Effects of Paecilomyces lilacinus and Aspergillus niger alone and in combination on the growth, chlorophyll contents and soft rot disease complex of carrot

Abstract

Application of P. lilacinus or A. niger to plants with M. javanica/P. carotovorum pv. carotovorum or X. campestris pv. carotae caused a significant increase in plant dry weight. Use of P. lilacinus and A. niger together to plants with single pathogen resulted in a greater increase in plant dry weight than the use of any of them. Similarly, application of P. lilacinus to plants with two or more pathogens in combinations caused 15.4–32.1% increase in plant dry weight while use of A. niger resulted in 9.6–19.9% increase. Increases in plant dry weight in these plants were 30.5–46.2% when both P. lilacinus and A. niger were applied together. Chlorophyll contents of pathogens inoculated plants were also increased by the application of P. lilacinus or A. niger or with both. Use of P. lilacinus caused a high reduction in galling and nematode multiplication than A. niger. Maximum reduction in galling and nematode multiplication was observed when P. lilacinus was used with A. niger. Inoculation of P. lilacinus/A. niger with P. carotovorum pv. carotovorum or X. campestris pv. carotae reduce soft rot and leaf blight indices to 2 while combined use of biocontrol agents reduce indices to 1. Disease indices were reduced 1- 3 when both biocontrol agents were used together to plants inoculated with two or more pathogens.