Domain:                Eukaryota
Kingdom:             Animalia
Phylum:                Arthropoda
Class:                   Insecta
Order:                   Hemiptera
Suborder:             Auchenorrhyncha
Family:                  Delphacidae
Subfamily:            Delphacinae
Genus:                   Nilaparvata
Species:                N. lugens
Binomial Name:   Nilaparvata lugens (Stål, 1854)

The BPH is distributed throughout Australia, Bangladesh, Bhutan, Burma (Myanmar), Cambodia, China, Fiji, India, [1] Indonesia, Japan, North and South Korea, Laos, Malaysia, India, Nepal, Pakistan, Papua New Guinea, Philippines, Sri Lanka, Taiwan, Thailand, and Vietnam.

পোষক পরিসীমা
Rice and wild grasses. Their alternative host plant other than rice is Leersia hexandra.

ডিমঃ Eggs are laid in a group of 2 to 12 in leaf sheath (near the plant base or in the ventral midribs of leaf blades). White, transparent, slender cylindrical and curved eggs are thrust in straight-line in two rows. (They are covered with a dome – shaped egg plug secreted by the female. Only the tips protrude from the plant surface).

Nymph: Freshly hatched nymph is cottony white, 0.6 mm long and it turns purple-brown, 3.0 mm long in the fifth instar.

প্রাপ্তবয়স্কঃ Adult hopper is 4.5-5.0 mm long and has a yellowish brown to dark brown body. The wings are sub hyaline with a dull yellowish tint. It has two characteristic wing morphs: macropterous (long winged) and brachypterous (short winged).

[NO INFORMATION AVAILABLE]

The brown planthopper is dimorphic, with fully winged ‘macropterous’ and truncate-winged ‘brachypterous’ forms. The macropterous forms are potentially migrants and are responsible for colonizing new fields. After settling on rice plants, they produce the next generation, where most of the female insects develop as brachypters and males as macropters. Adults usually mate on the day of emergence, and the females start laying eggs from the day following mating. Brachypterous females lay 300 to 350 eggs, whereas macropterous females lay fewer eggs. The eggs are thrust in a straight line generally along the mid-region of the leaf sheath. Eggs hatch in about six to nine days. The newly hatched nymphs are cottony white, and turn purple brown within an hour. They feed on plant sap. They pass through five instars before becoming adults.

Symptoms depend on variety, number of planthoppers, and plant age: all these affect the number of tillers and panicles that develop, plant height, the amount of unfilled grains, and injury from feeding and egg laying, which allows entry by fungi and bacteria, as well as blackening of stems by sooty moulds. Severe infestations cause plants in the ‘milk’ or ‘dough’ stages to gradually yellow from the tip, brown, dry out and collapse – a wilt, known as ‘hopperburn’. The most susceptible time is from tillering to flowering. Hopperburn is more common in paddy than dryland rice.

Eggs are laid in the midrib of the leaf blades, 4-10 in an egg mass; they are cylindrical, slightly curved, 1 mm long, white at first, darker when about to hatch, with two spots – the eyes of the nymph. The eggs hatch in 4-8 days. Nymphs are creamy white with a pale brown tinge, later becoming dark brown. There are four to five moults. The final nymphs are nearly 3 mm long, with a line from the top of the head to the middle of the body where it is widest. Adults are brownish black with a yellowish-brown body. There are two forms, long winged and short winged.

Infestations start with the arrival of the winged form, which lays eggs and produces the wingless form. Winged forms develop when numbers are high; females are about 4 mm and males 4.5 mm; wingless forms are smaller. After harvest, the planthoppers migrate to grasses, or spread to new crops of rice. Brown planthoppers live for up to 20 days.

BPH infest the rice crop at all stages of plant growth. Due to feeding by both the nymphs and adults at the base of the tillers, plants turn yellow and dry up rapidly. During the early infestation stage, round yellow patches appear, which soon become brownish due to the drying up of the plants. This condition is called ‘Hopper burn’. Temperature is a critical factor that affects the life activities of this insect. The hatchability and survival rate are the highest around 25 °C. The eggs are highly sensitive to desiccation and soon shrivel when the host plant starts wilting. BPH population growth is maximal in a temperature range from 28 to 30 °C.

Nymphs, winged and/or wingless adults appear at the base of the plants, where it is shady and humidity is high. A “sooty mould fungi” appears that often accompany large numbers of the insects. More than 3-5 insects per tiller is considered high, needing more intensive observation and possibly insecticide treatment.

Common symptoms include:
Both the nymphs and adults remain at the ground level and suck the plant sap.
It is a typical vascular feeder primarily sucking phloem sap leading to hopper burn.
At early infestation, circular yellow patches appear which soon turn brownish due to the drying up of the plants.
The patches of infestation then may spread out and cover the entire field.
The grain setting is also affected to a great extent. During sustained feeding, it excretes large amounts of honeydew.

Both adults and nymphs do the damage. They have piercing mouthparts that they insert into the leaf blades and leaf sheaths of rice plants to suck the sap. Also, egg laying blocks the water and food channels inside the plant. Large numbers of planthoppers cause hopperburn.

IRRI estimates that farmers lose nearly 40% of their rice crops to pests, and brown plant hoppers are one of the most serious.

Common symptoms include:
Hopperburn or yellowing, browning and drying of plants.
Circular patches of drying and lodging of matured plants.
Nymphs and adults congregate at the base of the plant above the water level.
Affected plant dries up and gives a scorched appearance called “hopper burn”.
It is a vector of grassy stunt, ragged stunt and wilted stunt diseases.
Hopper burn caused by the planthoppers is distinguished from other hopper burn symptoms by the presence of visible sooty molds at the bases of the rice plant. Virus infected plants may also be found.

[NO INFORMATION AVAILABLE]

Excessive use of urea as nitrogenous fertilizer and insecticides can lead to outbreaks by increasing the fecundity of the brown planthopper, and by reducing populations of natural enemies. It follows that the primary integrated pest management (IPM) approach includes restricting the inappropriate and excessive use of these inputs. For example in 2011, the Thai government announced an initiative to respond to a major brown planthoppers outbreak by restricting outbreak-causing insecticides including abamectin and cypermethrin; the decision was supported by the International Rice Research Institute (IRRI). IRRI also outlined recommendations for an Integrated Pest Management (IPM) action plan to limit planthopper outbreaks. In December 2011, the IRRI held a conference in Vietnam to address the threats of insecticide misuse and explore options for mitigation.
Rice varieties with resistance to BPH, e.g. IR64, are important for preventing outbreaks. However, in areas with low insecticide use, high levels of BPH resistance are not usually necessary. Chemical mutagenesis can significantly increase or decrease BPH resistance levels of rice. Some chemical insecticides, e.g. imidacloprid, can affect the gene expression of rice and thereby increase susceptibility to BPH.

In an attempt to make BPH control more species-specific, researchers are trying to develop methods of turning off specific BPH genes for digestion-, defense- and xenobiotic metabolism. Many novel genes for these functions have been detected in tissue from BPH intestines. In a study it has been found that water management impacts the physiology of BPH, which may be useful in understanding the relationship between drought stress and this damaging herbivore [6].

Some plant lectins are antifeedants to BPH and if properly formulated may have the potential to protect rice from BPH

Before planting:
Choose varieties that have tolerance to the brown plant hopper.
Avoid staggered planting, preventing planthoppers moving from older to younger crops in ever greater numbers. Plant at the same time as neighbours, within a period of 2-3 weeks.
Remove volunteer plants.
Rotate rice with other crops. Do not plant rice crops one after another so that large populations of the brown planthopper can migrate easily between them.

During growth:
Drain the paddies for 3-4 days during the early stage of infestation.
Apply split applications (three times) of nitrogen fertilizer, not all at one time.
Allow plants (weeds) on the bunds (and at the borders of dryland crops), and between fields, to flower in order to attract natural enemies.

After harvest:
Do not ratoon the crop, i.e., do not allow it to resprout and continue growing after harvest.
Plough the field after harvest, removing the stubble that would otherwise allow the brown planthoppers to continue to breed.

In a nutshell:
Avoid close planting and provide 30 cm rogue spacing at every 2.5 to 3.0 m to reduce the pest incidence.
Use resistant varieties like PY 3, CO 42, ADT 35, ADT 37, PTB 33 and PTB 21, Aruna, Kanaka, Karthika, Krishnaveni, Makon, Abhey, Asha, Divya.
There are varieties released by IRRI, which contain genes for Brown plant hopper resistance, like IR26, IR64, IR36, IR56, and IR72.
Synchronous planting within 3 weeks of staggering and maintaining a free-rice period could also decrease the build-up of Brown plant hopper.
Nitrogen application can be split to reduce Brown plant hopper buildup.
Draining the rice field for 3-4 days is recommended during the early stage of infestation.

Predators of this insect include the spiders Pardosa pseudoannulata and Araneus inustus. In some cases, BPHs lay eggs in the rice seed beds (also known as rice nurseries) shortly before transplanting, so enter the field in this manner.
Differential mortality of predators and hoppers does not appear to be the primary factor for insecticide-induced resurgence. Some insecticides evidently increase the protein content of BPH male accessory glands, and thereby increase planthopper fecundity. Some insecticides increase the amount of amino acids and sucrose available in the phloem of rice plants, and thereby increase BPH survival.
There are a number of natural predators of the brown planthopper: spiders eat the nymphs and adults, as do Coccinellid beetles (ladybird beetles), dragonflies, damselflies, and mirid egg-sucking bugs. There are two species of egg-sucking bugs in the Pacific islands – Cyrtorhinus chinensis and Cyrtorhinus lividipennis – and there are likely to be wasp parasitoids that attack eggs, as well as fungal pathogens and mites.

In a nutshell:
Release of natural enemies like Lycosa pseudoannulata, Cyrtorhinus lividipennis adult (200 – 250 bugs/ha) during the peak incidence of brown plant hopper at 10 days interval.
The common parasites of the eggs are the hymenopteran wasps. Eggs are preyed upon by mirid bugs and phytoseiid mites. Both eggs and nymphs are preyed upon by mirid bugs. Nymphs and adults are eaten by general predators, particularly spiders and coccinellid beetles.
Hydrophilid and Dytiscid beetles, dragonflies, damselflies, and bugs such as nepid, microveliid, and mesoveliid eat adults and nymphs that fall onto the water surface.
Fungal pathogens also infect brown plant hoppers.

RESISTANT VARIETIES:
Many varieties have been bred for resistance to brown planthoppers; unfortunately, there are many instances where changes occur in the planthoppers allowing them to overcome the resistance. Six red rice genotypes, namely Mata Meher, Manipuri Black, Hermonona, Sonahanan, Bavdi, and Bacharya Khuta fall under the highly resistant category, and can be utilized as valuable sources of resistance in breeding programs [8].

Insecticides should only be used when planthopper populations are likely to reach an economic injury level; otherwise natural enemies will be destroyed and planthopper populations will return greater than before. The systemic insecticide, acephate (Orthene), has been used for many years against the brown planthopper in Solomon Islands. Check for current recommendations from government agriculture extension personnel, as well as the timing and method of application.

Overuse of insecticides is the main cause of outbreaks of brown planthoppers. When insecticides are used, predators and parasites are killed, and brown planthopper populations ‘resurge’, i.e., the numbers after spraying are higher than before; this is because there are no natural enemies. Integrated Pest Management – IPM – programs stress the need to maintain biological control of natural enemies, and also include tolerant varieties. The routine use of broad-spectrum insecticides should always be avoided. It has been found in a study that Cycloxaprid could be an effective alternative insecticide for the management of N. lugens, which is urgently needed to prevent or delay further increases in insecticide resistance in N. lugens [7].

In a nutshell:
ETL : 2 / tiller when 1 spider / hill is present (or) 1 / tiller when spiders are not present (or) 1 hopper/ tiller in the absence of predatory spider and 2 hoppers /tiller when spider is present at 1/hill.
Drain the water before use of insecticides and direct the spray towards the base of the plants.
Avoid use of insecticides causing resurgence such as synthetic pyrethroids, methyl parathuion, fenthion and quinalphos.

Spray any one of the following:
Phosphamidon 40 SL 1000 ml/ha (or) Phosalone 35 EC 1500 ml/ha (or) Carbaryl 10 D 25 kg/ha (or) Methyl demeton 25 EC 1000 ml/ha (or) Acephate 75 SP 625 gm/ha (or) Chlorpyriphos 20 EC 1250 ml/ha Carbofuran 3 G 17.5 kg/ha (or) Dichlorvos 76 WSC 350 ml/ ha.
Use of botanical methods : Neem oil 3% 15 lit/ha (or) Iluppai oil 6% 30 lit/ha (or) Neem seed kernel extract 5% 25 kg/ha

তথ্য পাওয়া যায়নি।

তথ্য পাওয়া যায়নি।

https://www.sciencedirect.com/science/article/abs/pii/S0965174822001758

https://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-022-08846-5

https://pubmed.ncbi.nlm.nih.gov/29272461/

https://pubmed.ncbi.nlm.nih.gov/34442311/

https://pubs.acs.org/doi/10.1021/acs.jafc.1c05487

https://www.frontiersin.org/articles/10.3389/fphys.2023.1213654/full#:~:text=10.3389%2Ffphys.2023.1213654-,Roles%20of%20GFAT%20and%20PFK%20genes%20in,of%20brown%20planthopper%2C%20Nilaparvata%20lugens&text=Glutamine%3Afructose%2D6%2Dphosphate

https://pubmed.ncbi.nlm.nih.gov/35362159/

https://pubs.acs.org/doi/10.1021/acs.jafc.1c05487

https://pubmed.ncbi.nlm.nih.gov/36353600/

https://pubmed.ncbi.nlm.nih.gov/34923699/

https://pubmed.ncbi.nlm.nih.gov/33838707/

https://www.sciencedirect.com/science/article/abs/pii/S0965174822001758

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9318313/#:~:text=The%20results%20showed%20that%20LF,BPH%20but%20not%20to%20LF.

https://www.mdpi.com/14220067/23/14/7808

https://www.sciencedirect.com/science/article/abs/pii/S0048357520300377

https://pubmed.ncbi.nlm.nih.gov/35278009/

https://academic.oup.com/ee/article/50/1/1/5987376

https://pubmed.ncbi.nlm.nih.gov/33838707/

https://link.springer.com/article/10.1007/s13205-022-03337-6

https://en.wikipedia.org/wiki/Brown_planthopper

https://apps.lucidcentral.org/pppw_v10/text/web_full/entities/rice_brown_planthopper_064.htm

http://www.agritech.tnau.ac.in/expert_system/paddy/cppests_BPH.html

https://plantwiseplusknowledgebank.org/doi/10.1079/PWKB.Species.36301

http://www.agritech.tnau.ac.in/expert_system/paddy/cppests_BPH.html

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9028574/#:~:text=Water%20content%2C%20osmotic%20pressure%20of,fed%20on%20drought%2Dstressed%20rice.

https://academic.oup.com/jee/article-abstract/111/5/2359/5063815?redirectedFrom=fulltext

https://pubmed.ncbi.nlm.nih.gov/37504637/