In the Mediterranean area, the exotic tomato borer Tuta absoluta (Lepidoptera: Gelechiidae), is responsible for severe yield losses on tomato, its favourite host plant. This multivoltine pest spread very quickly and can survive in adverse climatic conditions. Besides tomato, T. absoluta is reported on other genera and species of Solanaceae family, both cropped and wild, such as potato, aubergine, European black nightshade, datura and Nicotiana glauca. For an effective and environmentally friendly pest management strategies, some generalist predators belonging to the tribe (: ) have demonstrated a good potential in controlling this pest.

Among them, the Palaearctic occurs naturally in organic tomato in NW Italy, preys upon several pests and lives omnivorously on several plants. tomato, aubergine, potato, courgette , melon, pumpkin, pot marigold, … Antirrhinum majus, Circaea lutetiana, Digitalis grandiflorum, Galeopsis tetrahit, Geranium pyrenaicum, G. robertianum, G. rotundifolium, Geranium sp., Hieracium sp., Salvia glutinosa, Silene alba, S. dioica, Solanum nigrum, Stachys sylvatica ,… • To study the behaviour of D. errans and T. absoluta on different cultivated and wild plants

V assessing host preference of both predator and prey on 10 plant species with multi- choice assays.

V comparing their life span on 2 plants species with developmental trials (tomato and European black nightshade)

V evaluating any possible effect of host plant on progeny behaviour with bioassays in olfactometer Multi-choice assays

10 plant species Multi-choice assays D. errans: 5 repetitions 2 plant/species (20) 2 ♀ and1 ♂/plant (60 adults) 72 h 1 month checking nymphs

T. absoluta: 5 repetitions 3 plant/species (30) 4 adults/plant (120 adults) 48 h eggs and larvae Developmental trials on 2 plant species: S. lycopersicum and S. nigrum D. errans: 20 newly emerged nymphs (<1-day-old) were placed individually on leaf disks of each plant species in single cells in 12-well tissue culture plate with Artemia salina cysts

T. absoluta: 15 eggs of the tomato borer were transferred on a potted plant of each plant species placed inside a Plexiglas cage (20 ´ 20 ´ 30 cm). All the emerged adults were counted. Six repetitions were done. 6 comparisons

Olfactometer assays vs

S. lycopersicum vs 30 ♀ and 30 ♂ 2 rearing plants Effect on progeny? S. nigrum vs

720 vs

vs

Adults of D. errans emerged from 5-9 days vs

2 χ Test ; H 0: 50:50 distribution Multi-choice assays

a

ab ab ab ab ab

b b b b

Herb Robert is the favourite plant Lower oviposition on smooth leaves compared to hairy

ANOVA, test di Tukey (P<0,05) Multi-choice assays

DE c Presence of BC larvae c DE almost only c on D Solanaceae c D c A a Courgette was BC b selected for AB oviposition but b few larvae C b emerged E c

Test Kruskal Wallis, test U di Mann-Whitney (P<0,05) Multi-choice assays Developmental trials

15.29±0.34 d 14.71±0.44 d Time from egg-hatching to adulthood took 18.54±0.20 d 18.50±0.21 d no significant differences in developmental time were found on tomato and European black night shade (D. errans : T test, DF=1, 28, F=0.656, P=0.425; T. absoluta : T test, DF=1, 28, F=0.656, P=0.425). Olfactometer assays In most comparison no significant differences were found between odour sources except for healthy tomato vs infested tomato

females chosed infested plants males chosed healthy plants

Plant species resulted equally attractive

No influence of host plant on progeny

Advantage for a succesfull establishment of the predator D. errans could be a key predator of the exotic tomato borer, allowing a higher probability of encountering on several plant species and a consequent more successful pest control in organic greenhouses.

Herb-Robert and courgette seem to be suitable plants to use as companion plants and in consociation with tomato to favour the predator and hamper the prey, respectively.

Thank you for your attention