Lavender (Lavendula)
Plant Health Problems
Growth and flowering of lavender is favored by planting in a bright, sunny location
with well-drained, moderately fertile soil. Lavender does not thrive in shady,
damp locations, with excessively wet soil. High levels of organic matter in
soil, which increases water-holding capacity, also are not favorable to the
growth and establishment of lavender. Careful selection of a planting site will
increase the chances of successfully growing lavender. Once established,
however, lavender is generally disease-free.
Insect Problems:
Orange tortrix caterpillar, Argyrotaenia citrana.
This and other caterpillars of moths chew the foliage of lavender. The orange
tortrix feeds on new foliage, webbing it together. At maturity, the caterpillar
is about 1/2" long. Pupation occurs in this nest. Adult moths lay eggs in
clusters on leaf surfaces or the smooth stems of new growth. There may be two
generations a year. When needed, young caterpillars can be controlled using Bacillus
thuringiensis var. kurstaki or acephate, which are among the
compounds registered for use against this pest in Connecticut. Consult the
labels for dosage rates and safety precautions.
Fourlined plant bug, Poecilocapsus lineatus.
This bug lays eggs in the soft stems. They hatch about the middle of May and
the young bugs suck the sap from the tender leaves. They molt five times and
when mature, about the middle of June, they have wings and are nearly 1/3"
long. The insect body is yellow, marked lengthwise on the wings with four black
stripes alternating with three green stripes. The injury to the leaves consists
of sunken areas around the punctures. These areas later appear as circular
transparent spots and finally as circular holes. This insect injures the new
leaves of many different kinds of annual and perennial plants and shrubs. There
is one generation each year. The nymphs can be managed by spraying with
azadirachtin, ultrafine horticultural oil, insecticidal soap or malathion,
which are among the compounds registered for control of this pest in
Connecticut. Consult the labels for dosage rates and safety precautions.