Assessing European egg parasitoids as a mean of controlling the invasive South American tomato pinworm Tuta absoluta.

The South American tomato pinworm (Tuta absoluta) has recently invaded Europe and is rapidly spreading in the Afro-Eurasian continent where it is becoming a major pest on tomato crops. Laboratory tests were undertaken to evaluate the potential of 29 European strains of Trichogramma parasitoids to control T. absoluta. In addition to the host itself, the host plant (tomato) was used during the laboratory tests in order to increase the chance of selecting the best parasitoid strains. Trichogramma females were placed with T. absoluta eggs on a tomato leaflet in tubes. We compared the parasitism of T. absoluta by the various Trichogramma species tested to the Trichogramma species currently commercially available for the pest control in Europe, i.e. Trichogramma achaeae. Thereafter, the more promising strains were tested on a larger scale, in mesocosm (i.e. cages in greenhouses) and in greenhouse compartments to evaluate efficiency of laboratory selected strains under cropping conditions. The most efficient strain from the laboratory screening trials did not perform as efficiently under the greenhouse conditions. We discuss differences in parasitism levels among species and strains and among the different scales tested in the experiments, as well as implications of these results for further screening for biocontrol agents

Acceptance of two hosts, <i>Tuta absoluta</i> and <i>Ephestia kuehniella</i>, by <i>Trichogramma</i> females.

<p>Data are presented as proportions (mean±SEM) of <i>Trichogramma</i> females that parasitized at least one egg on <i>T. absoluta</i> and on <i>E. kuehniella</i> in laboratory screening tubes.</p

Preference-performance relationship.

<p>Data are presented as proportions of parasitoid females (for a given <i>Trichogramma</i> strain) attacking the host (<i>T. absoluta</i>) under laboratory conditions and the mean numbers of <i>T. absoluta</i> eggs parasitized (log-transformed data) (regression line: y = 0.9001×−0.0856).</p

Parasitism of <i>Tuta absoluta</i> eggs in cages in greenhouse.

<p>Percentage (mean±SEM) of parasitized <i>T. absoluta</i> eggs per <i>Trichogramma</i> strain in cages in the greenhouse. Histograms bearing the same letter do not differ at <i>P</i><0.05 (GLM analysis).</p

Year of collection, initial host and host plant, country of origin and Thelythoky status (females produced from unfertilized) of the 29 <i>Trichogramma</i> strains studied.

<p>Asterisks indicate the strains for which diapause or quiescence capacity has been identified in our laboratory.</p>a<p>strain not collected in Europe but species is present in Europe.</p

Parasitism of <i>Tuta absoluta</i> eggs under laboratory conditions.

<p>Mean (±SEM) number of parasitized <i>T. absoluta</i> eggs per <i>Trichogramma</i> strain in laboratory screening tubes on tomato leaflets<b>.</b> Strains with an asterisk are significantly different from <i>Trichogramma achaeae</i> at <i>P</i><0.05 level (GLM analysis). One strain of <i>Trichogramma</i>, <i>Trichogramma euproctidis</i> 1, was significantly more efficient than <i>T. achaeae</i>.</p

Psychiatric symptoms and mortality in older adults with major psychiatric disorders: results from a multicenter study

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