VIII SIMPOSIO INTERNAZIONALE ICPBR

HAZARDS OF PESTICIDES TO BEES

Bologna, 4-6 Settembre 2002

Apicidi e schemi di monitoraggio

The death of honey bees (Apis mellifera L.) and environmental pollution by pesticides: the honey bees as a biological indicators

Claudio Porrini (1), Anna Gloria Sabatini (2), Stefano Girotti (3), Fabiana Fini (3), Lorenzo Monaco (2), Giorgio Celli (1), Laura Bortolotti (2) and Severino Ghini (3)

(1) Dipartimento Scienze e Tecnologie Agroambientali, University of Bologna, Via Filippo Re, 6 - 40126 Bologna, Italy. E-mail: cporrini@entom.agrsci.unibo.it
(2)Istituto Nazionale di Apicoltura, Via di Saliceto, 80 - 40128 Bologna, Italy
(3)Istituto Scienze Chimiche, University of Bologna, Via S. Donato, 15 - 40126 Bologna, Italy

The systems for monitoring honey bee incidents with pesticides, can be of various kinds. In Italy we described six types based on the different levels of complexity and sensitivity, depending on the context and the objectives pursued. The level we adopted, which has been carried out since the beginning of the 1980’s, is an extremely important technique not only for proving potential bee poisoning risks by the use of pesticides, but also in determining the degree of environmental contamination due to plant protection products. In fact, because of its morphological and ethological features (such as its wide area of patrol and its intense foraging activity), the honey bee can be considered an excellent bioindicator. In many cases, pollution caused by abuse or by erroneous application of pesticides could not be proven without the help of honey bees.

In this research work, which is being applied hitherto in some neighbour Bologna areas, each monitoring station consists of two beehives equipped with collection cages for dead bees. Once a week, families are checked and the number of dead bees is recorded. When the mortality rates exceeds the critical threshold (250 bees/week/station), laboratory analysis is carried out. Monitoring techniques, chemical and palinological analysis, and data processing (through the Environmental Hazard Index) enable us to characterise areas, to indicate periods of major bee poisoning risk, and to identify the most frequently used pesticides (also those that are prohibited) and the crops treated.

Our studies with honey bees revealed the type of plant protection management applied to the area under investigation. For example, in many cereal growing areas the honey bees die because of the extensive use of Dimethoate in controlling aphids on wheat. This treatment is often worthless, since the prevention of the damage caused by those phtyphagous insects often does not cover the cost of the treatment itself. Besides harming the pockets of the growers and the honey bees, Dimethoate also impoverishes the beneficial entomofauna (entomophagous ladybirds) within the agroecosystems.

Monitoring with bees also allows us to prove the application of molecules not permitted under certain circumstances or even forbidden. In 1995, during one of our monitoring campaigns, Lindane was found on the dead bees from hives placed in the city centre of Ravenna. There were no conditions justifying its use. In fact, the application of this product is allowed only on certain crops and/or under limited circumstances, for example soil disinfestation on sugar beet, disinfestation of stored cereals, seed tanning. Another bee poisoning incident occurred in 1998 in Ozzano (BO). Fenoxycarb was detected in a sample of bees. The use of this product, an IGR (Insect Growth Regulator) chemically classified as carbamate insecticide, is recommended primarily on apple and peach against mining and codling insects and on grapes against moths, but its sale and its application are forbidden all over Italy because of its harmful effects, mainly on the silk worm. Nevertheless, Fenoxycarb has been applied, probably on grapes against moths (Lobesia botrana and Eupoecilia ambiguella).