Achillea

Meteor Mix 2000 14 5
Meteor Rose 2000 17 7
Meteor Rose Pink 2000 15 6
Meteor Violet Blue 1998 22 6
Serenade Blue 1998 21 8
Serenade Blue/White 2000 17 6
Serenade Carmine 2000 16 5
Serenade Light Blue 2000 17 11
Serenade Red 1998 18 5
Serenade Rose 2000 15 6
Serenade Rose/White 2000 17 8
Serenade Scarlet 2000 16 12
Serenade White 1998 18 5
z = multiply (in) by 2.54 to obtain (cm)
CALLISTEPHUS CHINENSIS 159
Pests and Diseases
Aster yellows: This disease is caused by an unusual microbe called a phytoplasm.
Yellowing of all or part of the plant; distorted, malformed flowers (flowers
partly or entirely greenish and yellow); and spindly stems are indications of
aster yellows infection. Affected plants may also exhibit considerably increased
branching. Leafhoppers pick up the phytoplasm from weeds, and then transmit
it to the aster. The best means of control is to reduce or eliminate the population
of leafhoppers. Scout your area for leafhopper migrations, and, if at all
possible, plant asters only after leafhoppers have moved through your area. Once
plants have been infected, they must be discarded. If plants are infected early, the
leaves turn yellow while the veins retain their green color. The use of soil sterilants
reduces the incidence of the phytoplasm in the soil, but crop rotation
should be routinely practiced.
Aster wilt: Plants suddenly wilt, usually near maturity, when attacked by the
aster wilt fungus (Fusarium conglutinans var. callistephi). The stem rots completely
at the soil line, and often a streak of blackened tissue extends up one side. The
wilt fungus may be carried on the seed, which should be surface sterilized. The
advent of wilt-resistant cultivars has greatly reduced the severity of this problem.
Verticillium wilt is similar to fusarium wilt.
Aster spotted wilt: This disease causes streaks on the stems or circular patches
on the foliage. Infected plants may exhibit increased branching and should be
discarded. The wilt organism is spread by thrips, the presence of which must be
controlled.
Root rot and rust: Phytophthora cryptogea and Coleosporium solidaginis result in loss
of yield and flower quality, respectively.
Leafhoppers, leafminers, thrips, aphids, and Japanese beetles cause significant
damage and reduce the value of the crop. They may also be responsible for
the spread of disease. Reflective mulches are presently being trialed in Ventura
County, California, and they appear to reduce the populations of leafminers,