Water-extractable fraction of vermicomposts enriched with Trichoderma enhances the growth of bell pepper and tomato as well as their tolerance against Meloidogyne incognita

Abstract

Root-knot nematodes (RKN) are important pathogens on greenhouse-cultivated vegetables worldwide. The use of chemical inputs to cope with biotic stress is both more expensive and non-labor friendly. Therefore, effective control of RKN under tropical conditions is limited, but novel management methods comprising the use of microorganisms and soluble organic matter consist in promising alternatives. In the present study, water-extractable fraction of vermicomposts (WEFV) enriched or not with Trichoderma strains were evaluated for their efficiency in stimulating the growth and yield of bell pepper and tomato as well as their ability in increasing the tolerance of plants against Meloidogyne incognita. Treatments tested were: water-extractable fraction of a conventional vermicomposting process (V); water-extractable fraction of vermicompost enriched with Trichoderma asperellum (V + TA); water-extractable fraction of vermicompost enriched with Trichoderma virens (V + TV). A control treatment (water only) was also conducted for comparison. Bell pepper and tomato seedlings were inoculated with 5000 eggs and eventual second‐stage juveniles (J2) of Meloidogyne incognita race 1 and treated weekly with 200 ml of each vermicompost extract. Bell pepper plants treated with V + TV increased by 13 %, 29 %, and 56 % shoot dry mass, shoot height and root mass when compared to the control, respectively. A 10-fold increase in yield for tomato plants was observed when V + TV was applied when compared to the control. Regarding biocontrol of RKN, treatment V was able to reduce the number of eggs J2 in 62 % on bell pepper and 46 % on tomato plants when compared to the control. Treatment V also decreased RKN reproduction factor in 35 % for bell pepper and in 22 % for tomato plants, when compared to the control. The use of WEFV constitutes a potentially useful alternative to manage RKN and sustain plant growth in vegetable production systems.