Rose Gram Caterpillar Pest Management: Symptoms, Treatment, Chemical, Biological, and Organic Control

The Rose Gram Caterpillar, Helicoverpa armigera, belonging to the Family Noctuidae of the Order Lepidoptera, is a major agricultural pest that causes significant yield losses and reduces the quality of crops worldwide. This caterpillar pest is native to Africa. It is a destructive pest because it can reproduce and establish large populations quickly, making it difficult to control the pest.

Effective management strategies are essential to minimize the impact of this pest on rose production. To effectively manage this pest, it is necessary to understand its life cycle, its preferred habitats, and the best methods for controlling it. This article will provide an overview and discussion of the Rose Gram Caterpillar Pest in Rose crops, including its symptoms, identification techniques, and control.

Rose Gram Caterpillar Pest Management

Life Cycle of Rose Gram Caterpillar Pest in Rose Crop

The life cycle of the Rose Gram Caterpillar pest has four stages. They are egg, larva, pupa, and adult. The lifecycle of the Rose Gram Caterpillar begins when the female lays eggs singly or in clusters on the underside of the leaves. The eggs hatch in about 2-5 days, and the young larvae emerge to feed on the leaves and flowers of the rose plant. The larvae, commonly known as the rose gram caterpillar, go through five or six instars before pupating.

After the larval stage, the caterpillar enters the pupal stage, forming a cocoon around itself. The pupa is usually brown or gray and is found in a sheltered location, such as under leaves or in soil cracks. The pupal stage lasts 10-14 days, after which the adult moth emerges. The adult moth is short-lived and survives for only a few days, during which it mates and lays eggs, completing the life cycle. The lifecycle of the Rose Gram Caterpillar Pest can be completed in 30 days, depending on environmental conditions, such as temperature and humidity.

Occurrence of Rose Gram Caterpillar Pest in Rose Crop

Location of Rose Gram Caterpillar Pest: This pest infests Rose crops in India, Africa, Sri Lanka, China, Thailand, Vietnam, Indonesia, the United States, Mexico, Brazil, Colombia, Ecuador, the Philippines, and Australia.
Host Range: The Rose Gram Caterpillar pest infects crops like Rose, Cotton, Maize, Tomatoes, Sorghum, Tobacco, Legumes, and Soybeans.

Factors Favoring the Population Increase of Rose Gram Caterpillar Pest in Rose Crop

Temperature: The pest prefers warm and humid environments of 20-30°C for growth and development.
High Humidity: The pest prefers high humidity levels as it helps develop eggs, larvae, and pupae.
Soil: The pest overwinters in the soil as pupae; hence, the soil quality and moisture content helps the pest survive.
Plant Density: High-density plantations can provide shelter and create a favorable microclimate for the pest to thrive and cause infestation.

Identification of Rose Gram Caterpillar Pest in Rose Crop

Egg: The eggs are small, round, and pale green or yellow.
Larva: They are grayish-green or brownish, with longitudinal stripes and spines along their bodies.
Adult: The adult has a wingspan of about 30-40 mm and is brown or gray with a distinct pattern of spots and markings.

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Damage Symptoms of Rose Gram Caterpillar Pest in Rose Crop

The larvae of the pest feed voraciously on the flowers, buds, and leaves of roses, causing extensive damage to the plants.
The larvae feed on the foliage by forcing their head into the bud, leaving the remaining body outside.
The larvae leave behind a slimy trail when they move from one place to another.
The larvae make holes in the petals of the rose flowers reducing their marketability.

Percentage of Yield Loss in Roses Due to Rose Gram Caterpillar Pest

In India, the yield losses due to Rose Gram Caterpillar pests are 20%. In Thailand, the percentage of yield loss is 40-50%. In Vietnam, the losses are 10-20%. In Sri Lanka, the losses are 15%. In Indonesia, the losses are 20%. In Africa, it is 40%. In the United States, it is 5-10%. In Mexico, it is 30%. In Brazil, it is 40%. In China, it is 30%.
In Colombia, the losses are 35%. In Ecuador, it is 20%. In Australia, it is 5-10%. In the Philippines, the yield losses are 50%. The Economic Threshold Level (ETL) for the Rose Gram Caterpillar pest is set at 2-3 larvae per plant.

Cultural Management of Rose Gram Caterpillar Pest in Rose Crop

Trap Crops: Planting crops that are attractive to the pest can help to lure them away from the rose crop.
Mechanical Control: Handpick the caterpillars and the infested leaves manually and destroy or drop them into a bucket of soapy water to kill them.
Sanitation: Removing infected and infested plant parts, debris, and weeds from the field can help reduce the pest population.
Companion Planting: Plant crops like garlic, onion, and chives to repel or deter the pest.

Biological Management of Rose Gram Caterpillar Pest in Rose Crop

Predators: Predators like Ladybird beetles, Lacewings, Assassin bugs, and Spiders feed on the pest’s eggs and larvae.
Parasitoids: Parasitic wasps such as Braconid wasps and Ichneumonid wasps parasitize the larvae of the pest.
Entomopathogenic Fungi: Entomopathogenic fungi, such as Beauveria bassiana and Metarhizium anisopliae, infect and kill the pest.
Virus: Nuclear polyhedrosis virus (NPV) infects and kills the pest’s larvae.

Chemical Management of Rose Gram Caterpillar Pest in Rose Crop

Spray Insecticides on the crops like Carbaryl, Malathion, Chlorpyriphos, Dimethoate, Cypermethrin, Permethrin, Deltamethrin, Imidacloprid, and Thiamethoxam on the foliage to control the pest.
Fumigants: Treat the soil with Methyl Bromide to control the pupae in the ground.

Organic Control of Rose Gram Caterpillar Pest in Rose Crop

Neem oil and Garlic extract disrupt the pest’s nervous system and its ability to feed and reproduce, ultimately killing them.
Spinosad produced by the soil bacterium Saccharopolyspora spinosa should be sprayed on the leaves and stems of the plants to control the pest.
Bacillus thuringiensis-based bio-insecticides produce toxins that can kill the larvae of the pest.
Pyrethrum, obtained from chrysanthemum, contains neurotoxins that paralyze and kill the pest.
Diatomaceous earth damages the exoskeleton of insects, causing them to dehydrate and die.

Preventive Measures for Control of Rose Gram Caterpillar Pest in Rose Crop

Physical Barriers: The barriers like row covers, nettings, and screens can prevent adult moths from laying eggs on the plants.
Pheromone Traps: The use of pheromone traps can help capture adult pests and reduce the population.
Resistant Varieties: Planting healthy, resistant, or tolerant varieties can prevent pest incidence.
Regular Monitoring: Monitor the crops regularly to identify pest infestation in the early stages to keep it under control.
Sticky Traps: Use yellow sticky traps to monitor the pest’s activity and determine the control measures.

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Conclusion

The Rose Gram Caterpillar Pest, Helicoverpa armigera, is a serious pest that affects Rose crops worldwide, causing significant yield losses. An integrated approach that combines multiple pest management strategies can help to manage the pest effectively while minimizing the impact on the environment and human health.

Rose Gram Caterpillar Pest Management: Symptoms, Treatment, Chemical, Biological, and Organic Control

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