engleski

The sensitivity of Botrytis cinerea Pers.:Fr. to new botriticides in the protection of vineyards

Botrytis cinerea, the cause of grey mould, is a fungus well known for the fast development of fungicides resistance. The problem of B. cinerea resistance is especially pronounced in the protection of vineyards because grey mould is one of grapevine diseases with significant economic impact. In the continental part of our country, this disease inflicts damages to 50-60 %, and in the Mediterranean area to 3- 5% of vines, and continues in the wine making process. In order to overcome the problem of resistance there are continuous world efforts to develop new active ingredients. New ingredients, in addition to exhibiting good efficacy against B. cinerea should enable the control of biotypes resistant to existing fungicides and have a mode of action which prevents the selection of new resistant biotypes. As a part of these research, methods are being developed for testing the sensitivity of B. cinerea. By performing tests in field trials during the pre-registration phase of new fungicide, in B. cinerea populations it is possible to detect strains that are naturally resistant to the active ingredient that has not yet been applied. These can be signs for the rapid appearance of resistance if the active ingredient were to be applied intensively. During the last 5 years new active ingredients have been developed in the world, of which pyrimethanil and cyprodinil from the anilinopyrimidine groups were acknowledged in Croatia in 1997, and fenhexamide (hidroxianilide) in 1998. Until then, the palette of botriticides was based on dicarboximides, the use of which is limited to twice during vegetation due to resistance. In 1998 and 1999, we conducted trials in order to monitor the presence of strains resistant to the mentioned ingredients in field populations of B. cinerea, in vineyards in which those ingredients had been applied intensively, but also in vineyards in which they had never been used. The tests were performed by in vitro method. Strains of B. cinerea naturally resistant to pyrimethanil, cyprodinil and fenhexamide were detected both in vineyards under intensive control and in vineyards in which these ingredients had never been applied. The obtained results are a warning sign against the application of mentioned ingredients, but there is still no danger of practical resistance development.

Botrytis cinerea; resistance; botryticides; vineyard

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