties resistant to stem borers can help reduce damage caused by pests.
  2. Biological control: Using natural enemies such as predators, parasites, and pathogens can effectively control stem borer populations.
  3. Cultural practices: Proper field management practices such as timely planting, proper irrigation, and soil fertility management can help reduce stem borer infestation.
  4. Intercropping: Planting other crops alongside the paddy crop can reduce the population of stem borers.
  5. Use of botanical pesticides: Some plants, such as neem, tulsi, and garlic, have been found to have repellent properties against stem borers and can be used as botanical pesticides.

These methods may only be equally effective in some locations. Using the Integrated Pest Management (IPM) approach is also essential for the sustainable control of stem borers.

Chemical control measures for the management of paddy stem borer

To effectively manage paddy stem borer, it is essential to take preventative measures before an infestation occurs. It can include making early transplants, as late transplants are more susceptible to damage. Some commonly used insecticides include carbofuran, chlorpyriphos, and quinolphos. 

  1. Use Basudin 10G/ Furadan 3G/ Diginol 146 at rate of 16.5 kg/ ha.
  2. Use Dimecron/ Bennicron/ Pillarcron 100 SL at 344 mL per acre of land. 
  3. If the number of dying hearts is 5% or more, spray Carbofuron 3G 20 kg or monocrotophos 36 EC, 1.4 liters or cartap hydrochloride 4G, 25 kg or phorate 10G, 10 kg dissolved in 500-700 liters of water to manage this pest. Spray the solution when 3-4 cm of standing water is in the field.

Using an insecticide such as Virtako can provide excellent and long-lasting control over stem borer and promote plant vigor, leading to better quality and higher yield. Different chemical combinations can be used to control stem borers in paddy crops. The first option is a combination of Caldon 2 gm/L and Neemark 1% 1 mL/L, the second option is Coragen 0.33 mL/L and Raccalto Spraywell, and the third option is Jashn 2 mL/L and Active Neem Oil 1 mL/L. 

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Paddy Farming

Granular insecticides like Cover insecticide, 4 kg per acre, can also be applied to control stem borers. It is important to note that before using any of these chemicals, it is essential to read and follow the label instructions and safety precautions provided by the manufacturer. Additionally, it is recommended to use pesticides specific to the target pest that have minimal impact on beneficial insects.

Conclusion

Stem borers are a major pest in paddy farming and can cause significant damage to the crop. They are characterized by their small size, cylindrical shape, and brownish color. The nature of damage caused by stem borers include wilting of plants, discoloration of leaves, and reduction in yield. Symptoms of stem borer infestation include small holes in the stem, sawdust-like frass, and wilted or dead plants.

Effective management of stem borers involves a combination of organic and natural methods. These include crop rotation, the use of resistant varieties, biological control, cultural practices, intercropping, and the use of botanical pesticides. Using an Integrated Pest Management (IPM) approach is essential for the sustainable control of stem borers. By understanding the characteristics, nature of the damage, and symptoms of stem borers, farmers can take proactive measures to prevent infestation and protect their crops from damage.

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