Neoseiulus tunus (De Leon, 1967) (Acari: Phytoseiidae): is this a potential natural enemy of Aculops lycopersici (Massee, 1937) (Acari: Eriophyidae)?

This study aimed to determine the biological parameters of Neoseiulus tunus (De Leon, 1967) feeding on Aculops lycopersici (Massee, 1937). We conducted experiments to assess the predation rate of the former and its biological cycle when consuming A. lycopersici exclusively. Moreover, we assessed the preference of N. tunus for A. lycopersici concerning the pollen of Typha domingensis Pers. (Typhaceae) and Tetranychus urticae Koch, 1835, using free-choice tests. The obtained data indicates A. lycopersici is an appropriate prey to N. tunus, as it allows it to complete its development, reproduce and increase its population. We also noticed that this phytoseiid prefers A. lycopersici to the two other food sources. Though more robust studies will be needed, these preliminary results allow some inferences, such as N. tunus being a potential natural enemy of A. lycopersici.

Distribution and biological features of Typhlodromus (Anthoseius) recki (Acari: Phytoseiidae) on Tetranychus urticae, T. evansi (Acari: Tetranychidae) and Aculops lycopersici (Acari: Eriophyidae)

The mite family Phytoseiidae contains predatory species used in biological control. However, among the 2,521 valid species, only a few are presently considered for pest management. The study focuses on a species, frequently observed in agrosystems, but whose biology is almost totally unknown: Typhlodromus (Anthoseius) recki. The objectives were to assess its distribution and to determine under laboratory conditions: (i) the development of three populations fed on three tomato pests (Tetranychus urticae, T. evansi, Aculops lycopersici), (ii) the dispersion along the tomato stem, and (iii) the dispersion from mint to infested tomato leaf discs. Based on its distribution, this species seems to be adapted to Mediterranean climate, and is preferentially found on Boraginaceae, Solanaceae, Asteraceae and Lamiaceae. Results show that T. (A.) recki is a generalist predator, with good performance regarding the number of prey consumed. Differences were observed between the populations considered; one population out of the three tested shows even a higher mean consumption of T. urticae than that recorded for Neoseiulus californicus and N. cucumeris. It is attracted by food source and is able to walk along the tomato stem. These results are encouraging enough to consider T. (A.) recki as a good natural enemy candidate for biological control (especially based on biodiversity conservation). Further experiments should be developed to test the predatory ability of this species at larger scale (entire tomato plants and tomato fields or greenhouses).

Tritrophic relationships among tomato cultivars, the rust mite, Aculops lycopersici (Massee) (Eriophyidae), and its predators

Trichome-mediated defence in wild and cultivated tomato cultivars has been extensively studied against some mite species for several decades. Previous studies have shown that this mechanism negatively affects phytophagous mites and their predators. To better explain the tritrophic relationship of tomatoes, the interactions between population densities of the tomato rust mite, Aculops lycopersici (Massee) (Acari: Eriophyidae), and its predators on the tomato cultivars, namely, Dora, Etna, Grande, H2274, Jana and M1103, and the trichome densities of these cultivars were investigated in both a climatic room and an organic tomato field from 2014-2015. Under both controlled and field conditions, the A. lycopersici population density was significantly higher in the stake tomato cultivars, Jana and Etna, than in other tomato cultivars. When the tomato rust mite’s population density was the highest during mid-August and mid-September in the tomato field, the population density of the predator species, Tydeus kochi Oudemans (Tydeidae), showed a similar population pattern and significant positive correlation with the A. lycopersici density. However, density of this predator mite was significantly lower than that of A. lycopersici over the entire season. Remarkably, the glandular trichome type VI density was significantly higher in the stake cultivars than other cultivars. In contrast, significantly fewer glandular trichomes were found in the indeterminate tomato cultivars, Grande and H2274, which had fewer tomato rust mites and larger tydeid mite predator densities. These results support the hypothesis that trichomes provide excellent shelter for tomato rust mites and are obstacles for its predator mites. However, the population density of the insect predator, Macrolophus sp., was not affected by the trichome density or tomato cultivar, but its population density was not significantly correlated with that of the A. lycopersici population.