Efficacy of lantana (Lantana camara) extract application against aphids (Brevicoryne brassicae) in rape (Brassica napus) over varied periods of time

Contact bioefficacy of lantana (Lantana camara L.) leaf extract (LLE) against rape aphids (Brevicoryne brassicae L.) in three rape (Brassica napus L.) seed brands at given time (hours) periods was explored. Samples of pounded young leaves mixed with distilled water (3 kg l-1, 2 kg l-1 and 1 kg l-1) were prepared. Dimethoate (7.5 ml 10 l-1) and distilled water were the positive and negative controls, respectively. Treatments were arranged in a randomized complete block design (RCBD); 3 x 5 factorial arrangement, replicated 5 times. Adult aphids (10) were introduced to each plant. Aphid mortality at 6, 12, 18 and 24 h after application of treatments was evaluated. There was no significant interaction between seed brand and treatment at all times. Lantana treatments showed significant mortality effect (p < 0.001) on aphids at all times. The highest LLC (3 kg l-1) showed the highest aphid mortality at each period of time after application, and of all the periods, the longest time after application (24 h), showed the highest mortality (9.67). It is recommended that smallholder farmers use 3 kg l-1 LLC to control aphids on rape, and allow 24 h after application to get the greatest kill. Key words: Lantana leaf extract, rape, aphid mortality, hours after application.