Grapevine Moth: All You Need to Know for Healthy Vines

The European Grapevine Moth (Lobesia botrana or EGVM) is a significant agricultural pest that poses a threat to grapevines worldwide. Originating in Europe, the moth has caused considerable damage to grapes and other berries globally, with its presence first detected in the United States in 2009 before being officially eradicated in 2016. This pest is particularly destructive due to its ability to feed on the flowers and fruits of the host plant, often targeting grapes.

One of the primary concerns associated with the grapevine moth is the potential for vineyard powdery mildew outbreaks. These outbreaks can be tackled through a high volume application of water mixed with a wetting agent, which works by washing off all the spores from the grapevine and preventing further dispersal to healthier parts.

As grapevine moth infestations can lead to severe losses in grape production, it is crucial for vineyard owners and growers to be aware of the various preventative and control measures. Such measures can include monitoring moth populations, monitoring vineyards for signs of infestation, and implementing appropriate management practices.

Grapevine Moth Overview

Identifying the Grapevine Moth

The European Grapevine Moth (EGVM), or Lobesia botrana, is a type of pest from the Tortricidae family. Native to southern Italy, they are found in several other regions, including Europe, the Middle East, Africa, and even the United States. These moths were first detected in Napa County, California in 2009source. Key identifying features of the European Grapevine Moth include:

  • Adult moths are about 1/4-inch long
  • Wing color depends on the region they are found in, ranging from brownish-gray to light brown with dark markings
  • Larvae are small and yellowish-green in color with a brown head

Life Cycle of the Grapevine Moth

The life cycle of the European Grapevine Moth consists of four stages:

  1. Egg: Female moths lay eggs on the buds of the grapevine. Eggs hatch after about 3-6 days.
  2. Larvae: The larvae feed on the grapevine’s flower or fruit, causing significant damage. Their feeding period lasts around 21-28 days.
  3. Pupa: Following the feeding period, the caterpillars form a cocoon and pupate, which takes around 10-20 days.
  4. Adult: Adult moths emerge from the cocoon and continue the life cycle by laying eggs.

The European Grapevine Moth’s life cycle is impacted by the climate, with warmer temperatures causing faster development. In summary, the European Grapevine Moth is a significant pest that poses a threat to grapevines worldwide. Recognizing its identifying features and understanding its life cycle can greatly assist in pest control efforts.

Damage and Symptoms of Infestation

Effects on Grapevine Berries and Clusters

The European Grapevine Moth (Lobesia botrana) causes significant damage to grapevines, primarily by feeding on the berries, flowers, and fruits. When adult moths lay their eggs on grape flowers or developing fruit, the hatched larvae feed on these host plants, causing substantial harm 1.

  • Berries: Larvae burrow into the berries and consume the interior, causing them to lose their skin and seeds, eventually withering away 2.
  • Flowers: The moth feeds on this crucial reproductive part of the plant, affecting overall fruit production.

Impact on Grape Production

The damage caused by the European Grapevine Moth negatively impacts grape production in several ways:

  1. Quantity: As the larvae feed on flowers and developing fruits, the overall yield of grapes is significantly reduced.
  2. Quality: Affected grape clusters may have an increased presence of rot and fungal infections due to the larvae’s activity 3.

A comparison of healthy grapevines and those infested with the European Grapevine Moth:

Healthy Grapevine Infested Grapevine
Berry Appearance Intact and plump Hollowed out, skin and seeds exposed
Flower Condition Healthy, vibrant Damaged, lower fruit production
Presence of Rot Minimal Increased due to larval activity
Grape Yield Normal Significantly reduced

In conclusion, the European Grapevine Moth poses a considerable threat to grapevines, mainly through its damaging effects on grape berries, flowers, and fruit production. Understanding these symptoms enable early detection and appropriate management techniques to mitigate the pest’s influence on grapevines.

Control and Management of Grapevine Moths

Mating Disruption and Biological Controls

  • Mating disruption techniques involve using pheromones to confuse male grapevine moths and prevent mating.
  • Specific parasitoids such as Dibrachys spp. can help control European grapevine moth populations by attacking their larvae.

Grapevine moth control can begin with non-chemical methods, such as mating disruption and biological controls. Mating disruption uses pheromones to disrupt the communication between male and female moths, making it difficult for them to find each other and mate1. Biological controls, such as introducing natural enemies like parasitoids, can also help manage grapevine moth populations. For example, the parasitic wasp species Dibrachys spp. is known to attack the larvae of the European grapevine moth3.

Chemical Control and Insecticides

Common insecticides:

  • Insect growth regulators (IGRs)
  • Spinosyns
  • Bacillus thuringiensis (Bt)

Chemical control methods involve the use of insecticides, which can effectively manage grapevine moth populations when applied correctly and at the right time. Some common insecticides for grapevine moth control include insect growth regulators (IGRs), spinosyns, and Bacillus thuringiensis (Bt)2.

IGRs, as the name suggests, interfere with the growth and development of insects, making them unable to reproduce. Spinosyns are another group of insecticides derived from a naturally occurring soil bacterium; they target the nervous system of insects and are generally considered safe for non-target organisms4. Bacillus thuringiensis (Bt) is a naturally occurring soil bacterium that produces a toxin harmful to certain insects, including grapevine moths5. Bt can be applied as a biological insecticide to control larval populations.

Insecticide pros and cons:

Pros:

  • Effective in controlling grapevine moth populations
  • Can be applied in a targeted manner to minimize impact on non-target organisms

Cons:

  • Can cause resistance in pests if used improperly
  • May negatively affect beneficial insects and other non-target organisms

While insecticides can be effective, it is important to use them responsibly to prevent the development of resistance in pests, minimize harm to beneficial insects, and limit the impact on non-target organisms. The University of California’s Integrated Pest Management program recommends monitoring vineyards for grapevine moth presence and damage, and then applying insecticides when necessary6.

Geographical Spread and Quarantine Measures

Global Distribution of Grapevine Moths

The European Grapevine Moth (Lobesia botrana) is a significant agricultural pest, predominantly found in:

  • Europe: Native region
  • Mediterranean: Widespread presence
  • Southern Russia: Invasive species established in vineyards
  • Japan: Limited distribution
  • Middle East: Regional infestations
  • Near East: Sporadic occurrences
  • Northern and Western Africa: Non-native invader species (source)

The moth is particularly harmful to grapevine crops due to its larvae feeding on flowers and fruits, resulting in severe crop loss.

Quarantine and Detection Methods

The United States had its first detection of the European Grapevine Moth (EGVM) in California in 2009. Through rigorous quarantine efforts, the country successfully eradicated the pest by August 2016 (source).

Some common detection methods and practices are:

  • Pheromone traps: Attracts male moths for monitoring population trends
  • Visual inspections: Examination for eggs, larvae, and crop damage
  • Annual surveys: Ongoing efforts to monitor and prevent new infestations

In addition, biological control measures using parasitic wasps have proven effective in reducing EGVM populations. These wasps are natural enemies of the moth, targeting their eggs and larvae.

Comparing the two main generations of EGVM, researchers found the first generation affects flowers, while the second generation feeds on grape berries. Control measures must be adjusted accordingly to counter the moth at each stage of its lifecycle.

Prevention Strategies and Resources

Best Practices for Vineyard Management

  • Monitor vineyards: Regularly check for signs of infestation such as webbing, larvae, and damaged berries. This helps in early detection and prevention of grapevine moth damage.
  • Pruning and canopy management: Proper pruning and canopy management allow for better air circulation and sunlight penetration, reducing the risk of infections and moths finding a suitable habitat.
  • Remove infested berries: Remove and destroy any infected green berries or grape clusters to prevent larvae from developing and spreading.
  • Use reduced-risk insecticides: Apply reduced-risk insecticides when necessary to control grapevine moth populations. Examples include neem oil, which targets adult moths, and other compounds that target the Lepidoptera group.

Available Guidelines and Restrictions

Entity Pro Con
Japanese Beetles Can also be controlled with reduced-risk insecticides Not the primary focus of guidelines and restrictions
Neem Oil Targets adult moths, environmentally-friendly May not target other pests in the vineyard

A consistent and well-planned prevention strategy can help reduce the risk of grapevine moth infestations and the associated damage to grape production. Utilize the provided resources and guidelines, and tailor them to your vineyard’s specific conditions to maintain a healthy crop.

Footnotes

  1. USDA APHIS | European Grapevine Moth 2

  2. Center for Invasive Species Research 2

  3. UC Statewide IPM Program (UC IPM) 2

  4. https://www.canr.msu.edu/news/mid-season-management-of-grape-berry-moth

  5. https://www.cdfa.ca.gov/plant/egvm/index.html

  6. https://ipm.ucanr.edu/Invasive-and-Exotic-Pests/European-grapevine-moth/

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Grapevine Moth from Australia

 

Subjec:  Who is she?
Geographic location of the bug:  Townsville, QLD
Date: 01/28/2019
Time: 12:41 AM EDT
Your letter to the bugman:  Today I met this fashionable individual while taking shelter from the summer rain. Do you know their name?
How you want your letter signed:  Gabby

Grapevine Moth

Dear Gabby,
This is a Grapevine Moth and we identified it on Butterfly House where it is classified in the subfamily Agaristinae, called Day Flying Moths or Whistling Moths, in the family Noctuidae, the Owlet Moth.  According to Butterfly House:  “The adult is a day-flying moth, with a wingspan of up to 5 cm. The wings are black with striking white bands on the forewings, and a white outer margin on the hindwings. The abdomen is black on top and has orange stripes underneath.  The body has tufts of bright red hair on the tip of the abdomen, and at the bases of the legs. These red hairs project and are visible from above. The adults are gregarious, feed on nectar and live for 2-3 weeks. They had a characteristic fluttering flight and can ascend to 25 m or more. Their overall sex ratio is about 1:1. The adult males have anterior brush organs on which are secreted chemicals thought to be pheromones.”  There is a nice image on Alamy and according to Project Noah:  “A Noctuid moth endemic to the south-eastern part of Australia and is now an invasive species in many other parts of the world. In 1862 the Indian Myna (
Acridotheres tristis) was introduced into Australia to control the Grapevine Moth. The bird is now considered a pest and Grapvine moths are common. I watched a female for ten minutes – first seeking the location of a vine – second happy she was near one she just started releasing eggs; one every 30 seconds while fluttering her wings – third the eggs just fell to the ground around the base of the vine. Over the next few days I noticed scores of tiny caterpillars climbing slowly up the supporting posts. Near enough was good enough I guess.”    

Authors

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  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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