Attraction of the predatory mites Typhlodromalus manihoti and Typhlodromalus aripo to cassava plants infested by cassava green mite

Abstract

The attraction of the predatory mites, Typhlodromalus manihoti and Typhlodromalus aripo, to the host plant‐spider mite complex, Manihot esculenta–Mononychellus tanajoa, was investigated with a Y‐tube olfactometer. Factors examined included predator starvation period, several combinations of cassava leaf biomass and initial M. tanajoa infestations, M. tanajoa‐damaged leaves with mites and/or their residues removed, M. tanajoa alone, and mechanically damaged cassava leaves. We found that females of T. manihoti and T. aripo were significantly attracted to M. tanajoa‐infested cassava leaves when the predators were starved for 2, 6, or 10 h. Satiated T. aripo was significantly attracted to infested cassava leaves whereas satiated T. manihoti did not discriminate between infested and non‐infested leaves. When a choice was given between either two or four leaves infested with 200 female M. tanajoa and an equivalent number of non‐infested leaves, 2 h‐starved T. manihoti and T. aripo were significantly attracted to each of the infested groups of cassava leaves. At a density of 12 female M. tanajoa per leaf on four leaves, 2 h‐starved T. manihoti was still attracted to M. tanajoa‐infested leaves whereas 2 h‐starved T. aripo was not attracted. When a choice was given between non‐infested cassava leaves and either infested leaves from which only M. tanajoa females had been removed, or infested leaves from which all M. tanajoa and their visible products (web, feces) had been wiped off, T. aripo preferred odors from both types of previously infested leaves. Typhlodromalus manihoti was only attracted to infested leaves from which the M. tanajoa females only had been removed. Finally, the two predators were not attracted to 400 female M. tanajoa on clean cotton wool or to mechanically wounded leaves. This supports the hypothesis that M. tanajoa damage induces volatile cues in cassava leaves that attract T. manihoti and T. aripo to M. tanajoa‐infested leaves.

Odour-mediated responses of a predatory mirid bug and its prey, the two-spotted spider mite

“…1B) revealed a significant response to the former (PROC GLM F = 11.63, df = 7, P = 0.014 (SAS Institute Inc. 1989)). These results are in accordance with those of Sabelis et al (1984) who found that T. urticae in itself is not attractive to P. persimilis; and with those of Gnanvossou et al (2001), who showed that neither of two predatory mites (Typhlodromalus manihoti Moraes and T. aripo DeLeon (Acari: Phytoseiidae)), were attracted to the direct odour of the cassava green mite, Mononychellus tanajoa (Bondar) (Acari: Tetranychidae). Dong and Chant (1986), on the other hand, reported that both adult females and protonymphs of P. persimilis were attracted to adults and webbing odours of adult Tetranychus pacificus (McGregor) (Acari: Tetranychidae) (but not to odours from either prey eggs, larvae or protonymphs).…”

“…faeces, webbing etc.). However, predatory mites have been shown to react to odours emanated directly by tetranychid mites and their associated products (Sabelis et al 1984;Dong and Chant 1986;Gnanvossou et al 2001;Gols et al 2003) and it is therefore possible that also conspecific and heterospecific herbivores posses the ability to react not only to HIPVs but also to such direct odours.…”

Integrating cassava varieties and <i>Typhlodramulus aripo</i> to sustain biological control of cassava green mite

“…Gnanvossou et al (2001) and Magalhaes et al(2002) found that T. aripo has a high searching ability for CGM, at very low prey densities, which increases its efficiency as a biocontrol agent. Cassava varieties that sustain relatively low CGM population will facilitate biological control by T. aripo at a fast rate.…”

Does Methyl Salicylate, A Component of Herbivore-induced Plant Odour, Promote Sporulation of the Mite-pathogenic Fungus Neozygites tanajoae?

“…As a consequence of feeding damage, cassava plants release a blend of volatiles (including MeSA), which has been also found to attract several phytoseiid mites that are predators of M. tanajoa (Janssen et al 1990;Gnanvossou et al 2001). The entomopathogenic fungus N. tanajoae is specific to M. tanajoa (De Moraes and Delalibera 1992;Hountondji et al 2002;Delalibera and Hajek 2004).…”