In -vitro evaluation of different fungicides and the bio-control agent trichoderma harzianum against botryodiplodia theobromae, the cause of guava decline

Guava decline disease, caused by Botryodiplodia theobromae is becoming the countrywide threat in Pakistan and annually it brings severe economic losses to the guava production. The management of this disease is very essential. In-vitro evaluation of four different fungicides viz. Nativo, Antracol, Aliette and Topas, with different concentrations (30, 50, 100 ppm) and the bio-control agent Trichoderma harzianum (5mm mycelial disk) were tested against B. theobromae. The result revealed that the effectiveness of the fungicides increased with increased dosage rate. Nativo was proved to be the most effective fungicide; Antracol was moderately effective, whereas Aliette and Topas were found to be less effective in reducing the mycelial growth of B. theobromae. Similarly, invitro evaluation of the bio-control agent Trichoderma harzianum against B. theobromae was found to be very effective, resulting maximum inhibition of 40.34% in the colony growth of the test fungus within seven days. Thus, farther different fungicides and bio-control agents must be evaluated under in-vitro conditions and then applied in