Insect Management Handbook

Liriomyza trifolii

Pest description and crop damage Leafminer adults are small flies, the most common is Liriomyza trifolii, which is about 0.125 inches long and black and yellow. The larvae are legless maggots. Mines from larval feeding in the leaves can make plants unmarketable.

Includes

Bradysia coprophila
Bradysia impatiens
Bradysia paupera

Numerous species

Management-chemical control

The regulations for tree imports into Mexico are prescriptive and state: "A pesticide treatment is required 3 to 6 weeks prior to harvest using one of the following insecticides: permethrin at 36.8% active ingredient (ai), esfenvalerate at 8.4% ai or bifenthrin at 7.9% ai in accordance with doses recommended on the label." Check export regulations at harvest time as these may be phased out.

Vespula germanica

Pest description and crop damage German yellow jacket is an extremely rare hitchhiking pest and restricted in a number of export destinations. Adults have yellow and black marks with a spade shape on the 1st abdominal segment and black spots down the sides of the 2nd to 5th segments. Easily confused with common yellow jacket.

Management-cultural control

Various species

Pest description and crop damage There is no crop damage, but slugs and snails are hitchhiking pests that are restricted at a number of export destinations.

Management-cultural control

Shaking prior to loading will remove some. Minimizing the time trees are in contact with the ground prior to shipping will help limit numbers. Placing trees on pallets and using tarps should help.

Management-chemical control

Prociphilus americanus

Pest description and crop damage Tree above ground is stunted and off-color. Below ground colonies of white aphids attached to roots often tended by small ants. In severe cases, replanting may be required as unhealthy trees are slow to recover.

See table:

Adelges piceae

Pest description and crop damage Appear as cottony or grayish mass on stems. They produce swelling at nodes and tips and are especially damaging to Fraser fir.

See table:

Hosts and Symptoms of Major Aphid and Adelgid Pests of Christmas Trees

Management-chemical control

Mindarus abietinus

Pest description and crop damage Small, yellow-green aphids with woolly exudates attack new terminals.

See table:

Hosts and Symptoms of Major Aphid and Adelgid Pests of Christmas Trees

Management-chemical control

Pissodes strobi

Pest description and crop damage A small brown weevil, roughly 0.25 inch in length, with the "snout" typical of other weevils. Wing covers have irregular patches of brown and white scales. An important pest of spruce and pine, occasionally a pest of Douglas-fir.

Management-chemical control