The genus Cinnamomum

Leaf webber (Orthaga vitalis)
Pests and Diseases of Cinnamon and Cassia 247
The leaf webber is a major pest of cinnamon in Sri Lanka. The larvae of the pest web the
tender leaves into clusters, which gradually dry up. A webbed-up cluster of leaves can
harbour several larvae inside. Many such webbed clusters of leaves are seen in severely
infested plants, which present a sickly appearance. Eggs are laid in small clusters on tender
leaves and the incubation period lasts for four to five days. The larvae are initially
gregarious and feed by scraping the plant tissues. Fully grown larvae are pale green with
dark bands. The larval period, comprising of five to six instars, is completed in 28–30
days. Pupation takes place within a silken cocoon inside the webbed-up cluster of leaves
and lasts for 11–14 days (Rajapakse and Kulasekara, 1982).
Minor insect pests
Various other insects such as leaf hoppers, psyllids, whiteflies, aphids, scale insects,
mirid bugs, leaf-feeding caterpillars, leaf miners, leaf webbers, root grubs, leaf beetles
and weevils have also been recorded on cinnamon in many regions. These species mostly
infest foliage and can sometimes cause heavy damage in certain localities. A list of
these species and their distribution in various parts of the world is provided in Table
10.1. Wikardi and Wahyono (1991), who reviewed the insect pests of cinnamon and
their natural enemies from Indonesia, reported several insect pests and their natural
enemies (eleven parasitoids, three predators and three microorganisms) from the Bogor
region of Indonesia. The dominant pests are a kanani caterpillar (Exicula triferestrata), and
a mite (Eriophyes boiisi). C. burmannii is never affected by these pests. Less important
pests include a stem borer (Coleoptera, Scolitidae), which attacks seedlings in nurseries
and a red caterpillar (Lepidoptera, Cossidae), which attacks young trees. Mesocomys
orientalis (Hymenoptera, Eupelmidae), and a Graphium sp. are the dominant parasitoids.
The predator population is high in cinnamon stands; however, their predatory potential
is not known. Two unidentified microorganisms, one attacking a species of grasshopper
and a rod-shaped bacterium attacking the kanani caterpillar have also been found.
Management
Very little published information is available on the management of the insect pests of
cinnamon and cassia. The general recommendations suggested include spraying of
quinalphos 0.05% for the management of leaf-feeding caterpillars and beetles.
Monocrotophos 0.05% and quinalphos 0.05% is recommended for the management of
leaf miner on cinnamon (Devasahayam, 2000).
Diseases
Though many diseases have been recorded on cinnamon (C. verum), only a few are
serious, causing economic losses. These include stripe canker, leaf spot, dieback, brown
root rot and grey blight diseases. Very few diseases have been recorded on cassia
cinnamons (C. cassia, C. burmanii and C. tamala). Diseases of cultivated cinnamon
are presented briefly here and have also been tabulated along with diseases that occur
on other species of cinnamon (Table 10.3).