VIII SIMPOSIO INTERNAZIONALE ICPBR

HAZARDS OF PESTICIDES TO BEES

Bologna, 4-6 Settembre 2002

Effetti dell’imidacloprid sulle api

Risk of environmental contamination by the active ingredient imidacloprid used for treating corn seed. Preliminary data

Moreno Greatti (1), Renzo Barbattini (1), Simona Rossi (2) and Anna Gloria Sabatini (2)

(1) Dipartimento di Biologia Applicata alla Difesa delle Piante, Università di Udine, Italy. E-mail: moreno.greatti@aass.uniud.it
(2)Istituto Nazionale di Apicoltura, Via di Saliceto 80, 40128 Bologna, Italy

Pollutants dispersed in the environment can bring about the death of honey bees and other insect pollinators.

In recent years, the use of imidacloprid treated corn seeds has became widespread; all corn seed was sown by pneumatic seed drills. Precision seed drills distribute seeds by the air aspiration furnished by centrifugal fan; the air used for aspiring the seeds is then directed out of the seed drill through a drain.

This preliminary study was carried out to detect the possible loss of the active ingredient from pneumatic seed drills and verify the subsequent contamination of wild flowers near corn fields resulting in the death of insect pollinators.

In 2001, while sowing imidacloprid treated corn seed at the Experimental Farm of the University of Udine, paper filters were applied to the centrifugal fan drain of the pneumatic seed. Filters were left on the fan for 30, 60 and 120 seconds respectively.

Moreover in another field after corn sowing, two samples of flowers (sampled area = 1 mq) and two samples of grass (sampled area = 1 mq) were collected near the field.

As imidacloprid is quickly degraded its by-products were assessed. The method was suggested by Bayer regarding the determination of 6-chloronicotinic acid (an oxidation product of imidacloprid) using gas-chromatography.

Traces of 6-chloronicotinic acid were found on both paper filters and grass and flower samples.

On the grounds of these results the following conclusions can be drawn:

1) from the point of view of environmental contamination even sowing can be regarded as a critical stage;

2) better tackifiers should be used by seed industries during the treatment of seeds.

In 2002 another study was carried out in which more samples were collected but their analysis is still in progress.