History

Plutella xylostella L. is the main pest that attacks Brassicacea plants, especially broccoli (Brassica oleracea L. var. Italica). The attacks caused by these pests are sometimes so severe that the crops fail to harvest. This condition is very detrimental, so farmers often take control measures using synthetic insecticides to control pests. However, the use of synthetic insecticides has a negative impact on the environment, including soil contamination, killing natural predators, accumulation of chemical residues on plant parts, and causing pests to become resistant to insecticides. Therefore, it is necessary to have alternative control techniques using organic materials without using synthetic insecticides that are safe for the environment, namely by using vegetable insecticides such as citronella (Cymbopogon nardus L.). The citronella plant contains essential oils which can be used to control plant pests (OPT). The active compounds contained in citronella essential oil are: dipentene, farnesol, geraniol, myrsena, methyl heptenol, nerol, sitral and citronella. The purpose of this study was to determine the effect of citronella extract on the intensity of attack of P. xylostella L. and to determine the concentration of citronella extract which was able to suppress the intensity of attack of P. xylostella L. on broccoli plants. This study used a randomized block design (RBD), consisting of 6 treatments and 4 replications. Consisting of the application of lemon grass extract with a concentration of 15 ml/l water, 20 ml/l water, 25 ml/l water, 30 ml/l water, synthetic insecticide active ingredient metomyl 25% as much as 4 grams/liter water and control. The results showed that citronella extract had a significant effect on 30 HST starting at a concentration of 15 ml/l water and the greater the concentration, the greater the effect on reducing the intensity of P. xylostella attacks on broccoli plants. In addition, regarding the growth factor of broccoli, it also did not show any effect by the application of citronella extract vegetable insecticides.