Guava wilt- A challenge in Plant Pathology

Introduction

Guava is one of the most important fruits of India. It is also known as poor man’s apple, because it is full of nutrients and inexpensive. India grows the fruit in an area of approximately 268 thousand ha with a total production of 3668 thousand MT. The crop can be grown easily in all types of soil and almost in all states of India with highest area in UP (45.0 thousand ha).

Guava is affected by many pests, but wilt is a major problem in India. Guava wilt causes losses to the tune of 5-15% in UP. About 150and 300 acres of guava orchards in Punjab and Haryana respectively were uprooted during 1978-81 due to heavy incidence of guava wilt.

Symptoms

Symptoms of wilt in guava are not clear. All the drying plants may not be called as wilt. It is important to note here that guava wilt is a disease of grown up plants and not the disease of guava seedling or young guava plants. Wilt affected plants show two types of symptoms i.e. Slow and quick wilt. Quick wilt can be termed as true wilt and plants take 15-60 days for the complete wilting. In slow wilt plants take a year or more for complete wilting. Many times partial wilting may also be seen which is a atypical sign of wilt in guava. The affected plants show sudden drooping of leaves with yellow colouration.  At the later stage leaves may shed out.

Etiology

Etiology of the disease is still not clear. Various pathogens are reported as causal organisms by different workers, but only some may be causal organisms, while others are only associated with the affected plant. The reported pathogens by various workers are Fusarium oxysporum f. sp. Psidii, F. solani, Macrophomina phaseoli, Rhizoctonia bataticola, Cephalosporium sp. Gliocladium vermoesenii, G. roseum, Verticillium alboatrum and Acremonium sp. Guava wilt can better be called as guava wilt complex.

Wilting of the plant generally start after rains during August, September and maximum wilting occurs during October month.

Disease management

Chemical

Many chemicals have been used by different workers like Chaubatia paste, Water soluble 8-Quinolphos sulphate, Benlate or Bavistin, Metasystox and Zinc sulphate, Thiopanate methyl, Captafol and Thiobendazoles.

Besides fungicides, some soil amendments, chemicals/cakes/fertilizers were also found effective against wilt.  1.82 kg. lime or gypsum/tree control the wilt disease. Oil cakes like neem cake, mahua cake, kusum cake supplemented with urea @ 10 kg and 1kg respectively also mange the disease.

Cultural practices

• The disease could be controlled by proper sanitation in the orchard.

• Wilted trees should be uprooted, burnt and trench should be dug around the tree trunk.

• Maintenance of proper tree vigour by timely and adequate manuring, interculture and irrigation enable them to withstand infection.

• Intercropping with turmeric or marigold restrict the wilting of guava.

• Tillage should be avoided during monsoon and afterwards till December as it increases the incidence of the disease.

• The disease is soil borne, so flood irrigation is not recommended.

Varietal resistance

Cultivar Chittidar, Hafsi, Safeda, Riverside, Rolf and stone acid susceptible and guava sp. Psidium cattleianum var. lucidium and others cv. Chittidar is graded as reasonable good cultivar, which has reasonable level of resistance as well as good quality and taste and can be directly be used as resistant material.

Integrated eco-friendly approach

• Use resistant root stock ( molle x P. guajava)

• Apply bio-agent (Aspergillus niger, Trichoderma spp.) at the time of planting and regularly once every year in form of enriched FYM before monsoon.

• Intercropping with marigold or turmeric.

• Application of neem cake and gypsum.

• Minimum tillage.

• Separate basin irrigation or drip irrigation.

• Maintain plant population.

• Maintain sanitation in orchard.

Conclusion

Guava wilt is a complex disease of national importance. There is a need for detail study of etiology and management practices to fully control the disease. Integrated eco-friendly approaches can be used for the best management of the disease.

Author details

Sanjay Kumar Goswami, Scientist,  ICAR-Indian Institute of Sugarcane Research (IISR), Rae Bareli Road, Dilkusha, Lucknow-226002, UP

Mail:sanjaygoswami65@gmail.com