As our name implies, WCB is located in Riverside, Southern California basically on the outer edge of the San Bernardino Mountains.  Our summertime temps are in the high 90′s -105 during most of the summer, with a slightly cool Fall and Winter temps that drop into the low 40′s – 32 degrees at night. Because of this we really don’t get a winter die off of any pests. Our biggest problem is Pine Bark Beatles.

Following is a list of known pest that may damage your pine bonsai, most are just a nuisance and can be easily treated. I hope you find this useful.

Pest : Usually none serious, except Pine wilt nematode in the east and tip moth on recently transplanted Pines.

The Maskell scale has recently devastated large numbers of trees in New Jersey .

Some adelgids will appear as white cottony growths on the bark. All types produce honeydew which may support sooty mold. European Pine shoot moth causes young shoots to fall over. Infested shoots may exude resin. The insects can be found in the shoots during May.

Note: Pesticides are only effective when caterpillars are moving from over wintering sites to new shoots. This occurs in mid to late April or when needle growth is about half developed.

Bark beetles bore into trunks making small holes scattered up and down the trunk. The holes look like shot holes. Stressed trees are more susceptible to attack. Keep trees healthy. This is a serous problem in Southern California and the adjacent mountains.

Sawfly larvae caterpillars are variously colored but generally feed in groups on the needles. Some sawfly larvae will flex or rear back in unison when disturbed. Sawflies can cause rapid defoliation of branches if left unchecked.

Pine needle miner larvae feed inside needles causing them to turn yellow and dry up.

Pine needle scale is a white, elongated scale found on the needles. Pine tortoise scale is brown and found on twigs. Depending on the scale, horticultural oil may control over wintering stages.

Pine spittle bug lives and hides in a foamy mass.

Zimmerman Pine moth larvae bore into the trunk. The only outward symptoms may be death of parts of the tree or masses of hardened pitch on the branches.

The larvae of Pine weevils feed on the sapwood of the leaders. The leader is killed and the shoots replacing it are distorted. First symptoms are pearl white drops of resin on the leaders. The leaders die when the shoot is girdled as adults emerge in summer.

Aphids, mealy bug & red spider. Scale, shoot-tip moths and beetles may also attack the tree and can best be controlled with a systemic insecticide. Do a preventive fungicide spray every two to three weeks with Benomyl® or Daconil®.

Diseases : This pine is resistant to Diplodia tip blight.