Estelle Jourdan

Evaluation of new day neutral strawberries selections for their
resistance to the tarnished plant bug

Estelle Jourdan is carry out a 6 months training course during which she is charged to evaluate new day neutral strawberries selections for their resistance to the tarnished plant bug.

Abstract

The day neutral strawberry market in Québec has strongly increase the past few years. That’s why, answering to the strawberry growers wishes, the Horticulture Research and Development Center (HRDC) of St-Jean-sur-Richelieu has developed a day neutral strawberry selection program, in year 1998, with the strawberry growers association "les Fraises de l’Ile d’Orléans".

The day neutral strawberries have a continuous production, allowing producers to supply the market from spring to fall. But this characteristic allow also one of the major strawberry pest, the tarnished plant bug (Lygus lineolaris, P. de B.) to keep on strawberries fields and to cause great damages, in so far as chemical products are forbidden by the harvest frequency.

Two different way of management are tested in the HRDC, in order to reduce this pest’s damages : the genetic way and the integrated pest management way.

As a consequence, one of the objectives of the breeding program is to create new resistant to tarnished plant bug selections. To evaluate different genotypes, an experimental protocol has been built, in order to reveal a resistance, early in the selection scheme. The best way to evaluate this resistance is to calculate the deformation rate, that is to say number of misshapen strawberries compared to the total number of marketable strawberries. Among ten evaluated selections, one tolerant and three semi-tolerant selections has been found, but no real resistance yet.
The trials for integrated pest management are a good complement to the breeding program. They are based on the feeding behavior of the tarnished plant bug, which moves from hosts to hosts according to feeding resources. A comparison has been done between a control plot without any treatment, two plots with a chemical treatment, and one plot surrounded by white mustard as host plant. This experience has shown that the presence of host plant reduces strongly the damages caused by the tarnished plant bug. Nevertheless, those results are not yet as low as those of the chemically treated plots.
Thus, researches should be continued, as well in the breeding program as in the choice of host plant, in order to eliminate the tarnished plant bug on strawberries.

Key words : day neutral strawberry ; tarnished plant bug ; selection ; resistance ; host plant ; feeding behavior ; misshapen

Address :
Estelle Jourdan
L’Ecole Nationale des Ingénieurs des Travaux Agricoles de Clermont-Ferrand
Site de Marmilhat
63370 LEMPDES
FRANCE

Professeur responsable de la formation : PIQUET Agnès

Professeur responsable du suivi du stage : DUPARQUE Annie

 

The persons in charge of the training course: Shahrokh Khanizadeh & Johanne Cousineau