Fontes de matéria orgânica e seus efeitos na severidade da murcha-de-fusário do caupi

Abstract

Cowpea (Vigna unguigulata) is one of the most important crops in North and Northeast Brazil, posing an important socioeconomic role for many small and medium-size farms in these regions. The Fusarium wilt caused by Fusarium oxysporum f. sp. tracheiphilum is a major disease for cowpea crops grown in Northeast Brazil. Thus, the work was carried out to evaluate the effect of different organic matter sources on the severity of cowpea Fusarium wilt. The experiment was conducted in greenhouse conditions use a sandy loam soil with pH adjusted through liming and artificial F. oxysporum infestation. The sources of organic matter tested were cow manure (CM), hen manure (HM), earthworm humus (EH), textile residue sludge (TRS), and sewage sludge (SE). Such materials were added into soil in rates equivalent to 0, 20, 40, 60, and 80 t/ha and kept incubated for 15 days before sowing of cowpea seeds, cultivar BR-17 Gurgeia. The results for disease severity, number and viability of rizobium, fresh mass of cowpea shoots and roots, microbiological and chemical soil analysis were obtained 30 days after sowing. The results showed that the different sources of organic matter tested had contrasting effects on the cowpea fusarium wilt. For instance, both the cow and hen manure incorporated into the soil promoted a significant increase in the disease severity index whereas earthworm humus did not have any effect on disease severity.