Application of alkaline-stabilised biosolids for Meloidogyne incognita suppression in microplots

Abstract

Summary -N-Viro Soil (NVS) is an alkaline-stabilised biosolid that has been shown to suppress Meloidogyne incognita. In separate microplot studies, NVS was applied either alone at different rates (0, 25, 50, 75, 100 dry t ha −1 ), or in combination with M. incognitaresistant and M. incognita-susceptible cultivars, to different M. incognita initial densities (0, 37 500, 75 000 eggs/microplot). NVS suppressed M. incognita. During year 1, increasing rates of NVS resulted in higher soil solution pH and greater M. incognita J2 and egg suppression. Soil solution pH remained higher in NVS-amended plots compared to the unamended control in years 2 and 3. NVS was more effective in reducing moderate than in reducing high initial nematode populations, with 94-100% reduction in egg and juvenile populations compared to 75-79%, respectively. In all experiments, a reduction in nematode populations by NVS, alone or in combination with a resistant cultivar, did not occur consistently in years 2 or 3. Unfortunately, the application rate of NVS required to achieve this reduction in nematode populations is probably not agronomically realistic. Additional research may allow the rate of NVS required to suppress plant-parasitic nematodes to be reduced.Keywords -ammonia, biosolid, Glycine max, N-Viro Soil, pH, soybean.The N-Viro process mixes dewatered municipal biosolids with alkaline admixtures (i.e., cement kiln dust, fly ash or quicklime) to yield a pathogen-free, solid material with many beneficial agronomic properties (Logan & Burnham, 1995). The agricultural value-added benefits of N-Viro Soil (NVS) include improved soil fertility, addition of organic matter and suppression of plantparasitic nematodes (Welacky & Topp, 2001;Zasada & Tenuta, 2004;Zasada, 2005).N-Viro Soil has been shown to suppress plant-parasitic nematodes in a range of studies (Alptekin, 2001;Welacky & Topp, 2001;Zasada & Tenuta, 2004;Meyer et al., 2005;Zasada, 2005). In laboratory tests (Zasada & Tenuta, 2004), the lethal concentration of NVS that killed 90% (LC 90 ) of second-stage juvenile (J2) populations was 1.4% dry weight amendment/dry weight sand for Meloidogyne incognita and Heterodera glycines. The LC 90 values for eggs were 2.6 and >3.0% for M. incognita and H. glycines, respectively. Nematode mortality caused by NVS was positively correlated with sand suspension pH levels and, to a lesser extent, with ammonia accumula- * Corresponding author, e-mail: zasadai@ba.ars.usda.gov tion following amendment (Zasada & Tenuta, 2004;Zasada, 2005). Glasshouse and field experiments have also demonstrated some suppression of H. glycines (Alptekin, 2001;Welacky & Topp, 2001) and M. incognita (Meyer et al., 2005).We have previously reported on the ability of NVS to suppress M. incognita and H. glycines and the mechanisms involved (Zasada & Tenuta, 2004), the factors that may influence the efficacy of NVS (Zasada, 2005), and NVS in combination with a biological control agent for M. incognita suppression on melon (Meyer et al., 2005). The research reported here is a st...

Behavioural response of Meloidogyne incognita to benzyl isothiocyanate

“…Gall ratings of 0-8 were assigned to intact root systems according to the method of Daulton and Nusbaum (1961), with a 0 rating assigned for no galling and an 8 (maximum) rating assigned to heavily galled roots. Root length and wet weight were recorded, and the entire root system was destructively processed to extract M. incognita eggs (Zasada et al, 2007).…”