grape berry moth
Beginner
Scientific Name
Paralobesia viteana (previously Endopiza viteana)
Identification
- Opaque white, oval, scale-like, 0.7 mm diameter
- Laid singly among the flower clusters, on petals, fruit stems and berries
- Young larvae have a cream body and dark brown head
- Become green and then purple with a light brown head when mature
- 10 mm long at maturity
- Leave fine silken webs as they move about
- 5 mm long
- either light-brown with a green shade on the abdomen or entirely dark green
Adults
- 6 mm long
- brown body that has a grey-purple band across the wings and cream with brown spots near the wing tips
Damage
First generation larvae
- Larvae web together flowers and newly-set berries as they feed on them
- Affected plant parts often drop from vine
- Small berries will show feeding damage
Second generation larvae
- Larvae create a pin head size hole and burrow directly into green berries usually near the berry stem or side where berries touch
- Purple or dark spot may form around the pin-head size hole
- Winding dark tunnels are visible through the surface of the berry
Third and partial fourth generation larvae
- Infested berries turn purple or brown
- Eat berry flesh and leave hollowed-out berries with frass inside
- Often feed successively on multiple berries that are touching in cluster
- Infested berries are oten infected with bunch rots
- Infested berries may also be injured further by wasps and Multicoloured Asian Lady Beetle
Often Confused With
Downy mildew: berries turn colour prematurely but remain hard
Veraison: berries turn colour but are not filled with frass
Leafrollers: may feed inside berries; larvae remain green with a dark or green head
Spider webbing: no larvae or frass present
Episimus argutanus: may be caught in pheromone traps; mottled brown but without the grayish-purple bands on the wings of grape berry moth
Period of Activity
First generation: Adult moths first emerge and mate start to lay eggs once inflorescences are visible in wild grapes and elongating <shoots 20-25cm)in commercial vineyards and continue egg laying for a few weeks
Second generation: Adults appear when fruit are approximately shot size. Larvae of this generation appear several days after first adults are active and feed exclusively on the developing berries
Third generation: This generation begins appearing about veraison and adults continue to emerge throughout August into September. Egg deposition continues over a prolonged period of time and larval activity can extend until the first frost occurs
Scouting Notes
Place traps in the vineyard prior to the anticipated first flight in the spring. Replace traps at the end of the flight period for each generation. Leave traps in the vineyard until harvest is completed. A minimum of one set of five traps per four hectares is recommended. Place traps on the top wire of the trellis. Install one trap at the edge of the vineyard and the rest of the traps at 40 m intervals following a row into the vineyard. Check twice weekly, on the same days from week to week if possible. Examine moths carefully to avoid confusion with Episimus. Remove all moths each time the trap is inspected and record the data.
Be aware if mating disruption being used in the vineyard or in the area nearby as this may affect the success of this type of monitoring for seasonal moth activity.
Where mating disruption for grape berry moth has been applied, use sentinel traps. Monitoring methods will be the same as above except that the fifth trap is placed in the centre of the vineyard block.
In addition to monitoring adult flight in pheromone traps, clusters should be examined for injury. Be aware of hot spots in the vineyard, which tend to be in the borders or near wooded areas. See thresholdsfor monitoring protocol.
First generation: look for blossom caps and small berries matted together by webbing. Dissect these masses and look for larvae, feeding injury or frass.
Subsequent generations: look for berries that are prematurely changing colour and clumped together; dissect and examine for larvae and/or frass. After veraison, botrytis bunch rot may be associated with grape berry moth injury so examine rotted parts of cluster for larvae and/or frass.
Threshold
Monitor pheromone traps to identify upswing in trap counts. Depending on the product selected, insecticides may applied at upswing in pheromone trap counts or 6-10 days thereafter. A repeat application may be needed if emergence is extended or fresh injury continues to be detected.
Examine 10 clusters from 10 widely spaced vines in the outside 5 rows and 5 panels. If in this initial assessment more than 5% of the clusters have been infested with grape berry moth, a second sample of 100 clusters from further into the vineyard should be examined. Apply corrective measures if more that 5% of the clusters are injured.
If this damage appears confined to the outer 5 rows of the vineyard, a border treatment with an insecticide may be sufficient.
If mating disruption is working properly, very low numbers or no grape berry moth should be captured in these traps. If moths are captured in sentinel traps, this indicates a possible failure of mating disruption, and supplemental insecticide sprays may be required at borders and/or throughout the entire block.
For more information on mating disruption for GBM see OMAFRA Publication 360, Fruit Crop Protection Guide.
Advanced
Scientific Name
Paralobesia viteana (previously Endopiza viteana)
Identification
- Opaque white, oval, scale-like, 0.7 mm diameter
- Laid singly among the flower clusters, on petals, fruit stems and berries
- Young larvae have a cream body and dark brown head
- Become green and then purple with a light brown head when mature
- 10 mm long at maturity
- Leave fine silken webs as they move about
- 5 mm long
- either light-brown with a green shade on the abdomen or entirely dark green
Adults
- 6 mm long
- brown body that has a grey-purple band across the wings and cream with brown spots near the wing tips
Damage
First generation larvae
- Larvae web together flowers and newly-set berries as they feed on them
- Affected plant parts often drop from vine
- Small berries will show feeding damage
Second generation larvae
- Larvae create a pin head size hole and burrow directly into green berries usually near the berry stem or side where berries touch
- Purple or dark spot may form around the pin-head size hole
- Winding dark tunnels are visible through the surface of the berry
Third and partial fourth generation larvae
- Infested berries turn purple or brown
- Eat berry flesh and leave hollowed-out berries with frass inside
- Often feed successively on multiple berries that are touching in cluster
- Infested berries are oten infected with bunch rots
- Infested berries may also be injured further by wasps and Multicoloured Asian Lady Beetle
Often Confused With
Downy mildew: berries turn colour prematurely but remain hard
Veraison: berries turn colour but are not filled with frass
Leafrollers: may feed inside berries; larvae remain green with a dark or green head
Spider webbing: no larvae or frass present
Episimus argutanus: may be caught in pheromone traps; mottled brown but without the grayish-purple bands on the wings of grape berry moth
Biology
Grape berry moth overwinters as pupae in leaf litter in and around vineyards. Adult moths usually start to emerge about a week before wild grape bloom (3-5 leaves through pre-bloom in vineyards) and emergence continues for a few weeks. Mating occurs when temperatures exceed 13ºC. Eggs are laid on berry florets or berries shortly after mating and hatch 3-6 days later, depending on temperature. First generation larvae feed superficially on berry florets and developing berries. Once berries are 6 mm or larger larvae enter directly into the berry and feed on the pulp for 3-4 weeks. A single larva may feed on several berries and often these will be webbed together. When mature, larvae emerge from the fruit and may move to a leaf to cut out a flap then drop to the ground or just spin down to the ground to pupate for 10-14 days. Second generation larvae feed on the expanding berries, and feeding sites are visible as holes with a purple or reddish discolouration. The larvae feed just below the skin, but eventually the flesh of the berry is attacked. Larvae of the third generation feed on the flesh inside the berries before and after veraison. Berries may be hollowed out by feeding, and larvae at this time may be found in harvested fruit at the processor and be considered as a contaminant. Most fully developed third generation larvae spin down to the ground where they construct overwintering pupal cells in fallen leaves. Depending on weather conditions there may be a 3rd and a partial 4th generation of grape berry moth each growing season. Larvae from the 3rd and 4th generation can cause the greatest damage at harvest. Because of the extended emergence of adults and subsequent egg deposition, there can be a great range of larval instars present at harvest.
Period of Activity
First generation: Adult moths first emerge and mate start to lay eggs once inflorescences are visible in wild grapes and elongating <shoots 20-25cm)in commercial vineyards and continue egg laying for a few weeks
Second generation: Adults appear when fruit are approximately shot size. Larvae of this generation appear several days after first adults are active and feed exclusively on the developing berries
Third generation: This generation begins appearing about veraison and adults continue to emerge throughout August into September. Egg deposition continues over a prolonged period of time and larval activity can extend until the first frost occurs
Scouting Notes
Place traps in the vineyard prior to the anticipated first flight in the spring. Replace traps at the end of the flight period for each generation. Leave traps in the vineyard until harvest is completed. A minimum of one set of five traps per four hectares is recommended. Place traps on the top wire of the trellis. Install one trap at the edge of the vineyard and the rest of the traps at 40 m intervals following a row into the vineyard. Check twice weekly, on the same days from week to week if possible. Examine moths carefully to avoid confusion with Episimus. Remove all moths each time the trap is inspected and record the data.
Be aware if mating disruption being used in the vineyard or in the area nearby as this may affect the success of this type of monitoring for seasonal moth activity.
Where mating disruption for grape berry moth has been applied, use sentinel traps. Monitoring methods will be the same as above except that the fifth trap is placed in the centre of the vineyard block.
In addition to monitoring adult flight in pheromone traps, clusters should be examined for injury. Be aware of hot spots in the vineyard, which tend to be in the borders or near wooded areas. See thresholdsfor monitoring protocol.
First generation: look for blossom caps and small berries matted together by webbing. Dissect these masses and look for larvae, feeding injury or frass.
Subsequent generations: look for berries that are prematurely changing colour and clumped together; dissect and examine for larvae and/or frass. After veraison, botrytis bunch rot may be associated with grape berry moth injury so examine rotted parts of cluster for larvae and/or frass.
Threshold
Monitor pheromone traps to identify upswing in trap counts. Depending on the product selected, insecticides may applied at upswing in pheromone trap counts or 6-10 days thereafter. A repeat application may be needed if emergence is extended or fresh injury continues to be detected.
Examine 10 clusters from 10 widely spaced vines in the outside 5 rows and 5 panels. If in this initial assessment more than 5% of the clusters have been infested with grape berry moth, a second sample of 100 clusters from further into the vineyard should be examined. Apply corrective measures if more that 5% of the clusters are injured.
If this damage appears confined to the outer 5 rows of the vineyard, a border treatment with an insecticide may be sufficient.
If mating disruption is working properly, very low numbers or no grape berry moth should be captured in these traps. If moths are captured in sentinel traps, this indicates a possible failure of mating disruption, and supplemental insecticide sprays may be required at borders and/or throughout the entire block.
For more information on mating disruption for GBM see OMAFRA Publication 360, Fruit Crop Protection Guide.
Management Notes
Cultivating in early spring will bury the previous season’s leaves and prevent moths from emerging.
Use pheromone traps to monitor grape berry moth adult activity and determine insecticide application timing. The specific timing of pest control products varies depending on the target life stage, the insecticide’s mode of action and residual activity. Pheromone trap catch data provides critical information for management of grape berry moth using either insecticides or mating disruption technology.
Mating disruption of grape berry moth is a highly effective alternative to insecticides. For more information, consult OMAFRA Factsheet 03-079,Mating Disruption for Management of Insect Pests and See OMAFRA Publication 360, Fruit Crop Protection Guide - Chapter 4 Grapes: Recommendations for grape berry moth mating disruption at shoot length 20-25 cm.
Management with insecticides – Insecticides are used to control grape berry moth in most commercial vineyards. See OMAFRA Publication 360, Fruit Crop Protection Guide - Chapter 4 Grapes: Recommendations for grape berry moth at Trace bloom, Berries pea-sized, and Beginning of ripening (veraison) through harvest.
