Paddy Pests and their Management by agrifunda


Hi friends. Welcome to agrifunda. today post on Pests of Cereals and their Management. In this post we will understand pests of paddy and their management. Paddy is a major cereal crop in India. The crop is prone to attacks by a number of insect as well as non-insect pests. So far more than 100 pest species have been recorded on this crop, of which some of them are causing serious damage or economic damage. Some of the major pests on paddy includes yellow stem borer, brown plant hopper, white backed plant hopper, leaf folder, gall midges, gundi bugs, and non-insect pest like panicle mite.

Paddy Pests and their Management by agrifunda


Paddy Pests and their Management 


We will understand each pest in detail, particularly host range, adult identification character, nature of damage, damaging symptoms and management aspects. So we will start with paddy yellow stem borer. Scientific name is scirpophaga incertulas. It belongs to family Crambidae of the order Lepidoptera. It’s a monophagous pest. Female having black spot on each of the forewing. It also possess tuft of hairs at the tip of the abdomen. Then coming to life cycle. It has 4 life stages. Egg, larva, pupa and adult. Adult female lays eggs in groups on the leaves towards the leaf tip. These eggs are covered with brownish hairs. Larva; early instar, creamy white in color. Later it turns to pale yellow. Hence the name yellow stem borer. Pupation occurs inside the stem or the base. It takes 44 to 59 days to complete a single generation.


Nature of damage



Then coming to nature of damage. Larva is the damaging stage. It feeds on internal content of the stem, thereby it affects the supply of nutrients to the growing point. Causing death of the central shoot; commonly called ‘Dead Heart’. This dead heart symptom is noticed when the crop is at the vegetative stage. At reproductive stage ‘White Ear’ is produced. If we pull out the dead heart and white ear, it comes out very easily. So ultimately yield gets reduced.

Then coming to management. Before taking up any management practices, we should know the ETL of the pest. 5 to 10% dead heart at vegetative stage. 2% white ear at reproductive stage. Or 2 egg masses per meter square, or one moth per meter square area. Some of the management practices includes set-up of sex pheromone traps @ 2 to 3 traps per acre for monitoring the pest activity. As a preventive measure set up the light traps to attract the adult females and destroy them. Because females are more attracted to light than male. Other preventive measures are clipping of seedlings, before transplanting. This is to prevent the carrying of eggs from nursery to the main field. Few varieties are available, which are location specific.


curative measures



Then coming to curative measures. Collection and destruction of affected plant parts especially dead hearts and white ears along with larvae. Then collect the egg masses, since it lays eggs in masses and destroy them. Then release egg parasitoid, that is the trichogramma japonicum @ 40,000 per acre. Release 2 to 3 times, starting from 15 days after transplanting. Lastly spray any one of the insecticides at recommended dose.

Then another major pest on paddy is brown plant hopper. That is the Nilaparvata Lugens. It belongs to the family Delphicidae of the order Hemiptera. It causes 10 to 17% yield loss. Sometimes it appears in severe form or outbreak form. Causes cent percent yield loss. In addition to paddy it also attacks other graminaceous plants. Adult is small active brown colored hopper. Body is wedge shaped with flat movable spur on epical horizon of antibia. It occurs in two forms. One is Macropterous form. Another one is Brachypterous form. So here macropterous forms are strong fliers. While brachypterous forms




are weak fliers, because their wings are highly reduced or short. But they lay more number of eggs. In BPH biotypes are present. In Asia 4 or 5 biotypes are present. But in India single population is present throughout the country.


life cycle



Then coming to life cycle. It has three life stages. Egg stage, nymph stage and adult stage. So here adult female insert eggs into the tissues of their midribs, particularly on sides. Eggs are elongated almost banana shaped with white tips. Nymphs looks like adult, except size, development of wings and genitalia. It takes 20 to 24 days to complete a single generation.


Then coming to life cycle. Nymphs and adults are the damaging stage. They congregate at the base of the plant; particularly at stem, just above the water level, and they suck the sap from the phloem. While sucking the sap they inject toxic saliva causing ‘hopper burn’ symptom in circular patches. In addition to direct damage, indirectly it acts as a vector in transmission of grassy stunt virus disease.

Then another major pest on paddy is white backed plant hopper. That is sogetella furcifera. It belongs to the family Delphacidae of the order Hemiptera. Earlier it was considered a minor pest on paddy. Now it appearing in severe form, especially in southern India. It occurs along with the brown plant hopper. Adult is a small active, creamy white colored, wedge shaped body with flat movable spur on apical region of antibia. So here biology and damage symptoms almost similar to brown plant hopper, except damaging symptoms. Due to feeding it produces ‘hopper burn’ symptoms in irregular patches. Coming to ETL, 5 to 10 hoppers per hill.

Then management as a preventive measures. Go for alley cropping. That is skipping of one row for every 8 to 10 rows or avoid closer planting. Closer planting favors the multiplication of the pest. Use resistant varieties. Then do not use excess nitrogenous fertilizers. Go for alternative wetting and drying of fields to avoid water stagnation. So here water stagnation increases the incidence of the pest. Then other preventive measures are conserve natural enemies, particularly predators like spiders and mirid bugs. And lastly do not apply insecticide, which are causing resurgence of the pest, particularly methyl parathion and pyrathroids.


Then coming to curative measures. Herding or droving of ducks through paddy field, which is practiced in some parts of India. Then spray fungal pathogen like Metarhizium anisopliae. As a last option, you can spray any one of the insecticide at recommended dose.

Then another major pest on paddy is paddy leaf folder. That is Cnaphalocrosis medinalis. It belongs to the family Crambidae of the order Lepidoptera. Earlier it was considered as a minor pest on paddy. After introduction of high yielding varieties with broad leaves, it becomes serious. In addition to paddy it also attacks other cereals. Even it attacks commercial crops like sugarcane. Adult is small moth with 2 distinct wavy dark lines on the front wing. And a single dark wavy line on the hind wing.

Then coming to nature of damage. Larva is the damaging stage. It folds the leaf margin together with its saliva and feeds by scraping chlorophyll content of the leaves. Thereby it is causing white patches on dorsal region of folded leaf. Later this white patch turns to brown color. Under severe infestation plant appears a broomstick. ETL, 2 freshly damaged leaves per hill or 5% damage to leaves at vegetative stage. 10% damage to leaves at leaf boot stage.

Then coming to management. As a monitoring setup light traps @ 1 trap per acre. Then as a preventive measures, avoid excess use of nitrogenous fertilizers and apply ‘K’ fertilizer at higher dose. Then as a curative measure inundative release of egg parasitoid, that is the trichogramma chilonis @ 50,000 hectares per week. Release 5 to 6 times during the cropping period. Then spray anyone of the bio-



pesticides either Metarhizium rileyi or B.t products or NSK at 5% or you can use commercial product azadarachtin @ of 2 ml per liter of water. As a last option spray newer insecticide molecule like flubendiamide @ 0.25 gl per liter of water or indaxocarb @ 0.5 ml per liter of water.

Then another major pest on paddy is gall midge. That is Orseolia oryzae. It belongs to family Cecidomyiidae of the order Diptera. This pest is very common in coastal region. It occurs in the nursery as well as in the main field. Earlier it was recorded on lowland rice. But now it is appearing in upland rice also. Late planted rice suffers most damage. Usually it causes 50% yield loss. Adult looks like mosquito with long legs. Antennae is only from body’s bright side or yellowish brown in color. Adult female lays eggs on levels of the leaf blade. And on hatching maggots feeds on apical bud by lacerating the tissues of the tissues. While lacerating the tissues, the first instar maggot release a chemical called Cecidgen, which is responsible for formation of gall.

So here gall is in the form of silver shoot or Anekombu or onion shoot. Then coming to ETL. One gall per hill or 5% affected tillers or 5% gall. As a preventive measure avoid late planting. Use resistant varieties. Few resistant varieties are available, again which are location specific. As a curative measure, spray anyone of the insecticides at recommended dose.

Then gundhi bugs. Here 2 species of gundhi bugs are commonly occurring on paddy. So one is Leptocorisa acuta , another one is Leptocorisa oratorius. Both are belongs to family Alydidae of the order Hemiptera. Like gall midges, they are common in coastal region. They prefer to attack the milky stage of the crop. Here adults are greenish brown in color dorsally. Ventrally green in color. Nymphs and adults are the damaging stage. They suck the juice from the milky grains, resulted in formation of brown patch on the seeds. Further individual grains are seeds become brown and discolored, even shriveled. So such grains are unfit for marketing or consumption purpose.

ETL, 2 to 3 bugs per hill. Management, as a preventive measure, go for synchronized sowing. As a curative measure spray melathion 50 ec @ 2ml per liter of water, when the crop is at the milky stage.

Then another major pest on paddy is panicle mite. This is a non-insect pest. The scientific name is Steneotarsonemus spinki . It belongs to family Tarsonemidae of the order Acari. It causes serious damage to paddy crop in some parts of India. Usually it attacks panicle causing chaffy grains. It can be easily managed by spraying miticides.

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