5 Crop Protection

5.3 Insect & Mite Pests of Grape October 2020 Edition when monitoring has shown that pest D. Thomas Lowery, AAFC-SuRDC, Summerland numbers are likely to exceed the economic (Graphics by Robyn DeYoung) threshold; i.e. when the derived economic benefits exceed the costs of control. When Grapes grown in British Columbia are attacked insecticides are required, their selectivity, persis- by few insect and mite pests relative to those in tence, and effects on non-target organisms many other major production areas. Economic should be considered. Some have minimal losses from a small number of ‘key’ pests can be effects on beneficial insects and predacious considerable, however, requiring that producers mites, while others cause significant reductions implement timely and appropriate control in natural enemy populations. A brief descrip- measures. Although many growers in BC utilize tion and a few examples of the various conventional spray programs, the small number components of a grape IPM program are of economically important insect pests of grapes outlined below. For additional information, in this region more readily allows for adoption refer to the Integrated Pest Management section of sustainable and organic approaches to pest (5.1) of this guide. management that includes preservation of beneficial insects and predacious mites that help Biological Control of Insects and regulate secondary pests such as spider mites Mites and thrips. Adoption of sustainable* and Insect and mite pests of grapes are attacked by integrated pest management (IPM) practic- many species of beneficial organisms, including es that minimize the use of chemical sprays bacterial and viral diseases, spiders, insect reduces production costs and human expo- predators and parasitoids, predatory mites, and sure to insecticides and helps preserve the vertebrates such as toads and birds. Maintain- local environment. The companion to this guide, Insect and Mite Pests of Grape in British Columbia (Low- ing and enhancing numbers of these natural ery et al., 2014), contains colour photographs of enemies of grape pests forms the corner- many of the pests outlined in this chapter. In stone of a successful IPM program. Healthy the following descriptions of grapevine pests, populations of predators and parasitoids pre- numbers and letters indicated in parentheses vent outbreaks of secondary pests and also refer to the corresponding pages and plates of reduce the numbers of sprays required for the the pest photo guide. Beneficial Insects and Mites of control of primary pests such as leafhoppers. Grape in British Columbia, (Lowery et al. 2015) Beneficial organisms can be preserved or contains photos of natural enemies of grape enhanced in several ways. The negative impact pests. Additional sources for information on of pesticides can be minimized by spraying only insect and mite pests of grapes are listed at the when and where required. Monitoring of pest end of this chapter. numbers will often indicate that only a small portion of a vineyard requires treatment, and Integrated Pest Management selection of the most appropriate spray material will help reduce damage to non-target organ- IPM uses a number of principles and integrated isms. Broad-spectrum insecticides are often practices for the management of pests, including more toxic to beneficial insects than the pests biological, cultural, physical, and chemical they are intended to control. Insecticides that controls. Insecticides remain an essential are less damaging to beneficial insects and component applied as a last resort only predacious mites (e.g. AltacorTM) should be chosen whenever possible. Malathion is consid- *For details on the BCWGC Sustainable ered to be less damaging to beneficial insects Winegrowing British Columbia program, and mites than other insecticides in the same visit www.bcwgc.org/sustainable- class (organophosphates), and although it is an winegrowing-british-columbia. option for managing Virginia creeper leafhop- Best Practices Guide for Grapes for British Columbia Growers 5.3-1 5 Crop Protection per, Erythroneura ziczac, it will not control the better nutrition, softer tissues, and changes in western grape leafhopper, E. elegantula, that is concentrations of secondary plant compounds. resistant to this and other insecticides. Other At the other extreme, chlorotic vines with low materials, such as the microbial insecticide vigor are less able to tolerate insect feeding DipelTM (B.t.), are quite selective and require damage and are more susceptible to attack by that the pest consumes the treated plant part, wood boring beetles. Fortunately, the opti- reducing toxicity to most non-target species. As mum balance in vine growth that results in listed on the BC Ministry of Agriculture website the highest quality wines is also best for ‘Pest Control Products Recommended for Use on Grapes minimizing the growth of pest populations. in British Columbia’, all of the Class 4 neonico- Management of vine vigor is an important TM TM tinoid insecticides (Admire , Assail , consideration in the establishment of a new TM TM Clutch , Closer ) combined should not be vineyard and is discussed elsewhere in this applied more than twice per season to avoid guide. After vines are established, growth is mite outbreaks. These materials are listed as controlled by pruning, cropping, selection and toxic to bees. The Class 3 pyrethroids management of appropriate ground-cover TM TM TM (Pounce , Ambush , Ripcord ) and natural plants, and the provision of water and nutrients. TM pyrethrins (Pyganic ) are toxic to most benefi- Some of these practices can be manipulated to cial insects, but their activity persists for only 1- help manage grape pests. Recent research in 2 days to little more than a week. California, for example, has shown that moder- Thoughtful choice of management practices can ate deficit irrigation from berry-set to veraison also help preserve beneficial insects. Mowing reduced leafhopper numbers by more than less often and mowing only alternate rows at 60%. The modest reduction in yield, around one time are simple and cost-effective ways to 15%, was more than offset by a significant increase populations of most natural enemies. improvement in wine quality. In addition, Adults of many beneficial species feed on nectar berries were smaller and exposed to more light of flowering plants that also serve as hosts for and air and pruning costs were slightly lower. alternate prey species. As a general rule, in- The presence of broadleaf weeds in and be- creased plant diversity is associated with greater tween vine rows is associated with lower levels numbers of beneficial insects. A diversity of of cutworm damage. Having shepherd’s purse plants can be provided in the vineyard in mixed and other winter annual broadleaf weeds in the ground covers, or in hedgerows and uncultivat- vine row until after buds have broken can ed areas within or adjacent to the vineyard. provide effective control of cutworm. Removal of these alternate sources of food forces cut- Cultural and Physical Controls worm larvae to feed more on the buds of Vine Vigour and Resistance grapes. Perennial grasses in the vine rows should be managed over the summer, as they For most crops, varieties can be selected that compete with the vines and with these benefi- are partially or wholly resistant to one or more cial plants. pests and diseases. Except for rootstocks that are resistant to grape phylloxera or nematodes, Pruning this is generally not a viable option for wine grapes. Some hybrid grape varieties having Pruning can be altered to help reduce damage dense hairs on the leaf underside are less sus- from cutworm larvae. Slightly more buds can be ceptible to leafhoppers, but most desirable wine left on vines to compensate for damage, but this grape varieties possess little resistance to foliar will require the removal of more unwanted feeding pests. Vine vigor does, however, influ- shoots later in the season. Some growers delay ence insect and mite numbers. Leafhoppers and suckering and shoot thinning to divert some grape mealybug, for example, will reach signifi- leafhopper feeding and egg-laying to these cantly higher numbers on overly vigorous vines unwanted plant parts. Thinning of the canopy as they prefer the darker, sheltered environment by shoot removal, shoot positioning, and and elevated humidity that excessive vine removal of basal leaves improves air flow and growth provides. Insects developing on these light penetration, which is important for the plants survive better and grow faster due to management of diseases as well as insects. 5.3-2 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection

Leafhoppers and erineum or blister mite infest pest provides an economic return to the the first leaves that emerge in spring, and these grower. Sprays should be applied at the lower leaves can be removed in June to reduce appropriate time and life-stage of the pest. numbers of these pests. A study conducted in Monitoring of grape pests and determining commercial BC vineyards showed that removal thresholds is currently based mostly on visual of basal leaves in June rather than August inspections. Yellow sticky cards can be useful reduced numbers of leafhoppers and the inci- indicators of general population trends and pest dence of bunch rot. Vine growth and berry size developmental stages. Care should be taken to were reduced only slightly and there was little conduct a thorough inspection that takes into effect on ripening or quality of fruit. Early account the variable nature of the crop and the season leaf removal might not be suitable for uneven distribution of most grape pests. Partic- stressed vines or vines on sandy sites with ular attention should be given to field edges and intense heat and light where fruit can become to areas that have experienced damage previous- sunburned. As for late season removal, partial ly. The use of double sided clear tape applied removal of leaves from only the shaded sides of around shoots or the vine cordon can be used the vines might be more suitable in these areas. to assist with timing of sprays for the control of the young motile stages of grape mealybug and Physical controls soft scale insects. Maintaining yearly spray For some vineyards, the use of yellow sticky records and mapping of pest damage severity tape applied below the cordon in spring can be can be a useful tool. an effective way to manage leafhoppers. Alt- Grapevines should be monitored for pests hough costly to implement and remove, this throughout the year. It is easier to spot scale physical control method can often reduce or infestations during pruning or early in spring eliminate the need for additional insecticides before leaves are present. Grapes need to be later in the season. In comparison to sprays of visually inspected frequently in spring when broad-spectrum insecticides, this method helps unopened buds are susceptible to cutworm and preserve beneficial insects. Use of yellow sticky rootworm damage. When the first leaves have tape is most practical in vineyards where damag- fully expanded, watch for early infestations of ing numbers of leafhoppers occur in small, erineum mite and note the presence of leafhop- isolated areas or on a few outer rows of the per adults that begin laying eggs at this time. vineyard. Some other physical controls include Thrips damage table grapes from 75% bloom to the use of barriers to prevent cutworm larvae fruit set, and if scale or mealybug were noted from reaching the buds, collection of cutworm earlier, sprays can be timed based on the pres- larvae from vines at night, and removal of ence of crawlers. The need to spray for first infested shoots or leaves. generation leafhoppers should be based on monitoring for small nymphs from mid June to Monitoring and Chemical Controls mid July, while second generation nymphs will Insecticides should only be applied when reach their peak usually after the first week of monitoring indicates that sprays are warranted. August. In summer, the presence of soft scale The mere presence of a pest does not indi- and mealybug is often betrayed by the presence cate that a spray is required. Established of honeydew and attendant ants. Throughout grapevines can tolerate moderate amounts of summer, monitor for thrips, spider mites and leaf damage and small numbers of pests may grape leaf rust mite. For table grapes, watch for have little or no effect on vine growth and mealybug infesting clusters in mid-summer and yields. Even when pests have reached damaging for snailcase bagworm and earwigs closer to levels sprays should be withheld until the harvest. economic benefit of treating the crop exceeds If chemical control of a pest is indicated, refer the cost of controlling the pest, taking in to to the BCMA website Pest Control Products account the possible disruption of beneficial Recommended for Use on Grapes in British Columbia insects. In other words, sprays should only be for suitable spray materials, or consult with applied when pest populations reach the private consultants or your chemical supplier. It economic injury level where control of the is the legal responsibility of pesticide appli- Best Practices Guide for Grapes for British Columbia Growers 5.3-3 5 Crop Protection cators to follow the label instructions and Leafhoppers apply only those products that are registered Virginia Creeper Leafhopper, Erythroneura ziczac for use on grapes. The BC Wine Grape Western Grape Leafhopper, E. elegantula Council and the authors of these pest man- (Hemiptera: Cicadellidae) agement sections do not assume legal responsibility for the misuse of any pesti- In addition to the widespread Virginia creeper cides mentioned in this guide. For grapes or leafhopper (VCL), the western grape leafhopper wines destined for export, check to ensure that (WGL) that was first found in BC in 2007 the importing country has maximum residue infesting grapes on the east side of the Okana- levels (MRL) for the control products. Observe gan Valley from the north end of Penticton the days to harvest interval (PHI = pre-harvest south to the U.S. border has now spread interval) to avoid exceeding the MRL. Produc- throughout much of the Okanagan Valley and ers of organic grapes should also refer to the list into parts of the Similkameen Valley. The WGL of acceptable products and consult with an is more tolerant of insecticides and it is im- organic growers’ organization. portant to determine relative numbers of the two species in your vineyard. Malathion, for example, is an option when the leafhopper population is almost entirely VCL, but its use Major Pests of Grape can result in increased numbers of the resistant WGL. Leafhoppers are often distributed une- The major insect and mite pests of grapes in BC venly in vineyards and monitoring will help are cutworm larvae that attack buds in spring, determine which areas require treatment. Un- leafhoppers that feed on leaves throughout the necessary sprays reduce numbers of beneficial summer, wasps that eat ripe fruit and annoy or insects and spiders and can result in a rapid sting workers, and mealybug and soft scale that resurgence in pest numbers and outbreaks of transmit grapevine viruses. Grape phylloxera is thrips, mites, mealybugs, and soft scale. an important pest of grapes worldwide, but it Experience has shown that WGL numbers are occurs at damaging levels in only a few scattered generally lower in organic vineyards; damaging locations in the southern interior of BC, and populations in conventional vineyards generally was discovered more recently on Vancouver result from repeated sprays of insecticides that Island. Other than wasps and phylloxera, these do not control this species but damage numbers pests are largely absent from the Lower Main- of its most important natural enemy, the egg land and Vancouver Island. In addition to the parasitoid Anagrus erythroneurae. Successful major pests listed above, producers of table control of leafhoppers relies on proper monitor- grapes need to worry about spotted wing ing of numbers throughout the vineyard and the drosophila, earwigs and scarring of fruit by judicious use of insecticides in order to preserve thrips. Earwigs do not cause direct damage to beneficial insects and spiders. grapes but are considered a contaminant by many vendors of table grapes. Identification Proper management of these primary pests is Adults of both species are similar in appearance, the most important consideration in an IPM nearly ½ cm in length with reddish-brown program. Grape pests and the damage they cause needs to be recognized so that popula- tions can be monitored at the appropriate time of the season to determine if insecticide applica- tions are warranted. Avoiding unnecessary sprays will help prevent outbreaks of secondary pests that are normally regulated by an assort- ment of predators and parasitoids.

5.3-4 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection markings on a pale white or yellowish back- of fully expanded leaves during May and June. ground. Adult WGL (2d in photographic guide) The small, flattened opaque eggs (2c) are depos- can be distinguished by their pale eyes and ited side by side, usually in small groups of irregular reddish-orange markings on a whitish around two to six for the VCL and singly for background. VCL (2a) have reddish-brown eyes the WGL. Nymphs of this 1st generation emerge and a more regular reddish-brown zigzag from mid-June to the end of July. There are five pattern on the wings. The background body nymphal stages. Winged adults that appear in colour is pale yellow to light brownish-yellow, July and August lay eggs that produce the 2nd producing an overall darker appearance. Adult generation nymphs that develop throughout the leafhoppers are best identified on yellow sticky fall into overwintering adults. The WGL devel- cards placed in outer vineyard rows during late ops more slowly than the VCL and nymphs will April and May that can be inspected with the aid occur later into the year. of a hand lens or magnifying glass. Both adults and nymphs feed by piercing Immature WGL (nymphs) (2e) are distinguished individual leaf cells and sucking out the con- by their pale white colour, eyes appearing red tents. Light infestations cause leaves to appear due to lack of pigmentation, and the presence of stippled (2f) due to the death of individual cells. one to three pairs of pale indistinct yellow spots Heavier feeding results in brown, dried leaves on the thoracic segments of larger nymphs. that fall prematurely. Some studies have shown Under magnification a double row of longer that light infestations can actually improve the spine-like hairs are visible on the upper side of quality of grapes on vines that are overly vigor- the abdomen. VCL nymphs (2b) have reddish- ous, but excessive feeding reduces the brown eyes and a pale yellowish body colour. photosynthetic activity of the vines, resulting in Larger VCL nymphs develop a pair of dark delayed maturity, yield losses, and reduced fruit reddish-brown spots on the first body segment quality. Large infestations deplete carbohydrate behind the head and a pair of reddish-orange stores and weaken the vines. Light coloured spots on the other two thoracic segments. fruit varieties can become spotted and unsightly Nymphs of both species can be identified with excrement, which is a particular concern feeding on the undersides of fully expanded for table grapes (2g). Adult leafhoppers are also leaves that show signs of feeding damage an annoyance to pickers during harvest. (stippling). Monitoring and Spray Thresholds Overwintered adults usually congregate in higher numbers on the edges of vineyards or in sheltered locations, and these areas should receive particular attention in the spring. Leaf- hoppers prefer vigorous vines and those that leaf out earliest. Monitoring numbers of adults captured in spring on yellow sticky cards can help determine relative infestation levels, but because some eggs fail to develop and predation Life Cycle and Damage rates are variable, these numbers do not corre- late well with subsequent nymph counts. It is The biology and life cycles of the two species helpful to note where large numbers of adults are similar. There are two generations each year, occur early in the season, as these areas should with occasionally a partial 3rd. Adults of both be observed more closely later on. species spend the winter in leaf litter or under plant debris in the vineyard or in nearby vegeta- Adults are more tolerant of insecticides and are tion. Adults emerge on warm spring days to repelled by some materials; therefore, sprays feed on a wide variety of plants, moving to should be targeted against the wingless imma- grape, Virginia creeper and Boston ivy when the ture stages. Depending on the location of the st first leaves appear. The overwintered females vineyard, monitoring of 1 generation nymphs deposit eggs in the leaf tissue on the undersides should begin in early to mid-June. Monitor populations by counting the numbers of Best Practices Guide for Grapes for British Columbia Growers 5.3-5 5 Crop Protection nymphs on the lower surfaces of 5-10 leaves in vineyard. Nymph counts should be collected at at least 5 locations per block or variety. Select least weekly as the time for spraying approaches. older bottom leaves up to just above the fruiting For wine grapes, an approximate threshold zone. In order to prevent damage to any vines, of 20-25 nymphs per leaf on the more heavi- sampling should focus on more heavily infested ly infested leaves can be used as a rough areas. Sample from the north and east sides of guideline. This is an average value based on rows where more nymphs will be found and counts from several leaves as outlined above. focus on the leaf zone showing signs of feeding Again, for a particular area of the vineyard, damage. Infestation levels are based on the collect 5-10 leaves from at least 5 areas and average number of nymphs per leaf. calculate the average number of nymphs per leaf. For 2nd generation nymphs, sample leaves Established grapevines are tolerant of leafhop- from the middle of the canopy above the per damage during the first half of the season fruiting zone and from the north or east sides of when growth is rapid. Because of this, there are vines where numbers will be higher. Leafhop- no established thresholds for 1st generation pers will be distributed unevenly in a vineyard nymphs. The threshold of approximately 20-25 and it is important to sample adequately to nymphs per leaf established for the 2nd genera- determine which areas require treatment. Alt- tion in late summer can also be used as an hough the above threshold provides a rough approximate threshold for early summer sprays. guideline, an acceptable spray threshold should A higher threshold can be used for 1st genera- be determined by individual growers based on tion nymphs if healthy populations of predators their past experience and additional factors such are present and a high rate of parasitism is likely. as vine vigor and numbers of beneficial insects. Control of 1st generation nymphs is often more effective as there is less foliage, nymphs are confined to leaves around the fruiting zone, and Biological Control sprays can be directed in a narrow band to Predators, such as birds, spiders, and several ensure good coverage. It is recommended, species of hemipteran bugs, and parasitic wasps therefore, to treat vineyards with a history of attack leafhopper eggs, nymphs or adults. heavy leafhopper damage during this time. Soap Although occasionally contaminating table and oil sprays are much more effective when grapes, earwigs consume large numbers of targeted against 1st generation nymphs when leafhopper eggs, leaving behind small, shallow most of the eggs have hatched. Egg hatch can scraped areas on the undersides of leaves. A only be determined with the aid of a low power small egg parasitoid, Anagrus daanei, helps microscope, but the presence of mostly small, control VCL in some vineyards where parasit- young nymphs can be used as an approximate ism rates can approach nearly 100% late in the measure. season. A different parasitoid, A. erythroneurae, Special considerations are required when parasitizes eggs of the WGL and is largely managing leafhoppers in organic vineyards. responsible for the biological control of this Soaps and oils are not as effective as conven- pest. A. erythroneurae overwinters in eggs of the tional insecticides, and because BC currently rose leafhopper on wild and domestic roses, lacks certain effective organic spray materials apple, blackberry and plum. In early spring this widely used elsewhere (e.g. azadirachtin), con- parasitoid utilizes eggs of a leafhopper on a wide trol of leafhoppers in organic vineyards here is range of mints, including catnip and catmint. currently very difficult; requiring usually several Most vineyards have good numbers of A. complimentary practices. As such, it is best to erythroneurae and outbreaks of WGL are take preventative actions and to consider the largely associated with sprays of insecti- action threshold to be extremely low. cides that do not control this leafhopper but are toxic to the parasitoid. Excessive rates or Second generation nymphs should be moni- unnecessary insecticide sprays will also reduce tored beginning in late July/early August in a numbers of other beneficial insects and spiders. manner similar to that outlined above. Greater attention should be paid to vines in the center Cultural and Physical Control of the field as infestations will have spread from field edges and ‘hot spots’ to a larger area of the Leafhoppers prefer excessively vigorous plants 5.3-6 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection and vines should be irrigated and fertilized to Natural enemies should be preserved by apply- maintain moderate growth best suited to the ing the lowest effective rate only to areas where production of superior quality wine grapes. The the pest has exceeded the threshold level. It is use of yellow sticky tape applied below the often sufficient to spray small areas or treat cordon in spring just before bud break can be only the perimeter of the vineyard. Spraying an economical way to manage leafhoppers in in this fashion is more economical and helps some vineyards. Although costly, this method preserve beneficial insects. Neonicotinoids (e.g. helps preserve beneficial insects relative to AssailTM) and other broad-spectrum insecticides insecticide sprays. The use of sticky tape is likely (e.g. pyrethroids such as PounceTM) are toxic to not cost effective for large areas but it can be a predacious thrips and beneficial insects and useful method where infestations are confined have been shown to cause increases in spider to small areas or to the edges of vineyards. mites and other secondary pests. AssailTM is also repellent to adult leafhoppers and will cause A study conducted by SuRDC researchers them to move to unsprayed portions of the beginning in 2001 demonstrated that the re- vineyard. Sprays should, therefore, be targeted moval of basal leaves during the 2nd to 3rd weeks against small nymphs. Research at SuRDC has of June when most eggs of the 1st generation shown that certain strobilurin fungicides (e.g. had been laid effectively reduced numbers of Pristine) and some organosilicone surfactants leafhoppers by about 70%. As an added benefit, are also repellent to adult and immature leaf- early season removal of leaves from the fruiting hoppers. Their use might eliminate the need for zone also reduces the amount of bunch rot. No an insecticide spray, but this increased move- significant differences were noted in fruit quality ment of adult leafhoppers within and between other than a slight reduction in yield and berry vineyards requires greater vigilance. size. This practice might not be suitable for stressed vines or on sites with intense heat and Leafhopper numbers will be suppressed with light that might lead to sunburn. However, sprays of Safer’s Insecticidal SoapTM or Sur- sunburn is less likely to occur following early roundTM (kaolin clay), or by PureSpray GreenTM removal of leaves (June) as compared to late or VegolTM spray oils applied for the control of (August) removal. Exposure to light and air other pests. These products act by direct con- causes developing berries to produce thicker tact to smother the leafhopper nymphs and skins and more wax, and the subsequent growth should be applied in high volume sprays with of lateral shoots will provide some shading. This nozzles directed to ensure that the bottom leaf practice is labour intensive, but many growers surfaces are covered thoroughly. These materi- routinely remove leaves from the fruiting zone als are most effective when targeted against 1st later in the season in order to improve fruit generation nymphs. quality. Mechanized removal of leaves offers an approach, perhaps a little less effective, that Sharpshooters might be more cost effective over time. (Hemiptera: Cicadellidae) The poplar sharpshooter, Neokolla heiroglyphica, Chemical Control and the willow (=purple) sharpshooter, N. Some insecticides registered for leafhopper confluens, occasionally infest the shoots of grape- control are ineffective against the WGL and it is vines in sufficient numbers to warrant control. important to determine if this species is present The dark coloured adults appear oversized in in your vineyard. Malathion is currently regis- relation to the other leafhoppers found on tered for the control of leafhoppers on grapes, grapes in BC and they have more pronounced but it is ineffective against the WGL that is triangular shaped heads (2h). The large nymphs resistant to this and other insecticides. The VCL appear a uniform brown colour. Infestations are has not developed resistance to insecticides. generally restricted to vines growing in close When monitoring of leafhopper nymphs indi- proximity to the preferred host plants after cates that insecticide sprays are required, apply which these species are named. There are no one of the materials listed in the BCMA website chemicals registered for the control of sharp- publication, Pest Control Products Recommended for shooters in BC, but sprays applied for the Use on Grapes in British Columbia. control of leafhoppers should also help control Best Practices Guide for Grapes for British Columbia Growers 5.3-7 5 Crop Protection these species. they resume feeding and complete their devel- opment. Damage to grapes occurs during this Climbing Cutworms time when the rapidly growing larvae feed on (Lepidoptera: Noctuidae) developing buds and new shoots. Moths emerge in June and remain in a quiescent state through- More than 25 species of cutworm have been out the summer. In fall they become sexually identified feeding on the buds of grapevines in mature and begin laying eggs on the surface of the southern interior of BC; some of the more the soil that will hatch into the overwintering common being Barnes’ (= well-marked) climb- larvae. There is a single generation each year. ing cutworm, Abagrotis orbis, Reed’s dart, A. reedi, Unlike the Abagrotis species, the underwing and Abagrotis nefascia. The W-marked cutworm, moth lays eggs in clusters on the upper surfaces Spaelotis clandestina, old man dart, Abagrotis vetusta, of leaves. dark-sided cutworm, Euxoa messoria, and others can also cause considerable damage in certain Damage to grape buds varies with the size of locations in some years. The invasive lesser the cutworm larvae. Small larvae will often yellow underwing, Noctua comes, has increased in burrow into a bud, creating nearly circular holes numbers and distribution since it was first that were previously attributed to feeding by found in the Okanagan in 2001. Cutworm adult click beetles (1c). Larger cutworm larvae feeding damage to the buds of grapes can will chew sizeable, sometimes ragged, holes and vary greatly between years and locations remove a significant portion or all of the bud. and it is not uncommon for only parts of Feeding on new, tender shoots can cause the vineyards to be seriously damaged. Because shoots to break or wilt (1d). Larvae climb the populations fluctuate greatly and monitoring of vine trunks or support posts each night and cutworm larvae is difficult, damage can be return to the soil during the day, or they find considerable. refuge under loose bark of older vines.

Identification Monitoring and Spray Thresholds Cutworm larvae are Cutworm numbers vary over time and between smooth, soft, thick- and often within vineyards. Some vineyards bodied caterpillars rarely experience significant levels of cutworm measuring about 4 feeding damage while others are damaged to 5 cm when fully yearly. Damage is often higher in areas with dry grown (1a, 1b). gravelly or sandy soils that do not support good Larvae typically live stands of broadleaf weeds, or when weeds are in the soil or under debris and will curl up when controlled too early in the spring before shoots disturbed or handled. Depending on the species, have elongated. The new invasive yellow un- larvae are most often light to dark grey or derwing moth is an exception in that it prefers brown and marked with spots and stripes. heavier soils. Maintaining a record of previous Adults are mostly drab moths with bodies damage can help suggest which areas need to be around 2 to 2.5 cm long (1a insert). The hind monitored more closely and where damage is wings, which are sometimes distinctly marked, likely to occur first; however, bud damage needs are usually lighter in colour than the forewings. to be assessed throughout the vineyard. The lesser yellow underwing moth is most New vines planted in untreated land previously noticeable by the bright orange hind wings that in pasture are prone to damage. Cutworm are edged in black (1b). Cutworm moths are larvae are often sheltered and somewhat con- active at night and rest during the day in shel- fined within the protective milk cartons or tered locations. sleeves placed around new vines. Loss of buds on new vines can limit growth and delay fruit- Life Cycle and Damage ing, and they should be closely inspected in Cutworm that feed on grapes spend the winter spring for signs of damage and treated when as small larvae in the soil or under fallen leaves necessary. or debris. When the weather warms in spring Significant amounts of damage can occur over 5.3-8 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection a period of two or three days when the nights Control of vegetation with herbicides, cultiva- remain warm. It is especially important to tion, or establishment of a suitable cover crop frequently monitor for damaged buds during the year prior to planting will help reduce this time. At other times it is usually sufficient damage to newly planted vines by cutworm, flea to monitor vines weekly or twice weekly until beetles, root weevils and June beetles. shoots have elongated. An accurate threshold Cutworm damage is partially related to pruning based on the degree of bud damage is difficult practices and grape varieties. Vines with a to determine as it is influenced by the variety, greater number of retained buds in spring will training system, method of pruning, presence suffer marginally less damage; however, there of predators and parasitoids, and tolerance will be added costs related to removal of extra level of the individual vineyard manager. shoots. Most grape varieties produce fruit on Suggested economic thresholds provided by secondary shoots, but yields will still be reduced growers range from virtually zero to over 15%; and ripening can be delayed or uneven. a value around 3% bud loss is likely for most vinifera varieties. Establishment of spray Chemical Control thresholds should also consider the potential Sprays of the pyrethroid insecticide PounceTM for secondary pest outbreaks that will require (permethrin) should be directed to the soil at additional insecticide sprays later in the season. the base of vines, to vine trunks, and to support Biological Control posts so that larvae contact the insecticide while moving from the soil to the canopy. Do not Cutworm eggs are consumed by various preda- cultivate or disturb the soil for several days after tors and are parasitized by small wasps. Larvae treatment. Sprays should be directed into the are eaten by ground beetles, hunting spiders and milk cartons or other protective structures birds, and are parasitized by wasps and flies. placed around newly planted vines. PounceTM is Fungal and bacterial diseases that attack cut- harmful to all beneficial insects and can cause worm larvae are common, particularly when increases in secondary pests such as mites and conditions are cool and wet. The combined soft scale. effect of these natural controls is to eliminate AltacorTM (rynaxypyr) and IntrepidTM (methox- most cutworm eggs and larvae. Of the hundreds yfenozide) cause larval mortality through of eggs laid by a female moth, only a few sur- ingestion, and sprays should be directed to the vive to become reproductive adults. Even so, developing buds. These materials are less toxic damage resulting from the few remaining larvae to beneficial insects due to their greater selectiv- can be considerable. ity and reduced toxicity to non-target organisms. Follow the label instructions and wear appropri- Cultural Control ate protective clothing as for all pesticides. The Damage is generally much lower in vineyards list of materials registered for cutworm control with mixed ground cover vegetation and where is likely to change before the next printing of broadleaf weeds, particularly winter annual this guide and it is important to refer to the mustards such as shepherd’s purse, Capsella most recent edition of Pest Control Products bursa-pastoris, are present in the vine rows and Recommended for Use on Grapes in British Columbia drive rows in spring. Where possible, broad- for appropriate registered materials. leaf weeds growing in the vine rows should not be controlled in spring until shoots have Grape Phylloxera elongated and the first leaves have expand- Viteus vitifoliae (Hemiptera: Phylloxeridae) ed. With the exception of lesser yellow underwing that prefer heavier soils, cutworm Grape phylloxera, native to eastern North damage is usually more common in areas with America, is a type of aphid found on the roots well-drained sandy or sandy-loam soils that of grapes or in galls formed on the leaves of support fewer broadleaf weeds. Diseases that wild grapes and some hybrid varieties. Europe- infect larvae are also likely to be more prevalent an vinifera varieties are particularly susceptible to in soils that retain moisture. this pest and the accidental introduction of phylloxera to California, Europe, and elsewhere Best Practices Guide for Grapes for British Columbia Growers 5.3-9 5 Crop Protection initially devastated these industries. Manage- reproduce without having mated. Two or three ment of phylloxera with insecticides was not generations are produced each year. When successful and the wine grape industry was only populations are large or the vines are declining, rescued with the development of resistant some newly hatched nymphs leave the roots rootstocks derived from American Vitis species through cracks in the soil and migrate to the or hybrids between these and susceptible V. roots of nearby vines. These small crawlers have vinifera. Phylloxera were first identified in the been known to climb vine trunks and be blown Penticton area in 1961; infestations currently are on the wind for some distance. In late summer a scattered and at relatively low levels mostly due portion of the nymphs develop into winged to the use of resistant rootstocks and the failure females (alates) that leave the soil and fly to of this pest to thrive on sandy soils. Phylloxera other vines where they lay eggs in the crevices in were discovered infesting leaves of hybrid the bark that hatch into both males and females. grapes on Vancouver Island in 2020, but the After mating, these late summer females pro- extent and severity of the infestation is not yet duce a single larger overwintering egg. In spring known. the eggs hatch into females that feed on devel- oping leaves and produce galls on susceptible As early as 1914 it was recognized that grape varieties. Nymphs produced in the galls can phylloxera consisted of several distinct biotypes infest other leaves or migrate down to the roots. or races. Biotypes differ in their ability to form Most grapes grown in BC are not susceptible to galls on the leaves of certain cultivars, in the leaf galls and the life cycle here largely consists degree of feeding damage caused to roots, and of asexual forms confined to the roots of their propensity to form sexual or winged grapes. For this reason, infestations spread at a forms. One study demonstrated that rootstocks relatively slow rate. with unsatisfactory levels of resistance to phyl- loxera in Europe and South Africa were suitable Feeding by phylloxera on the roots of grape- for California, Australia and New Zealand. Loss vines results in severe water and nutrient stress of resistance can also occur over time as new and eventual death of the vines. Roots become biotypes of phylloxera arise. stunted and galled and die prematurely from the injection of harmful saliva and invasion of Identification fungal pathogens (4b). Depending on vine vigour and the size of the infestation, vines can Adults are very small, usually wingless, and less slowly become stressed and chlorotic, or they than 1mm long and half as wide (4a). Colour can decline rapidly. varies from pale green, yellowish-green or light brown on vigorous roots, to brown or orange- Monitoring and Spray Thresholds brown on declining roots; as adults age they become a darker brown or even purplish- Vines that fail to thrive and become chlorotic brown. Winged sexual forms are rare in BC and and unproductive should be inspected for the the northwestern United States, and they do not presence of phylloxera. Galls on leaves are an appear able to reproduce sexually on vinifera obvious indication of phylloxera on hybrid grapes. Leaf galls are formed on French- varieties; however, damage confined to roots of American hybrids, Concord juice grapes and vinifera wine grapes can be confused with dam- some rootstocks. The relatively small galls on age from nematodes or root diseases. To the undersides of leaves are green and roughly determine the cause of damage, carefully expose circular (4c). These should not be confused with the roots and search for the typical swellings the white or brown fuzzy galls of variable sizes and dying roots caused by phylloxera. A hand and shapes formed on the undersides of leaves lens or dissecting microscope will help verify by erineum (leaf blister) mite (4d). their presence. Areas of vineyards with phyllox- era will appear as expanding patches of severely Life Cycle and Damage stunted or dying vines. Phylloxera overwinter on roots as eggs or small, Insecticide treatments were previously not dark hibernating nymphs that complete devel- effective and there are no spray thresholds for opment in spring to become females that phylloxera on roots. Hybrid cultivars that develop leaf galls are better able to tolerate or 5.3-10 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection resist feeding damage to roots, but elimination Rootstocks vary in characteristics such as vigour of the leaf gall forms soon after they are detect- and it is often difficult to select an appropriate ed might help reduce the extent of the rootstock for a particular vineyard. Soil types, infestation. resistance to nematodes, vine spacing and several other factors need to be considered in Biological Control addition to phylloxera resistance. Prior to planting it is advisable to read appropriate Biological control of phylloxera has not been publications and consult with vineyard manag- studied in detail. A number of generalist preda- ers or consultants. A more complete listing of tors are known to feed on phylloxera in leaf phylloxera-resistant rootstocks that includes galls. In Ontario, larvae of two species of other characteristics can be found in other predaceous flies were commonly associated with sections of this guide leaf galls. Predaceous soil-dwelling carabid beetles undoubtedly feed on phylloxera infesting Vigorous vines resist phylloxera damage better roots, and because they do not produce honey- than stressed vines. Provision of additional dew, ants are likely to feed on phylloxera rather water and nutrients can help delay the rate of than protect and ‘milk’ them as they do aphids. decline. Infested vines should not be heavily Natural enemies and diseases are not thought to cropped and extra care is required to prevent provide effective control of phylloxera estab- additional stresses from insects and diseases. lished on roots of susceptible vinfera vines. Some varieties are more vigorous and are better able to resist damage. Phylloxera infestations Cultural Control are more damaging and spread more rapidly on heavier soils that are prone to cracking, When establishing a new vineyard, purchase while vines planted in sandy soils can be nearly plants from reputable suppliers and ensure that immune to attack. planting material is healthy and free of phylloxe- ra. Vines imported into BC are given a hot Chemical Control water treatment to prevent the importation of phylloxera and other grapevine pests. To ensure MoventoTM (spirotetramat) and ClutchTM that phylloxera are not moved from infested to (clothianidin) are systemic insecticides effec- clean areas on farm machinery, disinfest all tive against plant-feeding insects with sucking equipment. Less frequent cultivation is thought mouthparts that are registered for the control to be helpful. of grape phylloxera and mealybug. Sprays should be applied in a minimum spray volume Resistant rootstocks provide an effective of 500 L/ha as per the label instructions. Do means of combating phylloxera. Almost all not apply Movento to table grapes. Clutch is resistant rootstocks were developed from listed as being toxic to bees. Sprays of this and crosses between several species of wild grapes other materials belonging to the same chemi- native to eastern and southern North America cal class (4, neonicotinoids) should be limited (V. riparia, V. rupestris, V. berlandieri and others). to no more than 2 applications per season to Some of the grape rootstocks with good phyl- prevent mite outbreaks. loxera resistance that are commonly grown in BC include SO4, 5BB, 5C, 420A, and 161-49C.. Wasps Resources for resistant rootstocks: (Hymenoptera: Vespidae) A number of species of yellowjacket wasps Rootstock Selection (PDF), pgs 12-15. In, Wine are pests of grape; the most numerous and Grape Varieties in California by L.P. Christen- troublesome being the western yellowjacket, sen. U.C. Agric. & Nat. Res. Pub. Vespula pennsylvanica, and the German yellow- http://iv.ucdavis.edu/files/24347.pdf jacket, V. germanica. Two uncommon species of paper wasp (Polistes sp.) are native to our Rootstocks: Protection Against Phylloxera. area. The European paper wasp, P. dominula, Vinehealth Australia, Gov. South Australia. was found in BC in 2003 and has since be- https://vinehealth.com.au/tools/rootstocks/ come very common, particularly around Best Practices Guide for Grapes for British Columbia Growers 5.3-11 5 Crop Protection buildings. Yellowjackets, hornets and paper veloped larvae and pupae are killed. wasps are important predators of grape pests Wasps prey on other insects, scavenge food and throughout most of the year, but in fall they feed on nectar and the juice of fruit. It has been often feed in large numbers on damaged and reported that wasps do not damage fruit them- intact fruit. Wasps are also an annoyance and selves but take advantage of injury caused by potential health hazard to vineyard workers other insects or birds, by diseases such as sour and to pickers during harvest operations. rot, or splitting of fruit. There are contrary Paper wasps are less aggressive than yellow- reports, however, particularly relating to the jackets or hornets and are not as prone to European paper wasp, that they are able to sting. directly feed on intact fruit (5h). As mentioned Honey bees occasionally feed in large num- above, wasps are also a major annoyance and bers on ripe fruit. The extent of the damage is their stings result in swelling and a painful itch variable, mostly occurring on the edges of and can trigger severe allergic reactions in some only certain vineyards and in association with individuals. wasp damage. Honey bees will be uninten- tionally damaged by sprays directed at other Monitoring and Spray Thresholds grape pests and it is important to try to There are no established thresholds for wasps preserve these beneficial pollinators. and the need to spray is determined by the Identification variety of grape, past history of damage, and tolerance level of individual vineyard managers. Yellowjacket workers are about 1.5 cm in Trapping of wasps is most effective early in the length; the abdomen appears largely yellow season before the colonies have increased in with thin black bands. Hornets are slightly number. The arrival of the European paper larger and appear largely black with yellow or wasp has made it necessary to control wasps white bands. Paper wasps have thinner bodies more frequently. with a more pronounced constriction (stalk) between the thorax and abdomen. The body Biological Control is dark with some yellow markings, but they Wasp colonies can be attacked by other wasps appear reddish-brown due to the colour of the or hornets. Eastern and western kingbirds feed wings and distal parts of the legs (5h). In flight on foraging adults, and larvae are subject to the legs of paper wasps dangle visibly below certain diseases. The onset of winter eliminates the body. All of these wasps produce paper established colonies. The overwintering queens nests, but the brood cells of European paper may also succumb to cold or be eaten by other wasps are not enclosed within an outer insects or even by mice. covering. Cultural Control Life Cycle and Damage Elimination of nests early in the season can be Yellowjackets and paper wasps overwinter as an effective management strategy, but they are fertilized females in sheltered locations. These often located outside the vineyard or are well queens seek suitable nest sites in spring and hidden. Aerial nests in trees or under eaves can establish a new colony. Nests are initially small, be removed and placed in a plastic bag at night consisting of only a few paper cells, but as when wasps are inactive. Nests in walls or workers develop they assist in building up natural cavities can be treated by spraying or colony numbers and the size of the nest. De- puffing commercial wasp control products into pending on the species, nests can be in the the entrance holes at night. Sealing of entrances ground, under the eaves of houses, in hollow can help prevent future nests. trees, the walls of buildings, milk carton vine shelters, or exposed in trees. In fall, in addition Trapping can be used to reduce numbers of to workers, colonies produce both males foraging wasps in localized areas. Commercial (drones) and queens. When freezing weather wasp traps that use an attractant dissolved in arrives, all the drones, workers, and the unde- water have proven effective, as have homemade versions containing a sugary solution placed in 5.3-12 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection recycled 1 litre plastic pop bottles. Wasps enter vinegar fly. through small holes and eventually fall into the liquid solution and drown. Trapping early in the Life Cycle and Damage season when populations are low and queens are establishing colonies is generally more SWD overwinter as adults. Beginning in spring, effective than attempting to remove large several generations develop throughout the year numbers of wasps later in the season. Baiting on a range of available fruit (strawberry, black- traps with fish or other meats in spring when berry, cherry, etc.), including grapes in the late wasps are seeking a protein source can be an summer and fall. Females lay large numbers of effective alternative to other baits, but care eggs that hatch into larvae that mature at a rapid should be taken to avoid attracting unwanted rate. A generation can develop in as little as 1 to wildlife. 2 weeks when temperatures are warm, resulting in a rapid increase in numbers. Chemical Control Larvae of several species of vinegar fly develop Cypermethrin (RipcordTM) is currently regis- in damaged or decaying grapes late in the tered for the control of wasps feeding on wine season, causing little apparent damage. A grapes but not on table grapes. The pre-harvest recently published laboratory and field study* interval (PHI) is two days for wine grapes conducted in the Okanagan Valley found that harvested by machine and seven days for fruit SWD cause little direct economic damage to harvested by hand. wine grapes. It was not found in intact, healthy fruit and formed a very small proportion of all vinegar fly species in damaged or rotting wine For additional information on social wasps, grapes. SWD was found, however, infesting a management strategies, and design of wasp small proportion of apparently healthy table traps, visit the UC IPM Statewide IPM grapes of several varieties. The presence of Program posting Yellowjackets and Other Social vinegar fly larvae and pupae in fresh table Wasps. grapes is a major concern. Feeding by larvae http://ipm.ucanr.edu/PMG/PESTNOTES/pn directly damages the fruit and the holes created

7450.html during egg-laying allow the entry of disease- causing microorganisms. Unlike other Drosophila species, SWD does not prefer rotting fruit and Spotted Wing Drosophila its relationship to the spread of sour rot and Drosophila suzukii (Diptera: Drosophilidae) other pathogens has not been demonstrated. This pest of fruit crops was first found in Sour and bunch rots are best managed through Canada infesting blueberries in the Fraser Valley the combined use of early season removal of in September 2009 and trapped soon after in a basal leaves and judicious use of fungicide cherry orchard near Kelowna. It is native to sprays. Southeast Asia where it feeds on a range of soft skinned fruit. Unlike most species of vinegar fly Monitoring and Spray Thresholds (fruit fly) that feed on very ripe, damaged, or rotting fruit, the spotted wing drosophila (SWD) SWD has not been shown to cause economic is able to attack ripening, firm fruit. damage to intact wine grapes in BC and there are no established thresholds. For table grapes, Identification trap counts do not correlate with levels of damage and producers currently need to rely on Adult SWD are slightly larger (2-3 mm) than prophylactic sprays to susceptible table grape other vinegar flies and males have a dark grey to varieties. black spot toward the outer margin of each wing (5g). Females lack the wing spots and have *Acheampong, S., et al., 2020. Monitoring of a saw-like ovipositor visible with the aid of a Drosophila suzukii (Diptera: Drosophilidae) in good hand lens or microscope. The elongate Okanagan Valley vineyards, British Columbia, creamy white legless larvae, up to 3 mm long, Canada, and assessment of damage to table and wine are difficult to distinguish from other species of grapes (Vitaceae). The Canadian Entomologist. Best Practices Guide for Grapes for British Columbia Growers 5.3-13 5 Crop Protection

Previously, grape mealybug was not considered Biological Control to be a major pest of grapes grown in BC. Numbers were generally quite low due to the Parasitic wasps have been reared from SWD in activity of parasitoids and predators and direct BC and predators of other species of vinegar feeding damage is of little concern. Individual flies are likely to also attack this species. bunches of table grapes touching infested vines would occasionally become infested, resulting in Cultural Control fruit coated with sticky honeydew that reduced Sanitary measures suggested for other fruit their marketability. The recent recognition crops (i.e. removal of infested and unharvested that mealybug and soft scale are responsible fruit) might not be practical for commercially for the sometimes rapid spread of grapevine produced grapes. Increased exposure of fruit leafroll associated viruses has raised their early in the season (see leafhopper section for status to that of major pests. Largely due to details) that results in fruit with thicker skins changes in insecticide use, damaging popula- and a heavier wax layer, combined with judi- tions of mealybug have become more common cious use of fungicides provides the best means in recent years. Whenever possible, apply to manage sour and bunch rots that are associ- chemicals against major pests (leafhoppers, ated with increased numbers of vinegar flies. cutworm) of grapes only when required and Additional research would be helpful to deter- only to portions of the vineyard where control mine the relative susceptibilities of table grape is warranted. Select pesticides that are least varieties and conditions that favor SWD infesta- damaging to predators and parasitoids. tions. Identification Chemical Control The grape mealybug has a flattened, oval pink There have been frequent changes to the list of body covered in a mealy white wax coating (3f). insecticides registered for SWD control on It is somewhat segmented in appearance, but grapes, and the reader is advised to consult with the divisions between head, thorax and abdo- a local spray advisor or visit the BCMA website men are not distinct. The mature wingless ‘Pest Control Products Recommended for Use on Grapes females are about 5 mm long. They have long in British Columbia’. ImidanTM (phosmet) and waxy filaments along the edge of the body that HarvantaTM (cyclaniliprole) were registered for become progressively shorter toward the head. the control of SWD on grapes as of June 2020. Large numbers of eggs (50-800) are laid in Consult the label and observe the pre-harvest cottony masses. The smaller, winged males have interval (PHI). Imidan has a 14 day REI and is antennae that are half as long as their body and more acutely toxic to mammals than Harvanta. a pair of long, white anal filaments. Yellow to Both materials are listed as being toxic to bees. brown crawlers that emerge from the oval, orange eggs are not covered in wax. All stages are mobile though the crawlers are the most *For additional information see ‘Spotted Wing mobile stage. Drosophila (Fruit Fly) Pest Alert’ factsheet, BC Min. Agr., at: Life Cycle and Damage https://www2.gov.bc.ca/gov/content/indus try/agriculture-seafood/animals-and- Females move in late fall to old wood and lay crops/plant-health/insects-and-plant- overwintering eggs in cottony egg masses under diseases/tree-fruits/spotted-wing- loose bark. Crawlers, some of which might have hatched in fall and remained dormant through- drosophila out the winter, move to new shoots in spring. Grape mealybugs mature around mid-summer and produce a 2nd generation that matures in Grape Mealybug late autumn. They can occur on all aerial parts Pseudococcus maritimus (Hemiptera: Pseudococ- of the vines but are more common in summer cidae) on leaves and new growth, usually hidden within the canopy. 5.3-14 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection

Relevant to the spread of leafroll viruses, the enemies of grape mealybug are predaceous small crawler stage is mobile and active and they midge larvae that feed on eggs and several can be carried on the wind. Mealybugs can also species of lady beetles and other generalist be transported during mechanical harvesting or predators that prey on nymphs and adults. field operations, and on workers or plant Mealybug are susceptible to several diseases, material. including Entomopthora fungus. Direct damage is similar to that for soft scale. Plant sap is removed during feeding and large Cultural Control amounts of honeydew foul the fruit (3f) and Mealybugs prefer vigorous vines. Ensure ade- promote the growth of sooty mold fungus. quate nutrition and moisture to produce an Mealybugs can infest table grape bunches optimum crop, but avoid excessive vigor. during the development of the second brood in Research in California has shown that fruit on summer, reducing their marketability. cane-pruned varieties is less likely to suffer damage compared with spur-pruned vines. Monitoring and Spray Thresholds Clusters on cane-pruned vines hang farther away from the mealybug overwintering sites on To detect when crawlers are active, remove the old wood. Earlier varieties are not exposed to loose bark in an area near the infestation and honeydew to the same extent as later varieties. encircle the vine with clear tape applied sticky side out, or use double sided adhesive. Replace Heavy infestations of mealybugs and other the tape every three or four days and check for honeydew-producing pests of grape are usually the yellowish-brown crawlers. Separating tended by ants that feed on the sugary excretion mealybug crawlers from soft scale crawlers is and protect the mealybugs from predation. difficult and requires a good dissecting micro- Control of ants can often contribute to a signifi- scope. Inspect vines for the cottony egg masses, cant decline in mealybug numbers. For small leaves coated with shiny, sticky honeydew, and backyard plantings with an isolated infestation, the presence of attendant ants travelling up and painting a sticky material around vine trunks down the vine trunks. The need to inspect and posts and ensuring that ants cannot gain vineyards for mealybugs can be based partly on access to the mealybugs often eliminates the past infestations and prior use of broad- problem. Trials in California have also shown spectrum insecticides. Grape mealybug prefer that sprays directed against the Argentine ant, vigorous vines with thick canopies. Recent Iridomyrmex humilis, controlled damaging popula- research on grapevine virus vectors indicates tions of the obscure mealybug, Pseudococcus that grape mealybug is uncommon north of affinis. Insecticides are not currently registered Oliver. for the control of ants in BC vineyards.

Biological Control Chemical Control Parasitism of grape mealybug has not been VegolTM (formulated canola oil) can be applied studied in any detail in BC. However, a parasitic as a late dormant spray or summer application, wasp formerly introduced into Canada from while insecticidal soap and malathion are best California for mealybug biological control was targeted against the crawler stage in spring. recently reared from grape mealybugs in the PureSpray GreenTM horticultural oil applied in Okanagan. Based on the literature, more species summer for mite control will also help control of mealybug parasitoids are undoubtedly active mealybugs. Owing to their good systemic in BC. Research in California has shown that at activity, ClutchTM (clothianidin) and MoventoTM least six species of small parasitic wasps attack (spirotetramat) can be used against all stages mealybug, with late summer and fall rates of during the growing season. Movento should not parasitism often exceeding 90%. Silver flies be applied to table grapes. It and Clutch are were also recently reared from grape mealybug listed as toxic to bees. Combined use of neon- egg masses in the Okanagan where it was icotinoids should not exceed two sprays per observed the larvae consumed a large portion of season to avoid outbreaks of mites. the eggs (A. Brauner, SuRDC). Other natural

Best Practices Guide for Grapes for British Columbia Growers 5.3-15 5 Crop Protection

Soft Scale Life Cycle and Damage European Fruit Lecanium Scale, Parthenolecanium EFLS overwinter as 2nd instar nymphs on older corni wood where they can find shelter, often under Cottony Vine Scale (= Cottony Grape Scale), the bark. In spring when the sap begins to flow, Pulvinaria vitis nymphs go through a growth spurt and moult in (Hemiptera: Coccidae) April to become adult females. In May, females produce 2000-3000 eggs under the body cavity Approximately 20 species of soft scale insects that hatch into crawlers in June and July. The (Hemiptera: Coccidae) are known to attack crawlers disperse to the undersides of leaves grapevines in various regions of the world. Five where they settle and feed until early fall when species are now known to infest grapes in BC, they moult into 2nd instars for the winter. but only two are commonly found: European Occasionally there is a partial 2nd generation fruit lecanium scale (EFLS) and cottony vine with females producing fewer eggs while settled scale (CVS). Both EFLS and CVS have been on the current year’s shoots, clusters and leaf upgraded from minor to major pests due to petioles. their ability to transmit certain grapevine leafroll diseases, including Grapevine CVS overwinter as young adult females primari- leafroll associated virus 3 (GLRaV-3) that is ly on new canes. In spring the adult female will the most widespread and economically increase in size, become darker in colour, more damaging leafroll disease in BC. EFLS and convex in shape, and form a cottony-like egg CVS are also a concern in the production of mass. Adult females produce on average 3500 table grapes where the large quantities of hon- eggs but have been known to produce up to eydew they produce supports the growth of 5000. Crawlers disperse in June and July to the sooty mold fungus that can leave fruit unmar- undersides of leaves where they settle and feed ketable. until early fall. Mortality is as high as 90% during the crawler phase, primarily due to Identification environmental conditions and failure to success- fully settle on the host. Lacking a protective Female EFLS, also known as brown apricot waxy covering, the crawler stage is susceptible scale, when fully grown have a chestnut brown, to environmental conditions and is the stage smooth and slightly shiny protective shell that is most susceptible to insecticides. CVS increase in around 5 to 8 mm long and slightly longer than size over the summer, with the final moult in wide (3e). Certain races in some regions report- fall giving rise to the overwintering young adult edly produce males, but most females reproduce female that is no larger than 3 mm in size. In without mating. The small nymphs or crawlers autumn, the scale migrates from leaves to that hatch from the small oval, pearly white eggs woody tissues and develops a hardened protec- are yellow to orange in colour. tive shell for the winter. Mature female CVS are similar in size and Both species of soft scale feed on the phloem of colour to EFLS, but the body is slightly more grapes and other woody plants, including fruit elongate. The masses of cottony material con- trees and ornamentals. Soft scales have become taining orangey-red eggs that extrudes from more abundant recently. Direct feeding damage underneath the scale tilts the female upward from the removal of plant fluids is rarely a cause (3d). In other regions, male CVS are produced for concern, but the additional stress caused to in late summer, do not have mouthparts, live for weak vines might be sufficient to hasten death. only a few hours to a week and mate with As mentioned previously, the greatest cause for immature females. In North America it is concern is the ability of EFLS and CVS to presumed that the males are not present and transmit GLRaV-3 in vineyards and for the vast that the females reproduce without mating, amounts of honeydew they produce that fouls resulting in female offspring only. Mature the fruit and supports the growth of sooty mold female scales of both species become brittle fungus, potentially rendering table grapes after the eggs are laid and can easily be detached unmarketable. from the one to three-year-old wood with a fingernail. 5.3-16 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection Monitoring and Spray Thresholds portion of the eggs. Of nymphs collected from leaves throughout the summer, approximately Look for partly grown CVS during pruning and 67% were parasitized by 13 different parasitoid for mature females with cottony egg masses in species. late spring. Watch for honeydew on leaves and fruit during late spring and summer. Ants feed In addition to parasitoids and silver flies, soft on the honeydew and will protect the scale from scale are also preyed upon by lady beetles and predators (3d). They can often be seen in large other generalist predators. English sparrows and numbers hurriedly running up and down posts several species of warblers that feed on fully or vine trunks to and from infested canes. grown soft scale have been known to curtail infestations in some regions. To detect when small crawlers are active, remove the loose bark in an area near the Cultural Control infestation and encircle the vine with clear tape applied sticky side out or use double-sided Healthy vines of moderate vigor are less suscep- adhesive. Replace the tape weekly and check for tible to scale infestations and are better able to the orange coloured crawlers. A good magnify- withstand damage. Routine pruning removes ing glass or dissecting microscope is useful for many scales, and a small infestation might be this purpose. pruned out in spring or early summer. Removal of basal leaves in late June from the fruiting There are no established thresholds for direct zone for the control of leafhoppers will also damage from soft scale infestations and small to help reduce scale populations. moderate numbers of scale on a healthy vine are unlikely to result in direct damage due to the Chemical Control removal of fluids and nutrients; treatment of table grapes is required when the honeydew Oil or lime sulphur applied as high-volume they excrete fouls the fruit. It is important to dormant sprays to the trunks and cordons of control infestations of soft scale if vines or vines for the control of powdery mildew will neighbouring vines are known to be infect- help suppress soft sale and other small, soft ed with GLRaV-3 or other leafroll viruses. bodied pests of grapevines. Malathion, insecti- cidal soap, and VegolTM can be used against the Biological Control crawler stage, and the latter can be applied during the summer against nymphs. Repeat In European vineyards, scale populations are applications might be required as long as crawl- often controlled by parasitic wasps and preda- ers are active. MoventoTM (spirotetramat) is tors. Very little was known about the natural registered for the control of scale on wine enemies of soft scale, specifically CVS, in the grapes during the growing season, but it should Okanagan prior to an on-going study* initiated not be applied to table grapes. over the 2019 field season. Of 545 adult female CVS (with and without egg masses) collected in late May to early June, just over 80% were parasitized. A total of 990 parasitoids of six different species were reared from 42 adult females. On average, 23 parasitoids emerged per Secondary and Minor adult scale, while 68 were collected from one Pests individual. The most abundant parasitic wasp species was Coccophagus scutellaris (94%). Of the Several insect and mite pests of grapes occur scales producing egg masses, 93% had silver fly infrequently or only cause significant amounts larvae (Leucopis species) consuming a very large of damage after chemical sprays have reduced predator and parasitoid populations that nor- *Study of soft scale parasitism and updated mally regulate their numbers. The best way to information provided by A. Brauner, SuRDC, manage these pests, then, is to properly manage as part of the AAFC CAP, 2018-2023 Cana- populations of primary pests in order to pre- dian Grapevine Certification Network serve and enhance numbers of beneficial insects grapevine virus project. and predacious mites. Best Practices Guide for Grapes for British Columbia Growers 5.3-17 5 Crop Protection

Thrips Adult female thrips overwinter under leaves and plant debris on the ground. In spring they Western Flower Thrips, Frankliniella occidentalis deposit their eggs into developing leaf, stem, Flower Thrips, F. tritici and flower tissues. The time from egg to adult is Grape Thrips, Drepanothrips reuteri about three weeks during warm weather and (Thysanoptera: Thripidae) several generations are produced yearly. Most Several species of thrips can be found feeding, thrips feed on a wide range of host plants and at least occasionally, on grapes; the three most large numbers will often move to a succession common are the western flower thrips (WFT), of new succulent hosts throughout the year. the grape thrips (GT), and the flower thrips Both adults and nymphs feed by rasping the leaf (FT). Thrips are generally minor pests of surface and sucking up the escaping fluids. wine grapes but are important pests of table WFT adults enter vineyards in early spring, grapes due to scarring of fruit. Their popula- often in large numbers, when Saskatoon bushes tions often increase following applications of have finished flowering and other native vegeta- broad-spectrum insecticides that reduce num- tion is beginning to dry down. In addition to bers of beneficial insects. All species feed in a ground cover plants, WFT feed on flower and similar manner, but differences in biology and fruit tissues of grapes from bloom to just after timing of infestations results in differential fruit set. Their feeding under caps and persistent damage to grapes. flower parts causes berry scarring and russeting (5b). White and green grape varieties are also Identification damaged when females insert their eggs into All species have long, slender bodies with dark fruit, causing dark spots or halo spots. Feeding protruding eyes and relatively short beaded on developing shoots is occasionally so heavy antennae. Adults have two pairs of wings that that shoots are stunted and leaves deformed are heavily fringed along the edges. WFT are (5b), but damage of this sort often only occurs dark yellow to brown and 1 to 1.5 mm long (5a). around the perimeter of vineyards. WFT usually GT and FT are both around 1 mm long, the decline greatly in numbers following fruit set. former is amber yellow with a yellowy-orange FT have a similar biology and contribute to the thorax, and the latter is uniformly pale yellow to damage caused to fruit in spring, but they are nearly white. Nymphs of all species are similar not as numerous as WFT. in appearance to the adults except that they are smaller, slightly paler in colour and lack wings. GT are generally only found in significant Thrips tend to be very active; adults not only fly numbers on grape during the summer months but also run and hop rapidly. and their feeding is largely confined to leaves and shoots. Numbers can build up rapidly, Plant feeding thrips should not be confused however, particularly following insecticide with predaceous thrips. Adults of beneficial treatments for other grape pests. Leaf veins can thrips may be dark black or purplish black with be scarred and fail to expand properly, leaf clear wings or wings that appear light grey with edges can become necrotic, and shoot growth white bands; or they are pale with dark bands inhibited, resulting in shortened internodes. on the wings. They are slightly larger to nearly twice as large as the pest species. Nymphs of Monitoring and Spray Thresholds predaceous thrips have bodies that are banded yellow and orange, are reddish purple in colour, WFT often invade vineyards in or are pale with the joints of the appendages large numbers for only brief dark. Compared with phytophagous species, periods in spring and it and the predaceous thrips have enlarged and slightly FT are not normally an economic curved front legs that they use for grasping prey. concern for wine grapes. Scarring These features and the slightly larger mouth- of fruit has not been shown to parts are best observed under a dissecting affect wine quality and damage to microscope. leaves and shoots is usually minor. Damage usually occurs Life Cycle and Damage over a short period of time, which makes early detection and control 5.3-18 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection difficult. Inspect table grapes for the presence Spider Mites of WFT and FT in spring from around 75% European Red Mite, Panonychus ulmi bloom to the end of fruit set and apply insecti- Two-spotted Spider Mite, Tetranychus urticae cides as required. Verify the presence of thrips McDaniel Spider Mite, T. mcdanieli by sharply striking fruit clusters or leaves against (Acarida: Tetranychidae) a dull white or green coloured surface. The decision to spray should be based partly on the The main species of spider mites infesting table grape variety, records of past damage, and grapes in BC are the European red mite (ERM), the intended market for the fruit. There are no two-spotted spider mite (TSSM), and the firm thresholds for the control of thrips on McDaniel’s spider mite (MSM). A detailed grapes in BC. survey would likely reveal the presence of two Watch for GT damage to young leaves and other species known to occur in WA. They shoots during summer and early fall. Use an differ somewhat in biology, but feeding damage eyepiece or magnifying glass to verify that thrips and management strategies are largely the same. are present. As for fruit clusters, leaves and Spider mites should be considered second- shoots can be held over a piece of white card- ary or induced pests of grapes; their board and sharply hit to dislodge the thrips. numbers increase following the use of Control on mature vines is usually only warrant- broad-spectrum insecticides that reduce ed when growth is stunted sufficiently early in numbers of spider mite predators. Although the summer to delay ripening and affect growth they can be somewhat selective, insecticides the following season. such as AssailTM and Clutch are toxic to preda- cious thrips that are effective predators of mites Biological Control in BC vineyards. Studies in Washington State have also shown that the active ingredient in Predatory bugs such as the minute pirate bug Assail and related materials increases spider mite (Orius tristicolor), anthocorids (Anthocorus melanoce- reproduction. Due to its persistence, increases rus), and deraeocoris (Deraeocoris brevis) are all in mite numbers can occur up to several months known to feed on thrips. Studies in the Okana- after application. Mite outbreaks can also occur gan and Similkameen valleys have indicated that following applications of pyrethroid insecticides predatory thrips are important regulators of pest (e.g. permethrin) and other broad-spectrum thrips populations. In the laboratory, predatory insecticides. thrips at a density of one every 10 to 15 leaves is sufficient to control WFT. Identification Cultural Control Adults are small, around 0.5 mm in length, and best viewed with the aid of a magnifying lens. So that thrips are not forced to feed on table They are nearly spherical in shape and have grapes when they are most susceptible to fruit eight legs and short piercing mouthparts. The damage, avoid mowing cover crops during ERM is dark red in colour with long pale hairs bloom and fruit set. (setae) projecting from small pale circular areas on the dorsal surface (4h). The oval eggs are Chemical Control bright orange with a distinctive hair-like projec- Spinosad (SuccessTM or EntrustTM) is registered tion on the upper side. TSSM vary in colour for suppression of thrips on grapes. To protect bees, avoid using ClutchTM (clothianidin) or HarvantaTM (cyclaniliprole) before or during bloom. Avoid using Clutch and other members of the neonicotinoid class (4) of insecticides more than twice a season to avoid mite prob- lems. Insecticidal soap and oils applied for the control of other grape pests will help suppress thrips populations.

Best Practices Guide for Grapes for British Columbia Growers 5.3-19 5 Crop Protection from pale yellow to greenish yellow to orange; 45% in summer. A good hand lens or low- the common pale form has a distinct dark dorsal power dissecting microscope would help pro- spot on each side of the body (4g). Its eggs are vide accurate counts of infestation levels. An white. MSM appear similar to TSSM but with alternate fairly reliable method is to monitor more scattered diffuse dark dorsal markings on damage to leaves and spray when a moderate the abdomen. All species feed on the undersides 10% amount of ‘bronzing’ has occurred to of leaves. TSSM usually congregate in clusters leaves. Because mite numbers can increase very and produce large quantities of silk webbing, rapidly it is necessary to monitor grapes fre- while ERM produce less webbing and are more quently during hot weather. evenly distributed over the leaf surface. When monitoring for mite damage it is useful to Life Cycle and Damage consider previous infestation levels and the presence of predacious mites. Vineyards with ERM pass the winter as eggs laid on vine canes low chemical inputs that have not experienced and trunks. Eggs hatch in spring and the young severe spider mite outbreaks in the past are microscopic nymphs begin to feed on young unlikely to require treatment, while those that foliage. TSSM and MSM overwinter as fertilized have been treated with broad-spectrum insecti- females under the bark or in other sheltered cides should be observed more closely. More areas around the base of vines. When warmer than five applications of Sulphur in a growing weather arrives in spring the females begin to season is thought to increase numbers of spider feed and deposit eggs. There are multiple mites, as are dry and dusty conditions. overlapping generations each season and all stages can be found on grapes at any time Biological Control during the summer months. Females are able to produce 200 or more eggs each. With an ability Spider mites were of minor importance prior to to grow quickly, spider mite populations can the widespread use of synthetic pesticides. Due explode rapidly under favorable conditions. largely to the harmful effects of pesticides on populations of predators, spider mites are now Adults and nymphs feed by piercing individual the most important pests of grapes in many leaf cells and removing the fluid contents. regions of the world. The first course of Healthy grapevines can tolerate moderate action for the management of spider mites numbers of spider mites that cause chlorotic is the preservation and enhancement of stippling on the leaves. Heavy feeding results in beneficial species. Pesticides should only be brown leaves that fall prematurely, reducing applied when necessary and only to parts of the photosynthetic activity and vine vigour. Heavy vineyard where pest populations are sufficiently feeding damage can delay ripening of fruit. The high to warrant control. Whenever possible large amount of webbing produced, particularly select materials that are least damaging to non- by the TSSM, can also be a cosmetic problem target species. Numbers of spiders and benefi- for table grapes. cial insects are usually higher in vineyards with permanent, mixed groundcover that provides Monitoring and Spray Thresholds pollen and alternate sources of prey. Proximity Spider mites rarely cause significant damage to to uncultivated or unsprayed areas allows grapes prior to mid-summer. Stippling and beneficial insects and predatory mites to re- bronzing of leaves and the presence of webbing colonize vineyards following spray treatments. and cast skins is often the first indication of Several species of predatory mites (e.g. Metasei- damage in summer. No firm thresholds have ulus, Typhlodromus and Amblyseius species) feed on been developed for spider mites on grapes in spider mites and their eggs. Most beneficial BC. Firm thresholds have also not been estab- mites are a pale opaque colour, but they can lished in the Pacific Northwest of the U.S., but appear light orange if they have been feeding on it is suggested there that economic damage is ERM. They are oblong in shape and slightly unlikely at levels below 15 to 20 per leaf. An smaller than adult spider mites. The long-legged approximate guideline suggested from Europe- orange whirligig mite (Anystis agilis) is uncom- an research for ERM and TSSM is a threshold mon on grapes in BC. Like most other of 60 to 70% infested leaves in spring and 30 to predatory mites, this large species is more active 5.3-20 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection than its prey. Predatory mites are very sensitive mended for grapes, as is the insecticide mala- to a range of pesticides, including sulphur at thion. Safer’s Insecticidal SoapTM, VegolTM or high rates and pyrethroids such as permethrin PureSpray Green Spray OilTM provide a more (PounceTM). benign approach to mite control but offer only moderate suppression. Materials with different A number of spiders and predatory insects feed modes of action (chemical groups) should be on spider mites or their eggs. Many species, used in rotation to help prevent the develop- such as the minute pirate bug (Orius tristicolor), ment of resistance. are generalist predators that do not specialize on mites, while others such as the aptly named spider mite destroyer, Stethorus picipes, are very See also Grape-Spider Mites, Pacific North- effective predators that feed almost exclusively west Pest Management Handbooks, on mites. Stethorus picipes is a small, dark species of ladybeetle with a slightly hairy appearance. available at: The elongate bodies of the larvae are also nearly https://pnwhandbooks.org/insect/small- black in colour with a body covered with nu- fruit/grape/grape-spider-mite merous hairs. At least four species of predatory thrips can be found in Okanagan Valley vine- yards; adults of three of these are black, while Grape Erineum Mite the fourth, the six-spotted thrips, Scolothrips = Grape Leaf Blister Mite, Colomerus vitis sexmaculatus, is pale with dark spots on the (Acarida: Eriophyidae) wings. All four species feed on pest thrips and spider mites. The western flower thrips is Identification considered a pest of grapes, but it is also known to feed on the eggs of spider mites. Adult erineum mites are only 0.2 mm long and a dissecting microscope is required to observe Cultural Control them properly. Their creamy pale bodies are elongate with only two pairs of legs. Although Vineyards can be managed in ways that help erineum galls can be confused with certain alleviate mite problems. Hot, dry and dusty fungal diseases or phylloxera leaf galls, their conditions favour the buildup of spider mite characteristic appearance is the best way to populations. Where mites are a persistent identify these pests. The hemispherical concave problem, roadways can be treated with oils or galls or erinea formed on the undersides of other materials to reduce dust. Vineyards that leaves initially have a felty white appearance due are continuously cultivated will produce more to the presence of densely packed long leaf hairs dust than those with permanent ground covers. (4d). Opposite to these galls, bumps will be Moreover, a permanent mixed groundcover will visible on the upper surfaces of leaves. These support greater numbers of beneficial insects swellings are a reddish colour in spring and turn and predaceous mites. Compared with bare soil, green as the leaves mature. Small numbers of planted drive rows will decrease air tempera- mites feed on the dense hairs in each gall, which tures and raise humidity levels somewhat, eventually turn brown. providing less favourable conditions for spider mites. Spider mite populations can become Two other forms of erineum mite, the leaf- elevated on vines suffering drought stress and curling strain and bud-inhibiting strain, have these plants are also less able to tolerate damage. been reported recently from Washington State Overhead irrigation will help reduce mite and are possible in BC. The former causes slight infestations. to severe downward curling of leaves in summer with stunting of shoots and increased growth of Chemical Control lateral shoots. Feeding of the bud-inhibiting strain on buds causes a range of abnormalities, The miticides EnvidorTM (spirodiclofen), TM TM including scarified shoots, short zigzagging Nexter (pyridaben) and Agri-Mek internodes, dead terminal buds and malformed (abamectin) are listed for mite control on the leaves. BCMA guide to pest control products recom-

Best Practices Guide for Grapes for British Columbia Growers 5.3-21 5 Crop Protection

Life Cycle and Damage ed that removal of infested leaves in May did not alter yields or fruit quality. Removal of basal Adult erineum mites overwinter under the scales leaves in June for leafhopper control will re- of buds. Mites move in spring to developing move a significant portion of the erinea galls. shoots and create galls on young leaves around the fruiting zone. Several generations are pro- Chemical Control duced each year with new galls developing higher up the shoots. Beginning in late summer, Erineum mite is seldom a problem in vineyards adult mites move back to the buds for winter. where sulphur is applied routinely for powdery mildew control. Applications of sulphur are Leaves with erineum galls appear to function most effective early in the season when galls normally and there is little or no economic are first being formed on new leaves. Sulphur damage to mature vines until almost all leaves sprays should not be used on Foch or Vitis are covered with galls. Even then, damage labrusca varieties. Oils (VegolTM and PureSpray usually only occurs if vines are also suffering GreenTM) and insecticidal soap are registered for from other stresses. Establishment of newly suppression, and miticides such as NexterTM planted vines can be delayed somewhat by applied against spider mites and sprays of erineum mite feeding that will retard or reduce malathion for control of leafhoppers will also fruiting. reduce numbers of erineum mite. Recently published studies have suggested that the grape erineum mite is a possible vector of Grapevine pinot gris virus. The Grape Leaf Rust Mite economic status of this pest would change Calepitrimerus vitis (Aracida: Eriophyidae) considerably if further research verifies this to be true. Grape leaf rust mite, which belongs to the same family (Eriophyidae) as grape erineum mite, was Monitoring and Spray Thresholds identified for the first time on grapes in the Okanagan Valley in 2009. Erineum galls are usually very apparent during routine vineyard operations. Grape varieties Identification differ in susceptibility to this pest and it is important to check individual blocks for the A microscope is required to properly identify presence of mites. In order to prevent prema- these 0.2 mm long pale white wormlike mites ture loss of leaves, new vines should be that closely resemble erineum or blister mites inspected and treatments applied if large num- but do not form leaf galls. They are much bers of galls are found on most leaves during smaller than spider mites and elongate rather the spring or summer months. than round, tapering at the rear, and having two pair of legs near the head (4e). Their presence is Biological Control best determined by the bronzing of leaves The western predatory mite, Galendromus during July and August, a result of their feeding. occidentalis, is an important erineum mite preda- Unlike spider mites that cause similar bronzing tor. Predaceous thrips will feed on exposed to leaves, grape leaf rust mites are microscopic mites, but their effectiveness is likely limited and do not produce webbing. when mites are protected within the dense hairs of the galls. Life cycle and damage

Adult rust mites that spend the winter under Cultural Control bark or bud scales move in the spring to the New plants may become infested in the nursery. developing buds to feed and lay eggs. Large Ensure that material used to establish new vineyards is free of mites and other pests or See also: Jensen et al., 2017. Grape leaf rust diseases. Removing galled leaves can control mite, Calepitrimerus vitis (Acari: Eriophyidae), light infestations to some extent. Research a new pest of grapes in British Columbia. J. conducted in the Okanagan Valley demonstrat- Entomological Society of B.C. 5.3-22 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection numbers of adults concentrated on the available rust mite. green tissue in early spring can damage buds, resulting in deformed leaves, scarring of shoots, For additional information on grape leaf reduced shoot growth, reduction or loss of fruit rust mite control, see ‘Grapevine Pests and clusters, and even death of buds (4f). Early Their Management, G. Dunn & B. Zurbo, season rust mite damage can be confused with 2014. Primefact , New South Wales Dept. cold injury or damage from other causes. Primary Industries, NSW Austalia. Damage becomes less visible as the season https://www.dpi.nsw.gov.au/__data/assets progresses and shoots lengthen. /pdf_file/0010/110998/Grapevine-pests- Immature mites that hatch over a period of and-their-management.pdf several weeks feed under the bud scales, eventu- ally moving to feed on developing leaves. Unlike spider mites, rust mites equally infest the upper and lower leaf surfaces. Many generations are Snailcase Bagworm produced throughout the summer. Before Apterona helix (Lepidoptera: Psychidae) leaves drop in fall, adult rust mites migrate to the cordon and trunk for the winter. Bronzing Identification of leaves is most obvious during July and This introduced moth August, but damage to leaves at this time is not remains throughout most thought to seriously damage vine health. Exten- of its life within a snail-like sive bronzing of leaves is an indication, though, case made from particles that rust mites need to be controlled the follow- of soil and sand bound ing spring. together with silken threads. When fully grown Monitoring and Spray Thresholds the coiled case is approx- imately 4 mm in diameter (4f). There are no There are no established thresholds for this males and the wingless female moths remain pest. Control the following spring is indicated inside the case to deposit their eggs without when a significant proportion of leaves become having mated (parthenogenetic reproduction). bronzed in late summer. Large aggregations often form on posts, tree trunks, or vine trunks in late summer. Biological Control Life Cycle and Damage As for erineum mite, western predatory mite, Galendromus occidentalis, other mite predators, and Young caterpillars overwinter within the case predacious thrips are capable of keeping rust formed by the mother. They drop to the ground mites in check. To maintain healthy populations in spring, form C-shaped cases, and begin to of beneficial insects and predatory mites, it is feed on a wide range of weeds, native plants and important whenever possible to limit the use of cultivated crops. Feeding damage consists of insecticides and to apply selective materials that small excavated holes on the leaf surface. As the are less toxic to predatory mites. larva grows it eventually expands its case into the typical snail-like, helical shape. In mid- Chemical Control summer the fully grown larvae will climb vines, posts or buildings, attach themselves firmly with A successful rust mite control program devel- silk, and pupate within the case. Attachment to oped in Australia relies largely on spring overhead sprinkler rotators can occasionally applications of sulphur (e.g. KumulusTM DF, cause them to malfunction. Several weeks later or wettable sulphur) in high volume sprays the females emerge, lay eggs, and then exit the during bud swell to woolly bud stage. case to die. The eggs hatch in late summer and Sulphur sprays should not be used on Foch or the small first instar larvae spend the winter Vitis labrusca varieties, as they are susceptible to within the protective cases. There is only one leaf and fruit damage. There are no miticides generation per year. currently registered for the control of grape leaf

Best Practices Guide for Grapes for British Columbia Growers 5.3-23 5 Crop Protection

Monitoring and Spray Thresholds they feed to some extent on damaged grapes and their presence in table grapes is not appre- Larvae of the snailcase bagworm cause minimal ciated by some consumers. On grapes produced feeding damage to leaves and they are not for wine they should be considered important considered economic pests of wine grapes. The generalist predators. large aggregations are easily detected on build- ings, posts, wires, and the trunks of vines. If Identification contamination of table grapes is a concern, inspect vines and apply control measures before Adult earwigs are dark the overwintering aggregations form in late brown, about 1.5 cm long, summer. The non-feeding overwintering stage, with a pair of forcep-like secure within the case, is not susceptible to appendages (cerci) at the rear insecticides. of their elongate bodies. The anal forceps of females are Biological Control long and straight, while those of males are curved. Earwigs Because it has not yet been adequately studied, seldom fly and the membra- natural enemies of this pest of grapes in BC are nous hind wings usually remain folded under unknown. The protective case would provide the short leathery forewings, exposing the some shelter from certain generalist predators, abdomen. The four nymphal stages resemble but predators, parasitoids and diseases undoubt- the adults except that they are smaller and edly take their toll. wingless. Earwigs are largely nocturnal and hide during the day, often in large aggregations, in Cultural Control cracks and crevices or under bark. When dis- Snailcase bagworm prefer moist areas with thick turbed they move quickly. vegetation. Avoid excessive irrigation and drain areas that puddle or remain damp. Bagworm are Life Cycle and Damage uncommon in vineyards planted on light soils Adults overwinter in the ground in earthen cells. with drip irrigation. Proper drainage will also Clutches of eggs laid in cells in the top 5 cm of help reduce grapevine root diseases. Frequent soil in the fall and spring are opened by females mowing of areas of the vineyard where bag- in spring to release the young nymphs. Adults worm are a problem can help reduce are semi-social and tend their young for a period infestations. of time after birth; nymphs later disperse to secure locations under rocks, in crevices, or Chemical Control under bark. Adults develop by mid-summer and DipelTM and Bioprotec CAFTM (Bacillus thurin- there is only a single generation per year. Ear- giensis) are registered for snailcase bagworm wigs are nocturnal and feed at night on dam- control on grapes, and sprays applied for the aged fruit, tender plant tissue, small soft bodied control of other insects will provide protection. insects, and other foodstuffs. They rarely For this reason, they are more common in damage grape leaves. organic vineyards or conventional vineyards with low chemical inputs. Monitoring and Spray Thresholds Rolled up newspaper or cardboard, or flat boards placed on the ground, can be used to monitor earwigs. It might be possible to use European Earwig these same refuges to enhance their numbers in Forficula auricularia (Dermaptera: Forficulidae) wine grapes. (Order Dermaptera) The European earwig is both a beneficial Biological Control insect on wine grapes and a pest of table Birds, large spiders, wasps and ground beetles grapes. All stages feed on small, soft-bodied prey on earwigs. Earwigs, in turn, feed on the insects such as small leafhopper nymphs and eggs and small nymphs of leafhoppers and will scrape leafhopper eggs off of leaves. In fall 5.3-24 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection on other soft bodied insects. that required control. The raucus root weevil was reported from the Okanagan Cultural Control Valley for the first time in 1979 and there have been several localized outbreaks Tillage in spring and fall will destroy some of documented since that time. Damage by the earthen cells. For table grapes, mowing, these pests has increased as of late. tillage, removal of loose bark from vine trunks, and sanitation will remove hiding places and Identification help reduce earwig numbers. They can be kept out of small plantings of table grapes by apply- The flightless adults of both species have ing sticky tape or commercial Stickum® around long, broad ‘snouts’ typical of weevils. The trunks and posts. Washing table grapes after thick, roughened front wings are fused harvest will help dislodge many earwigs. They together. Adults range in size from 5.5-7.5 are less likely to seek refuge in table grape mm for the raucus root weevil and 7.5-10 varieties with loose, open fruit clusters. mm for the black vine weevil. In addition to their slightly smaller size, raucus root weevil Chemical Control can be differentiated from black vine weevil by their generally lighter, patchy appearance Earwigs are sensitive to most insecticides and often a distinct difference in colour applied for the control of other pests of between the head/thorax and the elytra that table grapes. For this reason, earwigs are a cover the abdomen (1f). greater concern for organic table grape production. Commercial earwig baits are Black vine weevil adults are a uniform black also available. colour. Unlike adult raucus root weevil that damage buds, leaves with deeply notched Root Weevils edges not associated with damage from other chewing pests are an indicator of Black Vine Weevil, Otiorhynchus sulcatus black vine weevil feeding. Traps for both Raucus Root Weevil, O. raucus species can be made from cardboard loosely (Coleoptera: Curculionidae) wrapped around vine trunks where the Life Cycle and Damage weevils will hide during the day. Adults can also be collected on beating trays placed Black vine weevil and raucus root weevil beneath canes and cordons that are hit spend the winter in the soil as pale, legless sharply with a stick. Care needs to be taken, larvae feeding on the roots of a wide range however, as adults often fall to the ground of plants. It is not known if they feed on the as they are approached. roots of grapevines to any extent. Adult black vine weevils feed during late Click Beetle spring and summer on grape clusters and (Coleoptera: Elateridae) leaves and sometimes girdle fruit clusters. Click beetles were They are active only at night and remain formerly considered to hidden under plant debris or loose bark be important pests of during the day, making detection difficult. grapes in BC, however Raucus root weevil adults, in contrast, can extensive study in often be found feeding on the buds of Okanagan vineyards grapes at twilight or on overcast days. over a number of years Earlier emergence in spring of adult raucus has shown that most of root weevil coinciding with the develop- the damage formerly ment of grape buds accounts for the greater attributed to click beetle damage by this species as compared with adults was in fact the black vine weevil. Although localized caused by half grown and usually confined to the edges of vine- cutworm larvae. Several yards, infestations of raucus root weevil species will feed occa- have occurred occasionally in large numbers Best Practices Guide for Grapes for British Columbia Growers 5.3-25 5 Crop Protection sionally on buds of grapes, but control is usually tles in a vineyard does not indicate feeding not warranted. Click beetles are also not consid- or correlate with damage. There are no ered pests of grape in Washington State. established thresholds in BC relating click beetle numbers to bud damage. To determine if bud Identification damage is due to click beetles or cutworm larvae, it is best to inspect vines with the aid of a Click beetle larvae, called wireworms, have long, flashlight after dark on warm spring nights. slender, hard bodies that are a light tan to a light orange-brown in colour and appear somewhat Biological Control shiny and polished. Their short legs and cylin- drical slender bodies allow them to burrow Little information is available on the biological through the soil to feed on the roots of plants. control of click beetles in BC vineyards. Adult beetles have elongate somewhat flattened bodies usually in shades of brown or black (1e). Cultural Control The segment behind the head has small projec- As for climbing cutworm, the presence of tions that point backward on each side of the broadleaf weeds in spring helps reduce click body. Adults of most species are around 1 to 1.5 beetle damage to grapes. cm in length but some are significantly larger. When adults are placed upside down in the Chemical Control palm of a hand or gently held between finger and thumb they will rapidly flex their bodies at Chemical control of click beetles is generally not both ends and attempt to right themselves or warranted and none are registered specifically escape with a characteristic clicking action. for adults on bearing vines. Sprays for cutworm larvae should help control adult click beetle. Life Cycle and Damage Adults that have spent the winter under debris Flea Beetles and leaves emerge with the arrival of warm (Coleoptera: Chrysomelidae) weather in spring to feed on the tender buds and leaves of a wide range of plants, occasional- An as yet unidentified species of flea beetle, ly including grapes. They are often quite Altica sp., has over the past several years been common on flowers where they feed on soft found feeding on the leaves and shoots of newly tissues and pollen. After feeding for a short planted grapevines in the south Okanagan. time, females begin to deposit eggs into the soil. Specimens sent to the Canadian National In two or three weeks the eggs hatch into larvae Collection of Insects, Arachnids and Nema- resembling small slender ‘worms’ that develop todes, AAFC-Ottawa, verified that it is not in the soil throughout the summer. Click beetles the grape flea beetle, Altica chalybea, native to can persist for a long time without feeding and eastern North America. Larvae of that species they often require more than one year to com- develop on grape leaves, while the larval host plete development to the adult stage. for this new pest of grapes in BC is not yet known. Damage has been sufficiently high in Larvae are not known to damage the roots of some vineyards to warrant control. Interestingly, grapes to any extent, preferring to feed on the feeding is largely restricted to new vines during roots of weeds or grasses. Click beetle adults are the year of planting. often seen feeding on sap from pruning cuts. As for cutworm larvae, feeding of click beetle Similar in appearance to the crucifer flea beetle, adults causes death of developing buds, reduced Phyllotreta cruciferae, adults are small (~2mm), yields, and delayed and uneven ripening of fruit. shiny metallic-looking beetles with an overall Little damage occurs after bud break. dark blue-black colour. The hind legs of these active insects are enlarged for jumping. This Monitoring and Spray Thresholds new presumably invasive pest is becoming more common and widespread and it would be Adult click beetles feed on buds so infrequently helpful to learn more about its biology, in that monitoring for these pests is generally not particular its larval development. There are no warranted. The presence of adult click bee- insecticides registered for control of this species, 5.3-26 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection however, sprays applied for the control of until they settle and develop into nearly translu- leafhoppers should also provide control of this cent, scale-like immobile nymphs. The ‘scales’ pest. have a fringe of waxy material projecting from the bottom edge (3g); the distribution and numbers of the projections can assist in species identification. The pupal stage that develops Miscellaneous Insect inside the case on the underside of leaves is somewhat bulbous and appears segmented. Pests There are several generations per year. Whitefly feed by sucking juices from the leaves, much as In addition to the major and secondary grape scale insects do, and they also produce large pests described in previous sections, a number amounts of sugary honeydew. Populations are of insects attack grapes in BC only very rarely controlled by parasitic Encarsia wasps that turn and are generally not of economic importance. the scales black, by several predatory insects, Following are brief descriptions of a few of and by pathogenic fungi. these occasional pests.

Minor Cicada Grasshoppers Platypedia minor (Hemiptera: Cicadidae) (Orthoptera: Acrididae) Adult minor cicada are about 2 cm long with Adults and nymphs of several species of grass- two pairs of large, transparent wings held roof- hopper feed on grape leaves, usually beginning like over the body (3b). The pale, wingless in late summer when preferred hosts begin to nymphs have enlarged front legs that they use to dry down. Feeding by these well-known, long- dig through soil. Cicadas are mostly known legged jumping insects consists of chewing from the loud buzzing or clicking noises that damage to leaf margins, most often on lower males produce on hot summer days. They are leaves. difficult to locate and will move around to the Grasshoppers suffer from pathogenic diseases opposite side of trees or posts when ap- when populations are high. Preying mantids, proached. Damage to individual shoots occurs toads, and many species of birds feed on adults, occasionally when females deposit eggs into while smaller nymphs are attacked by spiders canes with their long, saw-toothed ovipositor. and a number of predatory insects such as Deposition of several eggs into a cane can ground beetles. Maintaining the growth of drive weaken it or cause it to break. The oviposition row vegetation, particularly broadleaf plants, damage is recognizable by the slivers of wood over the season reduces feeding damage to protruding from a series of punctures. Newly grapes. Grasshoppers will be affected by most hatched nymphs drop to the ground to spend sprays directed against other pests of grapes. two to three years feeding on the roots of plants. It is not known if they feed on the roots Whitefly of grapes. (Hemiptera: Aleyrodidae) Buffalo Treehoppers Several species of whitefly occasionally infest Spissistilus bisonia and S. Bsalis grapes. Overwintering whitefly are relatively rare (Hemiptera: Membracidae) in BC. Some sub-tropical and tropical species, such as the common greenhouse whitefly, Ongoing research being conducted in the Trialeurodes vaporariorum (Westwood), infest Okanagan valley, BC, on potential vectors of outdoor plants each season from infested Grapevine red blotch virus (GRBV) has helped greenhouses, house plants, and vegetable and clarify the treehopper species present in this ornamental transplants. Adults are small, around area. The three-cornered alfalfa treehopper that 2 mm in length, with two pairs of wings that are is suspected of spreading GRBV in the U.S. has covered with a fine, white powder (3h). They not been found here. Rather, two closely related somewhat resemble small white moths. The species of buffalo treehopper have been identi- minute crawlers are mobile for only a few hours fied in BC vineyards. Adult buffalo treehopper

Best Practices Guide for Grapes for British Columbia Growers 5.3-27 5 Crop Protection are green or brown in colour and about 5-6 mm marked with black; while adults are dark brown in length. The 1st section behind the head with white banding on the antennae and legs. (pronotum) is elongated to the sides and ex- Adults are a little more than 1.5 cm in length. In tends to the rear of the abdomen so that they areas where they have become established they look somewhat triangular when viewed from are often found feeding in close proximity to the front. It has a hump-backed appearance of one another. Adults aggregate in large numbers the American Bison after which it is named in the fall to spend the winter in protected areas when viewed from the side. or invade houses. Damage to the lateral shoots of grapes caused For additional information see Brown Marmo- by treehoppers can somewhat resemble virus rated Stink Bug (BMSB) Pest Alert, BCMA, at infection or other diseases. In summer late https://www2.gov.bc.ca/gov/content/indust instar nymphs will produce a series of feeding ry/agriculture-seafood/animals-and- punctures around leaf petioles or stems (3a), crops/plant-health/insects-and-plant- resulting in decreased flow of water and nutri- diseases/tree-fruits/brown-marmorated- ents and eventual reddening of leaves beyond stink-bug#: the feeding site. The initial feeding punctures coalesce into a darkened band of sunken tissue encircling the stem or leaf petiole. Although *Wine Taint, Multicolored Asian damage is often restricted to lateral shoots and Ladybeetles, and the Environment generally not of economic concern, growth of newly planted vines could be stunted in areas Wine taint caused when multicolored Asian with lots of alfalfa or other suitable host plants. ladybeetles (MALB), Harmonia axyridis, contami- The economic status of the buffalo treehopper nate fruit at harvest is a concern for Ontario would change if it was shown to spread GRBV. growers. As the name suggests, MALB adults are variable in colour, ranging from black to Brown Marmorated Stink light orange and with a variable number of spots. Distinguishing features are its large size Bug and usually a dark ‘M’ (or ‘W’) on the white Halyomorpha halys (Hemiptera: Pentatomidae) pronotum. It is the most common ladybeetle species in Ontario and also in the interior of The brown marmorated stink bug (BMSB) was BC. As for other ladybeetles that are also first found in eastern North America in 2001 brightly coloured to warn off potential preda- and in BC in 2015. It has been trapped at tors, ladybeetles produce a number of defensive various locations throughout the Okanagan, compounds. One of several, isopropyl methoxy with the largest populations occurring in down- pyrazine, is higher in the hemolymph (blood) of town Kelowna. To date, BMSB has not been MALB than in any other ladybeetle species. collected from any vineyards in BC. Native to southeast Asia, the BMSB feeds on a wide range MALB, intentionally introduced to North of vegetables, field crops, ornamental trees and America for the biological control of aphids and shrubs, and fruit crops including grapes. Dam- scale, did not establish well or reach high age results from feeding punctures and removal numbers until the accidental arrival of its favor- of fluids from the plant, resulting in shrunken, ite aphid prey species, the soybean aphid. distorted buds, shoots and fruit. Fortunately, MALB populations in Ontario now increase grapes are reportedly not a preferred host. over the summer in soybean fields, after which Damage mostly occurs in late summer and fall they move in large numbers to find food and to when adults are congregating and moving to aggregate for the winter. After eliminating their sheltered locations prior to winter. At high preferred foods they will feed and aggregate on levels, contamination of fruit at harvest can lead grape clusters and be included in the fruit at to ‘wine taint’* due to the foul odor produced harvest. Lacking expansive soybean fields here, from the defensive glands of these insects. MALB has not become a pest of grapes in the Similar in size and shape to some of our native southern interior of BC and remains a beneficial stink bugs, first instar nymphs are bright red species helping to control leafhoppers, scale,

5.3-28 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection and other grape pests. Wood-Boring Beetles (Coleoptera: Bostrichidae) Hard Scale Several wood-boring beetle species, including (Hemiptera: Diaspididae) the branch and twig borer (Melalgus confertus), can Two species of hard scale, the oystershell scale, occasionally infest grapevines or cause damage Lepidosaphes ulmi L., and San Jose scale, Quad- to wine barrels. Depending on the species, raspidiotus perniciosus Comstock, are infrequently adults are brown to black, cylindrical in shape, found attacking two-year-old wood of weakened and from 5-10 mm in length. The head is largely vines. Hard scale do not produce large amounts hidden under the enlarged pronotum. They of honeydew and are currently of little im- have hardened forewings typical of beetles and portance to the BC grape industry. indistinct body sections. The white cylindrical The smaller hard scales (1-2 mm), which are larvae have enlarged brown-coloured heads. longer than wide, do not produce any cottony Adults burrow into the spurs and canes at the material and remain firmly attached to the canes base of new shoots to feed, causing them to wilt even after death. or break. The pale larvae or grubs burrow through weakened living or dead vine tissues, most often directly above or below a bud. The June Beetles perfectly round holes that they create are ~3 (Coleoptera: Scarabaeidae) mm in diameter. Infestations most often occur on weakened or diseased vines. The lead cable June beetles can occasionally damage the roots borer (Scobia declivis) feeds on grapevines, but the of grapes newly planted in land previously in greatest economic damage occurs from the pasture. The following description of ten-lined holes that larvae create in wine barrels. June beetle damage to tree fruits contained in the BC Tree Fruit Production Guide (bct- Control of these pests is best achieved through fpg.ca/pest_guide/info/ 74/) is applicable to sanitation and good vine health. Vineyards need grapes. to be kept free of wooden debris, and diseased “When grass or orchard land preparation for planting and weakened parts of vines should be re- trees destroys food plants, white grubs will feed on the fine moved. Higher levels of damage occur near root hairs and smaller roots of the transplanted trees. wooded and riparian areas that provide alternate The trees gradually weaken and eventually die from lack hosts. Insecticides applied in spring for cut- of water and attack by wood-boring insects.” worm control are likely to also reduce borer damage to some extent. Native to the western U.S. and Canada, adult ten-lined June beetles (Polyphylla decemlineata) are Western Grape Rootworm large (~3 cm) dark coloured scarab beetles Bromius obscurus (Coleoptera: Chrysomelidae) boldly marked with ten whitish stripes. Adults produce a hissing sound when held gently The western grape rootworm is a widespread between two fingers. Feeding of adults on pest of grapevines in Europe and California, but foliage causes little damage. The large white damage to grapes in BC was not reported until grubs or chafers grow to a size of 3-4 cm over a recently when an outbreak occurred in the 3-4 year developmental period while feeding on Kelowna area. Fully grown larvae are C-shaped the roots of grasses and various other plants. white grubs about 7 mm long with yellowish Other species of June beetles (June bugs) occur brown heads and dark mouthparts. Adult in the southern interior of BC, but the C-shaped beetles are about 4 mm long and somewhat white larvae (white grubs) of these smaller hairy with nearly black heads and dark bodies brown coloured beetles do not cause any (5d insert). Adults, which are all females, start significant damage to grapevines. emerging in May and feed on the expanding leaves of grapes, causing long slit-like holes (5d). There are no insecticides registered for the Larvae initially feed on root hairs before tunnel- control of June beetles. Control is achieved ing into the roots of grapevines. Feeding by through fallowing and preparation of land prior western grape rootworm larvae is known to to planting a new vineyard. Best Practices Guide for Grapes for British Columbia Growers 5.3-29 5 Crop Protection cause the death of vines in California due to areas known to harbor these pests is regulated direct damage to the roots and entry of second- and plants are inspected upon arrival or at the ary pathogens. source nursery. Information is provided to industry members and the general public For additional information on the western through talks, identification factsheets and grape rootworm, please see: brochures. It is inevitable that new economically https://www2.gov.bc.ca/assets/gov/farm important pests of grapevines will arrive in our ing-natural-resources-and- region from elsewhere. Growers can help industry/agriculture-and- prevent the establishment of new alien pests seafood/animal-and-crops/plant- by knowing the species currently found in health/western_grape_rootworm.pdf BC and reporting new pests and unfamiliar damage to grapevines. The list of potential grape pests that might arrive in BC from else- Termites where is very long. Following is a list of a few Reticulitermes sp. (Isoptera) economically important ones and sources for additional information. Native species of subterranean termites occur in the dry interior of BC where they occasionally consume woody heartwood tissue of old or Japanese Beetle weakened vines or untreated support posts, Popillia japonica (Coleoptera: Scarabaeidae) causing vines and trellises to collapse. Termites live in the soil in colonies comprised of various Japanese beetles were found for the first forms, including queens, kings, workers and time in BC in Vancouver in 2017. Efforts are soldiers. The eyeless workers are 3-5 mm long now underway to try to eradicate this pest of with creamy pale bodies, while the slightly larger lawns, gardens, parks and agricultural crops. soldiers have enlarged heads and black jaws. These distinctive looking beetles are about 12 They are distinguished from ants by their dull, mm in length with a bright metallic green body pale colour, bead-like antenna, and broad rather and shiny brown forewings (elytra). Tufts of than constricted waist connecting the abdomen. white hairs occur at the rear and along the edges Living deep in the ground and feeding on dead of the abdomen. The C-shaped larvae are woody tissue makes termites difficult to control similar to those of June beetles and other with insecticides. None are registered for this members of the scarab beetle family. Feeding by purpose in BC. There are no effective natural larvae is largely restricted to the roots of grasses. controls, but sanitation and removal of wooden Adults often feed in large aggregations on a debris prior to planting will help delay infesta- wide range of plants, with grapevines being one tions. Termites do not eat the outer living tissue, of the preferred hosts. Adults skeletonize leaves so maintaining healthy vines is helpful. Old, by eating the tissue between the leaf veins. heavily infested vineyard blocks may need to be Considerable economic damage is caused to replaced. grapes in Ontario, particularly those that are managed organically.

Additional information on Japanese Prevention of New Grape beetle damage to grapes is available at: Notes on Grape Insects: Japanese Pests beetle, OMAFRA http://www.omafra.gov.on.ca/english/cr Provincial Entomologists (currently Susanna ops/pub360/notes/grapejapbtl.htm#top Acheampong, Kelowna; Tracy Hueppelsheuser, Abbotsford), AAFC researchers, and Canadian Food Inspection Agency (CFIA) regulators and Light Brown Apple Moth inspectors contribute to the prevention of the Epiphyas postvittana (Lepidoptera: Tortricidae) arrival of new invasive pests of grapevines into BC. Importation of host plant material from The light brown apple moth, which is native to 5.3-30 Best Practices Guide for Grapes for British Columbia Growers 5 Crop Protection the cooler, wetter coastal regions of Australia, webbing and are subject to fungal infections. was found in parts of California in 2007. As for other members of this moth family (Tortri- cidae), it has a wide host range that includes For information on the European grape ornamentals, fruit trees, berries, and grapes. berry moth see; European Grapevine Moth, UC There likely would be two generations under IPM. our conditions. Larvae that grow to about 10-18 mm in length are pale to medium green with a https://www2.ipm.ucanr.edu/Invasive- tan coloured head. Adult moths are medium tan and-Exotic-Pests/Euopean-grapevine- often with oblique markings of darker tan to moth/ brown. Partly grown overwintering larvae feed For the American grape berry moth; Grape on grape buds in spring and continue to feed on Berry Moth Management, Cornell University, developing shoots, tender leaves and flower CALS. clusters as they mature. Damage to fruit later in https://grapesandwine.cals.cornell.edu/ne the season reduces the crop and allows the entry wsletters/appellation-cornell/2011- of disease organisms. newsletters/issue-6/grape-berry-moth- For additional information see, Grape: Light management/ Brown Apple Moth, UC IPM Online, Statewide Integrated Pest Management Guidelines. http://ipm.ucanr.edu/PMG/r302303011.ht ml Spotted Lanternfly Lycorma deliculata (Hemiptera: Fulgoridae)

Grape Berry Moths Native to southeast Asia, the spotted lanternfly European grape berry moth, Lobesia botrana was found in Pennsylvania in 2014. As of 2019 American grape berry moth, Paralobesia it has spread to New Jersey, Virginia, Maryland (=Endopiza) viteana and Delaware, with additional detections in The European grape berry moth and the Amer- New York, Connecticut and Massachusetts. The ican grape berry moth are similar in appearance spotted lanternfly has a wide host range that and cause similar damage to grapes. The former includes tree-of-heaven and grapes as preferred was first reported in Napa County, California, in hosts. It is a serious threat to the production of 2009, and reportedly eradicated from the state tree fruits, grapes, ornamental trees and forestry. by 2016 following a statewide trapping and Feeding of nymphs and adults on the trunks, management program. The American grape shoots and leaves of grapes removes large berry moth, native to eastern North America, is volumes of phloem which stresses the vines and now found in parts of western Colorado. The causes reduced fruit set, increased winter injury, slender larvae reach a maximum size of 1 to 1.5 and death. Feeding sites on woody tissues are cm and are green to light purplish with a darker marked by weeping wounds. The large amounts contrasting head and first thoracic segment. The of honeydew produced during feeding promotes adult moths are generally less than 0.75 cm long the growth of sooty mold that fouls table and of a medium brown colour mottled in grapes. In the northeastern U.S. adults will patches of lighter or darker brown, dark grey or appear starting in July, with large numbers blue depending on the species. Both are best suddenly appearing in vineyards until frost identified by the damage caused by larvae feeding on flowers and fruit. Larvae of the 1st These large, colourful and active insects have a generation feed on developing buds, flowers very distinctive appearance. Adults are 2-2.5 cm and small berries and produce a significant long with dark legs and a yellow abdomen amount of webbing. Larger 1st and 2nd genera- marked by a central black stripe. The front tion larvae burrow into and feed on the fruit, portion of the greyish-brown front wing is leaving hollowed out skins and seeds. Grape marked with black spots and the rear section bunches become contaminated with frass and marked with dark broken fine lines. The front Best Practices Guide for Grapes for British Columbia Growers 5.3-31 5 Crop Protection section of the hind wings is red with black spots; the rear section is white with black bands. Small nymphs are black with white spots; larger Additional Resources: nymphs are boldly coloured in black, white and Note!! Environmental conditions, the grape red. pest complex, and registered pesticides The overwintering eggs that are laid in masses differ for BC as compared to other grape- and initially covered in a wax-like covering producing regions. account for the rapid spread of this pest. A Pacific Northwest Pest Management preference for smooth vertical surfaces, such as Handbooks> Small Fruit Crops> Grape Pests. the sides of cars, transport trucks, and trains, on 2020. Skinkis, P., V. Walton, and B. Edmunds. which to lay eggs has resulted in eggs being https://pnwhandbooks.org/sites/pnwhandboo transported widely. There is one generation per ks/files/insect/chapterpdf/insect20-i-small- year. fruits.pdf

How to Manage Pests: Grape. UC IPM For additional information see: Online, Statewide IPM Program, UC Agr. & Nat. Res. Spotted Lanternfly – Lycorma deliculata. CFIA http://ipm.ucanr.edu/PMG/selectnewpest.gra website pes.html https://www.inspection.gc.ca/plant- 2019 Pest Management Guide for Wine health/plant-pests-invasive- Grapes in Oregon. Oregon State Univ. Skinkis, species/insects/spotted- P.A., J.W. Pscheidt, M.L. Moretti, V.M., Walton, lantern- K.C. Achala, and C. Kaiser. 2019 fly/eng/1433365581428/1433365581959 https://ir.library.oregonstate.edu/concern/tec hnical_reports/0c483r698 Spotted Lanternfly Management in Vineyards, Penn State Ext., 2019. 2017 Pest Management Guide for Grapes in https://extension.psu.edu/spotted- Washington. WSU Ext. EB0762. D. Walsh, lanternfly-management-in-vineyards Section Coordinator: Insects. https://research.libraries.wsu.edu/xmlui/bitst ream/handle/2376/6488/EB0762.pdf Information for Commercial Grape Grow- ers in Ontario. 2020. Ont. Min. Agr. Food & Rural Affairs. http://www.omafra.gov.on.ca/english/crops /hort/grape.html

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