How to Manage Pests

UC Pest Management Guidelines

Grape

Vine Mealybug

Scientific name: Planococcus ficus

(Reviewed 7/15)

In this Guideline:


DESCRIPTION OF THE PEST

Vine mealybugs are small (adult females are about 1/8 inch in length), soft, oval, flat, distinctly segmented, and covered with a white, mealy wax that extends into spines (filaments along the body margin and the posterior end). The vine mealybug has a pinkish body that is visible through the powdery wax, and it is slightly smaller than the Pseudococcus mealybugs. The waxy filaments that protrude from the body of the vine mealybug are shorter than those on the Pseudococcus mealybugs, and the vine mealybug does not possess long tail filaments. The adult male is smaller than the female, has wings, and flies short distances to mate. There are three to seven generations a year.

All or most life stages of the vine mealybug can be present year-round on a vine depending on the grape-growing region. In the North Coast during winter months, the only life stages found are nymphs located under the bark predominately at the graft union, on trunk pruning wounds, and below the base of spurs. In other regions during the winter months, vine mealybug eggs, crawlers, nymphs, and adults are under the bark, within developing buds, and on roots.

As temperatures warm in spring, vine mealybug populations increase and become more visible as they move from the roots or trunk to the cordons and canopy. By late spring and summer, vine mealybugs are found on all parts of the vine: hidden under bark and exposed on trunks, cordons, first- and second-year canes, leaves, clusters, and roots. Ants may transport vine mealybug from the roots to above ground plant parts where they continue to tend vine mealybugs throughout the remainder of the growing season.

In the North Coast, vine mealybug has not been found on vine roots; however, in other regions with sandy soils it spends the winter almost exclusively on the root system. Other mealybugs found infesting grapes are only found on the aboveground portions of the vine. In addition, the vine mealybug is much more likely to be found on leaves during the growing season than the other mealybugs. During summer when vine mealybugs are in the canopy, they can be located well above the fruit zone and will lay eggs on the leaves, while Pseudococcus mealybugs do not. Vine mealybug does not diapause during the winter, and it appears to be more sensitive to cold temperatures than grape mealybug.

DAMAGE

Damage by the vine mealybug is similar to that of other grape-infesting mealybugs in that it produces honeydew that drops onto the bunches and other vine parts and serves as a substrate for black sooty mold. If ants are not present, a vine with a large population of this pest can have so much honeydew that it resembles candle wax. Also, the mealybug itself will be found infesting bunches making them unfit for consumption. Like the grape, obscure, and longtailed mealybugs, vine mealybug can transmit grapevine leafroll-associated viruses.

MANAGEMENT

Vine mealybug occurs in all major California production areas. In California, the vine mealybug feeds predominantly on grapevines, although in other countries it can be a pest of fig, date palm, apple, avocado, citrus, and a few ornamentals.

Because several different species of mealybugs may infest grapevines, it is important to know which species of mealybug is present because management programs for the various mealybugs differ. If you find mealybugs in your vineyard, collect the largest mealybugs you can find and place them in a jar of alcohol or sealed plastic bag. Take the sample to either your University of California Cooperative Extension (UCCE) farm advisor or county Agricultural Commissioner.

Biological Control

The parasites that attack Pseudococcus mealybugs do not attack the vine mealybug; therefore two potential candidates for biological control have been imported and released in California. The most successful of these has been Anagyrus pseudococci. This species has provided up to 20% parasitism in some vineyards in the Coachella Valley and up to 90% parasitism of exposed mealybugs late in the season in the San Joaquin Valley. This parasitoid can be highly effective late in the season to reduce mealybug populations present after harvest before they return to the roots or lower trunk to overwinter. However, in the spring, the parasitoid does not emerge from its overwintering state until about bloom, providing minimal mealybug suppression during the early and midseason. Growers can attempt to overcome this biological limitation of A. pseudococci by doing early-season releases of parasitoids that are purchased from commercial insectaries. Management of ants can reduce disruption of parasitism by A. pseudococci.

In coastal regions, several lady beetles such as the mealybug destroyer, Cryptolaemus montrouzieri and Hyperaspis sp. attack vine mealybug eggs and crawlers. Larvae of predaceous midges (family Cecidomyiidae) feed on mealybug eggs.

Cultural Control

The female and nymphal mealybugs are wingless and are unable to fly so they must be carried by humans, equipment, wind, birds, or be present on vines at the time of planting. Do not allow contaminated equipment, vines, grapes, or winery waste near uninfested vineyards. Movement of equipment that pushes brush or any over-the-row equipment can be a major source of infestations in new locations; steam sanitize equipment before moving to uninfested portions of the vineyard. Do not spread infested cluster stems or pomace in the vineyard. To reduce contamination, cover all pomace piles with clear plastic for several weeks, and avoid creating piles that consist predominately of stems.

Reduce cluster infestation by pruning vines to prevent clusters hanging directly on the cordon. In areas where mealybugs overwinter exclusively on the roots, band application of Tanglefoot onto duct tape that has been wrapped around the trunk (with the bark removed) may help slow crawler movement up the vine in the spring.

Organically Acceptable Methods

Biological and cultural controls are organically acceptable management tools. Repeated applications of oil approved for organic production can suppress vine mealybug in wine and raisin grapes. Oil applications are not used in table grapes, because they potentially affect the appearance of the fruit surface. Additionally, there are concerns about using oil in conjunction with sulfur due to the potential phytotoxic effects. Mating disruption is also approved for organic vineyards.

Monitoring and Treatment Decisions
Monitoring

Monitor for vine mealybug by doing searches on the roots, trunk, cordon, leaves, and clusters depending on the time of year.

During the winter, look for vine mealybug on the lower crown; in areas with sandy soils, on the roots. During budbreak follow the monitoring guidelines in DELAYED-DORMANT AND BUDBREAK MONITORING (wine/raisin grapes or table grapes) to monitor these and other pests and record results on a monitoring form (example formPDF).

In the spring, monitor the crown and trunk for adult females and the presence of crawlers moving up the vine. Starting at bloom, monitor for vine mealybug along with other pests as outlined in MONITORING INSECTS AND SPIDER MITES. Survey cordons, canes, and basal leaves. In coastal areas, also continue to monitor the trunk.

When fruit is present, especially after veraison, monitor clusters to ensure vine mealybug life stages or honeydew are not contaminating the fruit. In table grapes and other hand-harvested vineyards, picking crews can be trained to be a valuable resource for reporting the presence of mealybugs in vineyards not known to be infested.

Monitoring efforts can be aided by looking for ants and honeydew. Argentine and gray ants tend vine mealybugs; therefore, observing ant activity can direct ones attention to where mealybugs are present on the vine. The presence of honeydew may also be an indication of vine mealybug presence. Thus, when searching for vine mealybugs during summer, look for honeydew exudates on the clusters, trunk, and cordons. These exudates will resemble melted candle wax; if the infestation is severe, basal leaves will appear shiny and sticky. Eventually, sooty mold will grow on the honeydew and permanent parts of the vine will appear greenish black during the fall and winter.

Pheromone traps can help determine if vine mealybug is present within or near your vineyard. Place pheromone lures in small red delta traps in and around the vineyard by April 1 in the southern San Joaquin Valley, by May in areas further north, and by June in the North and Central Coast region:

  • Choose two trap sites for each 20-40 planted acres.
  • Put one trap in the center of the block and the other on the edge near a staging area. These traps can attract vine mealybug males from as far away as 1/4 mile.
  • Attach traps to the trellis wires so that they are in the cluster area.
  • Label the trap with the block name and row number of its location and the dates it remains in the vineyard.
  • Check traps for the presence of male vine mealybug every 2 weeks through November.
  • Follow the manufacturer's recommendations for storing and replacing pheromone lures.
  • Record observations on a monitoring form (example form (PDF)

It is essential to use a dissecting microscope to identify the male mealybug. (Male vine mealybugs are smaller than adult thrips and are very difficult to see even with a hand lens.) The sex pheromone is specific to the vine mealybug, but the traps may also contain other male mealybugs depending on the site. If there are questions as to the identification of the mealybug species, take samples to a farm advisor or county agricultural commissioner or refer to the Male Vine Mealybug Identification Sheet.

The number of males found in a trap depends upon its proximity to the infestation and to the time of year. In the North Coast, new infestations have been located near traps that caught very low numbers in June (5 to 10 males per trap per week) and high numbers in fall (more than 50 males per trap per week). In the San Joaquin Valley, an infested vineyard will have between 20 to 300 or more males per trap per week. In either region, low numbers of male vine mealybugs found in a trap may mean that the infestation is located in an adjacent block or in a more distant vineyard. If males are found, increase the number of traps in the vineyard, and locate the infestation by examining lower leaves for honeydew.

Treatment

If vine mealybug is found in a vineyard, treatment is recommended. However, the level of treatment varies greatly depending on the region, type of grape, and harvest date:

  • Coastal regions only have two to three generations of vine mealybug per year, compared to five to seven in the lower San Joaquin Valley.
  • Table grapes have no allowance for mealybugs in the cluster, while wine grapes can tolerate low levels.
  • Harvest dates vary widely in table grapes. Fruit from a Flame Seedless vineyard, harvested on the first of July, is less susceptible to damage than fruit in a neighboring Crimson Seedless vineyard, which might be harvested in October.

Due to the complexity of these and other factors, such as biological control, decisions about the level of mealybug control need to be made on a vineyard-by-vineyard basis.

In vineyards with low mealybug pressure, a single insecticide application in the spring or at bloom is often sufficient for season-long mealybug control. Effective control in heavily infested table grape vineyards, planted to a late-harvested variety, may require three or more treatments.

When treating for vine mealybug, consider other pests. Chlorpyrifos is also effective on ants, insect growth regulators can control scale pests, spirotetramat provides suppression of nematodes and phylloxera, and neonicotinoids are effective against sharpshooters and leafhoppers. When using soil-applied neonicotinoids, growers should also be cognizant of soil type: imidacloprid (Admire Pro) and clothianidin (Belay) are more effective on sandy soils whereas thiamethoxam (Platinum) and dinotefuran (Venom) are more effective on heavier soil.

Mating disruption has recently become available and can be used as an alternative or supplement to chemical control. Mating disruption is most effective when insecticides are used aggressively in the first year to reduce vine mealybug to low densities. In subsequent years, mating disruption supplemented with insecticides (as needed) can maintain the population at low levels. Mating disruption is most effective when dispensers are applied over a large area (10 acres or greater). Greater success has been achieved in northern California, where there are fewer generations of vine mealybug per year.

Common name Amount per acre** R.E.I.‡ P.H.I.‡
(Example trade name)   (hours) (days)

UPDATED: 7/15
  Calculate impact of pesticide on air quality
The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Not all registered pesticides are listed. Always read the label of the product being used.
 
DELAYED DORMANT
 
A. CHLORPYRIFOS*
  (Lorsban Advanced) Label rates 24 35
  MODE-OF-ACTION GROUP NUMBER1: 1B
  . . . PLUS . . . (optional)
  NARROW RANGE OIL
  (Superior, Supreme) 1–2 gal See label See label
  MODE OF ACTION: Contact including smothering and barrier effects.
  COMMENTS: In spring, ants in southern California and the Central Valley move the female mealybugs from the roots to plant parts above ground. Spray to obtain thorough coverage of all aboveground plant parts, especially the trunk and cordons where mealybugs are located. Insecticide residues at the base of the vine will help control vine mealybugs in spring when they are being transported up the vine. Most effective when applied during warm weather (60°F or higher) because mealybugs are most active at this time. Apply during January for grapes harvested in June in the Coachella Valley. Do not apply in the North Coast; mealybugs are hidden under the bark at the graft union at this time of the year. Use allowed under a 24(c) registration (SLN CA-080009). Use chlorpyrifos for either ant control or mealybug control, but not for both pests on the same grape crop. Do not apply chlorpyrifos more than twice a year for the control of both vine mealybug and Pseudococcus mealybugs. Do not apply it between budbreak and harvest. Avoid drift and runoff into surface water. Chlorpyrifos has been found in surface waters at levels that violate federal and state water quality standards.
 
MATING DISRUPTION
 
A. MATING DISRUPTANT DISPENSERS
  (CheckMate VMB-XL)# 250 dispensers NA NA
  COMMENTS: Apply in the spring just before male emergence or when males are first detected in pheromone traps. Place dispensers on canes or trellis wire in the upper one-third of the canopy or higher. Most effective in large blocks or areawide, and when vine mealybug numbers are low. In sites with medium-to-high numbers, use an insecticide to reduce numbers.
 

EARLY SPRING

 
A. BUPROFEZIN
  (Applaud) 12 oz 12 30
  MODE-OF-ACTION GROUP NUMBER1: 16
  COMMENTS: An insect growth regulator. Good coverage is essential. Buprofezin targets young nymphs on the vine that are exposed and still moving around before they settle down under the bark to feed. In regions outside of the North Coast, apply once in the delayed dormant period and once in early summer (May or June). In the North Coast, the first application is during late spring when crawlers are present or early summer. Do not tank mix. Use allowed under a FIFRA 2(ee) Recommendation.
 
BLOOM
 
A. SPIROTETRAMAT
  (Movento) 6–8 fl oz 24 7
  MODE-OF-ACTION GROUP NUMBER1: 23
  COMMENTS: A foliar insecticide that is absorbed by the leaves and moves systemically in the phloem and xylem. Use with a non-ionic surfactant. Sufficient leaf canopy must be present for uptake and translocation. It takes about 4 weeks after treatment to see the full effect. To protect honey bees, apply only during late evening, night, or early morning when bees are not present.
 
B. IMIDACLOPRID
  (Admire Pro - Soil) 7–14 fl oz 12 30
  MODE-OF-ACTION GROUP NUMBER1: 4A
  COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Imidacloprid binds readily to certain soil particles, has low water solubility, and long persistence (months). These characteristics allow it to be very effective in light soils, but ineffective in heavy soils. When the soil is rewetted and plant roots are actively absorbing water, the insecticide is also absorbed by roots. Best when applied in a drip irrigation system; otherwise, French plow the soil, apply as a ground spray, and immediately irrigate. Apply 7 to 14 fl oz/acre in one or two drip irrigation applications. On coarse soils or where the longest period of protection is required, make two applications. Make the first application from bloom through the pea-sized berry stage and the second 21 to 45 days later, keeping in mind the preharvest interval. The full rate of 14 oz/acre is recommended where vigorous vine growth is expected or in warmer growing areas such as the San Joaquin or Sacramento valleys or where mealybug numbers are high. Do not exceed 0.5 lb a.i. of imidacloprid/acre per year. Adequate soil moisture is important at the time of application; follow label instructions carefully.
 
C. CLOTHIANIDIN
  (Belay - Soil) 6–12 fl oz 12 30
  (Belay - Foliar) 6 fl oz 12 0
  MODE-OF-ACTION GROUP NUMBER1: 4A
  COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Clothianidin has low water solubility, medium capacity to bind onto soil particles, and moderate to long persistence (weeks to months). Studies indicate it is effective in light soils. Adequate soil moisture is important at the time of application; follow label instructions carefully.
 
D. THIAMETHOXAM
  (Platinum) 8–17 oz 12 60
  MODE-OF-ACTION GROUP NUMBER1: 4A
  COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Thiamethoxam has high water solubility, medium capacity to bind onto soil particles, and short to medium persistence (days to weeks). Studies indicate this is the most effective neonicotinoid for heavy soils. Adequate soil moisture is important at the time of application; follow label instructions carefully.
 
E. DINOTEFURAN
  (Venom - Soil) 6 oz 12 28
  MODE-OF-ACTION GROUP NUMBER1: 4A
  COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Dinotefuran has very high water solubility, low capacity to bind onto soil particles, and short to moderate persistence (days to weeks). Studies indicate it is moderately effective in heavy soils. Adequate soil moisture is important at the time of application; follow label instructions carefully.
 
SUMMER
(To obtain clean fruit and to avoid spreading the pest at harvest or by premature leaf drop)
 
A. IMIDACLOPRID
  (Admire Pro - Soil) 7–14 fl oz 12 30
  MODE-OF-ACTION GROUP NUMBER1: 4A
  COMMENTS: If two applications are required because of coarse soils or where the longest period of protection is required, make the second application 21 to 45 days after the bloom application. Apply 7 to 14 fl oz/acre; the full rate of 14 oz/acre is recommended where vigorous vine growth is expected; in warmer growing areas such as the Coachella, San Joaquin, or Sacramento valleys; or where mealybug numbers are high. Do not exceed 0.5 lb a.i. of imidacloprid/acre per year. Adequate soil moisture is important at the time of application; follow label instructions carefully. Use allowed under a 24(c) registration.
 
B. BUPROFEZIN
  (Applaud) 12–24 oz 12 30
  MODE-OF-ACTION GROUP NUMBER1: 16
  COMMENTS: An insect growth regulator. Buprofezin targets early-stage nymphs on the vine that are exposed and still moving around before they settle under the bark to feed. Good coverage is essential. Do not tank mix. Most effective when applied during peak crawler emergence in the spring (typically late April–early May in the lower San Joaquin Valley and through June in the North Coast region). Buprofezin may harm the mealybug destroyer (Cryptolaemus montrouzieri) when applied during the summer.
 
C. CLOTHIANIDIN
  (Belay - Soil) 6–12 fl oz 12 30
  (Belay - Foliar) 6 fl oz 12 0
  MODE-OF-ACTION GROUP NUMBER1: 4A
  COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Clothianidin has low water solubility, medium capacity to bind onto soil particles, and moderate to long persistence (weeks to months). Studies indicate it is effective in light soils. Adequate soil moisture is important at the time of application; follow label instructions carefully.
 
D. THIAMETHOXAM
  (Platinum) 8–17 oz 12 60
  MODE-OF-ACTION GROUP NUMBER1: 4A
  COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Thiamethoxam has high water solubility, medium capacity to bind onto soil particles, and short to medium persistence (days to weeks). Studies indicate this is the most effective neonicotinoid for heavy soils. Adequate soil moisture is important at the time of application; follow label instructions carefully.
 
E. DINOTEFURAN
  (Venom - Soil) 6 oz 12 28
  MODE-OF-ACTION GROUP NUMBER1: 4A
  COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Dinotefuran has very high water solubility, low capacity to bind onto soil particles, and short to moderate persistence (days to weeks). Studies indicate it is moderately effective in heavy soils. Adequate soil moisture is important at the time of application; follow label instructions carefully.
 
F. ACETAMIPRID
  (Assail 30SG) 2.5 oz 12 3
  (Assail 70WP) 1.1 oz 12 3
  MODE-OF-ACTION GROUP NUMBER1: 4A
  COMMENTS: To protect honey bees, apply only during late evening, night, or early morning when bees are not present.
 
POSTHARVEST
 
A. SPIROTETRAMAT
  (Movento) 6–8 fl oz 24 7
  MODE-OF-ACTION GROUP NUMBER1: 23
  COMMENTS: A foliar insecticide that is absorbed by the leaves and moves systemically in the phloem and xylem. Use with a non-ionic surfactant. Sufficient leaf canopy must be present for uptake and translocation. It takes about 4 weeks after treatment to see the full effect. To protect honey bees, apply only during late evening, night, or early morning when bees are not present.
 
B. CHLORPYRIFOS*
  (Lorsban Advanced) Label rates 24 NA
  MODE-OF-ACTION GROUP NUMBER1: 1B
  COMMENTS: Apply in a minimum of 150 gal water/acre. Treat infested vineyards immediately after harvest to minimize the movement of live mealybugs. Use allowed under a Special Local Needs registration (SLN CA-080009). Growers may apply this material under SLN CA-080009 or under SLN CA-080010 but not both. Avoid drift and runoff into surface waters.
 
** Apply with enough water to provide complete coverage.
Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the R.E.I. exceeds the P.H.I. The longer of two intervals is the minimum time that must elapse before harvest.
* Permit required from county agricultural commissioner for purchase or use.
1 Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode-of-action group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.
NA Not applicable.

IMPORTANT LINKS

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Grape
UC ANR Publication 3448

Insects and Mites

L. G. Varela, UC IPM Program and UC Cooperative Extension, Sonoma County
D. R. Haviland, UC IPM Program and UC Cooperative Extension, Kern County
W. J. Bentley, UC IPM Program, Kearney Agricultural Research Center, Parlier
F. G. Zalom, Entomology, UC Davis
L. J. Bettiga, UC Cooperative Extension, Monterey County
R. J. Smith, UC Cooperative Extension, Sonoma County
K. M. Daane, Kearney Agricultural Research Center, Parlier

Acknowledgment for contributions to Insects and Mites:
M. C. Battany, UC Cooperative Extension, San Luis Obispo County
J. Granett, Entomology, UC Davis
P. A. Phillips, UC IPM Program, Ventura County
A. H. Purcell, Environmental Science, Policy and Management, UC Berkeley

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