Garlic is the main commodity of farmers in Tawangmangu, Central Java. The superior variety in the area is Tawangmangu Baru. Unfortunately this variety is susceptible to garlic root rot caused by Fusarium oxysporum f.sp. cepae. The infection of this pathogen was increased by the presence of the nematode Ditylenchus dipsaci. Besides the loss due to single infection, this nematode can predispose garlic to be susceptible to garlic root rot disease. Therefore, population decrease of D. capsaci is important as a component of integrated control of the two pests. Environmentally friendly control is a priority now and in the future, including biologically, such as the application of mycorrhizae and orgnically such as organic fertilizers. This paper reports a decrease in the population of D. dipsaci in garlic cultivation with the application of mycorrhizae and organic fertilizers. This research was conducted on farmer’s land in Tawangmangu Karanganyar Central Java at an altitude of 1000 m asl and Andosol soil type. The results showed that mycorrhizae, compost, and husk charcoal could decrease the population of D. capsaci. The effectiveness of nematode population decrease in the single treatment of mycorrhizae, compost, and husk charcoal were 18.45, 42.14, and 27.56%, respectively. While the combination of the three treatments gave the highest effectiveness value, namely 48.52%.

The main obstacle to garlic cultivation is the attack of Fusarium oxypsorum f. sp. cepae (FOCe) causes basal rot. Bacillus and Trichoderma are popular antagonist microorganisms that can act as biological control agents (BCA). This paper would like to report on the effectiveness and compatibility of Bacillus sp. and Trichoderma sp. as a biological control of basal rot of garlic based on laboratory and Greenhouse tests. The results of in vitro studies show that Bacillus and Trichoderma are potential antagonist agents through antibiosis and even Trichoderma through competition. Meanwhile, in vivo, the two biological control agents were not effective in reducing wilting intensity but effective in reducing basal rot intensity and increasing disease tolerance. Increasing disease tolerance is showed by the yield that is higher significantly than those control with no BCA. Bacillus sp. and Trichoderma sp. have been shown to be incompatible BCA based on both in vitro and in vivo tests, which are indicated by the effectiveness of the combination application being less effective than alone.