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Pests of paddy 1


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Pests of paddy 1

  1. 1. Identification of major insect pests of Paddy and their damage symptoms Dr. M. Thippaiah professor Dept. of Entomology College of Agriculture GKVK, UAS Bangalore- 65
  2. 2. Rice, Oryza sativa is the most important and staple food crop for more than two third of the population of India and more than 65 % of the world population. More than 100 Insect species are associated with rice crop at one stage or the other stage 20 of these are pests of major economic significance and these pests are classified as Borer pests Sucking pests Defoliator pests Non Insect pests
  3. 3. Insect PESTS OF PADDY Yellow stem borer Brown Plant hopper(BPH) Earhead bug Gall midge or Gall fly Thrips Green leaf hoppers (GLH) Mealybugs Borer pests of paddy Scirpophaga incertulas Orseolia oryzae Sucking pests of paddy 1. Nephotettix nigropictus 2. N. virescens White leaf hopper(WLH) Cofana spectra Nilaparvatha lugens Leptocorisa oratoria Stenchaetothrips biformis Brevennia rehi
  4. 4. CasewormLeaf roller Paddy skipper Horned caterpillar Defoliator pests of paddy Paddy swarming caterpillar Climbing caterpillar Yellow hairy caterpillar Eupterotid hairy caterpillar Nympula depunctalisCnaphalocrocis medinalis Melanitis leda ismene Pelopidas mathias Spodoptera mauritia Mythina separata Psalis pennatula Euproctis virguncula
  5. 5. Whorl maggot Blue beetleHispa Grass hoppers Hieroglyphus banian Oxya nitidula Hydrellia sasakii Dicladispa armigera Leptispa pygmaea
  6. 6. Panicle rice mite: Steneotarsonemus spinki Non insect pests on paddy crop Paddy mite : Oligonychus oryzae Rice field crab : Paratelphusa hydrodromus Field rat : Bandicota bengalensis
  7. 7. Paddy stem borer : Scirpophaga incertulas (Walker) (Pyralidae : Lepidoptera)  The adults are yellowish white with orange yellow front wings and they have sexual dimorphism  The female moth is bigger than the male and has a centrally situated black spot on each of the fore wings  The females also have a prominent tuft of brownish silken hair at the tip of their abdomen  Moths are attracted to light in the night during March-April and October-November
  8. 8. Male moths are small with Female moths are bigger pale yellow fore wings and fore wings are bright yellow without black spot in the and a prominent black spot centre and abdomen slender in the centre of each and the with out tuft of hairs anal end with tuft of yellowish hairs
  9. 9. Eggs are creamy coloured , flat, oval, laid in masses and covered with buff coloured hairs on the tip of the leaf The body of the larva is cream or Pale white or yellow colored and the head is reddish brown Pupa turns dark brown just before adult emergence Adult moth Pupate at the base of the plant
  10. 10. 5-10days 30-40 days 6-10days 50-60 days 7-8 days
  11. 11. Young larva, bore into the central shoots of young seedlings and tillers, and feeds internally on growing shoot causing ‘dead hearts’ symptom i.e drying of the central shoots and interrupting movement water and nutrients At boot leaf stage or ear head stage – the larva bores in to the top most node and feed at the base of the ear head and succulent ear head dries and becomes white ear or chaffy ear head and such ear heads are easily come out when they are pulled out Nature and symptoms of damage
  12. 12. Dead heart symptom Chaffy ear head
  13. 13. Symptoms The pest can be identified with the following symptoms Dead heart at vegetative stage which turns brownish, curls and dries White ears at ear heading stage with empty, partially filled grains Presence of egg masses near the tips of tender leaf blades Activity of moths in the vicinity Frass at the feeding site
  14. 14. Reasons for attaining major pest status  Expansion of rice area to new irrigation system  Multiple rice cropping system  High yielding varieties  Application of higher dose of nitrogen  Optimum temp.- 17- 300 C for all the stage If more than 350 C are not congenial  Warm humid condition i.e RH 80-90% are more suitable for population growth
  15. 15. Paddy case worm : Nymphula depunctalis (Pryalidae : Lepidoptera)  Adult is a tiny delicate moth measuring about 1.5cm in length  Wings are white and speckled with pale brown markings pale brown markings
  16. 16. Eggs are laid singly or arranged in rows at the tip of leaves I.P- 5-6 days • The caterpillar under goes 6 instars and is characterized by the presence of tubular gills on the body • The larval length 11-12mm and case length of 20-25mm L.P – 18-22 days Pupation takes place inside last larval case after attaching the leaf sheath above the water level and closing two ends PP – 5-6 days  Adult is a tiny delicate moth measuring about 1.5cm in length  Wings are white and speckled with pale brown markings Life cycle TLC – 30-40 days
  17. 17.  The pest attacks the crop in the early transplanted stage  The young larva cut the leaf blade into small bits and constructs a tubular case and larva remains inside the case  The larva feeds on foliage by scraping the green matter  As a result White patches are seen on the leaf blades in ladder like fashion on the under surface of the leaves Tillers become stunted and loose their vigour and often the plants are killed
  18. 18. 1. Leaf cases floating on water 2. Leaves cut at right angles to make cases 3. Leaves with papery upper epidermis that were fed on by larva 4. Skeletonized leaf tissues usually appear ladder-like fashion or ladder like scrapings 5. The tillers become stunted 6. Loss of vigour in plants 7. Maturity delayed by 7-10 days Symptoms
  19. 19. Infested plant leaves appears white and dry up
  20. 20. Paddy leaf roller : Cnaphalocrocis medinalis (Pryalidae : Lepidoptera)  Adult moth is a small and measures about 2 cm in length  Wings brownish yellow in colour with wavy distinct 2 or 3 dark markings  Male moths have a tufts of thick black hairs on the mid costa
  21. 21. These are small brownish yellow coloured moths and they have two or three distinct dark wavy lines on the brownish fore and hind wings which have a dark brown to gray band on their outer margin. Eggs are laid singly or in pairs on the lower surfaces of tender leaf blade; Incubation period is 4 – 8 days Larvae are yellowish green in colour with dark brown head They fold leaf margin longitudinally and feed the rolled leaves; larval period is 15-27 days; Pupation takes place inside the leaf roll PP - 6-8 days Total life cycle is 26-42 days. There are 4 generarions / year Adult Eggs
  22. 22. Larva yellowish green in colour and measures about 16-20mm in length Leaf folded longitudinally and larva live inside
  23. 23. Nature of folds depends on the stage of the crop  The crop is at nursery stage i.e seedlings and young plants are attacked and 3-4 leaves of adjacent plants are webbed together forming longitudinal folds and feed on green matter  In case of growing plants, one leaf folded longitudinally or transversely and larva live inside by scraping green matter and infested leaves appear white and leaf fold filled with excreta  Each larva damage the several leaves which prevents the photosynthetic activity of the plant Nature and symptoms of damage The pest damage throughout crop growing stage until boot leaf stage
  24. 24. Paddy leaf hoppers : a) Nephotettix virescens 1. Green leaf hoppers(GLH) b) Nephotettix nigropictus ( Cicadellidae : Hemiptera) Adults are smaller in size, green coloured insects with prominent black spot on the apical portion of fore wing and two black spots in the middle of the forewing and do not extend up to the black distal portion Adults are dark green in colour, with prominent black spot on the apical portion of fore wing and has two black spots in the middle of the forewing and extending up to the black distal portion on the forewing Nephotettix virescens Nephotettix nigropictus  Paddy leaf hoppers are found in all the rice growing regions of India  Adults are small green wedge shaped hoppers with hind legs having one or two rows of spines
  25. 25. GLH is common in irrigated wet land environments They are not prevalent in upland rice Life stages of the pest  Eggs are insert into the midribs in groups of 3-18 I.P – 3-5 days  Nymphal stage is completed in 12-21 days  Adults live for 7-12 days  There are six overlapping generations/ year
  26. 26. White leaf hopper : Cofana spectra (Cicadellidae : Hemiptera) Adult are whitish in colour and bigger in size This insect causes yellowing of leaves and stunting of tillers It does not transmit any diseases and direct damage as hopper burn rare Stage of the crop pest attack – second half of crop growth period and abundant only during the summer months
  27. 27. Nature and symptoms of Damage  The nymphs and adults cause direct damage to rice crop by sucking sap from leaf sheaths and Leaf blades and plants turns yellowish brown  The white specks on the young leaf are the symptoms of damage, severe infestation leads to ‘hopper burn’.  The affected leaves and plants turn to yellowish brown colour and growth is retarded.  They indirectly acts as vectors by transmitting viral diseases such as RiceTungro virus ( RTV) Transitory virus and Yellow dwarf.  They also feed on some grasses like Cynodon dactylon, Echinochloa crusgalli and Eleusine indica, etc.,
  28. 28. Green leafhopper and rice plants infected with RTV
  29. 29. Rice plants affected by tungro virus Virus particles under électron microscope
  30. 30. Brown plant hopper: Nilaparvata lugens (Delphicidae : Hemiptera) This is a number one enemy in Command areas , under favourable condition we can except 100 % crop loss Adults are brown in colour; 4-5 mm long, yellowish brown to dark brown body and more or less wedge shaped Hind tibia with a long movable spur Macropterans are strong fliers; Eggs are elongated, cigar shaped inserted by female in two rows on either side of the midrib of the leaf sheath I.P - 7-9 days Young nymphs are whitish in colour and measures 0.7 mm in length N.P – 15-20 days TLC – 18-24 days Eggs
  31. 31. Have well developed wings Have poorly developed wings Smaller abdomen Larger abdomen Move from one field to another Can not fly, move by irrigation water field as colonies Dominant at post flowering stage Dominant at pre flowering stage Egg laying capacity is less Egg laying capacity is more Macropterous form – Fully winged form Brachypterous form – Short winged form Adult insects appears in two forms
  32. 32. Young nymphs are whitish in colour and measures about 0.7mm in length and second instar nymphs are brownish black in colour and they congregate at the base of the plant and later instar are yellowish brown in colour N.P- 15-20 days
  33. 33. Nature and symptoms of damage • Stage of attack:- Early growth stage but some times serious infestation occurs at post flowering stage • Damaging stages:- Adults (especially brachypterans) and nymphs Both nymphs and adults suck the sap from leaf sheath and stem at lower portion of the plant, just above the water level, continuous drying of the plants due to feeding. The crop turn yellow followed by rapid drying of plants called as hopper burn in concentric rings and later spread to entire plot in severe case • Nature of damage:- Nymphs and adults Congregate at the base of the plant causing hopper burn • Peak occurrence is between Oct - Nov and Jan – Feb and the pest more severe in summer crop due to ideal condition, the loss is heavy in high rainfall condition
  34. 34. Circular dry patches in field Completely desapped plant Hopper burn more common in panicle initation stage to maturity stage of the crop
  35. 35. They are also transmit viral diseases called grassy stunt virus i.e It acts as vectors of viral disease
  36. 36. Most favourable conditions for pest out break or Reasons for BPH out break  Temp- 290C  RH-80-90%  Continuous cultivation of susceptible varieties  Continuous cultivation of monocrop  Use of high dose of nitrogenous fertilizers specially urea  Closer planting  Indiscriminate use of pesticides
  37. 37. Paddy thrips : Stenchaetothrips biformis (Thripidae : Thysanoptera) Nymph Adult Adults are small, 1mm long or elongate dark brown to black coloured insects, with narrow fringed wings This pest is observed when there is a dry spell, low humidity and high temp. favours the Pest build up Eggs – are laid in leaf tissues Fecundity – 100eggs I.P – 3-5 days Nymphs – there are 5 nymphal instars N.P – 10-12 days TLC- 20-25 days
  38. 38. Initial - inward rolling Symptoms of damage  Both nymphs and adults Lacerate the tender leaves and suck the plant sap of the seedlings in nursery and young transplanted plants in the main field  Rolling and drying of the leaf tips i.e leaves curl longitudinally margin in wards and all the stages with in leaf roll it self  Yellow (or) silvery streaks on the leaves of young seedlings  It causes damage both in nursery and main field Silvery streak
  39. 39. Paddy gall midge: Orseolia oryzae (Cecidomyiidae : Diptera)  Adult is a small, reddish, delicate fly, with long legs, resembling a mosquito and moniliform antennae  Wings are semitransferens  The male is ash grey in colour  Adults feeds on dew drops
  40. 40. Eggs : are laid singly or in small clusters at the base of the leaves near ligules and up to 200 eggs laid by each female I.P – 3-5 days Maggots: are minute, greyish white in colour, stout body and pointed towards anterior end, fully fed maggot 3mm length, pinkish in colour L.P - 7-15 days Pupa : it pupate within the gall P.P – 3-8 days Adults are positively phototrophic and lives for 1 to 5 days The tillering stage of the paddy crop is more susceptible to attack of this pest egg Larva
  41. 41. Nature and symptoms of damage The maggots crawls down between leaf sheath and reaches the growing point and start feeding and an oval shaped chamber is formed around the site of feeding and the irritation caused due to its feeing on primordia cover leads to formation of elongate cylindrical gall called ‘silver shoot’ or Anekombu or kane or Onion shoot As a result, further growth of tiller is arrested / stop The feeding by maggot and their larval secretion which contains active substance called “Cecidogen” is responsible for cell proliferation of the meristematic cells as a result gall formation takes place The galls are formed by gall fly are nothing but modification of leaf sheath The central shoot instead of producing leaf and produces a long tubular structure called gall and when gall elongates as an external symptoms of damage Infested tillers not producing panicles
  42. 42. symptoms of damage  Damaged tillers turns into tubular galls which dry off without bearing panicles  Main external symptom is SILVER SHOOT or GALL which resembles onion leaf  Fully developed gall is a silvery white hallow tube 1 cm wide and 10 – 30 cm long  Attack to rice seedlings leads to profuse tillering and these new tillers often become infested
  43. 43. Reasons for out breaks of the pest Early monsoon showers following a dry spell Continuous cloudy weather associated with intermittent rains High relative humidity Optimum temperature ranges from 28 – 320 C Late planting High yielding susceptible varieties Continuous cropping High nitrogen application Closer plant spacing Intensive management practices
  44. 44. Paddy Hispa : Dicaldispa armigera (chrysomelidae: coleoptera) Adults is a small bluish black beetle, measuring 5 mm in length and is easily recognized by numerous short spines on the elytra
  45. 45. Symptoms of damage  Adults feed on chlorophyll by scraping the green matter and causing white parallel streaks on the leaves or straight white lines on the leaf surface  White patches along the long axis of the leaf  Grubs mine into the leaves between epidermal layer, such leaves causes white blotches near leaf tips and finally dry up
  46. 46. Paddy ear head bug : Leptocorisa oratoria (Alydidae; Hemiptera) Adult is an active, greenish brown coloured bugs with slender body and prominent legs and antenna and measuring 2-2.5cm in length and producing pungent smell when touched Egg: female lays eggs on the leaf blade in long rows of 10-20 They are reddish brown in colour I.P – 6-7 days Pest generally appears on rice just before flowering stage and continue until the panicle ripening stage
  47. 47. The nymphs are slender, elongated yellowish or greenish in colour and suck the sap from milk grains N.P – 14-15 days
  48. 48. Both nymphs and adults emit a foul smell after disturbance
  49. 49. • Stage of attack:- Generally appears on rice just before the flowering stage and up to milky stage • Damaging stages:- Both adults and nymphs • Nature of damage:- Suck the sap of the peduncle, tender stem and milky grains, inserting their proboscis • Symptoms:- Grains become chaffy; At the spot of the puncture, the water soaked spots appear and become brown with white center; The ear heads in infested fields show the presence of many such chaffy grains and the quality of the affected grain gets deteriorated. Apart from rice, they also breed on other grasses.
  50. 50. Damaged grains caused by rice bug The quality of the affected grain gets deteriorate Symptoms of damage  The damage appears as a brownish spot on the grains  Such grains are chaffy, partially, entirely