Effects of organic and conventional pesticides on plant biomass, nematode diversity and the structure of the soil food web

Abstract

Due to the uncertain future of the soil fumigants most commonly used in the EU, there is a need to develop new integrated pest management programmes to control crop diseases. Different nematode management practices, such as solarisation and the use of ecological nematicides, including nematophagous fungi, are used to control populations of plant-parasitic nematodes, one of the most common pests affecting crops. The objective of this study was to determine the effects of organic (neem seed paste and a mixture of nematophagous fungi) and conventional (oxamyl and fenamiphos) nematicides on soil physical chemical properties, soil biodiversity and plant biomass. Such effects were investigated in two types of habitats: low diversity soils from an agricultural farm and high diversity soils from a natural vegetation area. The greater effect was observed with the neem treatment, which induced a large boost of dauer juveniles in the nutrient-depleted soil, while the same treatment induced an increase of populations of less opportunistic, generalist bacterivore nematodes in the pine forest soil, rich in organic matter. We have studied the effects of different biological and chemical nematicides on the whole soil nematode community through ecological indices and their relationship with plant biomass, but further research is needed to improve understanding of the effect of these products on nematode assemblages.

The fate of biological soil quality : Functional diversity and realised niche width

“…In Chapter 4, I observed higher levels of I CS in arable fields under conventional management in (BASIS) as well as in in the commercial farms, in line with the conclusions of Chapter 2 that increasing land use intensity leads to increases in the I CS . These results are in line with recent studies that show the potential of organic amendments to increase nematode richness and community structure (Liu et al 2016), and the use of inorganic fertilizers, as well as the use of pesticides to changes in the nematode community (Liu et al 2016;Carrascosa et al 2015). In the SHE, however, integrated management had a higher I CS than conventional practices, and both treatments had a much higher I CS (0.8 on average) than treatments at BASIS (between 0.4 and 0.6) or values found in commercial farms (between 0.2 and 0.4).…”

“…Disease suppression (another soil mediated function) can also be affected by microbes and nematodes. These groups are often the source of plant disease, but can also lead to suppression by, for example, direct predation on parasites (Carrascosa et al 2015;Sánchez-Moreno and Ferris 2007). Therefore, maintaining a functioning biological community in the soil is of utmost importance in sustainable soil management (Brussaard et al 2007;Lavelle et al 2006;Griffiths et al 2018).…”

Sensitivity of Nematode Community Analysis to Agricultural Management Practices and Inoculation with Local Effective Microorganisms in the Southeastern United States

“…Because of the Tyelenchidae family's ambiguous position in the soil food web [62], it was interesting to find that, in both seasons, nematodes from the Tylenchidae family showed a similar trend in correlations with CO 2 , N min and yield as the FF nematodes. In nematode trophic analysis it is unclear whether to place Tylenchidae among the plant parasitic nematodes or the fungal-feeders [63][64][65][66][67]. These findings suggest that, in our case, Tylenchidae are more closely associated with fungal-feeders.…”

Fungicidal potential of essential oils in control of Fusarium spp. and Sclerotinia sclerotiorum

“…When using the acetic extract of basil (O. basilicum) at 25% concentration, it gave 50% inhibition of the mycelial growth of Fusarium spp. (CAMATTI-SARTORI et al, 2011). The extract of Ocimum gratissimum at the concentration of 30% showed only 3.57% of control in the mycelial growth of S. sclerotiorum (GARCIA et al, 2012).…”