Isolation of Fungi Associated With Diseased Leaf of Guava ( Psidium Guajava L.)

The study of the fungi associated with leaf spot disease of P. guajava (guava) was conducted in order to compare the radial mycelial growth of the isolated fungi on both potato dextrose agar (PDA) and corn meal agar (CMA). Fungi associated with the diseased guava leaves were isolated using the direct plating method while the radial mycelial growth of the isolated fungi was done using radial mycelial measurement technique. Pestalotia psidii and L. theobromae were identified as the fungi associated with the diseased guava leaves. Cultural description shows P. psidii to form whitish to grey mycelium with sparse black sporulation on PDA but grows very slowly on CMA with rarely visible mycelial growth on the culture plate. Lasiodioplodia theobromae on the other hand developed cottony mycelia that transition from white to black as the colony matures on PDA and produces less whitish to dark, septate mycelia on CMA which barely turns black as the colony matures. The results the radial mycelial growth of P. psidii and L .theobromae on corn meal agar shows an increase in the average mycelial growth of P. psidii from 3.25cm on day 3 to 5.20cm on day 7 while L. theobromae was observed to increase from 3.63cm on day 3 to 5.63cm on day 7. On PDA the average mycelial growth of P. psidii increases from 5.05cm on day 3 to 8.5cm on day 7 while L. theobromae was observed to increase from 3.90cm on day 3 to 7.45cm on day 7. Findings of this study has shown P. psidii and L. theobromae to be the major fungi associated with leaf spot disease of guava leaves and also shown the growth medium PDA to be more suitable for the in vitro radial mycelial growth study of P. psidii and L. theobromae.