Multiple mechanisms of nematode control conferred by seed and root applications of microbial biocontrol agents, Trichoderma and Bacillus
M. CADLE-DAVIDSON (1), G. Harman (1), R. Hendriks (2), W. Nosir (1) (1) Advanced Biological Marketing, Inc, U.S.A.; (2) Advanced Biological Marketing, Inc South Africa Division, South Africa
Nematode diseases of plants are estimated to contribute $150B USD in annual crop losses around the world due to Cyst (Heterodera and Globodera spp) and Root knot nematode (Meloidogyne spp) infection in species ranging from Legumes to Solanaceae to Brassicaceae among others. Chemical and host resistance resources are available for control however a common recommended practice is rotation to nonhost crops. Biological control of nematode diseases has been shown in the literature with the main mechanism being direct antagonism. 2015 field observations of soybeans in Minnesota USA (strip plots) and Gauteng South Africa (replicated small plots) indicated significant control of Soybean cyst and Root knot nematodes using Trichoderma and Bacillus seed treatments. Subsequently, a split root greenhouse experiment was conducted to identify strain specific activities and gain insight into control mechanisms. Tomato plant root systems were split and transplanted into two pots, both infested with M. javanica, such that individual plants would be influenced by two pots each. One of the two pots was treated with an individual biocontrol strain or strain combination as a soil drench. Twelve treatments were tested each with six replicates. The results showed excellent control of nematodes by some strains and strain combinations, synergistic effects between strains, and multiple mechanisms of control. Mechanisms and implications for population control will be discussed.