Colored Plastic Mulch Effects on Plant Performance and Disease Suppression in Organically Grown Bell Pepper (Capsicum annuum)

Weeds and diseases are major biological competitors that pose significant threats to organic production of vegetables in southeastern US during the summer. We evaluated plasticulture as an alternative weed and disease management strategy for open field organic production of bell peppers. The objective of the research was to assess the effects of four colored plastic mulches on soil temperature, moisture, fruit yield and suppression of weeds and diseases on bell pepper. Bell pepper cv ‘King Arthur’ was planted on raised soil beds covered with colored (olive green, black, white and silver) mulch treatments including a control (bare soil). The experimental design was a randomized complete block with four replications. Soil temperature and moisture, disease incidence and severity, and fruit yield were determined. Plant performance (growth and yield) varied with mulch type. The black and olive plastic mulches warmed the soil significantly more than the reflective silver and bare soil. Bell pepper plants across all mulch treatments exhibited susceptibility to bacterial leaf spot (BLS). However, the incidence and severity of BLS varied with mulch type. Plants on reflective silver plastic displayed significant BLS incidence and severity compared to the olive plastic and bare soil. The black, white, and reflective silver plastic mulches significantly increased fruit yields, while the olive mulch and bare soil exhibited poor crop performance. These results suggest that the black and white plastic mulches retain the potential to be used in organic vegetable production in Alabama and the southeastern US.