Leaf curl of papaya

Host: Carica papaya
Pathogen: Papaya leaf curl virus (a begomovirus)
Vector:Whitefly (Bemisia tabaci)

Distribution

The disease has been reported from the tropical and subtropical countries like, Pakistan, China, Taiwan, Africa, Korea, Malaysia, India (Varun and Saxena, 2017). In India, the disease has been reported from the state of Karnataka, Gujarat and Uttar Pradesh. The disease was first described in 1939, whereas, the causal organism of the disease was described by Saxena et al. (1998).

Symptoms

Infected plants show upward and downward curling of the leaves. These symptoms appear because of many biochemical and cellular changes in the host during virus multiplication. Infected leaves are thickened, puckered and plants are stunted. Fruits are distorted and are small in size. In severe cases, petioles are twisted, leaves fall-off and there is no fruit formation.

Leaf curl of papaya
A growing shoot showing symptoms of leaf curl

Causal organism

Papaya leaf curl virus is DNA virus. This virus belongs to begomovirus of the Geminiviridae family. Genome of the virus is bipartite single-stranded circular DNA molecule (2400-2800 nucleotide). The genome codes for the coat proteins, and five to seven multifunctional proteins needed for the replication, transmission, movement and pathogenesis.

Disease transmission

Viruses need a suitable vector for transmission. Papaya leaf curl virus is transmitted through the vector whitefly (Bemisia tabaci).

Control measures

  • Leaf curl virus infects the plants at the seedling stage and at the apical meristem. The only remedy of the disease plant is the removal, burning and destruction.
  • The spread of the disease can be checked by controlling whiteflies’ population.
  • 3 % mustard oil proved to be repellent for the flies (Varun and Saxena, 2017).
  • The disease can be controlled to some extent by the application of insecticides to control white population, however use of insecticide is not recommended.
  • Integrated pest management (IPM) practices like roughing infected plants, postharvest sanitation considered as best to manage the whitefly.

References

  • Saxena, S., Hallan, V., Singh, B.P. and Sane, P.V., 1998. Leaf curl disease of Carica papaya from India may be caused by a bipartite geminivirus. Plant Disease, 82(1), pp.126-126.
  • Varun, P. and Saxena, S., 2017. Leaf Curl Disease of Carica papaya. In Begomoviruses: Occurrence and Management in Asia and Africa (pp. 111-135). Springer, Singapore.


Content first created on 18-01-2021
last updated on 11-08-2023