Juniperus chinensis - Chinese
Juniper
Phomopsis and
Kabatina blights kill young shoots, prevalent in early spring
and wet weather. Relatively trouble-free juniper.
Control: Space new plantings to provide good ventilation and air circulation and avoid heavily shaded areas. Water plants in early morning so the foliage will dry as soon as possible. Prune out diseased branch tips during dry summer weather and destroy them. Do so only when plants are dry and no rain or overhead irrigation is expected for several days.
Juniperus conferta - Shore
Juniper
Fair amount of dieback in large scale plantings. Plants in extremely heavy,
water-logged soils seem to languish.
Juniperus horizontalis -
Creeping Juniper
Phomopsis
blight can be extremely serious as well as spider
mites. Spider mites are about 1/50 of an inch long and are
not insects but closely related to spiders. They are very active during
hot, dry weather. Mites can complete their life cycle in five to eight
days depending on temperature. Theoretically, a single fertilized female
can produce 13 million mites in 30 days at a constant temperature of 80
degrees F. Most vegetables, and some ornamentals such as junipers and
hollies are preferred hosts. Feeding injury results in discolored, bronze-colored
leaves. Check for mites by tapping a branch onto a white sheet of paper
and looking for moving specks.
Control: Encourage predators. Wash off mites with a strong stream of water. Miticides are available.
Juniperus procumbens
- Japgarden Juniper
Phomopsis
can be a problem
Control: Space new plantings to provide good ventilation and air circulation and avoid heavily shaded areas. Water plants in early morning so the foliage will dry as soon as possible. Prune out diseased branch tips during dry summer weather and destroy them. Do so only when plants are dry and no rain or overhead irrigation is expected for several days.
Juniperus sabina - Savin Juniper
Juniper blight
can be a problem
Control: Space new plantings to provide good ventilation and air circulation and avoid heavily shaded areas. Water plants in early morning so the foliage will dry as soon as possible. Prune out diseased branch tips during dry summer weather and destroy them. Do so only when plants are dry and no rain or overhead irrigation is expected for several days.
Juniperus scopulorum
- Rocky Mountain Juniper, Colorado Redcadar
Phomopsis blight, also serves as an alternate host for apple
cedar rust. Canker caused by Botryosphaeria
stevensii has attacked J. scopulorum in windbreak and ornimental
plantings. Proved pathogenic and caused canker on other junipers in greenhouse.
Control: Remove cankers on diseased trees in winter or late spring.
Juniperus squamata
- Singleseed Juniper, Flaky Juniper
Susceptible to bagworm
Control: If the bags are few in number and easily reached they may be picked off the plant and squashed. Bacillus thuringiensis, is effective against bagworms if it is used against young larvae. Stomach insecticides are very useful for control of bagworms.
Juniperus virginiana
- Eastern Redcedar
Cedar apple
rust and bagworms
Control: Remove cankers on diseased
trees in winter or late spring for cedar apple rust.
Control: If the bags are few in number
and easily reached they may be picked off the plant and squashed. Bacillus
thuringiensis, is effective against bagworms if it is used against young
larvae. Stomach insecticides are very useful for control of bagworms.