Use of culture filtrates of Trichoderma strains as a biological control agent against Colletotrichum capsici causing Anthracnose fruit rot disease of chili

Culture filtrates of five Trichoderma strains viz. Trichoderma virens IMI-392430, T. pseudokoningii IMI-392431, T. harzianum IMI-392432, T. harzianum IMI-392433 and T. harzianum IMI-392434 were used as seed treatments alone and in combination with culture filtrates of Colletotrichum capsici, to assay their efficacy in suppressing Anthracnose fruit rot disease and promoting chili plant growth and yield, under field conditions. A pot trial experiment was conducted at the Botanical Garden, Rajshahi University, Bangladesh from July 2006 to March 2007. Application of culture filtrates of T. harzianum IMI-392433 (T8) significantly (p=0.05) suppressed the disease percentages (94.97 %) compared to C. capsici treatment and improved both plant growth and yield. The highest seed germination rate (100%) and the highest growth and yield (20.37gm/plant) were also recorded in the same treatment; while culture filtrates of C. capsici treatment (T1) alone significantly decreased these values. The correlation matrix showed that yield of chili had significant and positive correlation with plant height (r = 0.979**), number of leaf per plant (r = 0.877 **), number of primary branch (r = 0.916 **), number of secondary branch (r = 0.889**), total number of leaf (r = 0.949**) and total number of flower (r = 0.953**) at maximum flowering time, root number (r = 0.970**), root length(r = 0.923**), total number of fruit (r = 0.980**), fruit length (r = 0.935**), fresh fruit weight (r = 0.967**), dry fruit weight (r = 0.920**), total number of seed per fruit (r = 0.868**) and hundred seed weight (r = 0.955**). The significant and negative correlation (r = - 0.671**) was observed with the yield and percentages of infected fruits. The results suggest that T. harzianum IMI-392433 has growth promoting effects and this strain may be used as an effective bio control agent to control Anthracnose fruit rot disease of chili.