EFEKTIVITAS EKSTRAK BIJI MAHONI (Swietenia mahagoni) DAN PENGAPURAN TERHADAP PERTUMBUHAN PENYAKIT AKAR GADA PADA TANAMAN KUBIS (Brassica oleracea var. capitata)

Brassica oleracea L. (cabbage or Brassicaceae) is commonly known as cabbage, but it also includes various other popular vegetables such as cauliflower (including Romanesco), broccoli, Brussel sprout, kohlrabi, and kailan. Cabbage has been around since World War II and planted in mountainous areas for seeds always imported from abroad, Europe, especially from the Netherlands. (Permadi and Sastrosiswojo, 1993). The development of cabbage production in Indonesia is constrained by clubroot disease caused by the fungus Plasmodiophora brassicae. According to Pratiwi, et al (2015), the annual losses caused by pathogens that cause clubroot all over the world reached 10-15%. According to Semangun (2007), clubroots are difficult to control because pathogens can durable in the soil even without a host plant, so there is a need to develop sustainable controls. The efforts have also been made by Indonesian farmer with chemical control, but with very high dependence so that chemical drugs cannot overcome existing problems. The purpose of this study was to find the potential of mahogany seed extract and calcification in controlling clubroot disease in cabbage plants. This research has been conducted at Screen House, Kasin Hamlet, Ampeldento Village, Karangploso. The activity is held for four months starting October 2018 – January 2019. The experimental design uses a simple Randomized Group Design (RBD). The treatment was repeated 3 times, so there were 24 experimental units. The statistical analysis used was a simple RAK variance analysis (ANOVA) with a further test Different Honest Real Test (BNJ) of 5% to find out the treatment effect on variables measured including plant height, leaf number, crop wet weight, crop diameter, root weight, length root, and level of attack on the root. The treatments of mahogany seed extract 50% + calcification with the lowest percentage of attack intensity was 10.85% while the control with the percentage of attack intensity was 57.39%