While the Nordmann fir spoils our eyes with its lush green needle dress, various species of lice are after their inner values. They suck the plant sap without any measure and thus weaken their "provider". That must be stopped in time.
Ants are often an indication of lice
Lice species on the Nordmann fir
The following types of lice can mainly be seen on the Nordmann fir:
- pine aphids
- pine stem lice
- Mealybug
pine aphid
The pine aphid was introduced from the Caucasus, a region from which the Nordmann fir originally comes. Young trees and specimens weakened by the bark beetle are particularly susceptible. A warm location, for example on a southern slope, can also promote an infestation.
The larvae of the lice hatch from around May and immediately start sucking the sap of the Nordmann fir. They are about 0.5 mm in size and black. Three white back stripes are added later. The fir shows stunted shoot and branch tips. If the infestation repeats itself for several years, the fir can die.
The control is carried out with chemical sprays, which must be repeated several times. Control over the course of the year is also necessary so that all life stages of this louse species are recorded.
pine trunk aphid
White wax flakes on the bark are a typical indication of an infestation. These are the characteristics of the pest:
- adult lice are red-black in color
- they have a length of approx. 1 mm
- the body is spherical and covered with white wax threads
- Larvae are orange-red with black eyes
- the eggs are also orange
Since the transport of water and nutrients is impaired, individual branches can die off and the fir can lose needles. However, the damage caused by the pine trunk aphid is limited and cannot pose a threat to the Nordmann fir.
tips
Pine stem aphids are not always the only pests on the Nordmann fir. If pine aphids or pine bark beetles are also at work at the same time, control is imperative. Because together you can cause serious damage.
Mealybug
The infestation can also be seen with the naked eye based on the traces left by mealybugs. It is the woolly coating that contrasts with the green of the needles with its white colour. If the infestation is still weak, only small spots appear, while a stronger infestation can cover the entire fir. The longer and the more numerous the lice suck plant sap, the more they weaken the fir.
Beneficial lice can still be collected from small Nordmann firs by hand, but no specimens should be overlooked. Larger fir trees can be sprayed with soapy water.