Rice Hispa

Table of content

Introduction of the Insect
Classification
Distribution and Status
Identification
Problems with Identical signs
Habit and Habitat
Life cycle (Bionomics)
Damage
Common signs and symptoms of infestation
Symptoms of damage
Why is it important?
Management
Cultural practices
Biological control
Chemical treatment
Restrictions
Genome sequences
Published research.
References

Introduction of the Insect

Dicladispa armigera is a species of leaf beetle from Southeast Asia, often known by its common name: the “rice hispa”. These beetles are a well known invasive pest, and are responsible for significant crop damage across many countries.

English name Rice Hispa

Bangla name পামরি পোকা

Scientific name Dicladispa armigera

Classification

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Infraorder: Cucujiformia
Family: Chrysomelidae
Subfamily: Cassidinae
Genus: Dicladispa
Species: D. armigera

Distribution and Status

Rice hispa is found in various rice-producing regions, particularly in Asia. It is reported in countries such as India, Bangladesh, Myanmar, Thailand, Vietnam, and parts of China.

Host Range

The larvae and adults of rice hispa feed on rice leaves, causing characteristic damage, including pinholes and elongated lesions. The presence of grassy weeds in and near rice fields as alternate hosts harbor and encourage the pest to develop. Heavily fertilized field also encourages the damage.

Identification

Egg: Eggs are laid inside minute slits on the tender leaves generally toward the tip.

Crub: The grub is whitish yellow and flattened. It feeds inside the leaf tissue by mining. It pupates inside.

Adult: The adult beetle is somewhat square shaped about 1/6 to 1/8” in length and width. Dark blue or blackish in colour with spines all over the body.

Problems with Identical signs

No information found

Habit and Habitat

D. armigera is commonly found in the rice habitat. It may also be found on transitory hosts, and in other habitats including irrigation channels, river and canal banks, swamp, wetland, fallowland and grassland in the rice ecosystem and nearby areas.

Life cycle (Bionomics)

No information found

Damage

Direct seeding which result in close spacing causes greater leaf densities that favour the build-up of the rice hispa. The presence of grassy weeds in and near rice fields act as alternate hosts also harbour and encourage the pest to develop. A heavily fertilized field also encourages the damage. Heavy rains, especially in pre-monsoon or early monsoon periods, followed by abnormally low precipitation, minimum day-night temperature differentials for a number of days, and high humidity are favourable for the insect’s population built up.

Common signs and symptoms of infestation

The female rice hispa lays single eggs towards the tip on the ventral surface of rice leaves. The hatched yellow larvae immediately burrow into the leaf tissues, tunnelling and scraping the upper surface of leaf blades, leaving only the lower epidermis as white streaks parallel to the midrib. Translucent white patches that are parallel to the leaf veins form. When severely attacked, the leaves turn yellow and wither, resulting in damaged leaves. Growth may be greatly delayed.

Symptoms of damage

Adults feed on chlorophyll by scraping and causing white parallel streaks.
Grubs tunnel through leaf tissues and make blisters near leaf tips.
Whitish and membranous leaves. .
Scraping of the upper surface of the leaf blade leaving only the lower epidermis as white streaks parallel to the midrib
Irregular translucent white patches that are parallel to the leaf veins caused by tunneling of larvae through leaf tissue causes
Withering of damaged leaves.

Why is it important?

The insect pest is a problem particularly in Bangladesh. Records show that it can infest large areas and causes yield losses of up to 20%.

Management

ETL: 2 adults /hill
Avoid over-fertilizing the rice field. In situations of high hispa incidence, top-dressing of nitrogen fertilizer may be skipped.
Sustained collection of adults by sweep net and destruction.
Spray/broadcast/dust any one of the following insecticides per acre based on ETL: carbofuran 3% CG 10 kg; emamectin benzoate 1.9 EC 170 ml; malathion 5 DP 10 kg; malathion 50 EC 460 ml.

Cultural practices

A cultural control method that is recommended for the rice hispa is to avoid over fertilizing the field. Close plant spacing results in greater leaf densities that can tolerate higher hispa numbers. To prevent egg laying of the pests, the shoot tips can be cut. Clipping and burying shoots in the mud can reduce grub populations by 75−92%.

Biological control

Among the biological control agents, there are small wasps that attack the eggs and larvae. A reduviid bug eats upon the adults. There are three fungal pathogens that attack the adults.

Chemical treatment

All the emulsion sprays tested gave good results, but fenitrothion at 0.5 kg/ha was superior to diazinon, malathion and phosphamidon at 1.125, 1.425 and 0.688 kg/ha, respectively. All the dust treatments were effective, the best results being obtained with HCH at 0.75 kg/ha. Granular formulations of carbofuran and cartap (applied to give 1.125 and 1.25 kg/ha, respectively) were effective but slow acting in the period between 10 and 30 days after application. A granular formulation of diazinon was not effective.

Restrictions

No information found

Genome sequences

No information found

Published research

https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.27270

https://mausamjournal.imd.gov.in/index.php/MAUSAM/article/view/1365

https://www.sciencedirect.com/science/article/abs/pii/S0168169922006494

https://scialert.net/abstract/amp.php?doi=jbs.2002.5.7

https://arccjournals.com/journal/indian-journal-of-agricultural-research/A-4064

https://www.researchgate.net/publication/297547503_Seasonal_and_host-correlated_variation_in_the_susceptibility_of_rice_hispa_to_Beauveria_bassiana_in_the_field

https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.27270