Inhibitory Activity of Piper Caninum Leaf Extract against Curvularia Spotting Disease on Rice Plants

Rice is a plant that has been intensively breed, especially in Asia, most of the population’s staple food is rice. There were Many types of rice varieties have been developed for high yeald production. Different rice diseases arise that many treat to reduce production. Such as curvularia spotting disease caused by the fungus Curvularia sp. Infection of Curvularia species causing leaf spots, leaf blights, kernel root, grain deformation and other diseases are well known globally. It was discovered that the small brown oval spots on the Ciherang rice variety cultivated in Bali, Indonesia was caused by Curvularia verruculosa. This disease could reduce the rice yield up to almost 50%. The application of commercial fungicide by the local farmers has not been satisfactorily successful in term of controlling the disease but instead bring damages to the environment and the soil as well. Farmer’s safety is also another serious issue. The current studi develop a natural and green fungicide to check the efficacy of Piper caninum extract against the fungi. Research in the laboratory uses a completely randomized design and research in the field uses a randomized group design.The method of making leaf extracts uses maceration method. Diffusion well technique showed a strong inhibition of the abstract against the C. verruculosa with 22mm inhibition. Zone with a total inhibition of 4% extract concentration. The minimum inhibitory concentration (MIC) was low of 0.5%. Scanning electron images of the treated fungi showed hollow and wrinkled mycelia morphology indicating lysis of the cell has occurred. P. caninum leaf extract at a concentration of 3% provides the highest obstacle to the intensity of C. verruculosa disease, whereas in the treatment of leaf extract concentration p. caninum 4% intensity of C. verrucuosa disease has decreased because rice plants are toxic at a concentration of 4%. Further research is needed regarding the treatment of P. caninum leaf extract against C. verruculosa in rice fields. Key words: Curvularia verrucuosa, Piper caninum, Rice, Scanning electron images. INTRODUCTION Rice is the main food croop in Indonesia and there are many highly yielding varieties popular in local farmers. Rice production limits on different key factors viz small paddy fields, decreasing soil quality, limited irrigation facilities, as well as disease and pest infestation. One of the emerging rice diseases known as curvularia spotting disease caused by the fungus Curvularia sp. Which is characterized by the curvularia spotting in the form of brown spots on rice plants, especially on the leaves. This disease is also found on Lily plants (Hippeastrum striatum) in China (Yin et al, 2018), in Cymbopogon caesiusdi grass in India (Avinash, 2015). These fungal colonies are brownish black in the middle and grayish black at the edges (Su et al., 2015). Curvularia spots cause the rice spikelets to change color and experience tissue death. Curvularia spotting can cause yield loss of 49.53% in the Ciherang rice species (Karta et al., 2018). Today, farmers deal with Curvularia spotting diseases by using synthetic pesticides (nordox) that have the potential threat to the local agro-ecology. According to Kiss et al (2020), the curvularia fungus is a pathogen that has a conidia a septa and a hyphae. Curvularia crepinii fungus has reported to have secondary metabolites that are phytotoxic to Echinochloa crusgalli (Yin et al, 2018). Given the impact of the use of pesticides is very dangerous to the agro-ecology, the local Indonesia government began to launch the organic farming movement (Suprapta, 2014). Organic farming is starting to be in demand by some tourism communities in Bali, such as the development of organic agriculture in Jati Luwih village, Penebel, Tabanan Bali, which is one of the tourist villages (Fumitaka et al, 2015). The increase in use of biopesticides are very appropriate for sustainable agricultural development. These biopesticides can be biological agents derived from plant parts such as plant extracts. Kumari and Shanmugam (2020) in which of the 12 rice varieties tested on the organic farming system in Tamil India obtained culture CB 05022 has the largest production (4.88 tons/ha) can 1Udayana University, Bukit Jimbaran, Badung, Bali, Ind