Pre- and post- emergence control of Hovenia dulcis with extracts obtained from pepper (Capsicum baccatum)

Abstract

This study evaluated the efficiency of extracts obtained from Capsicum baccatum by ultrasound-assisted extraction in the control of Hovenia dulcis, which is an invasive species popularly known in Brazil as “uva-do-japão”. The effects of extraction time (20 – 60 min), maximum power fraction (50 – 100%), and pulse cycle (0.3 – 0.7) were investigated on the activities of extracts. The pre-emergence assays demonstrated inhibition of 45-100% on the 14th day. In the post-emergence, the root and shoot lengths were 3.0 and 2.6 times smaller than the control (without application of extract). The fresh mass and dry mass were 4.7 and 4.2 times lower than the control. All these best results were found in the assay with higher extraction time (60 min) and power fraction (100%), and lower pulse cycle (0.3). Chlorophyll a and b and carotenoids ranged from 0.84 to 1.15, 0.19 to 0.35 and 0.32 to 0.40 mg/g fresh mass, respectively. Overall, it is demonstrated that extracts from Capsicum baccatum presented an inhibitory effect on the germination of Hovenia dulcis. Although the extract did not completely inhibit germination or cause the death of seedlings, it presented an effect against the normal development of seedlings, including the roots and shoots, thus allowing it to be used as a control strategy before germination or for small plants of this invasive species.