Insect pests of sorghum

1. Identification of Insect pests of sorghum and their symptoms of damage Dr. M. Thippaiah professor Dept. of Entomology College of Agriculture GKVK, UAS Bangalore- 65

2. Sorghum is a major crop in Maharastra, TN, AP, UP, Rajasthan, Haryana, Gujarat, Karnataka In Karnataka – Major crop in Northern Karnataka i.e. Dharwad , Bijapur , Raichur, Bellary and in South grown in Chitradurga, Mysore ,Shivmoga More than 150 species of Insects have been reported to damage Sorghum. However, over a dozen species are very serious and constitute a major constraint in sorghum production These insect pests are classified as Borer pests Ear head feeders Sap feeders Defoliators Non insect pests

3. Borer pests of Sorghum

4. Sorghum shoot fly: Atherigona soccata ( Muscidae : Diptera ) Adult fly Maggot inside the shoot Fully grown maggot Adults resembles house fly, little smaller and grayish brown in colour with 6 black spots on the abdomen Eggs: are laid on 2 to 5 youngest leaves of sorghum seedlings Among this it prefers the basal half portion of ventral surface of leaves I.P: 1 to 2 days Larvae : there are 4 larval instars Maggots are apodous and yellowish in colour and tapering to wards anteriorly L.P : 6 to 12 days Pupa : pupation at base of the stem. PP – 6 to 8 days Life stages of the pest It is a major pest in all traditional sorghum growing areas like Maharashtra, TN, and Karnataka Alternate hosts – Maize, Ragi , Wheat, Bajra More incidence observed in late kharif and early rabi crop While Insects cause 12 % loss in Sorghum Production Shoot fly alone is responsible for 5 %

5. 6 black spots on the abdomen

6. Nature and symptoms of damage Maggots on hatching crawls on upper surface of the leaf and later, penetrate / enter between leaf sheath and stem and further maggot reaches ground level and feed on growing point between leaf sheath and leaf whorl as a result in wilting and drying of central shoot know as ‘ dead heart ‘ symptoms. Growing point soft, succulent protected by leaf sheath and starts decaying which is fed by maggots, the central shoot dies and more tillers will come out the maggots will affect these side shoots and when dead hearts are pulled out they come up easily and produce bad smell Dead heart ‘ symptom Incidence - The 1-6 weeks old seedlings are more susceptibl e In Karnataka – June – Sept. incidence will be more The pest will complete its life cycle quickly at conditions like Temp – 25-30 c RH - more than 60% Continuous rain fall decrease pest incidence

7. Sorghum stem borer: Chilo partellus ( pyralidae : Lepidoptera) Adult is a medium sized, straw coloured moth or light brown coloured moth, 2cm across the wing Fore wings are light brownish / yellowish with row of black dots on the apical margin or outer margin Hind wings are whitish in colour in females and straw coloured in males

8. E ggs are laid in clusters on the ventral surface of the leaves near the mid rib Each females lays – 225 eggs I.P- 2-5 days Larva passes 5-6 instars, the larva yellowish brown with reddish brown head and prothoracic shield and measures 25mmlong with series of black dots L.P-28-35 days It pupate inside the stem in a small chamber P.P- 8-15 days TLC- 30-40 days

9. Nature and symptoms of damage Larva is damaging stage The larvae bores into mid rib and the shoot and feeds on the internal tissues and causes typical ‘dead heart’ formation, thus killing young plants In the early stage – hatching larvae feed on the surface of leaf sheath and leaf whorls causing pin holes / shot holes on the whorls of newly opened leaves As the severity of leaf damage increases , blend of feeding punctures and scratches appears on leaves The infestation starts 20 days after seedling emergence and continued till maturity

10. After the inter node elongation the growing point moved up wards , the larvae make tunnel in to the stem and also presence of red patches on the inter nodal region Later infestation occurs on the top portion of the stem Both stem and peduncle are damaged by the larva leads to production of complete chaffy ear head or partial chaffy ear heads The infested peduncle may also break down Bored hole on the stem Presence of red patches on the inter nodal region

11. Larvae in side the stem Symptoms Mid rib tunneling by early instar larva A series of pin holes on emerging leaves In young plants the pest causes a typical dead hearts In older plants the upper part of the stem usually dies due to boring of the caterpillars in the stem pith

12. Ear head feeders

13. Jowar ear head bug : Calocoris angustatus ( Miridae : Hemiptera ) It is a key pest of Sorghum in Southern states It attack the crop from ear head emergence to head dough stage, Yield loss- 54-89% Adult is an active, slender yellowish green bug, measuring 5-8mm in length The bugs hover over the ear heads at the time of ear head formation Site of ovipositon: Eggs are laid in spikelet's on ear head or under glumes or middle of the florets Each female lays - 100-200 eggs I.P – 5-7 days Nymphs: The nymphs pass 5 instars Early instars light orange coloured and later changes to green colour or yellowish green in colour N.P – 15- 17 days, Two generations are noticed It inflict severe damage to irrigated Sorghum during April – May and to less extent to rainfed Sorghum during Aug - Jan

14. Older grain shows distinct feeding punctures that reduce grain quality Both nymphs and adults suck the milky juice from tender ear heads or developing grains, such grains shrink and turn black colour, thus make them turn chaffy or crinkled grains . Older grain shows distinct feeding punctures that reduce grain quality This bug has been recorded feeding on a number of Cereals, Millets and grasses, buts breeding is mainly restricted to sorghum Symptoms of damage

15. Sorghum ear head midge : Contarinia sorghicola ( Cecidomyiidae : Diptera ) Site of ovipostion: Eggs are laid in side the glumes of closed and open flowers Each female lays – 30 – 100 eggs I.P – 1-2 days Maggots: are minute, pink, fleshy apodous L.P – 9-10 days Pupa : In side the damaged flowers or pupal cases are usually present at the tip of the glumes P.P – 5-6 days Adults are fragile soft bodied reddish mosquito like fly with long legs and monili form antennae and a pair of transparent wings and they have long Telescopic ovipositor Long telescopic ovipositor

16. Nature and Symptoms of damage Maggots on hatching feed on developing grains such infested ear heads become chaffy i.e. The larvae starts feeding on the ovaries and destroy developing grains results chaffy ear heads or partial filling of grains partial filling of grains chaffy ear heads The affected spikelet's shrivel and fail to develop in to grains Symptoms Red ooze from the spikelet when squeezed indicating the presence of Maggots Chaffy grains with round holes indicating fly emergence Empty pupal cases protruding from glumes

17. They have whitish pupal cases protruding out of the of the damaged spikelets July sown crop – Severely affected Temp. - 25 – 30 C RH – 60% these factors encourage the pest population and also cloudy weather and intermittent rain fall increases the incidence

18. Ear head caterpillar: Helicoverpa armigera ( Noctuidae :Lepidoptera) The adult is a medium sized, light brown coloured moth Two prominent black spots on the fore wings Dull black border on the hind wings When crop is at flowering stage we can find the adult moth activity

19. Symptoms of damage Larva remains concealed in the inner branches of the ear and feed on the grains and damaged ears could be easily spotted in the field by their chalky appearance due to partially eaten grains chaffy ear heads Female moth lay eggs on inflorensce, the hatching caterpillar starts feeding on flowers till grain hardening stage

20. Caterpillar feed on the developing grains

21. Grass hopper feeds on the grains

22. Castor shoot and capsule borer: Conogethes punctiferalis ( Pyralidae : Lepidoptera) Adult is a medium sized moth with small black dots on pale yellow wings

23. It attacks the plant at flowering stage and lays eggs on inflorensce and young caterpillar make webbings and feed on flowers and grains and they pupate with in the webbings

24. Chafer beetle : Oxycetonia spp. ( Scarabaeidae : Coleoptera ) A light brown coloured beetle with white spots on the elytra Adults feeds on ear heads of sorghum and maize

25. Sap feeders

26. Shoot bug : Peregrinus maidis ( Delphacidae : Hemiptera ) Adults are small, active ,light brown or dark brown in colour with transparent wings and movable spur on the hind legs The brachypterous female is yellowish while macropterous female is yellowish brown and male dark brown in colour

27. Eggs are laid in groups of 1-4 inside the leaf tissue on midrib and covered with white Waxy substance Maximum 97 eggs are laid by a female in life span of 7-10 days There are 5 nymphal instars 4-10 days 16-18 days 7-10 days TLC – 18-31 days

28. Damage Both nymphs and adults suck the sap from young leaves and leaf sheath resulting attacked plants become unhealthy , stunted growth and yellow patches The leaves wither from top down wards and later turn reddish and finally attacked plants die in severe case. honey dew secreted by the bug causes growth of sooty mould on the leaves Vectors of viral diseases : 1. Sorghum stripe 2. Sorghum mosaic Nymphs and Adults Attack plants reddish and finally such plants die in severe case

29. Aphids: Rhopalosiphum maidis ( Aphididae : Hemiptera ) Adults are dark bluish green and some what ovate . It is 2mm long with black colored legs with cornicles on dorsal side of 5 th and 6 th abdominal segments Winged and wingless forms are common Corn leaf aphid Aphid damage Sugarcane aphid cornicle

30. Nature of damage Nymphs and adults suck the sap from the leaves as a results yellowing of leaves, colonies of aphids in central leaf whorl, stem or panicles The aphids produces an abundance of honey dew on which sooty moulds are grown In panicles, honey dew may hinder harvesting Presence of ants is the indication of attacked by aphids The aphids also transmits Maize dwarf mosaic virus

31. Stink bug : Nezara viridula ( Pentatomidae : Hemiptera ) Adults are large green coloured bug with 5 segmented filiform antennae Nymphs and adults suck the sap from the softer part of the plant but principally from the developing seeds The Injury is very negligible Adults congregate on The bajra ear head Nymph is brownish red or dark brown with multicoloured spots

32. Defoliators

33. Colemania spheneroides (I. Bolivar) on sorghum It is endemic / cyclic pest in Northern Karnataka i.e in Haveri district and it appears once in 5 years Deccan wingless grass hopper : Colemania sphenarioides ( Pyrgomorphidae : Orthoptra )

34. Adult is a medium sized, wingless grass hopper, measures 4-5 cm in length Antennae short filiform Body light green with pink and yellow stripes on lateral sides Eggs : are laid in batches in the forms egg pod at 5 cm depth in soil in the month of Octo - N ov. and hatch in June - July

35. Symptom of damage After monsoon showers the nymphs will come out and first feed on grasses and later take over to sorghum They feed on leaves and also feed on flowers, ripening ear heads and all parts are eaten leaving only stalk

36. Army worm : Mythimna separata ( Noctuidae : Lepidoptera) It is serious in heavy rainfall areas The adult is stout bodied, medium sized moth, greyish brown in colour On the fore wings we find 2 white spots and prominent veins in the wings

37. Caterpillars Pupae Pale Brown coloured moth Caterpillar feeds on leaf margin and mid rib and thus causing severe defoliation

38. Red headed hairy caterpillar: Amsacta alibistriga ( Arctiidae : Lepidoptera ) Caterpillars are reddish-brown in colour and hairy Adults are medium sized moths Fore wings : are white with brown streak all over the wings and yellowish streak along the anterior margin Hind wings : are white with black spots Caterpillars are the voracious feeders of the foliage They move from field to field in large swarms in search of suitable host plants thus causing large scale devastation of millet crops

39. Red hairy caterpillar It is a polyphagous pest, often do considerable injury to young sorghum seedlings and caterpillars are the voracious feeders of the foliage

40. Sorghum leaf roller : Marasmia trapezalis ( Pyralidae : Lepidoptera) Adult is a small, pale yellow brown coloured moth with black wavy markings on the wings Site of ovipostion : Eggs are laid singly on the upper leaf surface I.P – 4-5 days

41. Larva : there are 5 larval instars, pale brown with reddish brown head and brown prothorax L.P – 15-20 days Pupa : Pupation takes place with in leaf fold, P.P – 7-8 days Symptoms of damage The larva folds or roll the leaves and feeds on the green matter Longitudinal patches on leaves with drying tips Broad leaf varieties are more susceptible for this pest

42. Jowar flea beetle : 1. Chaetocnema sp. ( Chrysomelidae : Coleoptera ) Black shinning beetle and very active, jump when slightly touched with enlarged hind femora It is often serious in seedlings of summer and rabi sown crop Adults feeds on leaves and pin holes observed on leaves

43. 2. Monolepta signata ( Chrysomelidae : Coleoptera ) Adult is a black coloured beetle with long antennae and four pale yellow spots on the elytra

44. Adults feeds on the leaves make holes on the leaves

45. Non insect pest

46. Jowar mite : Oligonychus indicus ( Tetranychidae : Acarina ) Both nymphs and adults suck the sap from the leaves as a results infested areas become pale yellow but later turn to reddening of tissues on dorsal side which coalesce and entire leaf red in colour and dry up The plant growth and grain development is affected Webbing can be seen on the undersurface of the leaf These are microscopic, greenish yellow oval shaped mites and they found on ventral surface in colonies, they forms webs Nymphs are pale yellow in colour

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