ISHS Acta Horticulturae 347: II International Symposium on Integrated Fruit Production
BIOLOGICAL CONTROL OF PANONYCHUS ULMI IN APPLE ORCHARDS IN LLEIDA (NE OF SPAIN) |
| Authors: | J. Avilla, D. Bosch, M.J. Sarasúa, J. Costa-Comelles |
| Abstract:
The European Red Mite (Panonychus ulmi (Koch)) has been an important pest in apple orchards in Spain only since the 1980's. Studies carried out since 1984 in the apple growing area of Lleida (NE of Spain) have led to the development of a decision making strategy for the biological control of P. ulmi by its main predator in this area, the acarid Amblyseius andersoni (Chant). This control strategy is based on the definition of the Economic Threshold which is a function of the number of cumulative mite*days and the relative densities of the populations of the predator and the prey. Both variables are represented in two graphs to simplify the decision-making process. The management programme was applied in 21 apple orchards in Lleida in 1991, in 16 of these for the first time. Successful biological control was achieved in 12 out of 21 orchards. Nine out of these 12 were orchards where the programme was applied for the first time in 1991. | |
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