riceDoctor

Black Bug

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Adult black bug

Diagnostic summary

  • sap removal by adults and nymphs
  • browning of leaves or deadheart or bugburn
  • plant stunting
  • reduced tiller number
  • weakening of plants and preventing them from producing seeds
  • formation of whiteheads

  • greenish or pinkish rounded eggs
  • brown or yellow nymphs
  • brownish black to black adults

  • rainfed and irrigated wetland environments
  • vegetative stages of the rice plant
  • continuously cropped irrigated rice areas
  • poorly drained fields
  • densely planted fields
  • staggered planting of the rice crop
  • excessive use of nitrogen
  • presence of alternate hosts/plants
  • lunar phase

 

Full fact sheet

Black bug, Malayan black bug, Japanese rice black bug

Scotinophara coarctata (Fabricius), S. lurida (Burmeister), S. latiuscula Breddin

  • Deadheart
  • Reddish brown or yellowing of plants
  • Chlorotic lesions on leaves
  • Decreased tillering
  • Bugburn
  • Stunting of plant
  • Stunted panicles, no panicles, or incompletely exerted panicles, and unfilled spikelets or whiteheads at booting
  • Incomplete and unfilled spikelets at crop maturation

 

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Bugburn(PhilRice)

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Nymphs of black bug (IRRI)

The deadheart damage caused by black bug may be confirmed if the infected plants cannot be pulled at the bases. The symptom “bugburn” occurs, the wilting of tillers with no visible honeydew deposits or sooty molds.

The deadheart damage caused by black bug may be confirmed if the infected plants cannot be pulled at the bases. The symptom “bugburn” occurs, the wilting of tillers with no visible honeydew deposits or sooty molds.

The insect is common in rainfed and irrigated wetland environments during the vegetative stages of the rice crop. It prefers continuously cropped irrigated rice areas and poorly drained fields. Damages are observed more frequently in dry season rice crops and densely planted fields are preferred.

Black bug flight patterns are affected by the lunar cycle and on full moon nights, large numbers of adults swam to light sources.

Staggered planting of the rice crop and excessive nitrogen favors the buildup of the pest. Presence of alternate breeding site favors population increase during non-rice periods.

The newly emerged adult is white and tinged with green and pink. Mature adults are shiny dark brown or black.

Different nymphal instars vary in size. They are brown or yellow with black spots on the body.

They have rounded eggs, which are greenish or pinkish.

Its primary hosts include maize and rice. Its alternate hosts are Hymenachae pseudointerrupta (Steud.) Gilliland, Salix sp. (willow), and Scirpus grossus L. f. (greater club grass).

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Both the adults and nymphs remove the plant sap by using its sucking mouthparts. They prefer the stem nodes because of the large sap reservoirs.

Black bugs feed on the rice plant from seedling to maturity growth stages. Heavy infestation and “bugburn” is usually visible after heading or maturing.

Feeding damage of black bugs causes half-filled and empty grains. Ten adults per hill can cause losses of up to 35% in some rice.

  1. One of the cultural control practices to reduce the population of the black bug is to maintain a clean field by removing the weeds and drying the rice field during plowing. Rice varieties of the same maturity date may be planted to break the insect’s cycle. Direct-seeded rice crops tend to have less tillers in one planting point and thus discourage population growth. During early infestation, the water level in the field may be raised for 2-3 days to force the insects to move upwards. Flooding the fields can also cause higher egg mortality. After harvest, fields might be plowed to remove remaining insects.

    Mechanical control measures include the use of mercury bulbs as light traps for egg-laying adults. Light trapping of insects should start 5 days before and after the full moon.

    In the field, there are biological control agents such as small wasps that parasitize the eggs. Ground beetles, spiders, crickets, and red ants attack the eggs, nymphs, and adults. Both the eggs and the nymphs are fed-upon by coccinellid beetles. Ducks and toads also eat the nymphs and adults. There are 3 species of fungi attacking the nymphs and adults.

    Two IRRI varieties resistant to black bugs are available.

    For chemical control, foliar spraying of insecticides directed at the base of the rice plant is the most effective.

Selected references

  • Chong KK, Ooi PAC, Tuck HC. 1991. Crop pests and their management in Malaysia. Kuala Lumpur (Malaysia): Tropical Press Sdn. Bhd. 242 p. 
  • Corbett GH, Yusope M. 1924. Scotinophara coarctata (F.), the black bug of padi. Malayan Agric. J. 12:91-106. 
  • Hill DS. 1975. Agricultural insect pests of the tropics and their control. Cambridge (UK): University Printing House. 516 p. 
  • Lim GS. 1975. Effect of feeding by Scotinophora coarctata (F.) on the rice plant. Rice Entomol. Newsl. 3:26-27. 
  • Pathak MD, Khan ZR. 1994. Insect pests of rice. Manila (Philippines): International Rice Research Institute. 89 p. 
  • Philippine Rice Research Institute (PhilRice). 2002. Field guide on harmful and useful organisms in Philippine ricefields. DA-PhilRice Maligaya, Munoz, Nueva Ecija. 58 p. 
  • Philippine Rice Research Institute (PhilRice). 2002. Metarhizium: microbial control agent for rice black bug. Rice Technology Bulletin 44. DA-PhilRice Maligaya, Munoz, Nueva Ecija. 12 p. 
  • Philippine Rice Research Institute (PhilRice). 2000. Management of the rice black bug. Rice Technology Bulletin 31. DA-PhilRice Maligaya, Munoz, Nueva Ecija. 12 p. 
  • Reissig WH, Heinrichs EA, Litsinger JA, Moody K, Fiedler L, Mew TW, Barrion AT. 1986. Illustrated guide to integrated pest management in rice in tropical Asia. Manila (Philippines): International Rice Research Institute. 411 p. 
  • Shepard BM, Barrion AT, Litsinger JA. 1995. Rice-feeding insects of tropical Asia. Manila (Philippines): International Rice Research Institute. 228 p.
  • Shepard BM, Perez VA. Influence of cultivation on survival of the Malayan black bug in ricefields. Int. Rice Res. Newsl. 12(3):35. 
  • Yunus A, Balasubramaniam A. 1975. Major crop pests in Peninsular Malaysia. Malaysia Ministry of Agriculture and Rural Development, Bulletin No. 138.

Contributors:

JLA Catindig and KL Heong