Istifadah et al., The J. Anim. Plant Sci. 30(2):2020 377 EFFECTIVENESS OF COMPOST AND MICROBIAL-ENRICHED COMPOST TO SUPPRESS POWDERY MILDEW AND EARLY BLIGHT DISEASES IN TOMATO N. Istifadah * , A. R. Firman and M. F. Desiana Department of Plant Pests and Diseases, Faculty of Agriculture, Universitas Padjadjaran Jl. Raya Bandung – Sumedang Km. 21 Jatinangor 45363, West Java, Indonesia. * Corresponding author’s email: n.istifadah@unpad.ac.id ABSTRACT Compost and its water extract have the potential to suppress plant diseases. This study aimed to compare the effectiveness of compost and compost enriched with antagonistic fungi (compost plus) in controlling powdery mildew and early blight diseases in tomatoes, in the greenhouse and in the field. Compost and compost plus were applied as water extract sprayed onto the leaves every three or seven days, with or without combination with its applications in the planting media. The results showed that the microbial-enriched compost resulted in better disease suppression than the non-enriched compost. The application of compost or compost plus to the growth medium enhanced the effects of the water extract sprayed on the leaves. The compost plus incorporated in the nursery medium and planting holes, as well as spraying the water extract on the leaves every three or seven days, suppressed powdery mildew and early blight diseases by 41–49%. This study revealed that even though the enriched compost was intended for controlling soilborne diseases, their water extract can also be used for controlling airborne diseases. Key words: antagonistic fungi, field-grown tomato, compost plus, water extract. https://doi.org/10.36899/JAPS.2020.2.0031 Published online March 02, 2020 INTRODUCTION Tomatoes can be cultivated in greenhouses or in plastic houses, as well as in the fields. One of the limiting factors in greenhouse tomato cultivation is powdery mildew disease caused by Oidium neolycopersici (Jacob et al., 2008; Cerkauskas and Brown, 2015). The pathogen infects all aerial parts of tomato plants, excluding the fruits. Severe infections lead to premature senescence of the leaves and reduction in the fruit size (Jacob et al., 2008). In field-grown tomatoes, one of destructive diseases is early blight disease (Alternaria solani). The pathogen infects all aerial parts of the plants, leading to leaf defoliation and significant yield loss (Gulzar et al., 2018). The most common control measure of the diseases is the use of pesticides. However, the intensive use of pesticides for long periods can lead to many negative impacts, such as the development of resistant pathogens, environmental pollution and accumulation of pesticide residues on the agricultural products (Mahmood et al., 2016). The increase in environmental awareness and the demands of pesticide-free products have encouraged the development of environmentally friendly disease control measures, including the use of organic matters, such as compost. The ability of compost to control soil-borne diseases has been reviewed (Mehta et al., 2014). In addition to its effects on soilborne diseases, compost can also induce plant resistance to air-borne diseases (Yogev et al., 2010; Segarra et al., 2013). For controlling airborne diseases, compost can be applied in the form of water extract or compost tea, applied as foliar sprays. The efficacies of compost tea to suppress various air-borne diseases have been reported (Marín et al., 2013; St. Martin, 2014). The suppressive effects of compost tea on plant diseases could be due to several mechanisms. Generally, the suppressive effects of compost tea are associated with microorganisms, as the suppressive effects were usually decreased or eliminated by sterilisation (Marín et al., 2013; St. Martin, 2014). Microorganisms in the compost tea can also induce the plants resistance to the pathogens (Sang et al., 2010; Sang and Kim, 2011). In some cases, the disease control by compost tea was also due to heat- stable chemical compounds (Sang et al., 2010; Marín et al., 2013). The disease suppressive effects of compost, however, are usually inconsistent. The addition of antagonistic microbes to compost can improve the level and consistency of the suppressive effects (Mehta et al., 2014). For example, the enrichment of compost with Trichoderma harzianum (Pugliese et al., 2011; Ros et al., 2017) or Trichoderma asperellum (Ros et al., 2017) have been reported to enhance the disease suppressive effects. We have developed compost enriched with several antagonistic fungi (Trichoderma harzianum, Papulaspora sp. and Paecilomyces fumosoroseus), called ‘compost plus’. The incorporation of compost plus into the nursery medium and planting holes suppressed The Journal of Animal & Plant Sciences, 30(2): 2020, Page: 377-383 ISSN: 1018-7081