Tricking pine shoot beetle with trap logs

Trap logs are very effective in reducing pine shoot beetle populations in Scotch pine Christmas tree fields. Growers enrolling in the Pine Shoot Beetle Compliance Program need to place trap logs in fields by March 1 or 15, depending on location.

The Pine Shoot Beetle Compliance Management Program is designed to reduce pine shoot beetle populations. Under this management plan, growers use a combination of cultural practices plus a cover spray to control the pest.

The cultural practices include destroying cull piles and removing stumps so that the pine shoot beetle does not have brood sites in the field. Also, trap logs are used to trick the overwintering adult beetles when they are searching for brood material in spring. You set out fresh pine logs, let the adult beetles colonize the logs, then destroy the logs before the new generation of beetles can emerge. When the trap logs and any other brood materials are destroyed in the spring, the new generation pine shoot beetle in these materials is also destroyed.

Trap logs
Culled Scotch pine trees can be used as trap logs.

A trap log consists of a pine log or cut tree at least 3 to 4 inches in diameter and 2 to 3 feet long. Culled trees can be used as trap logs – you don’t need to trim the branches off. For example, a 6-foot tall Scotch pine tree with gall rust or Zimmerman pine moth damage makes two to three trap logs. Don’t use white pine logs; the beetles avoid them.

The trap logs need to be cut no earlier than six months prior to use; that is no earlier than Oct. 1 of the preceding year. If they are cut before Oct. 1, they may not be fresh enough to attract the adult beetles in the spring.

You will need to set out eight to 12 trap logs per acre by March 1 in Zone 1 and by March 15 in Zone 2. Set the logs around the edges and in the lanes of the fields that you will harvest. You don’t need to set trap logs in every field, just the ones that you will harvest. Be sure that you can find all the trap logs.

Note: If you would like to participate in the Pine Shoot Beetle Compliance Management Program this year, complete the required documents and submit them by April 1. The forms and other information on the Pine Shoot Beetle Compliance Program can be found at the Michigan Department of Agriculture and Rural Development website.

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