**1. Introduction**

Banana crops is as old as Indian culture and known to be one of the earliest fruit crops produced by humankind from ancient times in India with extraordinary socio-economic significance, interlink in the social and cultural legacy of the country. It is likewise the fourth most significant food crop after paddy, wheat and maize and forms an important crop for survival of farmers. Considering the wholesome importance of banana, it is so noticeable and well known among the Indians so that it is loved by both poor and rich individuals. It is otherwise called 'poor man's apple' since it is that the most economical among fruit grown up within the country with healthy qualities and wholesome values. The yearly losses of banana in the world are 60–90% [1] and in India 30–40% [2]. The most economically significant pathogen of banana is *Fusarium oxysporum* species. Fusarium wilt disease was earlier reported from Panama canal of Australia. In India, this disease was first reported by Stover [3] from West Bengal. The Fusarium wilt pathogen survives in soil and penetrates into the roots with the assistance of nematodes, from where it gradually spreads until it achieves the centre of the corm that is the reason the plant showed quick wilting. Purplish darker shading shows up in the xylem vessels and are blocked, external leaves turn yellow and finally breakdown. Soon, only a few

of the youngest leaves remain functional. Later the older leaves and pseudostem show yellow and longitudinal part with patches at the leaf edge. The symptoms become evident after 5–6 months of planting and are expressed both externally and internally.

## **2. Symptoms**

The first internal symptoms develop in feeder roots at the primary sites of infection. They progress toward rhizome and are most noticeable where the stele joins the cortex. As the infection in pseudostem is colonized, blackout dark coloured streaks or flecks become apparent on and inside more seasoned leaf sheaths. Eventually, enormous segments of the xylem turn a black red to darker shading. The first external symptoms of Panama disease are a yellowing of the most seasoned leaves or a longitudinal splitting of the lower part of the external leaf sheaths on the pseudostem (**Figure 1**). This is further trailed by wilting and collapsing of leaves from the petiole base. At initial phases of infection, these leaves stay green. As the disease advances, more tender and young leaves breakdown until the whole plant covering comprises with dead leaves.

At the point when external symptoms are obvious on banana plants, however internal symptoms are missing from the pseudostem, it winds up for critically examine the rhizome. The plant sliced open at soil level to uncover the pseudostem base, and after that pushed over. Diseased plants have a trademark yellow to dim dark discolouration of the internal rhizome, which for the most part begins at the edges and advances inwards. Regularly some parts of the inward rhizome is influenced, yet with movement of the disease the whole internal rhizome winds up influenced. The external rhizome is rarely influenced. The piece of the rhizome that had been pushed over will show yellow strands of the rhizome which are appended

**Figure 1.** *External and internal symptoms of Panama wilt of banana.*

to both the top and base portions of the rhizome. At the point when no discolouration is seen inside the rhizome, the outside symptoms are brought about by an option that is other than Foc. In such cases, the internal rhizome may show dark spots rather than the consistent yellow to reddish darker discolouration related with panama wilt.
