Green FruitWorm
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Beginner
This pest affects:
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Scientific Name
Othosia hibisci
Identification
Eggs
- 0.8 mm in diameter and 0.5 mm in height
- white with a greyish tinge
- visible when viewed through a microscope
Larvae
- When full-grown, 30-40 mm long
- Lime to dark green, including the head
- Small white spots cover the body with several white longitudinal stripes running the length of the body
- 20-30 mm long and about 100 mm wide
Adults
- Dark forewings and hind wings that are much lighter
- Wingspans of 25-40 mm
Injury
- Small entry holes in buds, chewed petals and flower parts
- Most flower buds and blossoms damaged by GFW larvae abort
Leaves
- Chewed young terminal leaves
Fruit
- Most fruit damaged just prior to and shortly after petal fall drop prematurely
- Wide irregular holes in small fruit resulting in large russeted scars and deep corky pits in mature fruit; feeding often distorts pears
Often Confused With
Leafroller injury- The deep corky feeding scars of green fruitworm are difficult to distinguish from leafroller injury. Oblique-banded leafroller larvae are light green to yellowish green to dark green.with a dark head and no speckles
Period of Activity
Green fruitworm begins emerging in early spring. Their eggs are laid on new leaves forming on trees. After the eggs hatch, they begin feeding on leaves and the forming fruit. Green Fruitworms are only active in orchards until early summer.
Scouting Notes
Approximately 70% of attacked fruit will abort prior to or during June drop. Larvae often feed extensively on one fruit, but sometimes can damage up to a dozen or more.
During the period between tight cluster to petal fall, check 5 terminal shoots and 5 fruit buds in each of 10 trees (50 terminals and 50 fruit buds in total) for signs of caterpillar feeding activity.
Thresholds
12-15 larvae per 100 terminals or fruit bud injury is observed.
Advanced
This pest affects:
| ; |
Scientific Name
Othosia hibisci
Identification
Eggs
- 0.8 mm in diameter and 0.5 mm in height
- white with a greyish tinge
- visible when viewed through a microscope
Larvae
- When full-grown, 30-40 mm long
- Lime to dark green, including the head
- Small white spots cover the body with several white longitudinal stripes running the length of the body
- 20-30 mm long and about 100 mm wide
Adults
- Dark forewings and hind wings that are much lighter
- Wingspans of 25-40 mm
Injury
- Small entry holes in buds, chewed petals and flower parts
- Most flower buds and blossoms damaged by GFW larvae abort
Leaves
- Chewed young terminal leaves
Fruit
- Most fruit damaged just prior to and shortly after petal fall drop prematurely
- Wide irregular holes in small fruit resulting in large russeted scars and deep corky pits in mature fruit; feeding often distorts pears
Often Confused With
Leafroller injury- The deep corky feeding scars of green fruitworm are difficult to distinguish from leafroller injury. Oblique-banded leafroller larvae are light green to yellowish green to dark green.with a dark head and no speckles
Biology
Green fruitworm overwinters as pupae underground. Adults emerge in early spring. After mating, eggs are laid singly on developing leaves. Larvae, resembles tiny inchworms when they first hatch, feed on buds, leaves, blossoms and developing fruitlets. There is only one generation per year. Many predatory and parasitic insects attack green fruitworm caterpillars. Predators include ground beetles, stink bugs, assassin bugs and spiders. Parasitic wasps and flies attack caterpillars and minute Trichogramma wasps often parasitize moth eggs.
Period of Activity
Green fruitworm begins emerging in early spring. Their eggs are laid on new leaves forming on trees. After the eggs hatch, they begin feeding on leaves and the forming fruit. Green Fruitworms are only active in orchards until early summer.
Scouting Notes
Approximately 70% of attacked fruit will abort prior to or during June drop. Larvae often feed extensively on one fruit, but sometimes can damage up to a dozen or more.
During the period between tight cluster to petal fall, check 5 terminal shoots and 5 fruit buds in each of 10 trees (50 terminals and 50 fruit buds in total) for signs of caterpillar feeding activity.
Thresholds
12-15 larvae per 100 terminals or fruit bud injury is observed.
Management Notes
Insecticide options are provided in OMAFRA Publication 360, Fruit Crop Protection Guide.
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Chapter 5 - Pear Calendar: Recommendations for green fruitworm at Petal fall. |
Some information included above excerpted from;
