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AVOCADOS & COFFEE, WHAT HAVE THEY GOT IN COMMON?

Avocado leafroller in coffee

Bruno Pinese, Harry Fay & Rod Elder, Department of Primary Industries and Fisheries

Coffee- Two avocado leafroller (Homona spargotis) larvae feeding on a leaf
Two avocado leafroller (Homona spargotis ) larvae feeding on a leaf

Description

Adult

Marked differences between the sexes occurs in the moth stage. The male is smaller (18 to 20 mm wingspan) than the female (25 to 30 mm wingspan). The forewings in the male are light brown with dark brown banding; in the female the forewings are dark tan to light brown with a darker oblique band and darker wing tip. The female has prominent wingtips and at rest the folded wings give the adult moths a bell shape.

Coffee- Female       moth of avocado leafroller
Female moth of avocado leafroller

Immature stages

The pale, flattened, yellow/orange eggs are laid in masses (sometimes exceeding 400) and overlap like fish scales. They are laid on the upper surface of mature leaves.

The young larvae drop on silken threads to be dispersed by the wind or they crawl a short distance to new shoots. They feed within shelters that they construct by rolling and webbing young foliage.

Life history

Little is known of the life history other than the eggs hatch after six to eight days, and that several generations occur each year.

Distribution

North Queensland

Host range

Hosts include avocado, custard apple, carambola, coffee, tea and other horticultural crops but on these it is a relatively minor pest.

Management

Importance

Major and frequent. Avocado leafroller is a serious pest in coffee and avocado in north Queensland. It is also a frequent minor pest of, custard apple, carambola and tea.

Damage

The caterpillars of this moth roll and web leaves together and also web leaves to berries. Inside these shelters the larvae live and feed on the leaf and berry tissue. Although severe leaf damage may be caused, the damage inflicted on the berries is more important. Large areas of the skin of berries may be eaten, sometimes to a depth of four millimetres. Damaged berries may be infected with anthracnose and drop or the injury may heal, forming scar tissue. Trees in flush are most susceptible since larvae prefer to feed on young growth and cause proportionately more damage on small, unexpanded leaves.

Action level

Examine five trees at each of six widely spaced locations throughout the crop. Spray if more than 300 larvae are found. Check trees weekly. This action level requires further study and should be taken as a suggestion only.

Control methods

Biological

Several natural enemies have been recorded attacking leafrollers. These include a predatory of a syrphid fly larva, several wasp parasitoids, a tachinid fly parasitoid and egg parasitoids.

The extent to which these biocontrols operate depends on the level of disruption caused by pesticides applied to control other pests.

Chemical

Use chlorpyrifos to suppress populations.

Sprays during flowering must be avoided to prevent death of bees and other pollinators.

Recommended chemicals

Chlorpyrifos Note: This information was correct at the time of publication. However, it is the user’s responsibility to ensure that registered agricultural chemicals are used in accordance with legal requirements. (See Further information).

Always read the label.

October 7th, 2010
Topic: AGRICULTURE, FOOD DRINK, FRUIT VEG SMALL CROPS, INSECTS REPTILES, Moths & Nymphs, PESTS DISEASES BACTERIA VIRUSES Tags: , , , , ,

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