krishireview
२०७८ भदौ ९ , बुधबार १०:०८ मा प्रकाशित | ९२० पटक पढिएको
Introduction:
There are 5 main types of rice hopper in the world and this rice hopper is known as the main important rice insect in Asia and Australia.
Planthopper comes under family DELPHACIDAE and leafhopper comes under family CICADELLIDAE are the main insect which infects the rice plant.
Among the planthoppers (brown planthoppers, Nilaparvata lugens), (small brown plant hoppers, Laodelphax striatellus) and (white back planthopper, Sogetella furcufera) are included.
Among the leaf hoppers (Green paddy leaf hopper, Nephotettix virescens), and rice green leafhopper, Nephotettix cincticeps) are included.
Types of damages:
Hoppers are also known as soaking insects.
Adult and nymphs of hoppers damage the plant by soaking liquid sap from the base of the rice plant to the upper parts of rice and rice does not grow well.
Generally, after the adult female leafhopper lays egg hatched into nymphs, they start attacking upper plant parts like new leaves, stem, apical buds, etc.
But the plant hoppers attack the lower part i.e. toward the base of the plant-like leaves and stems.
Damaged plants by the hoppers look like fire burn, dried and brown colored. And this type of damage is called Hopper Burn.
Source:irri.org
Hoppers damage the plant by directly soaking and by indirectly transmitting the virus-like green leafhoppers transmitted rice tungro virus and brown planthoppers transmit the Grassy stunt virus.
Damage of plants by These types of hoppers, the lower surface of plant leaves become yellow.
Source:irri.org
The plant will be dried and die.
Tillers won’t be formed and the plant becomes a stunt.
Just above the water level in the field of stem region and in leaf black fungus occur.
Tiller no becomes low
immature leaves look scattered.
Source:irri.org
Fig: damages of hoppers insects
Life Cycle:
lifecycle of hopper insect complete in three stages (egg, nymph, adult)
for completing one full life cycle about 42-53 days are required.
The baby of the hopper insect in English is called a nymph
Fig: Life Cycle of Rice Hopper
Egg:
One adult female hopper insect lays generally 200-300 eggs on the lower surface of the leaf in the cluster form.
At the start eggs are white color later some time they will turn into black color which is covered by white things.
Generally, 6-9 days are required to prepare the egg at the given temperature of 20 degrees Celsius.
Fig: Eggs of hoppers in clusters
Nymph:
Recently hatched nymphs are in cotton white color and later according to types of hopper color change into brown, green, etc.
The Head of the nymph is triangular in shape and the upper part is a little small.
In this stage, this insect molds 5 times and to reach the adult stage insect requires 10-18 days from nymph stage which depends upon the availability of food and environment.
One perfect mature nymph have about 2.99 mm long body
Fig: Nymph of rice hopper
Adult:
Green leaf hoppers
Adults males have black spots in the middle and last portion of the first wing but not in females.
Color of these insects is green but the last portion of the wing has a black spot and the wings look inclined.
The body of adults is 3-5 mm long.
Fig: adult of green rice hopper
3.2 Brown hopper
The body of adult brown hoppers is brown in color and the body of these hoppers is 2.5-3.4 mm long.
Both male and female hoppers have front and hind wings large and small.
The middle back part of an adult has 3 brown lines and wings have blurred nerves, and eyes are red or yellow in color.
Fig: adult of brown rice hopper
3.3 White back hopper:
The upper body surfaces of these hoppers are black in color.
Adults have 3.5-4 mm long bodies and have a narrow face.
Wings are transparent and the wings have black nerves and the front wing has a black color.
Generally, the lifetime of a hopper insect is 25-26 days but is altered according to time, environment. If it gets a suitable environment it will live up to 46 days.
Fig: adult of white back rice hopper
Management:
These insects are soaking in nature and they will cause large damages in the field if we don’t manage it. These insects transmit the disease and virus by plant sap in the process of soaking.
Cultural methods:
Choose perfectly suitable land for rice cultivation. Infestation of hoppers insects is lower in early transplanted than late transplanted and early matured than late matured.
The density of plants per hill should be reduced. During the transplanting of rice, seedlings don’t transplant more than 2-3 seedlings per hill.
Use and apply the nitrogen fertilizer in the best and perfect way like in the recommended dose and split application.
Weeding and sanitation should be done from time to time and destroy the alternative host of hoppers.
Source: JICA
The water of the rice field should be increase, decrease and dry in the interval of 3-4 day
Source: MDPI and IRRI
Should use the light trap.
Source: IJPAB
2. Chemical Method:
Acephate 75% SP 2 mm per liter of water
Source: Indiamart
Buprophezin 25% SC 1.5 mm per litre of water
Source: Indiamart
Fipronil 5% SG 2-3 mm per liter of water
Source: Indiamart
Imidacloprid 17.8 SL 1 mm per 4 liters of water
Source: Amazon
Carbosulfan 25% EC 1 mm per liter of water
Source: indiamart
Azadiractin 0.03 % EC 2 mm per liter of water and spray 3 times per week, during spraying the insecticide, should spray from the upper part of rice to the lower part of the rice plant.
Note: during spraying the insecticide we must wear a safety dress and follow the instructions given in insecticide.
3.Biological Method:
In this method, different friendly insects help to control the hoppers by feeding them. Some are given in below
Female aphids
fig; female aphids
Green mirid bug
fig;green mirid bug
3.Carabidae-Ground Beetle
fig; ground Beetle
(Manoj shrestha is the undergraduate student of agriculture studying currently at fourth semester of Agriculture and Forestry Universityy at Rampur ,Chitawan)
