OSU Extension Catalog

Regulations for Mexico

Current regulations for Mexico call for tree shaking for 15 seconds. A number of details can improve (or reduce) the effectiveness of shaking.

• Prune tree bases to sufficient height to fit in the receiving cone on the shaker. Otherwise, if the stiff lower branches sit on top of the cone, they act as shock absorbers and reduce the shaking efficiency.
• Clean out the receiving cone on the shaker frequently. The cone can quickly fill with needles. If the needles are allowed to build up, they act as a shock absorber and minimize the effect of shaking. Some receiving cones have openings on the sides to allow debris to shake out automatically; this can be an effective feature.

Debris piles

Besides containing dead needles, debris piles contain pests previously shaken off. These pests can migrate to piles of harvested trees and cause recontamination. Move your shaking operation away from the landing area or frequently remove the piles of debris. At the loading site, separate the debris piles and the trees, and remove the debris often.

Some pests (e.g., snails, slugs, and beetles) may move from the ground to the tree after cutting. Minimize the time trees are in contact with the ground (e.g., place the trees on pallets).

Other pests, such as yellowjackets, can fly into piles of shaken, baled trees before or during the loading of trees into trailers. This is particularly a problem on warm, dry days, when yellowjacket queens are looking for overwintering sites and are not attracted to baits. Growers’ control options are limited, but some helpful steps include:

• Minimize the time trees remain in piles
• Control the populations of yellowjackets around loading areas beginning in May
• Put netting around trees in piles and screening on trailer loading doors