Interaction between Paranosema locustae and Metarhizium anisopliae var. acridum, two pathogens of the desert locust, Schistocerca gregaria under laboratory conditions

Interactions of two insect pathogens, Paranosema locustae (Protista: Microsporidia) and Metarhizium acridum (Fungi: Hypocreales), during a mixed infection of Locusta migratoria (Insecta: Orthoptera) nymphs

“…A remarkable negative effect on locust survival due to mixed infection was observed only when fungus was applied at the onset of microsporidian spore maturation, resulting in significantly decreased LT 50 . Similar effects were observed in P. locustae-infected desert locusts, treated with Metarhizium (Tounou et al, 2008b). In this study, synergism was observed when microsporidia were applied at higher doses, which are known to invoke mass spore maturation earlier as compared to lower dosages (Issi, 1986).…”

“…Median survival time (LT 50 ) was estimated using Kaplan-Meier procedure followed by log rank test (SigmaStat v3.10, Systat Software Inc.). Analyses for additive, antagonistic and synergistic interactions were based on a binominal test which involved comparing the expected and observed mortalities due to mixed treatment, following the approach described in Tounou et al (2008b), on a daily basis.…”

“…Locust nymphal mortality due to infection with fungi, microsporidia, or fungi applied at days 3 (A), 6 (B) and 9 (C) after locusts were treated with microsporidia (data pooled from four experiments; number of nymphs per treatment N = 80). The mortality expected from the combination of two pathogens, as well as antagonism and synergism between microsporidia and fungi at given days are estimated as in Tounou et al (2008b). (Table 1).…”

Ecological factors in the inundative use of fungal entomopathogens

“…For example, Brinkman and Gardner (2000) observed that fire ants (Solenopsis invicta L.) from microsporidian-infected colonies were 4.5 times more susceptible to B. bassiana than ants from healthy colonies, based on the LD 50 ratio. Similarly, at low doses, joint infections of Paranosema (Nosema) locustae Canning and B. bassiana had a faster onset of mortality than nymphs with single infections and at high doses were synergistic (Tounou et al 2008). Infections of M. acridum and a B. bassiana complemented each other under oscillating high and low temperatures (Inglis et al 1999).…”

Immunological mechanisms of synergy between fungus Metarhizium robertsii and bacteria Bacillus thuringiensis ssp. morrisoni on Colorado potato beetle larvae

“…Analyses for additive and synergistic interactions were based on a binominal test, which involved comparing the expected and observed mortalities due to mixed treatment following the approach described in Tounou et al (Tounou et al, 2008) on a daily basis. The activity of enzymes, THC and encapsulation rate are given as the arithmetic mean ± S.E.…”