Search for effective natural enemies of Tetranychus evansi in south and southeast Brazil

Abstract

Tetranychus evansi Baker & Pritchard is an important pest of Solanaceae in several countries. Introduced accidentally to Africa, it presently occurs in many countries of that continent. In some of them, it is considered a key pest. The suspected area of origin of this mite is South America. The objective of the present study was to identify phytoseiid mites on solanaceous plants in association with T. evansi in south and southeast Brazil for introduction in the African continent for use in a classic biological control program. Almost 1,400 predatory mites of the family Phytoseiidae were collected, on 22 solanaceous species. The Amblyseiinae were the most diverse group in this study. Twenty-three of the species found belong to this subfamily, while only three belong to the Typhlodrominae and two to the Phytoseiinae. The most abundant and most frequent phytoseiid species were Phytoseius guianensis De Leon and Galendromus annectens (De Leon) of the Phytoseiinae and Typhlodrominae, respectively. The most frequent and abundant species of Amblyseiinae was Neoseiulus tunus (De Leon). Phytoseius guianensis and N. tunus were never found in association with T. evansi and G. annectens was found only once in association with it. Two factors suggested Phytoseiulus longipes Evans as the most promising predator found in this study. It could walk very well on tomato leaves infested by T. evansi, without being hampered by the profuse webbing produced by the prey and by the trichomes. In addition, several specimens of both sexes including eggs and nymphs of the predator were found associated with T. evansi on three different plant species and in two different periods of the year, when T. evansi was the only arthropod present on the leaves.

Recent emergence and worldwide spread of the red tomato spider mite, Tetranychus evansi: genetic variation and multiple cryptic invasions

“…The restricted geographical distribution of T. evansi in South America, which has been confirmed by several intensive surveys (Da Silva et al 2008;Furtado et al 2005;Furtado et al 2006) might be explained by climatic conditions, but could also reflect other environmental or ecological factors. Low densities of T. evansi were generally observed in South America compared to most of the newly invaded continents where the mite undergoes heavy outbreaks, such as in Africa (Saunyama and Knapp 2003) and in Southern Europe along the Spanish Mediterranean coast (Ferragut and Escudero 1999).…”

“…Among the factors that might account for different mite densities in the native and invaded areas is competition with other tetranychid species, which are abundant on solanaceous plants in Brazil [32 and 17 tetranychid species have been reported from solanaceous plants in South America and Europe, respectively (Migeon and Dorkeld 2006)]. In addition, effective native natural enemies in South America maintain T. evansi populations at low densities (Furtado et al 2005;Furtado et al 2006;Rosa et al 2005). For example the neotropical predatory mite Phytoseiulus longipes has been described as successfully developing on T. evansi (Maxime Ferrero, personal communication; Furtado et al 2007), and several other mite predators of the family Phytoseiidae have been reported associated with T. evansi on tomato and wild solanaceous plants in Brazil (Fiaboe et al 2006;Furtado et al 2006;Rosa et al 2005).…”

“…In addition, effective native natural enemies in South America maintain T. evansi populations at low densities (Furtado et al 2005;Furtado et al 2006;Rosa et al 2005). For example the neotropical predatory mite Phytoseiulus longipes has been described as successfully developing on T. evansi (Maxime Ferrero, personal communication; Furtado et al 2007), and several other mite predators of the family Phytoseiidae have been reported associated with T. evansi on tomato and wild solanaceous plants in Brazil (Fiaboe et al 2006;Furtado et al 2006;Rosa et al 2005). A fungal pathogen was also suggested as the causative agent of the decline of T. evansi populations in northeastern Brazil, when in 1979 occasional outbreaks in tomato field crops were reported (Humber et al 1981).…”

Visual, vibratory, and olfactory cues affect interactions between the red spider mite Tetranychus evansi and its predator Phytoseiulus longipes

“…Several studies undertaken in the past to control T. evansi using Phytoseiulus persimilis (AthiasHenriot) and N. idaeus (Denmark & Muma) have not been promising ). However, a southern Brazilian population of P. longipes was found effective on T. evansi in laboratory and greenhouse assays, and subsequently, introduced into Kenya for the successful control of the pest (Fiaboe et al 2006;Furtado et al 2006;Ferrero et al 2007). …”

Efficiency of Phytoseiulus longipes Evans as a control agent of Tetranychus evansi Baker & Pritchard (Acari: Phytoseiidae: Tetranychidae) on screenhouse tomatoes

“…When found, population levels are usually low, what could at least partly be due to the effect of natural enemies. A promising phytoseiid predator was found in Uruguaiana, Rio Grande do Sul State, southern Brazil (Furtado et al 2006). Furtado et al (2007) and Ferrero et al (2007) showed that Phytoseiulus longipes Evans could develop and reproduce on T. evansi as prey, which was never observed for other phytoseiids, including an African population of P. longipes tested by Moraes & McMurtry (1985).…”