Protecting maize from rootworm damage with the combined application of arbuscular mycorrhizal fungi, Pseudomonas bacteria and entomopathogenic nematodes

Abstract

Diabrotica virgifera virgifera LeConte, the western corn rootworm (WCR), is the most destructive pest of maize in North America, and has recently spread across central Europe. Its subterranean larval stages are hard to reach with pesticides and it has evolved resistance to conventional management practices. The application of beneficial soil organisms is being considered as a sustainable and environmental friendly alternative. In a previous study, the combined application in wheat fields of arbuscular mycorrhizal fungi, entomopathogenic Pseudomonas bacteria, and entomopathogenic nematodes was found to promote growth and protection against a natural pest infestation, without negative cross effects. Because of the insect-killing capacity of the bacteria and nematodes, we hypothesized that the application of these organisms would have similar or even greater beneficial effects in WCR-infested maize fields. During three consecutive years (2015–2017), we conducted trials in Missouri (USA) in which we applied the three organisms, alone or in combinations, in plots that were artificially infested with WCR and in non-infested control plots. For two of the three trials, we found that in plots treated with entomopathogenic nematodes and/or entomopathogenic Pseudomonas bacteria, roots were less damaged than the roots of plants in control plots. During one year, WCR survival was significantly lower in plots treated with Pseudomonas than in control plots, and the surviving larvae that were recovered from these plots were lighter. The bacterial and nematodes treatments also enhanced yield, assessed as total grain weight, in one of the trials. The effects of the treatments varied considerable among the three years, but they were always positive for the plants.

Patterns of Occurrence and Activity of Entomopathogenic Fungi in the Algarve (Portugal) Using Different Isolation Methods

“…Moreover, the description of the EPF/EPN community assemblage by the soil properties provides new insights on shared niches among different guilds. Under a restrictive and prohibitive context of many agrochemical products, identifying the best ecological scenarios for the mutual use of different beneficial soil organisms [ 73 , 74 ], promoting cooperation and avoiding competition for hosts [ 11 ], will provide more effective bio-tools that can contribute to a more sustainable agriculture.…”

Bacillus velezensis BM21, a potential and efficient biocontrol agent in control of corn stalk rot caused by Fusarium graminearum

“…Excessive use and misuse of these chemicals have caused food contamination, weed and disease resistance, and negative environmental outcomes with a serious impact on human health (Alori and Babalola 2018). However, the application of beneficial soil organisms is being considered as a sustainable and environmental friendly alternative (Jaffuel et al 2019). Thus, biological control may overcome the shortage of chemical agents and ensure healthy growth of corn plants throughout the entire growth period, and therefore has become a crucial research focus.…”

Biology and Management of Pest Diabrotica Species in South America

“…Promising results were obtained with the strain of B. bassiana ESALQ PL63, used in seed treatments, which decreased the defoliation caused by D. speciosa adults in beans for more than three weeks after seeding [116]. Similar results were obtained in maize when the soil was treated with Pseudomonas (Pseudomonadales: Pseudomonadaceae) [117] and Bacillus pumilus [118].…”