Early recognition of disease, insect
and mite problems in vineyards is important for the prevention of heavy infestations
and serious crop losses. The mere presence of a pest does not necessarily mean
that control measures are needed. While some diseases, insects or mites may be
present every year, seasonal fluctuations in disease severity and insect or mite
populations may cause a pest to be a major problem one year and not the next.
As a result, the pest complex and the control measures may vary each year. To
aid in the management decisions for pest problems, the Disease and Insect Monitoring
Guideline contained within this factsheet has been produced to give an overview
of activity of the grape pest complex. This factsheet describes the major and
minor pests most frequently found on grapes and should be used in conjunction
with pictorial factsheets and field guides to help identify pests in grapes. The
information may aid growers and industry personnel in identifying disease, insect
and mite problems early so that control measures can be implemented before serious
problems arise.
Good management of disease
and insect problems involves both cultural and chemical applications. Spring cultivation
that buries any debris that may carry overwintering disease and/or insects and
may help to reduce the initial population for that season. For both disease and
insect control, proper pruning is necessary to allow good spray coverage and,
in the case of disease control, good air movement for rapid drying of foliage.
In addition to various cultural practices, monitor changes in pest activity with
regular scouting throughout the vineyard during the growing season. For the chemical
control of pests, consult OMAFRA Publication 360, Fruit
Production Recommendations. A variety of chemicals are registered for
use on major pests, however, fewer and often none are registered for minor pests.
Table 4. Insect Information Table
| Insect |
Damage Caused by Insect |
Insect Appearance |
Control Measures and References |
|
Grape Berry Moth (GBM) | - damage is
caused by the larval (caterpillar) stage
- 1st generation larvae web together
buds, flowers and newly-set berries; affected plant parts often drop from vine
- 2nd
generation larvae burrow into green berries near the berry stem or side where
berries touch. A purple spot may form around the pin-head size hole. Berries may
split, shrivel, become infected by disease, or fall off when damaged
- 3rd
generation larvae can cause direct fruit injury (tunnel directly into one berry
and then move from berry to berry within the cluster) and lead to significant
disease infection prior to harvest
| overwinters
as pupae with adults emerging in early Mayadult moth is 6 mm when fully
grown and has a brown body with wings that are grey-blue near the body and cream
with brown spots near the tipsyoung larvae have a cream body and dark
brown head. As they mature, the larvae become green and then purple with a light
brown head when maturelarvae are 10 mm long at maturity |
remove nearby wild grape and abandoned grapesbury leaf debris on
vineyard floorlisten to local crop reports for activity patterns and
preferred control optionsrefer to OMAFRA factsheets on GBM and Publication
360 for control optionsmating disruption products for control of GBM
affect only this pest |
|
Grape Leafhopper (GLH) | - adults and
nymphs feed on underside of leaves by sucking leaf cell contents
- tissue
around feeding puncture turns pale and dies
- feeding injury appears first
along leaf veins but later affects whole leaf
- no thresholds established
through research in Ontario
| adult
GLH are pale yellow with darker yellow lines on forewings and 3 black spots on
wingssmall wedge-shaped insect (3 mm adult)fast moving and activenymphs
resemble adults without fully developed wings |
overwinters as adultfall cultivation and clean-up of adjacent weedy
areas eliminates favourable overwintering sitesmonitor for activity in
early spring starting at first warm days after leaf tissue is presentlisten
to control suggestions on local crop reports |
|
Potato Leafhopper (PLH) | - adults
and nymphs suck leaf cell contents
- potato leafhoppers (PLH) also inject
a toxin that blocks vascular system of the plant
- leaves curl upwards and
yellow at edges
- extensive PLH feeding causes leaf edges to turn brown
("hopper burn")
- damage to grapes often observed after 1st cut
in nearby hay fields. Mowing of weeds along roads in June also sends PLH into
vineyards
- no thresholds established through research in Ontario
|
similar shape to grape leafhopper but all stages of PLH are pale greennymphs
move sideways or backwards when disturbed | PLH
does not overwinter in OntarioPLH travel from the midwest and southern
U.S. under suitable weather conditions monitor for activity in early
Junelisten to control suggestions on local crop reports |
| Three banded Leafhopper
| - adults and nymphs feed on underside
of leaves by sucking leaf cell contents
- tissue around feeding puncture
turns pale and dies
- feeding injury appears first along veins but later
affects whole leaf
- heavy infestations can lead to leaf drop
- no
thresholds established through research in Ontario
|
adult three banded leafhoppers appear similar to grape leafhopper but possess
3 distinct bands across the wings at rest | overwinters
as adultsmonitor for activity in early spring with first warm days after
leaf tissue is presentlisten to control suggestions on local crop reports
|
| Spring
Feeding Caterpillar Complex | - entire
leaves or the interveinal areas of leaves are chewed and webbing may be present
on leaves
- terminal leaves of shoots are webbed together and chewing damage
is evident
- damage is most severe along the peripheries of vineyards and
in rows near bushes, woods or weedy areas
|
3 main species cause damage: 1. eight spotted forester:
3.3 cm larva with orange, yellow, black and white stripes and black spots
2. grape plume moth: 2 cm green larva with white hairs 3. pyramidal
fruitworm 34 cm green larva with white specks, a whitish or yellow stripe
down the back and a pyramid-like hump on its rear |
insecticides used for grape berry moth are usually effective against these
caterpillarsif using GBM mating disruption, specific sprays may be required
for spring feeding caterpillarslisten to control suggestions on local
crop reports |
|
Blossom Midge | - flower buds are enlarged
with a slightly reddish colour at the base of the flower bud
- many small
larvae (maggots) live in a watery fluid inside the bud and eat the internal flower
parts
- injury is more common in rows next to wooded or weedy areas
|
larvae are yellowish to reddishlarvae complete development, drop
to the ground to pupate, and remain inactive until the following spring |
generally does not cause economic injury |
|
Phylloxera | - green or red fleshy
galls, 620 mm in diameter, appear on undersurface of leaves and tendrils
| young adults are 1 mm long, yellow
and non mobilenymphs are inside galls and migrate to young leaf tissue
and growing points to establish new colonies |
can cause significant injury to young vines such as Baco Noir and other hybrids
|
| Grape
Flea Beetle | - a few to many buds on
a cane may be injured by the adult when it chews through the ends and sides of
swelling buds
- a circular hole is evident in the chewed buds and no shoots
are produced
- damage occurs in rows adjacent to bushes or wooded areas
| adult beetle is 5 mm long and has
a dark metallic, greenish-blue or steel-blue colour |
greatest injury from this pest is during prolonged cool springs with slow
bud growthapply insecticide if adult beetles present in damaging numbers
early in the season |
|
European Red Mite | - leaves become
bronze-coloured due to adults and nymphs feeding on leaf underside; photosynthesis
is reduced and berry ripening can be affected
|
adult female is < 0.5 mm with a red to reddish-brown oval body and 8 legsadult
male is dull green to brown with a pointed abdomen and is smaller than female
| high populations may require treatment
with an effective miticide good coverage with sufficient water volume is
important |
|
Erineum Mite | - white, indented galls
appear on the lower leaf surface and pink or reddish blisters develop directly
above these galls; the galls later turn yellow and then reddish-brown
- abnormal
growth of new shoots, downward curling of leaves and premature leaf drop occur
- in
severe cases, terminal buds are destroyed and secondary shoots develop
|
adults are whitish, wormlike and about 0.2 mm longeggs are oval
and whitelarge numbers of adults exist in colonies |
sulphur, when used for early season disease suppresion, also helps control
erineum miteoften found on Riesling and Vidal in areas near bush lots
and areas with tall weeds |