Effect of trichomes on the predation of Tetranychus urticae (Acari: Tetranychidae) by Phytoseiulus macropilis (Acari: Phytoseiidae) on tomato, and the interference of webbing

Abstract

The two-spotted spider mite, Tetranychus urticae Koch, is an important pest of tomato in different parts of the world. Biological control of this pest on this crop has not been very successful. Phytoseiulus macropilis (Banks) has been used commercially for the control of T. urticae on different crops, but no information has been published on its potential to control T. urticae on tomato. The objective of this work was to compare the performance of a Brazilian population of P. macropilis on tomato with its performance on other plant species, relating the observed variation to the respective types and densities of trichomes. It has been hypothesized that the presence of the webbing produced by T. urticae could help the predator to avoid contact with trichomes and consequently to improve its performance on tomato plants. This hypothesis was also evaluated. Phytoseiulus longipes Evans was included in the work as a control, given that it has been reported to be a promising predator of Tetranychus species on tomato. The study was conducted under laboratory conditions. It was found that the performance of P. macropilis was similar to that of P. longipes and that trichomes hampered the locomotion as well as prey consumption and oviposition rate of both predators; that the presence of webbing resulted in higher levels of prey consumption and of predator oviposition; and that the presence of webbing eliminated the negative effect of trichomes of eggplants and partially eliminated the negative effect of trichomes of the 'cerasiforme' tomato variety. The observed density of trichomes in 'Carmem' one of the most common tomato varieties grown in Brazil, seems not to have interfered significantly with the prey consumption and the oviposition rate of P. macropilis. The results suggest that the latter is a promising predator of T. urticae on tomato. Complementary studies are warranted, to further evaluate the potential of P. macropilis for use as a biological control agent of this pest.

Herbivory-associated degradation of tomato trichomes and its impact on biological control of Aculops lycopersici

“…This may take effect especially when they have to move from leaf to leaf because tomato cultivars commonly used in practice exhibit the highest densities of glandular trichomes on the stems (Van Haren et al 1987; Sato et al 2011). However, TRM is too small to be hindered by tomato trichomes and whitefly nymphs hardly move over the plant surface whereas their adults can fly.…”

Living on an unfriendly plant host: impact of tomato on the predatory mite Amblyseius swirskii

“…Phytoseiulus macropilis and P. longipes walking, predation and oviposition rates were reduced on tomato leaves, when compared to strawberry (Sato et al, 2011 pepper, but the mite survival was similar on the leaves of both plants (Davidson et al, 2016).…”

“…The negative effects of trichomes on the fitness of predatory mites have been reported for Phytoseiulus persimilis (Athias-Henriot), (Krips et al 1999, Van Haren et al, 1987, Nihoul, 1993, Neoseiulus californicus (McGregor) (Castagnoli et al, 1999;Cedola et al, 2001;Cedola & Sánchez, 2003;Koller et al, 2007) and Phytoseiulus macropilis (Banks) (Sato et al, 2011). Tomato cultivars with increased trichome density have direct negative effects on N. californicus (Cédola & Sánchez, 2003 Currently, cultivars used for tomato production are often selected for high density of trichomes, since they show increased tolerance to herbivore attacks.…”

“…Increases in temperature appeared to increase entrapment rates because the trichome glandular heads are more sensitive to rupture and may contribute to variation in the effectiveness of mite control by P. persimilis (Nihoul 1993(Nihoul , 1994. Tomato trichomes hampered the searching efficiency as well as the prey consumption and oviposition rate of both Phytoseiulus macropilis (Banks) and Phytoseiulus longipes (Evans) (Acari: Phytoseiidae) (Sato et al, 2011). Tomato cultivars with increased trichome density had direct negative effects on the survival of Neoseiulus californicus (McGregor) (Acari: Phytoseiidae), as well (Cédola & Sánchez, 2003).…”

Survey of Phytoseiids (Acari: Phytoseiidae) on the Central Coast of California

“…Conversely, Phytoseiulus macropilis Banks appeared to exploit the presence of CW type webbing, using it to avoid contact with trichomes of tomato leaves (Sato, 2011).…”