Chemical Control of Cone Pests in a Norway Spruce Seed Orchard

1991

2 Abb., 4 Tab., 18 Lit. Ang.

Unselbständiges Werk

2767

200040884

The effect of three pesticides containing either dimethoate (0.5% a.i.), permethrin (0.05%) or triadimephon (0.05%) on the cone pests and flowering biology of Norway spruce was tested in a seed orchard in southern Finland. The developing cones were treated in mid May or in the beginning of June. The pesticide treatments significantly reduced infestation by Laspeyresia strobilella and Kaltenbachiella strobi only. Variation in the number of cones infested by both insects and cone rusts was high between the spruce clones. Generally, the pesticides did not affect flower viability, seed quality or seed germination, but reduced drastically the germinating capacity of the pollen in vitro. In practice, sufficient control cannot be achieved with the concentrations or methods used in the present study.