Brown planthopper
Encyclopedia
The brown planthopper Nilaparvata lugens (Stål) (Homoptera: Delphacidae), feeds on rice
plants (Oryza sativa L.). BPH are among the most important pests of rice, and rice is the major staple crop for about half the world's population. BPH damage rice directly through feeding and also by transmitting two viruses, rice ragged stunt virus
and rice grassy stunt virus
. Up to 60% yield loss is common in susceptible rice cultivars attacked by BPH.
Distribution:Australia, Bangladesh,Bhuthan, Burma, China, Fiji, India, Indonesia, Japan, Korea, Laos, Malaysia, Nepal, Pakistan, Papua New Guinea, Philippines, Srilanka, Taiwan, Thailand, Vietnam.
host plant other than rice is Leersia hexandra Sw.
Biology:
The brown plant hopper is dimorphic, with fully winged 'macropterous' and truncate-winged 'brachypterous' forms. The macropterous are potentially migrants and are responsible for colonizing new fields.after settling down on the rice plants, they produce the next generation in which most of the female insects develop as brachypters and males as macropters.Adults usually mate on the day of emergence and the female starts laying eggs from the day following mating. Brachypterous females lay 300 to 350 eggs, while macropterous lay less eggs. The eggs are thrust in a straight line generally along the mid-region of the leaf sheath. Eggs hatch in about 6 to 9 days. The newly hatched nymph is cottony white and turns purple brown with in an hour,feeding on plant sap. It undergoes five instars to become an adult. It infests the rice crop at all stages of plant growth. As a result of feeding by both nymphs and adults at the base of the tillers, plants turn yellow and dry up rapidly. At early infestation, round yellow patches appear which soon turn brownish due to the drying up of the plants.This condition is called 'hopper burn'.
Temperature is a critical factor in the life activities of the insect. The hatchability and survival rate are the highest around 25 degree celsius. Eggs are very sensitive to desiccation and soon shrivel when the host plant starts wilting. The population growth of Brown plant hopper is is maximum at a temperature range of 28 to 30 degree celsius.
Excessive use of urea
as nitrogen
ous fertilizer
and insecticides can lead to outbreaks by increasing the fecundity
of the brown planthopper, and by reducing populations of natural enemies. In 2011, the Thai Government announced an initiative to address brown planthoppers that included restricting the use of outbreak-causing insecticides including abamectin
and cypermethrin
- the decision was supported by the International Rice Research Institute
(IRRI). IRRI also outlined recommendations in an action plan to help smartly manage planthopper outbreaks. In December 2011 the IRRI will hold a conference in Vietnam that tackles the threats of insecticide misuse and explores options for mitigation.
Predators of this insect include the spider
s Pardosa pseudoannulata and Araneus inustus. In some cases BPH lay eggs in the rice seed beds (also known as rice nurseries) shortly before transplanting and BPH enter the field in this manner.
Differential mortality of predators and hoppers does not appear to be the primary factor for resurgence. There is evidence that some insecticides 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.
Rice varieties with resistance to BPH 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 plant lectins are antifeedants to BPH.
Rice
Rice is the seed of the monocot plants Oryza sativa or Oryza glaberrima . As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in East Asia, Southeast Asia, South Asia, the Middle East, and the West Indies...
plants (Oryza sativa L.). BPH are among the most important pests of rice, and rice is the major staple crop for about half the world's population. BPH damage rice directly through feeding and also by transmitting two viruses, rice ragged stunt virus
Rice ragged stunt virus
Rice ragged stunt virus is a plant pathogenic virus of the family Reoviridae.Family: ReoviridaeGenus: OryzavirusSpecies: Rice ragged stunt virusAcronym: RRSV...
and rice grassy stunt virus
Rice grassy stunt virus
Rice grassy stunt virus is a plant pathogenic virus transmitted by the brown planthopper , Nilaparvata lugens, and by two other Nilaparvata species, N. bakeri and N. muiri. The virus is found in South and Southeast Asia, China, Japan, and Taiwan. From 1970 to 1977 RGSV incidence was high in...
. Up to 60% yield loss is common in susceptible rice cultivars attacked by BPH.
Distribution:Australia, Bangladesh,Bhuthan, Burma, China, Fiji, India, Indonesia, Japan, Korea, Laos, Malaysia, Nepal, Pakistan, Papua New Guinea, Philippines, Srilanka, Taiwan, Thailand, Vietnam.
host plant other than rice is Leersia hexandra Sw.
Biology:
The brown plant hopper is dimorphic, with fully winged 'macropterous' and truncate-winged 'brachypterous' forms. The macropterous are potentially migrants and are responsible for colonizing new fields.after settling down on the rice plants, they produce the next generation in which most of the female insects develop as brachypters and males as macropters.Adults usually mate on the day of emergence and the female starts laying eggs from the day following mating. Brachypterous females lay 300 to 350 eggs, while macropterous lay less eggs. The eggs are thrust in a straight line generally along the mid-region of the leaf sheath. Eggs hatch in about 6 to 9 days. The newly hatched nymph is cottony white and turns purple brown with in an hour,feeding on plant sap. It undergoes five instars to become an adult. It infests the rice crop at all stages of plant growth. As a result of feeding by both nymphs and adults at the base of the tillers, plants turn yellow and dry up rapidly. At early infestation, round yellow patches appear which soon turn brownish due to the drying up of the plants.This condition is called 'hopper burn'.
Temperature is a critical factor in the life activities of the insect. The hatchability and survival rate are the highest around 25 degree celsius. Eggs are very sensitive to desiccation and soon shrivel when the host plant starts wilting. The population growth of Brown plant hopper is is maximum at a temperature range of 28 to 30 degree celsius.
Excessive use of urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....
as nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
ous fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
and insecticides can lead to outbreaks by increasing the fecundity
Fecundity
Fecundity, derived from the word fecund, generally refers to the ability to reproduce. In demography, fecundity is the potential reproductive capacity of an individual or population. In biology, the definition is more equivalent to fertility, or the actual reproductive rate of an organism or...
of the brown planthopper, and by reducing populations of natural enemies. In 2011, the Thai Government announced an initiative to address brown planthoppers that included restricting the use of outbreak-causing insecticides including abamectin
Abamectin
Abamectin is a widely used insecticide and anthelmintic.-Chemistry:Abamectin is a mixture of avermectins containing more than 80% avermectin B1a and less than 20% avermectin B1b. These two components, B1a and B1b have very similar biological and toxicological properties...
and cypermethrin
Cypermethrin
Cypermethrin is a synthetic pyrethroid used as an insecticide in large-scale commercial agricultural applications as well as in consumer products for domestic purposes. It behaves as a fast-acting neurotoxin in insects. It is easily degraded on soil and plants but can be effective for weeks when...
- the decision was supported by the International Rice Research Institute
International Rice Research Institute
The International Rice Research Institute is an international NGO. Its headquarters are in Los Baños, Laguna, Philippines, and it has offices in sixteen countries...
(IRRI). IRRI also outlined recommendations in an action plan to help smartly manage planthopper outbreaks. In December 2011 the IRRI will hold a conference in Vietnam that tackles the threats of insecticide misuse and explores options for mitigation.
Predators of this insect include the spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
s Pardosa pseudoannulata and Araneus inustus. In some cases BPH lay eggs in the rice seed beds (also known as rice nurseries) shortly before transplanting and BPH enter the field in this manner.
Differential mortality of predators and hoppers does not appear to be the primary factor for resurgence. There is evidence that some insecticides 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.
Rice varieties with resistance to BPH 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 plant lectins are antifeedants to BPH.